* [PATCH net 0/3] Two BPF fixes for range marking
@ 2017-10-21 0:34 Daniel Borkmann
2017-10-21 0:34 ` [PATCH net 1/3] bpf: fix off by one for range markings with L{T,E} patterns Daniel Borkmann
` (3 more replies)
0 siblings, 4 replies; 8+ messages in thread
From: Daniel Borkmann @ 2017-10-21 0:34 UTC (permalink / raw)
To: davem; +Cc: alexei.starovoitov, john.r.fastabend, netdev, Daniel Borkmann
The set contains two fixes for direct packet access range
markings and test cases for all direct packet access patterns
that the verifier matches on.
They are targeted for net tree, note that once net gets merged
into net-next, there will be a minor merge conflict due to
signature change of the function find_good_pkt_pointers() as
well as data_meta patterns present in net-next tree. You can
just add bool false to the data_meta patterns and I will
follow-up with properly converting the patterns for data_meta
in a similar way.
Thanks a lot!
Daniel Borkmann (3):
bpf: fix off by one for range markings with L{T,E} patterns
bpf: fix pattern matches for direct packet access
bpf: add test cases to bpf selftests to cover all access tests
kernel/bpf/verifier.c | 57 +++-
tools/testing/selftests/bpf/test_verifier.c | 480 ++++++++++++++++++++++++++++
2 files changed, 525 insertions(+), 12 deletions(-)
--
1.9.3
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH net 1/3] bpf: fix off by one for range markings with L{T,E} patterns
2017-10-21 0:34 [PATCH net 0/3] Two BPF fixes for range marking Daniel Borkmann
@ 2017-10-21 0:34 ` Daniel Borkmann
2017-10-21 16:39 ` John Fastabend
2017-10-21 0:34 ` [PATCH net 2/3] bpf: fix pattern matches for direct packet access Daniel Borkmann
` (2 subsequent siblings)
3 siblings, 1 reply; 8+ messages in thread
From: Daniel Borkmann @ 2017-10-21 0:34 UTC (permalink / raw)
To: davem; +Cc: alexei.starovoitov, john.r.fastabend, netdev, Daniel Borkmann
During review I noticed that the current logic for direct packet
access marking in check_cond_jmp_op() has an off by one for the
upper right range border when marking in find_good_pkt_pointers()
with BPF_JLT and BPF_JLE. It's not really harmful given access
up to pkt_end is always safe, but we should nevertheless correct
the range marking before it becomes ABI. If pkt_data' denotes a
pkt_data derived pointer (pkt_data + X), then for pkt_data' < pkt_end
in the true branch as well as for pkt_end <= pkt_data' in the false
branch we mark the range with X although it should really be X - 1
in these cases. For example, X could be pkt_end - pkt_data, then
when testing for pkt_data' < pkt_end the verifier simulation cannot
deduce that a byte load of pkt_data' - 1 would succeed in this
branch.
Fixes: b4e432f1000a ("bpf: enable BPF_J{LT, LE, SLT, SLE} opcodes in verifier")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
---
kernel/bpf/verifier.c | 33 +++++++++++++++++++++------------
1 file changed, 21 insertions(+), 12 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 20f3889..49cb5ad 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2430,12 +2430,15 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
}
static void find_good_pkt_pointers(struct bpf_verifier_state *state,
- struct bpf_reg_state *dst_reg)
+ struct bpf_reg_state *dst_reg,
+ bool range_right_open)
{
struct bpf_reg_state *regs = state->regs, *reg;
+ u16 new_range;
int i;
- if (dst_reg->off < 0)
+ if (dst_reg->off < 0 ||
+ (dst_reg->off == 0 && range_right_open))
/* This doesn't give us any range */
return;
@@ -2446,9 +2449,13 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *state,
*/
return;
- /* LLVM can generate four kind of checks:
+ new_range = dst_reg->off;
+ if (range_right_open)
+ new_range--;
+
+ /* Examples for register markings:
*
- * Type 1/2:
+ * pkt_data in dst register:
*
* r2 = r3;
* r2 += 8;
@@ -2465,7 +2472,7 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *state,
* r2=pkt(id=n,off=8,r=0)
* r3=pkt(id=n,off=0,r=0)
*
- * Type 3/4:
+ * pkt_data in src register:
*
* r2 = r3;
* r2 += 8;
@@ -2483,7 +2490,9 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *state,
* r3=pkt(id=n,off=0,r=0)
*
* Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8)
- * so that range of bytes [r3, r3 + 8) is safe to access.
+ * or r3=pkt(id=n,off=0,r=8-1), so that range of bytes [r3, r3 + 8)
+ * and [r3, r3 + 8-1) respectively is safe to access depending on
+ * the check.
*/
/* If our ids match, then we must have the same max_value. And we
@@ -2494,14 +2503,14 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *state,
for (i = 0; i < MAX_BPF_REG; i++)
if (regs[i].type == PTR_TO_PACKET && regs[i].id == dst_reg->id)
/* keep the maximum range already checked */
- regs[i].range = max_t(u16, regs[i].range, dst_reg->off);
+ regs[i].range = max(regs[i].range, new_range);
for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) {
if (state->stack_slot_type[i] != STACK_SPILL)
continue;
reg = &state->spilled_regs[i / BPF_REG_SIZE];
if (reg->type == PTR_TO_PACKET && reg->id == dst_reg->id)
- reg->range = max_t(u16, reg->range, dst_reg->off);
+ reg->range = max(reg->range, new_range);
}
}
@@ -2865,19 +2874,19 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
} else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGT &&
dst_reg->type == PTR_TO_PACKET &&
regs[insn->src_reg].type == PTR_TO_PACKET_END) {
- find_good_pkt_pointers(this_branch, dst_reg);
+ find_good_pkt_pointers(this_branch, dst_reg, false);
} else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JLT &&
dst_reg->type == PTR_TO_PACKET &&
regs[insn->src_reg].type == PTR_TO_PACKET_END) {
- find_good_pkt_pointers(other_branch, dst_reg);
+ find_good_pkt_pointers(other_branch, dst_reg, true);
} else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGE &&
dst_reg->type == PTR_TO_PACKET_END &&
regs[insn->src_reg].type == PTR_TO_PACKET) {
- find_good_pkt_pointers(other_branch, ®s[insn->src_reg]);
+ find_good_pkt_pointers(other_branch, ®s[insn->src_reg], false);
} else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JLE &&
dst_reg->type == PTR_TO_PACKET_END &&
regs[insn->src_reg].type == PTR_TO_PACKET) {
- find_good_pkt_pointers(this_branch, ®s[insn->src_reg]);
+ find_good_pkt_pointers(this_branch, ®s[insn->src_reg], true);
} else if (is_pointer_value(env, insn->dst_reg)) {
verbose("R%d pointer comparison prohibited\n", insn->dst_reg);
return -EACCES;
--
1.9.3
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH net 2/3] bpf: fix pattern matches for direct packet access
2017-10-21 0:34 [PATCH net 0/3] Two BPF fixes for range marking Daniel Borkmann
2017-10-21 0:34 ` [PATCH net 1/3] bpf: fix off by one for range markings with L{T,E} patterns Daniel Borkmann
@ 2017-10-21 0:34 ` Daniel Borkmann
2017-10-21 16:39 ` John Fastabend
2017-10-21 0:34 ` [PATCH net 3/3] bpf: add test cases to bpf selftests to cover all access tests Daniel Borkmann
2017-10-22 0:13 ` [PATCH net 0/3] Two BPF fixes for range marking David Miller
3 siblings, 1 reply; 8+ messages in thread
From: Daniel Borkmann @ 2017-10-21 0:34 UTC (permalink / raw)
To: davem; +Cc: alexei.starovoitov, john.r.fastabend, netdev, Daniel Borkmann
Alexander had a test program with direct packet access, where
the access test was in the form of data + X > data_end. In an
unrelated change to the program LLVM decided to swap the branches
and emitted code for the test in form of data + X <= data_end.
We hadn't seen these being generated previously, thus verifier
would reject the program. Therefore, fix up the verifier to
detect all test cases, so we don't run into such issues in the
future.
Fixes: b4e432f1000a ("bpf: enable BPF_J{LT, LE, SLT, SLE} opcodes in verifier")
Reported-by: Alexander Alemayhu <alexander@alemayhu.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
---
kernel/bpf/verifier.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 49cb5ad..c48ca2a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2874,18 +2874,42 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
} else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGT &&
dst_reg->type == PTR_TO_PACKET &&
regs[insn->src_reg].type == PTR_TO_PACKET_END) {
+ /* pkt_data' > pkt_end */
find_good_pkt_pointers(this_branch, dst_reg, false);
+ } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGT &&
+ dst_reg->type == PTR_TO_PACKET_END &&
+ regs[insn->src_reg].type == PTR_TO_PACKET) {
+ /* pkt_end > pkt_data' */
+ find_good_pkt_pointers(other_branch, ®s[insn->src_reg], true);
} else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JLT &&
dst_reg->type == PTR_TO_PACKET &&
regs[insn->src_reg].type == PTR_TO_PACKET_END) {
+ /* pkt_data' < pkt_end */
find_good_pkt_pointers(other_branch, dst_reg, true);
+ } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JLT &&
+ dst_reg->type == PTR_TO_PACKET_END &&
+ regs[insn->src_reg].type == PTR_TO_PACKET) {
+ /* pkt_end < pkt_data' */
+ find_good_pkt_pointers(this_branch, ®s[insn->src_reg], false);
+ } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGE &&
+ dst_reg->type == PTR_TO_PACKET &&
+ regs[insn->src_reg].type == PTR_TO_PACKET_END) {
+ /* pkt_data' >= pkt_end */
+ find_good_pkt_pointers(this_branch, dst_reg, true);
} else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGE &&
dst_reg->type == PTR_TO_PACKET_END &&
regs[insn->src_reg].type == PTR_TO_PACKET) {
+ /* pkt_end >= pkt_data' */
find_good_pkt_pointers(other_branch, ®s[insn->src_reg], false);
} else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JLE &&
+ dst_reg->type == PTR_TO_PACKET &&
+ regs[insn->src_reg].type == PTR_TO_PACKET_END) {
+ /* pkt_data' <= pkt_end */
+ find_good_pkt_pointers(other_branch, dst_reg, false);
+ } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JLE &&
dst_reg->type == PTR_TO_PACKET_END &&
regs[insn->src_reg].type == PTR_TO_PACKET) {
+ /* pkt_end <= pkt_data' */
find_good_pkt_pointers(this_branch, ®s[insn->src_reg], true);
} else if (is_pointer_value(env, insn->dst_reg)) {
verbose("R%d pointer comparison prohibited\n", insn->dst_reg);
--
1.9.3
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH net 3/3] bpf: add test cases to bpf selftests to cover all access tests
2017-10-21 0:34 [PATCH net 0/3] Two BPF fixes for range marking Daniel Borkmann
2017-10-21 0:34 ` [PATCH net 1/3] bpf: fix off by one for range markings with L{T,E} patterns Daniel Borkmann
2017-10-21 0:34 ` [PATCH net 2/3] bpf: fix pattern matches for direct packet access Daniel Borkmann
@ 2017-10-21 0:34 ` Daniel Borkmann
2017-10-21 16:40 ` John Fastabend
2017-10-22 0:13 ` [PATCH net 0/3] Two BPF fixes for range marking David Miller
3 siblings, 1 reply; 8+ messages in thread
From: Daniel Borkmann @ 2017-10-21 0:34 UTC (permalink / raw)
To: davem; +Cc: alexei.starovoitov, john.r.fastabend, netdev, Daniel Borkmann
Lets add test cases to cover really all possible direct packet
access tests for good/bad access cases so we keep tracking them.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
---
tools/testing/selftests/bpf/test_verifier.c | 480 ++++++++++++++++++++++++++++
1 file changed, 480 insertions(+)
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 3c7d3a4..2911868 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -6659,6 +6659,486 @@ struct test_val {
.result = REJECT,
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
+ {
+ "XDP pkt read, pkt_end mangling, bad access 1",
+ .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_ALU64_IMM(BPF_ADD, BPF_REG_3, 8),
+ BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_end mangling, bad access 2",
+ .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_ALU64_IMM(BPF_SUB, BPF_REG_3, 8),
+ BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_data' > pkt_end, good access",
+ .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_JGT, BPF_REG_1, BPF_REG_3, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_data' > pkt_end, bad access 1",
+ .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_JGT, BPF_REG_1, BPF_REG_3, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -4),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
+ },
+ {
+ "XDP pkt read, pkt_data' > pkt_end, bad access 2",
+ .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_JGT, BPF_REG_1, BPF_REG_3, 0),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_end > pkt_data', good access",
+ .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_JGT, BPF_REG_3, BPF_REG_1, 1),
+ BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
+ },
+ {
+ "XDP pkt read, pkt_end > pkt_data', bad access 1",
+ .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_JGT, BPF_REG_3, BPF_REG_1, 1),
+ BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_end > pkt_data', bad access 2",
+ .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_JGT, BPF_REG_3, BPF_REG_1, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_data' < pkt_end, good access",
+ .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, 1),
+ BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
+ },
+ {
+ "XDP pkt read, pkt_data' < pkt_end, bad access 1",
+ .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, 1),
+ BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_data' < pkt_end, bad access 2",
+ .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, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_end < pkt_data', good access",
+ .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_3, BPF_REG_1, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_end < pkt_data', bad access 1",
+ .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_3, BPF_REG_1, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -4),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
+ },
+ {
+ "XDP pkt read, pkt_end < pkt_data', bad access 2",
+ .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_3, BPF_REG_1, 0),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_data' >= pkt_end, good access",
+ .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_JGE, BPF_REG_1, BPF_REG_3, 1),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
+ },
+ {
+ "XDP pkt read, pkt_data' >= pkt_end, bad access 1",
+ .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_JGE, BPF_REG_1, BPF_REG_3, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_data' >= pkt_end, bad access 2",
+ .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_JGE, BPF_REG_1, BPF_REG_3, 0),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
+ },
+ {
+ "XDP pkt read, pkt_end >= pkt_data', good access",
+ .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_JGE, BPF_REG_3, BPF_REG_1, 1),
+ BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_end >= pkt_data', bad access 1",
+ .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_JGE, BPF_REG_3, BPF_REG_1, 1),
+ BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -4),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
+ },
+ {
+ "XDP pkt read, pkt_end >= pkt_data', bad access 2",
+ .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_JGE, BPF_REG_3, BPF_REG_1, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_data' <= pkt_end, good access",
+ .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_JLE, BPF_REG_1, BPF_REG_3, 1),
+ BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_data' <= pkt_end, bad access 1",
+ .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_JLE, BPF_REG_1, BPF_REG_3, 1),
+ BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -4),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
+ },
+ {
+ "XDP pkt read, pkt_data' <= pkt_end, bad access 2",
+ .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_JLE, BPF_REG_1, BPF_REG_3, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_end <= pkt_data', good access",
+ .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_JLE, BPF_REG_3, BPF_REG_1, 1),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
+ },
+ {
+ "XDP pkt read, pkt_end <= pkt_data', bad access 1",
+ .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_JLE, BPF_REG_3, BPF_REG_1, 1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ },
+ {
+ "XDP pkt read, pkt_end <= pkt_data', bad access 2",
+ .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_JLE, BPF_REG_3, BPF_REG_1, 0),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 offset is outside of the packet",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
+ },
};
static int probe_filter_length(const struct bpf_insn *fp)
--
1.9.3
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH net 1/3] bpf: fix off by one for range markings with L{T,E} patterns
2017-10-21 0:34 ` [PATCH net 1/3] bpf: fix off by one for range markings with L{T,E} patterns Daniel Borkmann
@ 2017-10-21 16:39 ` John Fastabend
0 siblings, 0 replies; 8+ messages in thread
From: John Fastabend @ 2017-10-21 16:39 UTC (permalink / raw)
To: Daniel Borkmann, davem; +Cc: alexei.starovoitov, john.r.fastabend, netdev
On 10/20/2017 05:34 PM, Daniel Borkmann wrote:
> During review I noticed that the current logic for direct packet
> access marking in check_cond_jmp_op() has an off by one for the
> upper right range border when marking in find_good_pkt_pointers()
> with BPF_JLT and BPF_JLE. It's not really harmful given access
> up to pkt_end is always safe, but we should nevertheless correct
> the range marking before it becomes ABI. If pkt_data' denotes a
> pkt_data derived pointer (pkt_data + X), then for pkt_data' < pkt_end
> in the true branch as well as for pkt_end <= pkt_data' in the false
> branch we mark the range with X although it should really be X - 1
> in these cases. For example, X could be pkt_end - pkt_data, then
> when testing for pkt_data' < pkt_end the verifier simulation cannot
> deduce that a byte load of pkt_data' - 1 would succeed in this
> branch.
>
> Fixes: b4e432f1000a ("bpf: enable BPF_J{LT, LE, SLT, SLE} opcodes in verifier")
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
> Acked-by: Alexei Starovoitov <ast@kernel.org>
> ---
Acked-by: John Fastabend <john.fastabend@gmail.com>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH net 2/3] bpf: fix pattern matches for direct packet access
2017-10-21 0:34 ` [PATCH net 2/3] bpf: fix pattern matches for direct packet access Daniel Borkmann
@ 2017-10-21 16:39 ` John Fastabend
0 siblings, 0 replies; 8+ messages in thread
From: John Fastabend @ 2017-10-21 16:39 UTC (permalink / raw)
To: Daniel Borkmann, davem; +Cc: alexei.starovoitov, john.r.fastabend, netdev
On 10/20/2017 05:34 PM, Daniel Borkmann wrote:
> Alexander had a test program with direct packet access, where
> the access test was in the form of data + X > data_end. In an
> unrelated change to the program LLVM decided to swap the branches
> and emitted code for the test in form of data + X <= data_end.
> We hadn't seen these being generated previously, thus verifier
> would reject the program. Therefore, fix up the verifier to
> detect all test cases, so we don't run into such issues in the
> future.
>
> Fixes: b4e432f1000a ("bpf: enable BPF_J{LT, LE, SLT, SLE} opcodes in verifier")
> Reported-by: Alexander Alemayhu <alexander@alemayhu.com>
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
> Acked-by: Alexei Starovoitov <ast@kernel.org>
> ---
Acked-by: John Fastabend <john.fastabend@gmail.com>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH net 3/3] bpf: add test cases to bpf selftests to cover all access tests
2017-10-21 0:34 ` [PATCH net 3/3] bpf: add test cases to bpf selftests to cover all access tests Daniel Borkmann
@ 2017-10-21 16:40 ` John Fastabend
0 siblings, 0 replies; 8+ messages in thread
From: John Fastabend @ 2017-10-21 16:40 UTC (permalink / raw)
To: Daniel Borkmann, davem; +Cc: alexei.starovoitov, john.r.fastabend, netdev
On 10/20/2017 05:34 PM, Daniel Borkmann wrote:
> Lets add test cases to cover really all possible direct packet
> access tests for good/bad access cases so we keep tracking them.
>
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
> Acked-by: Alexei Starovoitov <ast@kernel.org>
> ---
Acked-by: John Fastabend <john.fastabend@gmail.com>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH net 0/3] Two BPF fixes for range marking
2017-10-21 0:34 [PATCH net 0/3] Two BPF fixes for range marking Daniel Borkmann
` (2 preceding siblings ...)
2017-10-21 0:34 ` [PATCH net 3/3] bpf: add test cases to bpf selftests to cover all access tests Daniel Borkmann
@ 2017-10-22 0:13 ` David Miller
3 siblings, 0 replies; 8+ messages in thread
From: David Miller @ 2017-10-22 0:13 UTC (permalink / raw)
To: daniel; +Cc: alexei.starovoitov, john.r.fastabend, netdev
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Sat, 21 Oct 2017 02:34:20 +0200
> The set contains two fixes for direct packet access range
> markings and test cases for all direct packet access patterns
> that the verifier matches on.
>
> They are targeted for net tree, note that once net gets merged
> into net-next, there will be a minor merge conflict due to
> signature change of the function find_good_pkt_pointers() as
> well as data_meta patterns present in net-next tree. You can
> just add bool false to the data_meta patterns and I will
> follow-up with properly converting the patterns for data_meta
> in a similar way.
Series applied and thanks for the merge info.
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2017-10-22 0:13 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-10-21 0:34 [PATCH net 0/3] Two BPF fixes for range marking Daniel Borkmann
2017-10-21 0:34 ` [PATCH net 1/3] bpf: fix off by one for range markings with L{T,E} patterns Daniel Borkmann
2017-10-21 16:39 ` John Fastabend
2017-10-21 0:34 ` [PATCH net 2/3] bpf: fix pattern matches for direct packet access Daniel Borkmann
2017-10-21 16:39 ` John Fastabend
2017-10-21 0:34 ` [PATCH net 3/3] bpf: add test cases to bpf selftests to cover all access tests Daniel Borkmann
2017-10-21 16:40 ` John Fastabend
2017-10-22 0:13 ` [PATCH net 0/3] Two BPF fixes for range marking David Miller
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