* [PATCH stable 4.15 0/8] BPF stable patches
@ 2018-03-08 12:16 Daniel Borkmann
2018-03-08 12:16 ` [PATCH stable 4.15 1/8] bpf: fix mlock precharge on arraymaps Daniel Borkmann
` (8 more replies)
0 siblings, 9 replies; 18+ messages in thread
From: Daniel Borkmann @ 2018-03-08 12:16 UTC (permalink / raw)
To: gregkh; +Cc: ast, daniel, stable
All for 4.15 backported and tested.
Thanks!
Daniel Borkmann (5):
bpf: fix mlock precharge on arraymaps
bpf, x64: implement retpoline for tail call
bpf, arm64: fix out of bounds access in tail call
bpf: allow xadd only on aligned memory
bpf, ppc64: fix out of bounds access in tail call
Eric Dumazet (1):
bpf: add schedule points in percpu arrays management
Yonghong Song (2):
bpf: fix memory leak in lpm_trie map_free callback function
bpf: fix rcu lockdep warning for lpm_trie map_free callback
arch/arm64/net/bpf_jit_comp.c | 5 +-
arch/powerpc/net/bpf_jit_comp64.c | 1 +
arch/x86/include/asm/nospec-branch.h | 37 +++++++++++++
arch/x86/net/bpf_jit_comp.c | 9 ++--
kernel/bpf/arraymap.c | 33 +++++++-----
kernel/bpf/lpm_trie.c | 14 ++---
kernel/bpf/verifier.c | 42 +++++++++------
tools/testing/selftests/bpf/test_verifier.c | 84 +++++++++++++++++++++++++++++
8 files changed, 184 insertions(+), 41 deletions(-)
--
2.9.5
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH stable 4.15 1/8] bpf: fix mlock precharge on arraymaps
2018-03-08 12:16 [PATCH stable 4.15 0/8] BPF stable patches Daniel Borkmann
@ 2018-03-08 12:16 ` Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf: fix mlock precharge on arraymaps" has been added to the 4.15-stable tree gregkh
2018-03-08 12:16 ` [PATCH stable 4.15 2/8] bpf: fix memory leak in lpm_trie map_free callback function Daniel Borkmann
` (7 subsequent siblings)
8 siblings, 1 reply; 18+ messages in thread
From: Daniel Borkmann @ 2018-03-08 12:16 UTC (permalink / raw)
To: gregkh; +Cc: ast, daniel, stable, Dennis Zhou
[ upstream commit 9c2d63b843a5c8a8d0559cc067b5398aa5ec3ffc ]
syzkaller recently triggered OOM during percpu map allocation;
while there is work in progress by Dennis Zhou to add __GFP_NORETRY
semantics for percpu allocator under pressure, there seems also a
missing bpf_map_precharge_memlock() check in array map allocation.
Given today the actual bpf_map_charge_memlock() happens after the
find_and_alloc_map() in syscall path, the bpf_map_precharge_memlock()
is there to bail out early before we go and do the map setup work
when we find that we hit the limits anyway. Therefore add this for
array map as well.
Fixes: 6c9059817432 ("bpf: pre-allocate hash map elements")
Fixes: a10423b87a7e ("bpf: introduce BPF_MAP_TYPE_PERCPU_ARRAY map")
Reported-by: syzbot+adb03f3f0bb57ce3acda@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Dennis Zhou <dennisszhou@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
kernel/bpf/arraymap.c | 28 ++++++++++++++++------------
1 file changed, 16 insertions(+), 12 deletions(-)
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index ab94d30..e76aa67 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -52,11 +52,11 @@ static int bpf_array_alloc_percpu(struct bpf_array *array)
static struct bpf_map *array_map_alloc(union bpf_attr *attr)
{
bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
- int numa_node = bpf_map_attr_numa_node(attr);
+ int ret, numa_node = bpf_map_attr_numa_node(attr);
u32 elem_size, index_mask, max_entries;
bool unpriv = !capable(CAP_SYS_ADMIN);
+ u64 cost, array_size, mask64;
struct bpf_array *array;
- u64 array_size, mask64;
/* check sanity of attributes */
if (attr->max_entries == 0 || attr->key_size != 4 ||
@@ -101,8 +101,19 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr)
array_size += (u64) max_entries * elem_size;
/* make sure there is no u32 overflow later in round_up() */
- if (array_size >= U32_MAX - PAGE_SIZE)
+ cost = array_size;
+ if (cost >= U32_MAX - PAGE_SIZE)
return ERR_PTR(-ENOMEM);
+ if (percpu) {
+ cost += (u64)attr->max_entries * elem_size * num_possible_cpus();
+ if (cost >= U32_MAX - PAGE_SIZE)
+ return ERR_PTR(-ENOMEM);
+ }
+ cost = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
+
+ ret = bpf_map_precharge_memlock(cost);
+ if (ret < 0)
+ return ERR_PTR(ret);
/* allocate all map elements and zero-initialize them */
array = bpf_map_area_alloc(array_size, numa_node);
@@ -118,20 +129,13 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr)
array->map.max_entries = attr->max_entries;
array->map.map_flags = attr->map_flags;
array->map.numa_node = numa_node;
+ array->map.pages = cost;
array->elem_size = elem_size;
- if (!percpu)
- goto out;
-
- array_size += (u64) attr->max_entries * elem_size * num_possible_cpus();
-
- if (array_size >= U32_MAX - PAGE_SIZE ||
- bpf_array_alloc_percpu(array)) {
+ if (percpu && bpf_array_alloc_percpu(array)) {
bpf_map_area_free(array);
return ERR_PTR(-ENOMEM);
}
-out:
- array->map.pages = round_up(array_size, PAGE_SIZE) >> PAGE_SHIFT;
return &array->map;
}
--
2.9.5
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH stable 4.15 2/8] bpf: fix memory leak in lpm_trie map_free callback function
2018-03-08 12:16 [PATCH stable 4.15 0/8] BPF stable patches Daniel Borkmann
2018-03-08 12:16 ` [PATCH stable 4.15 1/8] bpf: fix mlock precharge on arraymaps Daniel Borkmann
@ 2018-03-08 12:16 ` Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf: fix memory leak in lpm_trie map_free callback function" has been added to the 4.15-stable tree gregkh
2018-03-08 12:16 ` [PATCH stable 4.15 3/8] bpf: fix rcu lockdep warning for lpm_trie map_free callback Daniel Borkmann
` (6 subsequent siblings)
8 siblings, 1 reply; 18+ messages in thread
From: Daniel Borkmann @ 2018-03-08 12:16 UTC (permalink / raw)
To: gregkh; +Cc: ast, daniel, stable, Yonghong Song
From: Yonghong Song <yhs@fb.com>
[ upstream commit 9a3efb6b661f71d5675369ace9257833f0e78ef3 ]
There is a memory leak happening in lpm_trie map_free callback
function trie_free. The trie structure itself does not get freed.
Also, trie_free function did not do synchronize_rcu before freeing
various data structures. This is incorrect as some rcu_read_lock
region(s) for lookup, update, delete or get_next_key may not complete yet.
The fix is to add synchronize_rcu in the beginning of trie_free.
The useless spin_lock is removed from this function as well.
Fixes: b95a5c4db09b ("bpf: add a longest prefix match trie map implementation")
Reported-by: Mathieu Malaterre <malat@debian.org>
Reported-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
kernel/bpf/lpm_trie.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c
index 885e4547..61c0b53 100644
--- a/kernel/bpf/lpm_trie.c
+++ b/kernel/bpf/lpm_trie.c
@@ -560,7 +560,10 @@ static void trie_free(struct bpf_map *map)
struct lpm_trie_node __rcu **slot;
struct lpm_trie_node *node;
- raw_spin_lock(&trie->lock);
+ /* Wait for outstanding programs to complete
+ * update/lookup/delete/get_next_key and free the trie.
+ */
+ synchronize_rcu();
/* Always start at the root and walk down to a node that has no
* children. Then free that node, nullify its reference in the parent
@@ -574,7 +577,7 @@ static void trie_free(struct bpf_map *map)
node = rcu_dereference_protected(*slot,
lockdep_is_held(&trie->lock));
if (!node)
- goto unlock;
+ goto out;
if (rcu_access_pointer(node->child[0])) {
slot = &node->child[0];
@@ -592,8 +595,8 @@ static void trie_free(struct bpf_map *map)
}
}
-unlock:
- raw_spin_unlock(&trie->lock);
+out:
+ kfree(trie);
}
static int trie_get_next_key(struct bpf_map *map, void *key, void *next_key)
--
2.9.5
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH stable 4.15 3/8] bpf: fix rcu lockdep warning for lpm_trie map_free callback
2018-03-08 12:16 [PATCH stable 4.15 0/8] BPF stable patches Daniel Borkmann
2018-03-08 12:16 ` [PATCH stable 4.15 1/8] bpf: fix mlock precharge on arraymaps Daniel Borkmann
2018-03-08 12:16 ` [PATCH stable 4.15 2/8] bpf: fix memory leak in lpm_trie map_free callback function Daniel Borkmann
@ 2018-03-08 12:16 ` Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf: fix rcu lockdep warning for lpm_trie map_free callback" has been added to the 4.15-stable tree gregkh
2018-03-08 12:16 ` [PATCH stable 4.15 4/8] bpf, x64: implement retpoline for tail call Daniel Borkmann
` (5 subsequent siblings)
8 siblings, 1 reply; 18+ messages in thread
From: Daniel Borkmann @ 2018-03-08 12:16 UTC (permalink / raw)
To: gregkh; +Cc: ast, daniel, stable, Yonghong Song
From: Yonghong Song <yhs@fb.com>
[ upstream commit 6c5f61023c5b0edb0c8a64c902fe97c6453b1852 ]
Commit 9a3efb6b661f ("bpf: fix memory leak in lpm_trie map_free callback function")
fixed a memory leak and removed unnecessary locks in map_free callback function.
Unfortrunately, it introduced a lockdep warning. When lockdep checking is turned on,
running tools/testing/selftests/bpf/test_lpm_map will have:
[ 98.294321] =============================
[ 98.294807] WARNING: suspicious RCU usage
[ 98.295359] 4.16.0-rc2+ #193 Not tainted
[ 98.295907] -----------------------------
[ 98.296486] /home/yhs/work/bpf/kernel/bpf/lpm_trie.c:572 suspicious rcu_dereference_check() usage!
[ 98.297657]
[ 98.297657] other info that might help us debug this:
[ 98.297657]
[ 98.298663]
[ 98.298663] rcu_scheduler_active = 2, debug_locks = 1
[ 98.299536] 2 locks held by kworker/2:1/54:
[ 98.300152] #0: ((wq_completion)"events"){+.+.}, at: [<00000000196bc1f0>] process_one_work+0x157/0x5c0
[ 98.301381] #1: ((work_completion)(&map->work)){+.+.}, at: [<00000000196bc1f0>] process_one_work+0x157/0x5c0
Since actual trie tree removal happens only after no other
accesses to the tree are possible, replacing
rcu_dereference_protected(*slot, lockdep_is_held(&trie->lock))
with
rcu_dereference_protected(*slot, 1)
fixed the issue.
Fixes: 9a3efb6b661f ("bpf: fix memory leak in lpm_trie map_free callback function")
Reported-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
kernel/bpf/lpm_trie.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c
index 61c0b53..424f89a 100644
--- a/kernel/bpf/lpm_trie.c
+++ b/kernel/bpf/lpm_trie.c
@@ -574,8 +574,7 @@ static void trie_free(struct bpf_map *map)
slot = &trie->root;
for (;;) {
- node = rcu_dereference_protected(*slot,
- lockdep_is_held(&trie->lock));
+ node = rcu_dereference_protected(*slot, 1);
if (!node)
goto out;
--
2.9.5
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH stable 4.15 4/8] bpf, x64: implement retpoline for tail call
2018-03-08 12:16 [PATCH stable 4.15 0/8] BPF stable patches Daniel Borkmann
` (2 preceding siblings ...)
2018-03-08 12:16 ` [PATCH stable 4.15 3/8] bpf: fix rcu lockdep warning for lpm_trie map_free callback Daniel Borkmann
@ 2018-03-08 12:16 ` Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf, x64: implement retpoline for tail call" has been added to the 4.15-stable tree gregkh
2018-03-08 12:16 ` [PATCH stable 4.15 5/8] bpf, arm64: fix out of bounds access in tail call Daniel Borkmann
` (4 subsequent siblings)
8 siblings, 1 reply; 18+ messages in thread
From: Daniel Borkmann @ 2018-03-08 12:16 UTC (permalink / raw)
To: gregkh; +Cc: ast, daniel, stable
[ upstream commit a493a87f38cfa48caaa95c9347be2d914c6fdf29 ]
Implement a retpoline [0] for the BPF tail call JIT'ing that converts
the indirect jump via jmp %rax that is used to make the long jump into
another JITed BPF image. Since this is subject to speculative execution,
we need to control the transient instruction sequence here as well
when CONFIG_RETPOLINE is set, and direct it into a pause + lfence loop.
The latter aligns also with what gcc / clang emits (e.g. [1]).
JIT dump after patch:
# bpftool p d x i 1
0: (18) r2 = map[id:1]
2: (b7) r3 = 0
3: (85) call bpf_tail_call#12
4: (b7) r0 = 2
5: (95) exit
With CONFIG_RETPOLINE:
# bpftool p d j i 1
[...]
33: cmp %edx,0x24(%rsi)
36: jbe 0x0000000000000072 |*
38: mov 0x24(%rbp),%eax
3e: cmp $0x20,%eax
41: ja 0x0000000000000072 |
43: add $0x1,%eax
46: mov %eax,0x24(%rbp)
4c: mov 0x90(%rsi,%rdx,8),%rax
54: test %rax,%rax
57: je 0x0000000000000072 |
59: mov 0x28(%rax),%rax
5d: add $0x25,%rax
61: callq 0x000000000000006d |+
66: pause |
68: lfence |
6b: jmp 0x0000000000000066 |
6d: mov %rax,(%rsp) |
71: retq |
72: mov $0x2,%eax
[...]
* relative fall-through jumps in error case
+ retpoline for indirect jump
Without CONFIG_RETPOLINE:
# bpftool p d j i 1
[...]
33: cmp %edx,0x24(%rsi)
36: jbe 0x0000000000000063 |*
38: mov 0x24(%rbp),%eax
3e: cmp $0x20,%eax
41: ja 0x0000000000000063 |
43: add $0x1,%eax
46: mov %eax,0x24(%rbp)
4c: mov 0x90(%rsi,%rdx,8),%rax
54: test %rax,%rax
57: je 0x0000000000000063 |
59: mov 0x28(%rax),%rax
5d: add $0x25,%rax
61: jmpq *%rax |-
63: mov $0x2,%eax
[...]
* relative fall-through jumps in error case
- plain indirect jump as before
[0] https://support.google.com/faqs/answer/7625886
[1] https://github.com/gcc-mirror/gcc/commit/a31e654fa107be968b802786d747e962c2fcdb2b
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
arch/x86/include/asm/nospec-branch.h | 37 ++++++++++++++++++++++++++++++++++++
arch/x86/net/bpf_jit_comp.c | 9 +++++----
2 files changed, 42 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 76b0585..81a1be3 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -177,4 +177,41 @@ static inline void indirect_branch_prediction_barrier(void)
}
#endif /* __ASSEMBLY__ */
+
+/*
+ * Below is used in the eBPF JIT compiler and emits the byte sequence
+ * for the following assembly:
+ *
+ * With retpolines configured:
+ *
+ * callq do_rop
+ * spec_trap:
+ * pause
+ * lfence
+ * jmp spec_trap
+ * do_rop:
+ * mov %rax,(%rsp)
+ * retq
+ *
+ * Without retpolines configured:
+ *
+ * jmp *%rax
+ */
+#ifdef CONFIG_RETPOLINE
+# define RETPOLINE_RAX_BPF_JIT_SIZE 17
+# define RETPOLINE_RAX_BPF_JIT() \
+ EMIT1_off32(0xE8, 7); /* callq do_rop */ \
+ /* spec_trap: */ \
+ EMIT2(0xF3, 0x90); /* pause */ \
+ EMIT3(0x0F, 0xAE, 0xE8); /* lfence */ \
+ EMIT2(0xEB, 0xF9); /* jmp spec_trap */ \
+ /* do_rop: */ \
+ EMIT4(0x48, 0x89, 0x04, 0x24); /* mov %rax,(%rsp) */ \
+ EMIT1(0xC3); /* retq */
+#else
+# define RETPOLINE_RAX_BPF_JIT_SIZE 2
+# define RETPOLINE_RAX_BPF_JIT() \
+ EMIT2(0xFF, 0xE0); /* jmp *%rax */
+#endif
+
#endif /* _ASM_X86_NOSPEC_BRANCH_H_ */
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 0554e8a..940aac7 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -13,6 +13,7 @@
#include <linux/if_vlan.h>
#include <asm/cacheflush.h>
#include <asm/set_memory.h>
+#include <asm/nospec-branch.h>
#include <linux/bpf.h>
int bpf_jit_enable __read_mostly;
@@ -287,7 +288,7 @@ static void emit_bpf_tail_call(u8 **pprog)
EMIT2(0x89, 0xD2); /* mov edx, edx */
EMIT3(0x39, 0x56, /* cmp dword ptr [rsi + 16], edx */
offsetof(struct bpf_array, map.max_entries));
-#define OFFSET1 43 /* number of bytes to jump */
+#define OFFSET1 (41 + RETPOLINE_RAX_BPF_JIT_SIZE) /* number of bytes to jump */
EMIT2(X86_JBE, OFFSET1); /* jbe out */
label1 = cnt;
@@ -296,7 +297,7 @@ static void emit_bpf_tail_call(u8 **pprog)
*/
EMIT2_off32(0x8B, 0x85, 36); /* mov eax, dword ptr [rbp + 36] */
EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
-#define OFFSET2 32
+#define OFFSET2 (30 + RETPOLINE_RAX_BPF_JIT_SIZE)
EMIT2(X86_JA, OFFSET2); /* ja out */
label2 = cnt;
EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
@@ -310,7 +311,7 @@ static void emit_bpf_tail_call(u8 **pprog)
* goto out;
*/
EMIT3(0x48, 0x85, 0xC0); /* test rax,rax */
-#define OFFSET3 10
+#define OFFSET3 (8 + RETPOLINE_RAX_BPF_JIT_SIZE)
EMIT2(X86_JE, OFFSET3); /* je out */
label3 = cnt;
@@ -323,7 +324,7 @@ static void emit_bpf_tail_call(u8 **pprog)
* rdi == ctx (1st arg)
* rax == prog->bpf_func + prologue_size
*/
- EMIT2(0xFF, 0xE0); /* jmp rax */
+ RETPOLINE_RAX_BPF_JIT();
/* out: */
BUILD_BUG_ON(cnt - label1 != OFFSET1);
--
2.9.5
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH stable 4.15 5/8] bpf, arm64: fix out of bounds access in tail call
2018-03-08 12:16 [PATCH stable 4.15 0/8] BPF stable patches Daniel Borkmann
` (3 preceding siblings ...)
2018-03-08 12:16 ` [PATCH stable 4.15 4/8] bpf, x64: implement retpoline for tail call Daniel Borkmann
@ 2018-03-08 12:16 ` Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf, arm64: fix out of bounds access in tail call" has been added to the 4.15-stable tree gregkh
2018-03-08 12:16 ` [PATCH stable 4.15 6/8] bpf: add schedule points in percpu arrays management Daniel Borkmann
` (3 subsequent siblings)
8 siblings, 1 reply; 18+ messages in thread
From: Daniel Borkmann @ 2018-03-08 12:16 UTC (permalink / raw)
To: gregkh; +Cc: ast, daniel, stable
[ upstream commit 16338a9b3ac30740d49f5dfed81bac0ffa53b9c7 ]
I recently noticed a crash on arm64 when feeding a bogus index
into BPF tail call helper. The crash would not occur when the
interpreter is used, but only in case of JIT. Output looks as
follows:
[ 347.007486] Unable to handle kernel paging request at virtual address fffb850e96492510
[...]
[ 347.043065] [fffb850e96492510] address between user and kernel address ranges
[ 347.050205] Internal error: Oops: 96000004 [#1] SMP
[...]
[ 347.190829] x13: 0000000000000000 x12: 0000000000000000
[ 347.196128] x11: fffc047ebe782800 x10: ffff808fd7d0fd10
[ 347.201427] x9 : 0000000000000000 x8 : 0000000000000000
[ 347.206726] x7 : 0000000000000000 x6 : 001c991738000000
[ 347.212025] x5 : 0000000000000018 x4 : 000000000000ba5a
[ 347.217325] x3 : 00000000000329c4 x2 : ffff808fd7cf0500
[ 347.222625] x1 : ffff808fd7d0fc00 x0 : ffff808fd7cf0500
[ 347.227926] Process test_verifier (pid: 4548, stack limit = 0x000000007467fa61)
[ 347.235221] Call trace:
[ 347.237656] 0xffff000002f3a4fc
[ 347.240784] bpf_test_run+0x78/0xf8
[ 347.244260] bpf_prog_test_run_skb+0x148/0x230
[ 347.248694] SyS_bpf+0x77c/0x1110
[ 347.251999] el0_svc_naked+0x30/0x34
[ 347.255564] Code: 9100075a d280220a 8b0a002a d37df04b (f86b694b)
[...]
In this case the index used in BPF r3 is the same as in r1
at the time of the call, meaning we fed a pointer as index;
here, it had the value 0xffff808fd7cf0500 which sits in x2.
While I found tail calls to be working in general (also for
hitting the error cases), I noticed the following in the code
emission:
# bpftool p d j i 988
[...]
38: ldr w10, [x1,x10]
3c: cmp w2, w10
40: b.ge 0x000000000000007c <-- signed cmp
44: mov x10, #0x20 // #32
48: cmp x26, x10
4c: b.gt 0x000000000000007c
50: add x26, x26, #0x1
54: mov x10, #0x110 // #272
58: add x10, x1, x10
5c: lsl x11, x2, #3
60: ldr x11, [x10,x11] <-- faulting insn (f86b694b)
64: cbz x11, 0x000000000000007c
[...]
Meaning, the tests passed because commit ddb55992b04d ("arm64:
bpf: implement bpf_tail_call() helper") was using signed compares
instead of unsigned which as a result had the test wrongly passing.
Change this but also the tail call count test both into unsigned
and cap the index as u32. Latter we did as well in 90caccdd8cc0
("bpf: fix bpf_tail_call() x64 JIT") and is needed in addition here,
too. Tested on HiSilicon Hi1616.
Result after patch:
# bpftool p d j i 268
[...]
38: ldr w10, [x1,x10]
3c: add w2, w2, #0x0
40: cmp w2, w10
44: b.cs 0x0000000000000080
48: mov x10, #0x20 // #32
4c: cmp x26, x10
50: b.hi 0x0000000000000080
54: add x26, x26, #0x1
58: mov x10, #0x110 // #272
5c: add x10, x1, x10
60: lsl x11, x2, #3
64: ldr x11, [x10,x11]
68: cbz x11, 0x0000000000000080
[...]
Fixes: ddb55992b04d ("arm64: bpf: implement bpf_tail_call() helper")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
arch/arm64/net/bpf_jit_comp.c | 5 +++--
tools/testing/selftests/bpf/test_verifier.c | 26 ++++++++++++++++++++++++++
2 files changed, 29 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index bb32f7f..be155f7 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -238,8 +238,9 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx)
off = offsetof(struct bpf_array, map.max_entries);
emit_a64_mov_i64(tmp, off, ctx);
emit(A64_LDR32(tmp, r2, tmp), ctx);
+ emit(A64_MOV(0, r3, r3), ctx);
emit(A64_CMP(0, r3, tmp), ctx);
- emit(A64_B_(A64_COND_GE, jmp_offset), ctx);
+ emit(A64_B_(A64_COND_CS, jmp_offset), ctx);
/* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
* goto out;
@@ -247,7 +248,7 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx)
*/
emit_a64_mov_i64(tmp, MAX_TAIL_CALL_CNT, ctx);
emit(A64_CMP(1, tcc, tmp), ctx);
- emit(A64_B_(A64_COND_GT, jmp_offset), ctx);
+ emit(A64_B_(A64_COND_HI, jmp_offset), ctx);
emit(A64_ADD_I(1, tcc, tcc, 1), ctx);
/* prog = array->ptrs[index];
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 5ed4175..13036a1 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -2255,6 +2255,32 @@ static struct bpf_test tests[] = {
.result = ACCEPT,
},
{
+ "runtime/jit: pass negative index to tail_call",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_3, -1),
+ BPF_LD_MAP_FD(BPF_REG_2, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_tail_call),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_prog = { 1 },
+ .result = ACCEPT,
+ },
+ {
+ "runtime/jit: pass > 32bit index to tail_call",
+ .insns = {
+ BPF_LD_IMM64(BPF_REG_3, 0x100000000ULL),
+ BPF_LD_MAP_FD(BPF_REG_2, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_tail_call),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_prog = { 2 },
+ .result = ACCEPT,
+ },
+ {
"stack pointer arithmetic",
.insns = {
BPF_MOV64_IMM(BPF_REG_1, 4),
--
2.9.5
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH stable 4.15 6/8] bpf: add schedule points in percpu arrays management
2018-03-08 12:16 [PATCH stable 4.15 0/8] BPF stable patches Daniel Borkmann
` (4 preceding siblings ...)
2018-03-08 12:16 ` [PATCH stable 4.15 5/8] bpf, arm64: fix out of bounds access in tail call Daniel Borkmann
@ 2018-03-08 12:16 ` Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf: add schedule points in percpu arrays management" has been added to the 4.15-stable tree gregkh
2018-03-08 12:16 ` [PATCH stable 4.15 7/8] bpf: allow xadd only on aligned memory Daniel Borkmann
` (2 subsequent siblings)
8 siblings, 1 reply; 18+ messages in thread
From: Daniel Borkmann @ 2018-03-08 12:16 UTC (permalink / raw)
To: gregkh; +Cc: ast, daniel, stable, Eric Dumazet
From: Eric Dumazet <edumazet@google.com>
[ upstream commit 32fff239de37ef226d5b66329dd133f64d63b22d ]
syszbot managed to trigger RCU detected stalls in
bpf_array_free_percpu()
It takes time to allocate a huge percpu map, but even more time to free
it.
Since we run in process context, use cond_resched() to yield cpu if
needed.
Fixes: a10423b87a7e ("bpf: introduce BPF_MAP_TYPE_PERCPU_ARRAY map")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
kernel/bpf/arraymap.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index e76aa67..8596aa3 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -26,8 +26,10 @@ static void bpf_array_free_percpu(struct bpf_array *array)
{
int i;
- for (i = 0; i < array->map.max_entries; i++)
+ for (i = 0; i < array->map.max_entries; i++) {
free_percpu(array->pptrs[i]);
+ cond_resched();
+ }
}
static int bpf_array_alloc_percpu(struct bpf_array *array)
@@ -43,6 +45,7 @@ static int bpf_array_alloc_percpu(struct bpf_array *array)
return -ENOMEM;
}
array->pptrs[i] = ptr;
+ cond_resched();
}
return 0;
--
2.9.5
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH stable 4.15 7/8] bpf: allow xadd only on aligned memory
2018-03-08 12:16 [PATCH stable 4.15 0/8] BPF stable patches Daniel Borkmann
` (5 preceding siblings ...)
2018-03-08 12:16 ` [PATCH stable 4.15 6/8] bpf: add schedule points in percpu arrays management Daniel Borkmann
@ 2018-03-08 12:16 ` Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf: allow xadd only on aligned memory" has been added to the 4.15-stable tree gregkh
2018-03-08 12:16 ` [PATCH stable 4.15 8/8] bpf, ppc64: fix out of bounds access in tail call Daniel Borkmann
2018-03-09 22:17 ` [PATCH stable 4.15 0/8] BPF stable patches Greg KH
8 siblings, 1 reply; 18+ messages in thread
From: Daniel Borkmann @ 2018-03-08 12:16 UTC (permalink / raw)
To: gregkh; +Cc: ast, daniel, stable
[ upstream commit ca36960211eb228bcbc7aaebfa0d027368a94c60 ]
The requirements around atomic_add() / atomic64_add() resp. their
JIT implementations differ across architectures. E.g. while x86_64
seems just fine with BPF's xadd on unaligned memory, on arm64 it
triggers via interpreter but also JIT the following crash:
[ 830.864985] Unable to handle kernel paging request at virtual address ffff8097d7ed6703
[...]
[ 830.916161] Internal error: Oops: 96000021 [#1] SMP
[ 830.984755] CPU: 37 PID: 2788 Comm: test_verifier Not tainted 4.16.0-rc2+ #8
[ 830.991790] Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.29 07/17/2017
[ 830.998998] pstate: 80400005 (Nzcv daif +PAN -UAO)
[ 831.003793] pc : __ll_sc_atomic_add+0x4/0x18
[ 831.008055] lr : ___bpf_prog_run+0x1198/0x1588
[ 831.012485] sp : ffff00001ccabc20
[ 831.015786] x29: ffff00001ccabc20 x28: ffff8017d56a0f00
[ 831.021087] x27: 0000000000000001 x26: 0000000000000000
[ 831.026387] x25: 000000c168d9db98 x24: 0000000000000000
[ 831.031686] x23: ffff000008203878 x22: ffff000009488000
[ 831.036986] x21: ffff000008b14e28 x20: ffff00001ccabcb0
[ 831.042286] x19: ffff0000097b5080 x18: 0000000000000a03
[ 831.047585] x17: 0000000000000000 x16: 0000000000000000
[ 831.052885] x15: 0000ffffaeca8000 x14: 0000000000000000
[ 831.058184] x13: 0000000000000000 x12: 0000000000000000
[ 831.063484] x11: 0000000000000001 x10: 0000000000000000
[ 831.068783] x9 : 0000000000000000 x8 : 0000000000000000
[ 831.074083] x7 : 0000000000000000 x6 : 000580d428000000
[ 831.079383] x5 : 0000000000000018 x4 : 0000000000000000
[ 831.084682] x3 : ffff00001ccabcb0 x2 : 0000000000000001
[ 831.089982] x1 : ffff8097d7ed6703 x0 : 0000000000000001
[ 831.095282] Process test_verifier (pid: 2788, stack limit = 0x0000000018370044)
[ 831.102577] Call trace:
[ 831.105012] __ll_sc_atomic_add+0x4/0x18
[ 831.108923] __bpf_prog_run32+0x4c/0x70
[ 831.112748] bpf_test_run+0x78/0xf8
[ 831.116224] bpf_prog_test_run_xdp+0xb4/0x120
[ 831.120567] SyS_bpf+0x77c/0x1110
[ 831.123873] el0_svc_naked+0x30/0x34
[ 831.127437] Code: 97fffe97 17ffffec 00000000 f9800031 (885f7c31)
Reason for this is because memory is required to be aligned. In
case of BPF, we always enforce alignment in terms of stack access,
but not when accessing map values or packet data when the underlying
arch (e.g. arm64) has CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS set.
xadd on packet data that is local to us anyway is just wrong, so
forbid this case entirely. The only place where xadd makes sense in
fact are map values; xadd on stack is wrong as well, but it's been
around for much longer. Specifically enforce strict alignment in case
of xadd, so that we handle this case generically and avoid such crashes
in the first place.
Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
kernel/bpf/verifier.c | 42 +++++++++++++--------
tools/testing/selftests/bpf/test_verifier.c | 58 +++++++++++++++++++++++++++++
2 files changed, 84 insertions(+), 16 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 13551e6..7125ddb 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -985,6 +985,13 @@ static bool is_ctx_reg(struct bpf_verifier_env *env, int regno)
return reg->type == PTR_TO_CTX;
}
+static bool is_pkt_reg(struct bpf_verifier_env *env, int regno)
+{
+ const struct bpf_reg_state *reg = cur_regs(env) + regno;
+
+ return type_is_pkt_pointer(reg->type);
+}
+
static int check_pkt_ptr_alignment(struct bpf_verifier_env *env,
const struct bpf_reg_state *reg,
int off, int size, bool strict)
@@ -1045,10 +1052,10 @@ static int check_generic_ptr_alignment(struct bpf_verifier_env *env,
}
static int check_ptr_alignment(struct bpf_verifier_env *env,
- const struct bpf_reg_state *reg,
- int off, int size)
+ const struct bpf_reg_state *reg, int off,
+ int size, bool strict_alignment_once)
{
- bool strict = env->strict_alignment;
+ bool strict = env->strict_alignment || strict_alignment_once;
const char *pointer_desc = "";
switch (reg->type) {
@@ -1108,9 +1115,9 @@ static void coerce_reg_to_size(struct bpf_reg_state *reg, int size)
* if t==write && value_regno==-1, some unknown value is stored into memory
* if t==read && value_regno==-1, don't care what we read from memory
*/
-static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno, int off,
- int bpf_size, enum bpf_access_type t,
- int value_regno)
+static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno,
+ int off, int bpf_size, enum bpf_access_type t,
+ int value_regno, bool strict_alignment_once)
{
struct bpf_verifier_state *state = env->cur_state;
struct bpf_reg_state *regs = cur_regs(env);
@@ -1122,7 +1129,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
return size;
/* alignment checks will add in reg->off themselves */
- err = check_ptr_alignment(env, reg, off, size);
+ err = check_ptr_alignment(env, reg, off, size, strict_alignment_once);
if (err)
return err;
@@ -1265,21 +1272,23 @@ static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_ins
return -EACCES;
}
- if (is_ctx_reg(env, insn->dst_reg)) {
- verbose(env, "BPF_XADD stores into R%d context is not allowed\n",
- insn->dst_reg);
+ if (is_ctx_reg(env, insn->dst_reg) ||
+ is_pkt_reg(env, insn->dst_reg)) {
+ verbose(env, "BPF_XADD stores into R%d %s is not allowed\n",
+ insn->dst_reg, is_ctx_reg(env, insn->dst_reg) ?
+ "context" : "packet");
return -EACCES;
}
/* check whether atomic_add can read the memory */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
- BPF_SIZE(insn->code), BPF_READ, -1);
+ BPF_SIZE(insn->code), BPF_READ, -1, true);
if (err)
return err;
/* check whether atomic_add can write into the same memory */
return check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
- BPF_SIZE(insn->code), BPF_WRITE, -1);
+ BPF_SIZE(insn->code), BPF_WRITE, -1, true);
}
/* Does this register contain a constant zero? */
@@ -1763,7 +1772,8 @@ static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx)
* is inferred from register state.
*/
for (i = 0; i < meta.access_size; i++) {
- err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B, BPF_WRITE, -1);
+ err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B,
+ BPF_WRITE, -1, false);
if (err)
return err;
}
@@ -3933,7 +3943,7 @@ static int do_check(struct bpf_verifier_env *env)
*/
err = check_mem_access(env, insn_idx, insn->src_reg, insn->off,
BPF_SIZE(insn->code), BPF_READ,
- insn->dst_reg);
+ insn->dst_reg, false);
if (err)
return err;
@@ -3985,7 +3995,7 @@ static int do_check(struct bpf_verifier_env *env)
/* check that memory (dst_reg + off) is writeable */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_WRITE,
- insn->src_reg);
+ insn->src_reg, false);
if (err)
return err;
@@ -4020,7 +4030,7 @@ static int do_check(struct bpf_verifier_env *env)
/* check that memory (dst_reg + off) is writeable */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_WRITE,
- -1);
+ -1, false);
if (err)
return err;
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 13036a1..0694527 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -8852,6 +8852,64 @@ static struct bpf_test tests[] = {
.result = REJECT,
.prog_type = BPF_PROG_TYPE_CGROUP_SOCK,
},
+ {
+ "xadd/w check unaligned stack",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
+ BPF_STX_XADD(BPF_W, BPF_REG_10, BPF_REG_0, -7),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .errstr = "misaligned stack access off",
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ },
+ {
+ "xadd/w check unaligned map",
+ .insns = {
+ BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_IMM(BPF_REG_1, 1),
+ BPF_STX_XADD(BPF_W, BPF_REG_0, BPF_REG_1, 3),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 3),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .result = REJECT,
+ .errstr = "misaligned value access off",
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ },
+ {
+ "xadd/w check unaligned pkt",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+ offsetof(struct xdp_md, data)),
+ BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
+ offsetof(struct xdp_md, data_end)),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 2),
+ BPF_MOV64_IMM(BPF_REG_0, 99),
+ BPF_JMP_IMM(BPF_JA, 0, 0, 6),
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 0),
+ BPF_ST_MEM(BPF_W, BPF_REG_2, 3, 0),
+ BPF_STX_XADD(BPF_W, BPF_REG_2, BPF_REG_0, 1),
+ BPF_STX_XADD(BPF_W, BPF_REG_2, BPF_REG_0, 2),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 1),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .errstr = "BPF_XADD stores into R2 packet",
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
};
static int probe_filter_length(const struct bpf_insn *fp)
--
2.9.5
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH stable 4.15 8/8] bpf, ppc64: fix out of bounds access in tail call
2018-03-08 12:16 [PATCH stable 4.15 0/8] BPF stable patches Daniel Borkmann
` (6 preceding siblings ...)
2018-03-08 12:16 ` [PATCH stable 4.15 7/8] bpf: allow xadd only on aligned memory Daniel Borkmann
@ 2018-03-08 12:16 ` Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf, ppc64: fix out of bounds access in tail call" has been added to the 4.15-stable tree gregkh
2018-03-09 22:17 ` [PATCH stable 4.15 0/8] BPF stable patches Greg KH
8 siblings, 1 reply; 18+ messages in thread
From: Daniel Borkmann @ 2018-03-08 12:16 UTC (permalink / raw)
To: gregkh; +Cc: ast, daniel, stable
[ upstream commit d269176e766c71c998cb75b4ea8cbc321cc0019d ]
While working on 16338a9b3ac3 ("bpf, arm64: fix out of bounds access in
tail call") I noticed that ppc64 JIT is partially affected as well. While
the bound checking is correctly performed as unsigned comparison, the
register with the index value however, is never truncated into 32 bit
space, so e.g. a index value of 0x100000000ULL with a map of 1 element
would pass with PPC_CMPLW() whereas we later on continue with the full
64 bit register value. Therefore, as we do in interpreter and other JITs
truncate the value to 32 bit initially in order to fix access.
Fixes: ce0761419fae ("powerpc/bpf: Implement support for tail calls")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
arch/powerpc/net/bpf_jit_comp64.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index d183b48..35591fb 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -242,6 +242,7 @@ static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32
* goto out;
*/
PPC_LWZ(b2p[TMP_REG_1], b2p_bpf_array, offsetof(struct bpf_array, map.max_entries));
+ PPC_RLWINM(b2p_index, b2p_index, 0, 0, 31);
PPC_CMPLW(b2p_index, b2p[TMP_REG_1]);
PPC_BCC(COND_GE, out);
--
2.9.5
^ permalink raw reply related [flat|nested] 18+ messages in thread
* Patch "bpf: add schedule points in percpu arrays management" has been added to the 4.15-stable tree
2018-03-08 12:16 ` [PATCH stable 4.15 6/8] bpf: add schedule points in percpu arrays management Daniel Borkmann
@ 2018-03-09 22:17 ` gregkh
0 siblings, 0 replies; 18+ messages in thread
From: gregkh @ 2018-03-09 22:17 UTC (permalink / raw)
To: daniel, edumazet, gregkh, syzkaller; +Cc: stable, stable-commits
This is a note to let you know that I've just added the patch titled
bpf: add schedule points in percpu arrays management
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-add-schedule-points-in-percpu-arrays-management.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From foo@baz Fri Mar 9 14:15:30 PST 2018
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu, 8 Mar 2018 13:16:47 +0100
Subject: bpf: add schedule points in percpu arrays management
To: gregkh@linuxfoundation.org
Cc: ast@kernel.org, daniel@iogearbox.net, stable@vger.kernel.org, Eric Dumazet <edumazet@google.com>
Message-ID: <96ee52a83c789138e21bf415a34569d15b12948a.1520507630.git.daniel@iogearbox.net>
From: Eric Dumazet <edumazet@google.com>
[ upstream commit 32fff239de37ef226d5b66329dd133f64d63b22d ]
syszbot managed to trigger RCU detected stalls in
bpf_array_free_percpu()
It takes time to allocate a huge percpu map, but even more time to free
it.
Since we run in process context, use cond_resched() to yield cpu if
needed.
Fixes: a10423b87a7e ("bpf: introduce BPF_MAP_TYPE_PERCPU_ARRAY map")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/bpf/arraymap.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -26,8 +26,10 @@ static void bpf_array_free_percpu(struct
{
int i;
- for (i = 0; i < array->map.max_entries; i++)
+ for (i = 0; i < array->map.max_entries; i++) {
free_percpu(array->pptrs[i]);
+ cond_resched();
+ }
}
static int bpf_array_alloc_percpu(struct bpf_array *array)
@@ -43,6 +45,7 @@ static int bpf_array_alloc_percpu(struct
return -ENOMEM;
}
array->pptrs[i] = ptr;
+ cond_resched();
}
return 0;
Patches currently in stable-queue which might be from daniel@iogearbox.net are
queue-4.15/bpf-fix-mlock-precharge-on-arraymaps.patch
queue-4.15/bpf-x64-implement-retpoline-for-tail-call.patch
queue-4.15/bpf-arm64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-fix-memory-leak-in-lpm_trie-map_free-callback-function.patch
queue-4.15/bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-add-schedule-points-in-percpu-arrays-management.patch
queue-4.15/bpf-allow-xadd-only-on-aligned-memory.patch
queue-4.15/bpf-fix-rcu-lockdep-warning-for-lpm_trie-map_free-callback.patch
^ permalink raw reply [flat|nested] 18+ messages in thread
* Patch "bpf: allow xadd only on aligned memory" has been added to the 4.15-stable tree
2018-03-08 12:16 ` [PATCH stable 4.15 7/8] bpf: allow xadd only on aligned memory Daniel Borkmann
@ 2018-03-09 22:17 ` gregkh
0 siblings, 0 replies; 18+ messages in thread
From: gregkh @ 2018-03-09 22:17 UTC (permalink / raw)
To: daniel, ast, gregkh; +Cc: stable, stable-commits
This is a note to let you know that I've just added the patch titled
bpf: allow xadd only on aligned memory
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-allow-xadd-only-on-aligned-memory.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From foo@baz Fri Mar 9 14:15:30 PST 2018
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu, 8 Mar 2018 13:16:48 +0100
Subject: bpf: allow xadd only on aligned memory
To: gregkh@linuxfoundation.org
Cc: ast@kernel.org, daniel@iogearbox.net, stable@vger.kernel.org
Message-ID: <3cc2bcb1248a1821430d0e7574a8dbd9d387f7ec.1520507630.git.daniel@iogearbox.net>
From: Daniel Borkmann <daniel@iogearbox.net>
[ upstream commit ca36960211eb228bcbc7aaebfa0d027368a94c60 ]
The requirements around atomic_add() / atomic64_add() resp. their
JIT implementations differ across architectures. E.g. while x86_64
seems just fine with BPF's xadd on unaligned memory, on arm64 it
triggers via interpreter but also JIT the following crash:
[ 830.864985] Unable to handle kernel paging request at virtual address ffff8097d7ed6703
[...]
[ 830.916161] Internal error: Oops: 96000021 [#1] SMP
[ 830.984755] CPU: 37 PID: 2788 Comm: test_verifier Not tainted 4.16.0-rc2+ #8
[ 830.991790] Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.29 07/17/2017
[ 830.998998] pstate: 80400005 (Nzcv daif +PAN -UAO)
[ 831.003793] pc : __ll_sc_atomic_add+0x4/0x18
[ 831.008055] lr : ___bpf_prog_run+0x1198/0x1588
[ 831.012485] sp : ffff00001ccabc20
[ 831.015786] x29: ffff00001ccabc20 x28: ffff8017d56a0f00
[ 831.021087] x27: 0000000000000001 x26: 0000000000000000
[ 831.026387] x25: 000000c168d9db98 x24: 0000000000000000
[ 831.031686] x23: ffff000008203878 x22: ffff000009488000
[ 831.036986] x21: ffff000008b14e28 x20: ffff00001ccabcb0
[ 831.042286] x19: ffff0000097b5080 x18: 0000000000000a03
[ 831.047585] x17: 0000000000000000 x16: 0000000000000000
[ 831.052885] x15: 0000ffffaeca8000 x14: 0000000000000000
[ 831.058184] x13: 0000000000000000 x12: 0000000000000000
[ 831.063484] x11: 0000000000000001 x10: 0000000000000000
[ 831.068783] x9 : 0000000000000000 x8 : 0000000000000000
[ 831.074083] x7 : 0000000000000000 x6 : 000580d428000000
[ 831.079383] x5 : 0000000000000018 x4 : 0000000000000000
[ 831.084682] x3 : ffff00001ccabcb0 x2 : 0000000000000001
[ 831.089982] x1 : ffff8097d7ed6703 x0 : 0000000000000001
[ 831.095282] Process test_verifier (pid: 2788, stack limit = 0x0000000018370044)
[ 831.102577] Call trace:
[ 831.105012] __ll_sc_atomic_add+0x4/0x18
[ 831.108923] __bpf_prog_run32+0x4c/0x70
[ 831.112748] bpf_test_run+0x78/0xf8
[ 831.116224] bpf_prog_test_run_xdp+0xb4/0x120
[ 831.120567] SyS_bpf+0x77c/0x1110
[ 831.123873] el0_svc_naked+0x30/0x34
[ 831.127437] Code: 97fffe97 17ffffec 00000000 f9800031 (885f7c31)
Reason for this is because memory is required to be aligned. In
case of BPF, we always enforce alignment in terms of stack access,
but not when accessing map values or packet data when the underlying
arch (e.g. arm64) has CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS set.
xadd on packet data that is local to us anyway is just wrong, so
forbid this case entirely. The only place where xadd makes sense in
fact are map values; xadd on stack is wrong as well, but it's been
around for much longer. Specifically enforce strict alignment in case
of xadd, so that we handle this case generically and avoid such crashes
in the first place.
Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/bpf/verifier.c | 42 ++++++++++++--------
tools/testing/selftests/bpf/test_verifier.c | 58 ++++++++++++++++++++++++++++
2 files changed, 84 insertions(+), 16 deletions(-)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -985,6 +985,13 @@ static bool is_ctx_reg(struct bpf_verifi
return reg->type == PTR_TO_CTX;
}
+static bool is_pkt_reg(struct bpf_verifier_env *env, int regno)
+{
+ const struct bpf_reg_state *reg = cur_regs(env) + regno;
+
+ return type_is_pkt_pointer(reg->type);
+}
+
static int check_pkt_ptr_alignment(struct bpf_verifier_env *env,
const struct bpf_reg_state *reg,
int off, int size, bool strict)
@@ -1045,10 +1052,10 @@ static int check_generic_ptr_alignment(s
}
static int check_ptr_alignment(struct bpf_verifier_env *env,
- const struct bpf_reg_state *reg,
- int off, int size)
+ const struct bpf_reg_state *reg, int off,
+ int size, bool strict_alignment_once)
{
- bool strict = env->strict_alignment;
+ bool strict = env->strict_alignment || strict_alignment_once;
const char *pointer_desc = "";
switch (reg->type) {
@@ -1108,9 +1115,9 @@ static void coerce_reg_to_size(struct bp
* if t==write && value_regno==-1, some unknown value is stored into memory
* if t==read && value_regno==-1, don't care what we read from memory
*/
-static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno, int off,
- int bpf_size, enum bpf_access_type t,
- int value_regno)
+static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno,
+ int off, int bpf_size, enum bpf_access_type t,
+ int value_regno, bool strict_alignment_once)
{
struct bpf_verifier_state *state = env->cur_state;
struct bpf_reg_state *regs = cur_regs(env);
@@ -1122,7 +1129,7 @@ static int check_mem_access(struct bpf_v
return size;
/* alignment checks will add in reg->off themselves */
- err = check_ptr_alignment(env, reg, off, size);
+ err = check_ptr_alignment(env, reg, off, size, strict_alignment_once);
if (err)
return err;
@@ -1265,21 +1272,23 @@ static int check_xadd(struct bpf_verifie
return -EACCES;
}
- if (is_ctx_reg(env, insn->dst_reg)) {
- verbose(env, "BPF_XADD stores into R%d context is not allowed\n",
- insn->dst_reg);
+ if (is_ctx_reg(env, insn->dst_reg) ||
+ is_pkt_reg(env, insn->dst_reg)) {
+ verbose(env, "BPF_XADD stores into R%d %s is not allowed\n",
+ insn->dst_reg, is_ctx_reg(env, insn->dst_reg) ?
+ "context" : "packet");
return -EACCES;
}
/* check whether atomic_add can read the memory */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
- BPF_SIZE(insn->code), BPF_READ, -1);
+ BPF_SIZE(insn->code), BPF_READ, -1, true);
if (err)
return err;
/* check whether atomic_add can write into the same memory */
return check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
- BPF_SIZE(insn->code), BPF_WRITE, -1);
+ BPF_SIZE(insn->code), BPF_WRITE, -1, true);
}
/* Does this register contain a constant zero? */
@@ -1763,7 +1772,8 @@ static int check_call(struct bpf_verifie
* is inferred from register state.
*/
for (i = 0; i < meta.access_size; i++) {
- err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B, BPF_WRITE, -1);
+ err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B,
+ BPF_WRITE, -1, false);
if (err)
return err;
}
@@ -3933,7 +3943,7 @@ static int do_check(struct bpf_verifier_
*/
err = check_mem_access(env, insn_idx, insn->src_reg, insn->off,
BPF_SIZE(insn->code), BPF_READ,
- insn->dst_reg);
+ insn->dst_reg, false);
if (err)
return err;
@@ -3985,7 +3995,7 @@ static int do_check(struct bpf_verifier_
/* check that memory (dst_reg + off) is writeable */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_WRITE,
- insn->src_reg);
+ insn->src_reg, false);
if (err)
return err;
@@ -4020,7 +4030,7 @@ static int do_check(struct bpf_verifier_
/* check that memory (dst_reg + off) is writeable */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_WRITE,
- -1);
+ -1, false);
if (err)
return err;
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -8852,6 +8852,64 @@ static struct bpf_test tests[] = {
.result = REJECT,
.prog_type = BPF_PROG_TYPE_CGROUP_SOCK,
},
+ {
+ "xadd/w check unaligned stack",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
+ BPF_STX_XADD(BPF_W, BPF_REG_10, BPF_REG_0, -7),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .errstr = "misaligned stack access off",
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ },
+ {
+ "xadd/w check unaligned map",
+ .insns = {
+ BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_IMM(BPF_REG_1, 1),
+ BPF_STX_XADD(BPF_W, BPF_REG_0, BPF_REG_1, 3),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 3),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .result = REJECT,
+ .errstr = "misaligned value access off",
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ },
+ {
+ "xadd/w check unaligned pkt",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+ offsetof(struct xdp_md, data)),
+ BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
+ offsetof(struct xdp_md, data_end)),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 2),
+ BPF_MOV64_IMM(BPF_REG_0, 99),
+ BPF_JMP_IMM(BPF_JA, 0, 0, 6),
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 0),
+ BPF_ST_MEM(BPF_W, BPF_REG_2, 3, 0),
+ BPF_STX_XADD(BPF_W, BPF_REG_2, BPF_REG_0, 1),
+ BPF_STX_XADD(BPF_W, BPF_REG_2, BPF_REG_0, 2),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 1),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .errstr = "BPF_XADD stores into R2 packet",
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
};
static int probe_filter_length(const struct bpf_insn *fp)
Patches currently in stable-queue which might be from daniel@iogearbox.net are
queue-4.15/bpf-fix-mlock-precharge-on-arraymaps.patch
queue-4.15/bpf-x64-implement-retpoline-for-tail-call.patch
queue-4.15/bpf-arm64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-fix-memory-leak-in-lpm_trie-map_free-callback-function.patch
queue-4.15/bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-add-schedule-points-in-percpu-arrays-management.patch
queue-4.15/bpf-allow-xadd-only-on-aligned-memory.patch
queue-4.15/bpf-fix-rcu-lockdep-warning-for-lpm_trie-map_free-callback.patch
^ permalink raw reply [flat|nested] 18+ messages in thread
* Patch "bpf, arm64: fix out of bounds access in tail call" has been added to the 4.15-stable tree
2018-03-08 12:16 ` [PATCH stable 4.15 5/8] bpf, arm64: fix out of bounds access in tail call Daniel Borkmann
@ 2018-03-09 22:17 ` gregkh
0 siblings, 0 replies; 18+ messages in thread
From: gregkh @ 2018-03-09 22:17 UTC (permalink / raw)
To: daniel, ast, gregkh; +Cc: stable, stable-commits
This is a note to let you know that I've just added the patch titled
bpf, arm64: fix out of bounds access in tail call
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-arm64-fix-out-of-bounds-access-in-tail-call.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From foo@baz Fri Mar 9 14:15:30 PST 2018
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu, 8 Mar 2018 13:16:46 +0100
Subject: bpf, arm64: fix out of bounds access in tail call
To: gregkh@linuxfoundation.org
Cc: ast@kernel.org, daniel@iogearbox.net, stable@vger.kernel.org
Message-ID: <cfd483610bf9031695ecf1216af706d1114da98a.1520507630.git.daniel@iogearbox.net>
From: Daniel Borkmann <daniel@iogearbox.net>
[ upstream commit 16338a9b3ac30740d49f5dfed81bac0ffa53b9c7 ]
I recently noticed a crash on arm64 when feeding a bogus index
into BPF tail call helper. The crash would not occur when the
interpreter is used, but only in case of JIT. Output looks as
follows:
[ 347.007486] Unable to handle kernel paging request at virtual address fffb850e96492510
[...]
[ 347.043065] [fffb850e96492510] address between user and kernel address ranges
[ 347.050205] Internal error: Oops: 96000004 [#1] SMP
[...]
[ 347.190829] x13: 0000000000000000 x12: 0000000000000000
[ 347.196128] x11: fffc047ebe782800 x10: ffff808fd7d0fd10
[ 347.201427] x9 : 0000000000000000 x8 : 0000000000000000
[ 347.206726] x7 : 0000000000000000 x6 : 001c991738000000
[ 347.212025] x5 : 0000000000000018 x4 : 000000000000ba5a
[ 347.217325] x3 : 00000000000329c4 x2 : ffff808fd7cf0500
[ 347.222625] x1 : ffff808fd7d0fc00 x0 : ffff808fd7cf0500
[ 347.227926] Process test_verifier (pid: 4548, stack limit = 0x000000007467fa61)
[ 347.235221] Call trace:
[ 347.237656] 0xffff000002f3a4fc
[ 347.240784] bpf_test_run+0x78/0xf8
[ 347.244260] bpf_prog_test_run_skb+0x148/0x230
[ 347.248694] SyS_bpf+0x77c/0x1110
[ 347.251999] el0_svc_naked+0x30/0x34
[ 347.255564] Code: 9100075a d280220a 8b0a002a d37df04b (f86b694b)
[...]
In this case the index used in BPF r3 is the same as in r1
at the time of the call, meaning we fed a pointer as index;
here, it had the value 0xffff808fd7cf0500 which sits in x2.
While I found tail calls to be working in general (also for
hitting the error cases), I noticed the following in the code
emission:
# bpftool p d j i 988
[...]
38: ldr w10, [x1,x10]
3c: cmp w2, w10
40: b.ge 0x000000000000007c <-- signed cmp
44: mov x10, #0x20 // #32
48: cmp x26, x10
4c: b.gt 0x000000000000007c
50: add x26, x26, #0x1
54: mov x10, #0x110 // #272
58: add x10, x1, x10
5c: lsl x11, x2, #3
60: ldr x11, [x10,x11] <-- faulting insn (f86b694b)
64: cbz x11, 0x000000000000007c
[...]
Meaning, the tests passed because commit ddb55992b04d ("arm64:
bpf: implement bpf_tail_call() helper") was using signed compares
instead of unsigned which as a result had the test wrongly passing.
Change this but also the tail call count test both into unsigned
and cap the index as u32. Latter we did as well in 90caccdd8cc0
("bpf: fix bpf_tail_call() x64 JIT") and is needed in addition here,
too. Tested on HiSilicon Hi1616.
Result after patch:
# bpftool p d j i 268
[...]
38: ldr w10, [x1,x10]
3c: add w2, w2, #0x0
40: cmp w2, w10
44: b.cs 0x0000000000000080
48: mov x10, #0x20 // #32
4c: cmp x26, x10
50: b.hi 0x0000000000000080
54: add x26, x26, #0x1
58: mov x10, #0x110 // #272
5c: add x10, x1, x10
60: lsl x11, x2, #3
64: ldr x11, [x10,x11]
68: cbz x11, 0x0000000000000080
[...]
Fixes: ddb55992b04d ("arm64: bpf: implement bpf_tail_call() helper")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/arm64/net/bpf_jit_comp.c | 5 +++--
tools/testing/selftests/bpf/test_verifier.c | 26 ++++++++++++++++++++++++++
2 files changed, 29 insertions(+), 2 deletions(-)
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -238,8 +238,9 @@ static int emit_bpf_tail_call(struct jit
off = offsetof(struct bpf_array, map.max_entries);
emit_a64_mov_i64(tmp, off, ctx);
emit(A64_LDR32(tmp, r2, tmp), ctx);
+ emit(A64_MOV(0, r3, r3), ctx);
emit(A64_CMP(0, r3, tmp), ctx);
- emit(A64_B_(A64_COND_GE, jmp_offset), ctx);
+ emit(A64_B_(A64_COND_CS, jmp_offset), ctx);
/* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
* goto out;
@@ -247,7 +248,7 @@ static int emit_bpf_tail_call(struct jit
*/
emit_a64_mov_i64(tmp, MAX_TAIL_CALL_CNT, ctx);
emit(A64_CMP(1, tcc, tmp), ctx);
- emit(A64_B_(A64_COND_GT, jmp_offset), ctx);
+ emit(A64_B_(A64_COND_HI, jmp_offset), ctx);
emit(A64_ADD_I(1, tcc, tcc, 1), ctx);
/* prog = array->ptrs[index];
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -2255,6 +2255,32 @@ static struct bpf_test tests[] = {
.result = ACCEPT,
},
{
+ "runtime/jit: pass negative index to tail_call",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_3, -1),
+ BPF_LD_MAP_FD(BPF_REG_2, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_tail_call),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_prog = { 1 },
+ .result = ACCEPT,
+ },
+ {
+ "runtime/jit: pass > 32bit index to tail_call",
+ .insns = {
+ BPF_LD_IMM64(BPF_REG_3, 0x100000000ULL),
+ BPF_LD_MAP_FD(BPF_REG_2, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_tail_call),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_prog = { 2 },
+ .result = ACCEPT,
+ },
+ {
"stack pointer arithmetic",
.insns = {
BPF_MOV64_IMM(BPF_REG_1, 4),
Patches currently in stable-queue which might be from daniel@iogearbox.net are
queue-4.15/bpf-fix-mlock-precharge-on-arraymaps.patch
queue-4.15/bpf-x64-implement-retpoline-for-tail-call.patch
queue-4.15/bpf-arm64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-fix-memory-leak-in-lpm_trie-map_free-callback-function.patch
queue-4.15/bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-add-schedule-points-in-percpu-arrays-management.patch
queue-4.15/bpf-allow-xadd-only-on-aligned-memory.patch
queue-4.15/bpf-fix-rcu-lockdep-warning-for-lpm_trie-map_free-callback.patch
^ permalink raw reply [flat|nested] 18+ messages in thread
* Patch "bpf: fix memory leak in lpm_trie map_free callback function" has been added to the 4.15-stable tree
2018-03-08 12:16 ` [PATCH stable 4.15 2/8] bpf: fix memory leak in lpm_trie map_free callback function Daniel Borkmann
@ 2018-03-09 22:17 ` gregkh
0 siblings, 0 replies; 18+ messages in thread
From: gregkh @ 2018-03-09 22:17 UTC (permalink / raw)
To: daniel, ast, gregkh, malat, yhs; +Cc: stable, stable-commits
This is a note to let you know that I've just added the patch titled
bpf: fix memory leak in lpm_trie map_free callback function
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-fix-memory-leak-in-lpm_trie-map_free-callback-function.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From foo@baz Fri Mar 9 14:15:30 PST 2018
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu, 8 Mar 2018 13:16:43 +0100
Subject: bpf: fix memory leak in lpm_trie map_free callback function
To: gregkh@linuxfoundation.org
Cc: ast@kernel.org, daniel@iogearbox.net, stable@vger.kernel.org, Yonghong Song <yhs@fb.com>
Message-ID: <92a9bac0950f4c6def7378bc548eeaea6518b4da.1520507630.git.daniel@iogearbox.net>
From: Yonghong Song <yhs@fb.com>
[ upstream commit 9a3efb6b661f71d5675369ace9257833f0e78ef3 ]
There is a memory leak happening in lpm_trie map_free callback
function trie_free. The trie structure itself does not get freed.
Also, trie_free function did not do synchronize_rcu before freeing
various data structures. This is incorrect as some rcu_read_lock
region(s) for lookup, update, delete or get_next_key may not complete yet.
The fix is to add synchronize_rcu in the beginning of trie_free.
The useless spin_lock is removed from this function as well.
Fixes: b95a5c4db09b ("bpf: add a longest prefix match trie map implementation")
Reported-by: Mathieu Malaterre <malat@debian.org>
Reported-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/bpf/lpm_trie.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
--- a/kernel/bpf/lpm_trie.c
+++ b/kernel/bpf/lpm_trie.c
@@ -560,7 +560,10 @@ static void trie_free(struct bpf_map *ma
struct lpm_trie_node __rcu **slot;
struct lpm_trie_node *node;
- raw_spin_lock(&trie->lock);
+ /* Wait for outstanding programs to complete
+ * update/lookup/delete/get_next_key and free the trie.
+ */
+ synchronize_rcu();
/* Always start at the root and walk down to a node that has no
* children. Then free that node, nullify its reference in the parent
@@ -574,7 +577,7 @@ static void trie_free(struct bpf_map *ma
node = rcu_dereference_protected(*slot,
lockdep_is_held(&trie->lock));
if (!node)
- goto unlock;
+ goto out;
if (rcu_access_pointer(node->child[0])) {
slot = &node->child[0];
@@ -592,8 +595,8 @@ static void trie_free(struct bpf_map *ma
}
}
-unlock:
- raw_spin_unlock(&trie->lock);
+out:
+ kfree(trie);
}
static int trie_get_next_key(struct bpf_map *map, void *key, void *next_key)
Patches currently in stable-queue which might be from daniel@iogearbox.net are
queue-4.15/bpf-fix-mlock-precharge-on-arraymaps.patch
queue-4.15/bpf-x64-implement-retpoline-for-tail-call.patch
queue-4.15/bpf-arm64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-fix-memory-leak-in-lpm_trie-map_free-callback-function.patch
queue-4.15/bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-add-schedule-points-in-percpu-arrays-management.patch
queue-4.15/bpf-allow-xadd-only-on-aligned-memory.patch
queue-4.15/bpf-fix-rcu-lockdep-warning-for-lpm_trie-map_free-callback.patch
^ permalink raw reply [flat|nested] 18+ messages in thread
* Patch "bpf: fix mlock precharge on arraymaps" has been added to the 4.15-stable tree
2018-03-08 12:16 ` [PATCH stable 4.15 1/8] bpf: fix mlock precharge on arraymaps Daniel Borkmann
@ 2018-03-09 22:17 ` gregkh
0 siblings, 0 replies; 18+ messages in thread
From: gregkh @ 2018-03-09 22:17 UTC (permalink / raw)
To: daniel, ast, dennisszhou, gregkh; +Cc: stable, stable-commits
This is a note to let you know that I've just added the patch titled
bpf: fix mlock precharge on arraymaps
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-fix-mlock-precharge-on-arraymaps.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From foo@baz Fri Mar 9 14:15:30 PST 2018
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu, 8 Mar 2018 13:16:42 +0100
Subject: bpf: fix mlock precharge on arraymaps
To: gregkh@linuxfoundation.org
Cc: ast@kernel.org, daniel@iogearbox.net, stable@vger.kernel.org, Dennis Zhou <dennisszhou@gmail.com>
Message-ID: <95c9eef7020bed6b0c05547ad9987ef060c0b9cb.1520507630.git.daniel@iogearbox.net>
From: Daniel Borkmann <daniel@iogearbox.net>
[ upstream commit 9c2d63b843a5c8a8d0559cc067b5398aa5ec3ffc ]
syzkaller recently triggered OOM during percpu map allocation;
while there is work in progress by Dennis Zhou to add __GFP_NORETRY
semantics for percpu allocator under pressure, there seems also a
missing bpf_map_precharge_memlock() check in array map allocation.
Given today the actual bpf_map_charge_memlock() happens after the
find_and_alloc_map() in syscall path, the bpf_map_precharge_memlock()
is there to bail out early before we go and do the map setup work
when we find that we hit the limits anyway. Therefore add this for
array map as well.
Fixes: 6c9059817432 ("bpf: pre-allocate hash map elements")
Fixes: a10423b87a7e ("bpf: introduce BPF_MAP_TYPE_PERCPU_ARRAY map")
Reported-by: syzbot+adb03f3f0bb57ce3acda@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Dennis Zhou <dennisszhou@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/bpf/arraymap.c | 28 ++++++++++++++++------------
1 file changed, 16 insertions(+), 12 deletions(-)
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -52,11 +52,11 @@ static int bpf_array_alloc_percpu(struct
static struct bpf_map *array_map_alloc(union bpf_attr *attr)
{
bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
- int numa_node = bpf_map_attr_numa_node(attr);
+ int ret, numa_node = bpf_map_attr_numa_node(attr);
u32 elem_size, index_mask, max_entries;
bool unpriv = !capable(CAP_SYS_ADMIN);
+ u64 cost, array_size, mask64;
struct bpf_array *array;
- u64 array_size, mask64;
/* check sanity of attributes */
if (attr->max_entries == 0 || attr->key_size != 4 ||
@@ -101,8 +101,19 @@ static struct bpf_map *array_map_alloc(u
array_size += (u64) max_entries * elem_size;
/* make sure there is no u32 overflow later in round_up() */
- if (array_size >= U32_MAX - PAGE_SIZE)
+ cost = array_size;
+ if (cost >= U32_MAX - PAGE_SIZE)
return ERR_PTR(-ENOMEM);
+ if (percpu) {
+ cost += (u64)attr->max_entries * elem_size * num_possible_cpus();
+ if (cost >= U32_MAX - PAGE_SIZE)
+ return ERR_PTR(-ENOMEM);
+ }
+ cost = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
+
+ ret = bpf_map_precharge_memlock(cost);
+ if (ret < 0)
+ return ERR_PTR(ret);
/* allocate all map elements and zero-initialize them */
array = bpf_map_area_alloc(array_size, numa_node);
@@ -118,20 +129,13 @@ static struct bpf_map *array_map_alloc(u
array->map.max_entries = attr->max_entries;
array->map.map_flags = attr->map_flags;
array->map.numa_node = numa_node;
+ array->map.pages = cost;
array->elem_size = elem_size;
- if (!percpu)
- goto out;
-
- array_size += (u64) attr->max_entries * elem_size * num_possible_cpus();
-
- if (array_size >= U32_MAX - PAGE_SIZE ||
- bpf_array_alloc_percpu(array)) {
+ if (percpu && bpf_array_alloc_percpu(array)) {
bpf_map_area_free(array);
return ERR_PTR(-ENOMEM);
}
-out:
- array->map.pages = round_up(array_size, PAGE_SIZE) >> PAGE_SHIFT;
return &array->map;
}
Patches currently in stable-queue which might be from daniel@iogearbox.net are
queue-4.15/bpf-fix-mlock-precharge-on-arraymaps.patch
queue-4.15/bpf-x64-implement-retpoline-for-tail-call.patch
queue-4.15/bpf-arm64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-fix-memory-leak-in-lpm_trie-map_free-callback-function.patch
queue-4.15/bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-add-schedule-points-in-percpu-arrays-management.patch
queue-4.15/bpf-allow-xadd-only-on-aligned-memory.patch
queue-4.15/bpf-fix-rcu-lockdep-warning-for-lpm_trie-map_free-callback.patch
^ permalink raw reply [flat|nested] 18+ messages in thread
* Patch "bpf: fix rcu lockdep warning for lpm_trie map_free callback" has been added to the 4.15-stable tree
2018-03-08 12:16 ` [PATCH stable 4.15 3/8] bpf: fix rcu lockdep warning for lpm_trie map_free callback Daniel Borkmann
@ 2018-03-09 22:17 ` gregkh
0 siblings, 0 replies; 18+ messages in thread
From: gregkh @ 2018-03-09 22:17 UTC (permalink / raw)
To: daniel, davem, edumazet, gregkh, yhs; +Cc: stable, stable-commits
This is a note to let you know that I've just added the patch titled
bpf: fix rcu lockdep warning for lpm_trie map_free callback
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-fix-rcu-lockdep-warning-for-lpm_trie-map_free-callback.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From foo@baz Fri Mar 9 14:15:30 PST 2018
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu, 8 Mar 2018 13:16:44 +0100
Subject: bpf: fix rcu lockdep warning for lpm_trie map_free callback
To: gregkh@linuxfoundation.org
Cc: ast@kernel.org, daniel@iogearbox.net, stable@vger.kernel.org, Yonghong Song <yhs@fb.com>
Message-ID: <3181ff4299652cbcfec7f1f2632ce1e486a3a25a.1520507630.git.daniel@iogearbox.net>
From: Yonghong Song <yhs@fb.com>
[ upstream commit 6c5f61023c5b0edb0c8a64c902fe97c6453b1852 ]
Commit 9a3efb6b661f ("bpf: fix memory leak in lpm_trie map_free callback function")
fixed a memory leak and removed unnecessary locks in map_free callback function.
Unfortrunately, it introduced a lockdep warning. When lockdep checking is turned on,
running tools/testing/selftests/bpf/test_lpm_map will have:
[ 98.294321] =============================
[ 98.294807] WARNING: suspicious RCU usage
[ 98.295359] 4.16.0-rc2+ #193 Not tainted
[ 98.295907] -----------------------------
[ 98.296486] /home/yhs/work/bpf/kernel/bpf/lpm_trie.c:572 suspicious rcu_dereference_check() usage!
[ 98.297657]
[ 98.297657] other info that might help us debug this:
[ 98.297657]
[ 98.298663]
[ 98.298663] rcu_scheduler_active = 2, debug_locks = 1
[ 98.299536] 2 locks held by kworker/2:1/54:
[ 98.300152] #0: ((wq_completion)"events"){+.+.}, at: [<00000000196bc1f0>] process_one_work+0x157/0x5c0
[ 98.301381] #1: ((work_completion)(&map->work)){+.+.}, at: [<00000000196bc1f0>] process_one_work+0x157/0x5c0
Since actual trie tree removal happens only after no other
accesses to the tree are possible, replacing
rcu_dereference_protected(*slot, lockdep_is_held(&trie->lock))
with
rcu_dereference_protected(*slot, 1)
fixed the issue.
Fixes: 9a3efb6b661f ("bpf: fix memory leak in lpm_trie map_free callback function")
Reported-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/bpf/lpm_trie.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/kernel/bpf/lpm_trie.c
+++ b/kernel/bpf/lpm_trie.c
@@ -574,8 +574,7 @@ static void trie_free(struct bpf_map *ma
slot = &trie->root;
for (;;) {
- node = rcu_dereference_protected(*slot,
- lockdep_is_held(&trie->lock));
+ node = rcu_dereference_protected(*slot, 1);
if (!node)
goto out;
Patches currently in stable-queue which might be from daniel@iogearbox.net are
queue-4.15/bpf-fix-mlock-precharge-on-arraymaps.patch
queue-4.15/bpf-x64-implement-retpoline-for-tail-call.patch
queue-4.15/bpf-arm64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-fix-memory-leak-in-lpm_trie-map_free-callback-function.patch
queue-4.15/bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-add-schedule-points-in-percpu-arrays-management.patch
queue-4.15/bpf-allow-xadd-only-on-aligned-memory.patch
queue-4.15/bpf-fix-rcu-lockdep-warning-for-lpm_trie-map_free-callback.patch
^ permalink raw reply [flat|nested] 18+ messages in thread
* Patch "bpf, ppc64: fix out of bounds access in tail call" has been added to the 4.15-stable tree
2018-03-08 12:16 ` [PATCH stable 4.15 8/8] bpf, ppc64: fix out of bounds access in tail call Daniel Borkmann
@ 2018-03-09 22:17 ` gregkh
0 siblings, 0 replies; 18+ messages in thread
From: gregkh @ 2018-03-09 22:17 UTC (permalink / raw)
To: daniel, ast, gregkh, naveen.n.rao; +Cc: stable, stable-commits
This is a note to let you know that I've just added the patch titled
bpf, ppc64: fix out of bounds access in tail call
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From foo@baz Fri Mar 9 14:15:30 PST 2018
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu, 8 Mar 2018 13:16:49 +0100
Subject: bpf, ppc64: fix out of bounds access in tail call
To: gregkh@linuxfoundation.org
Cc: ast@kernel.org, daniel@iogearbox.net, stable@vger.kernel.org
Message-ID: <b1f767c847d0fdc55743d3c45f9bf65341ec3b0c.1520507630.git.daniel@iogearbox.net>
From: Daniel Borkmann <daniel@iogearbox.net>
[ upstream commit d269176e766c71c998cb75b4ea8cbc321cc0019d ]
While working on 16338a9b3ac3 ("bpf, arm64: fix out of bounds access in
tail call") I noticed that ppc64 JIT is partially affected as well. While
the bound checking is correctly performed as unsigned comparison, the
register with the index value however, is never truncated into 32 bit
space, so e.g. a index value of 0x100000000ULL with a map of 1 element
would pass with PPC_CMPLW() whereas we later on continue with the full
64 bit register value. Therefore, as we do in interpreter and other JITs
truncate the value to 32 bit initially in order to fix access.
Fixes: ce0761419fae ("powerpc/bpf: Implement support for tail calls")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/powerpc/net/bpf_jit_comp64.c | 1 +
1 file changed, 1 insertion(+)
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -242,6 +242,7 @@ static void bpf_jit_emit_tail_call(u32 *
* goto out;
*/
PPC_LWZ(b2p[TMP_REG_1], b2p_bpf_array, offsetof(struct bpf_array, map.max_entries));
+ PPC_RLWINM(b2p_index, b2p_index, 0, 0, 31);
PPC_CMPLW(b2p_index, b2p[TMP_REG_1]);
PPC_BCC(COND_GE, out);
Patches currently in stable-queue which might be from daniel@iogearbox.net are
queue-4.15/bpf-fix-mlock-precharge-on-arraymaps.patch
queue-4.15/bpf-x64-implement-retpoline-for-tail-call.patch
queue-4.15/bpf-arm64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-fix-memory-leak-in-lpm_trie-map_free-callback-function.patch
queue-4.15/bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-add-schedule-points-in-percpu-arrays-management.patch
queue-4.15/bpf-allow-xadd-only-on-aligned-memory.patch
queue-4.15/bpf-fix-rcu-lockdep-warning-for-lpm_trie-map_free-callback.patch
^ permalink raw reply [flat|nested] 18+ messages in thread
* Patch "bpf, x64: implement retpoline for tail call" has been added to the 4.15-stable tree
2018-03-08 12:16 ` [PATCH stable 4.15 4/8] bpf, x64: implement retpoline for tail call Daniel Borkmann
@ 2018-03-09 22:17 ` gregkh
0 siblings, 0 replies; 18+ messages in thread
From: gregkh @ 2018-03-09 22:17 UTC (permalink / raw)
To: daniel, ast, gregkh; +Cc: stable, stable-commits
This is a note to let you know that I've just added the patch titled
bpf, x64: implement retpoline for tail call
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-x64-implement-retpoline-for-tail-call.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From foo@baz Fri Mar 9 14:15:30 PST 2018
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu, 8 Mar 2018 13:16:45 +0100
Subject: bpf, x64: implement retpoline for tail call
To: gregkh@linuxfoundation.org
Cc: ast@kernel.org, daniel@iogearbox.net, stable@vger.kernel.org
Message-ID: <def7cc3ac79d37ada804c3860a5a0007bc112c00.1520507630.git.daniel@iogearbox.net>
From: Daniel Borkmann <daniel@iogearbox.net>
[ upstream commit a493a87f38cfa48caaa95c9347be2d914c6fdf29 ]
Implement a retpoline [0] for the BPF tail call JIT'ing that converts
the indirect jump via jmp %rax that is used to make the long jump into
another JITed BPF image. Since this is subject to speculative execution,
we need to control the transient instruction sequence here as well
when CONFIG_RETPOLINE is set, and direct it into a pause + lfence loop.
The latter aligns also with what gcc / clang emits (e.g. [1]).
JIT dump after patch:
# bpftool p d x i 1
0: (18) r2 = map[id:1]
2: (b7) r3 = 0
3: (85) call bpf_tail_call#12
4: (b7) r0 = 2
5: (95) exit
With CONFIG_RETPOLINE:
# bpftool p d j i 1
[...]
33: cmp %edx,0x24(%rsi)
36: jbe 0x0000000000000072 |*
38: mov 0x24(%rbp),%eax
3e: cmp $0x20,%eax
41: ja 0x0000000000000072 |
43: add $0x1,%eax
46: mov %eax,0x24(%rbp)
4c: mov 0x90(%rsi,%rdx,8),%rax
54: test %rax,%rax
57: je 0x0000000000000072 |
59: mov 0x28(%rax),%rax
5d: add $0x25,%rax
61: callq 0x000000000000006d |+
66: pause |
68: lfence |
6b: jmp 0x0000000000000066 |
6d: mov %rax,(%rsp) |
71: retq |
72: mov $0x2,%eax
[...]
* relative fall-through jumps in error case
+ retpoline for indirect jump
Without CONFIG_RETPOLINE:
# bpftool p d j i 1
[...]
33: cmp %edx,0x24(%rsi)
36: jbe 0x0000000000000063 |*
38: mov 0x24(%rbp),%eax
3e: cmp $0x20,%eax
41: ja 0x0000000000000063 |
43: add $0x1,%eax
46: mov %eax,0x24(%rbp)
4c: mov 0x90(%rsi,%rdx,8),%rax
54: test %rax,%rax
57: je 0x0000000000000063 |
59: mov 0x28(%rax),%rax
5d: add $0x25,%rax
61: jmpq *%rax |-
63: mov $0x2,%eax
[...]
* relative fall-through jumps in error case
- plain indirect jump as before
[0] https://support.google.com/faqs/answer/7625886
[1] https://github.com/gcc-mirror/gcc/commit/a31e654fa107be968b802786d747e962c2fcdb2b
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/nospec-branch.h | 37 +++++++++++++++++++++++++++++++++++
arch/x86/net/bpf_jit_comp.c | 9 ++++----
2 files changed, 42 insertions(+), 4 deletions(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -177,4 +177,41 @@ static inline void indirect_branch_predi
}
#endif /* __ASSEMBLY__ */
+
+/*
+ * Below is used in the eBPF JIT compiler and emits the byte sequence
+ * for the following assembly:
+ *
+ * With retpolines configured:
+ *
+ * callq do_rop
+ * spec_trap:
+ * pause
+ * lfence
+ * jmp spec_trap
+ * do_rop:
+ * mov %rax,(%rsp)
+ * retq
+ *
+ * Without retpolines configured:
+ *
+ * jmp *%rax
+ */
+#ifdef CONFIG_RETPOLINE
+# define RETPOLINE_RAX_BPF_JIT_SIZE 17
+# define RETPOLINE_RAX_BPF_JIT() \
+ EMIT1_off32(0xE8, 7); /* callq do_rop */ \
+ /* spec_trap: */ \
+ EMIT2(0xF3, 0x90); /* pause */ \
+ EMIT3(0x0F, 0xAE, 0xE8); /* lfence */ \
+ EMIT2(0xEB, 0xF9); /* jmp spec_trap */ \
+ /* do_rop: */ \
+ EMIT4(0x48, 0x89, 0x04, 0x24); /* mov %rax,(%rsp) */ \
+ EMIT1(0xC3); /* retq */
+#else
+# define RETPOLINE_RAX_BPF_JIT_SIZE 2
+# define RETPOLINE_RAX_BPF_JIT() \
+ EMIT2(0xFF, 0xE0); /* jmp *%rax */
+#endif
+
#endif /* _ASM_X86_NOSPEC_BRANCH_H_ */
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -13,6 +13,7 @@
#include <linux/if_vlan.h>
#include <asm/cacheflush.h>
#include <asm/set_memory.h>
+#include <asm/nospec-branch.h>
#include <linux/bpf.h>
int bpf_jit_enable __read_mostly;
@@ -287,7 +288,7 @@ static void emit_bpf_tail_call(u8 **ppro
EMIT2(0x89, 0xD2); /* mov edx, edx */
EMIT3(0x39, 0x56, /* cmp dword ptr [rsi + 16], edx */
offsetof(struct bpf_array, map.max_entries));
-#define OFFSET1 43 /* number of bytes to jump */
+#define OFFSET1 (41 + RETPOLINE_RAX_BPF_JIT_SIZE) /* number of bytes to jump */
EMIT2(X86_JBE, OFFSET1); /* jbe out */
label1 = cnt;
@@ -296,7 +297,7 @@ static void emit_bpf_tail_call(u8 **ppro
*/
EMIT2_off32(0x8B, 0x85, 36); /* mov eax, dword ptr [rbp + 36] */
EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
-#define OFFSET2 32
+#define OFFSET2 (30 + RETPOLINE_RAX_BPF_JIT_SIZE)
EMIT2(X86_JA, OFFSET2); /* ja out */
label2 = cnt;
EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
@@ -310,7 +311,7 @@ static void emit_bpf_tail_call(u8 **ppro
* goto out;
*/
EMIT3(0x48, 0x85, 0xC0); /* test rax,rax */
-#define OFFSET3 10
+#define OFFSET3 (8 + RETPOLINE_RAX_BPF_JIT_SIZE)
EMIT2(X86_JE, OFFSET3); /* je out */
label3 = cnt;
@@ -323,7 +324,7 @@ static void emit_bpf_tail_call(u8 **ppro
* rdi == ctx (1st arg)
* rax == prog->bpf_func + prologue_size
*/
- EMIT2(0xFF, 0xE0); /* jmp rax */
+ RETPOLINE_RAX_BPF_JIT();
/* out: */
BUILD_BUG_ON(cnt - label1 != OFFSET1);
Patches currently in stable-queue which might be from daniel@iogearbox.net are
queue-4.15/bpf-fix-mlock-precharge-on-arraymaps.patch
queue-4.15/bpf-x64-implement-retpoline-for-tail-call.patch
queue-4.15/bpf-arm64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-fix-memory-leak-in-lpm_trie-map_free-callback-function.patch
queue-4.15/bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.15/bpf-add-schedule-points-in-percpu-arrays-management.patch
queue-4.15/bpf-allow-xadd-only-on-aligned-memory.patch
queue-4.15/bpf-fix-rcu-lockdep-warning-for-lpm_trie-map_free-callback.patch
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH stable 4.15 0/8] BPF stable patches
2018-03-08 12:16 [PATCH stable 4.15 0/8] BPF stable patches Daniel Borkmann
` (7 preceding siblings ...)
2018-03-08 12:16 ` [PATCH stable 4.15 8/8] bpf, ppc64: fix out of bounds access in tail call Daniel Borkmann
@ 2018-03-09 22:17 ` Greg KH
8 siblings, 0 replies; 18+ messages in thread
From: Greg KH @ 2018-03-09 22:17 UTC (permalink / raw)
To: Daniel Borkmann; +Cc: ast, stable
On Thu, Mar 08, 2018 at 01:16:41PM +0100, Daniel Borkmann wrote:
> All for 4.15 backported and tested.
>
> Thanks!
All applied, thanks for these.
greg k-h
^ permalink raw reply [flat|nested] 18+ messages in thread
end of thread, other threads:[~2018-03-09 22:17 UTC | newest]
Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-03-08 12:16 [PATCH stable 4.15 0/8] BPF stable patches Daniel Borkmann
2018-03-08 12:16 ` [PATCH stable 4.15 1/8] bpf: fix mlock precharge on arraymaps Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf: fix mlock precharge on arraymaps" has been added to the 4.15-stable tree gregkh
2018-03-08 12:16 ` [PATCH stable 4.15 2/8] bpf: fix memory leak in lpm_trie map_free callback function Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf: fix memory leak in lpm_trie map_free callback function" has been added to the 4.15-stable tree gregkh
2018-03-08 12:16 ` [PATCH stable 4.15 3/8] bpf: fix rcu lockdep warning for lpm_trie map_free callback Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf: fix rcu lockdep warning for lpm_trie map_free callback" has been added to the 4.15-stable tree gregkh
2018-03-08 12:16 ` [PATCH stable 4.15 4/8] bpf, x64: implement retpoline for tail call Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf, x64: implement retpoline for tail call" has been added to the 4.15-stable tree gregkh
2018-03-08 12:16 ` [PATCH stable 4.15 5/8] bpf, arm64: fix out of bounds access in tail call Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf, arm64: fix out of bounds access in tail call" has been added to the 4.15-stable tree gregkh
2018-03-08 12:16 ` [PATCH stable 4.15 6/8] bpf: add schedule points in percpu arrays management Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf: add schedule points in percpu arrays management" has been added to the 4.15-stable tree gregkh
2018-03-08 12:16 ` [PATCH stable 4.15 7/8] bpf: allow xadd only on aligned memory Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf: allow xadd only on aligned memory" has been added to the 4.15-stable tree gregkh
2018-03-08 12:16 ` [PATCH stable 4.15 8/8] bpf, ppc64: fix out of bounds access in tail call Daniel Borkmann
2018-03-09 22:17 ` Patch "bpf, ppc64: fix out of bounds access in tail call" has been added to the 4.15-stable tree gregkh
2018-03-09 22:17 ` [PATCH stable 4.15 0/8] BPF stable patches Greg KH
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