* [PATCH bpf-next v3 0/6] bpf: add __user tagging support in vmlinux BTF
@ 2022-01-27 15:45 Yonghong Song
2022-01-27 15:46 ` [PATCH bpf-next v3 1/6] compiler_types: define __user as __attribute__((btf_type_tag("user"))) Yonghong Song
` (6 more replies)
0 siblings, 7 replies; 8+ messages in thread
From: Yonghong Song @ 2022-01-27 15:45 UTC (permalink / raw)
To: Alexei Starovoitov, Andrii Nakryiko, bpf, Daniel Borkmann,
Linus Torvalds
Cc: Arnaldo Carvalho de Melo, Jose E . Marchesi, kernel-team,
Masami Hiramatsu
The __user attribute is currently mainly used by sparse for type checking.
The attribute indicates whether a memory access is in user memory address
space or not. Such information is important during tracing kernel
internal functions or data structures as accessing user memory often
has different mechanisms compared to accessing kernel memory. For example,
the perf-probe needs explicit command line specification to indicate a
particular argument or string in user-space memory ([1], [2], [3]).
Currently, vmlinux BTF is available in kernel with many distributions.
If __user attribute information is available in vmlinux BTF, the explicit
user memory access information from users will not be necessary as
the kernel can figure it out by itself with vmlinux BTF.
Besides the above possible use for perf/probe, another use case is
for bpf verifier. Currently, for bpf BPF_PROG_TYPE_TRACING type of bpf
programs, users can write direct code like
p->m1->m2
and "p" could be a function parameter. Without __user information in BTF,
the verifier will assume p->m1 accessing kernel memory and will generate
normal loads. Let us say "p" actually tagged with __user in the source
code. In such cases, p->m1 is actually accessing user memory and direct
load is not right and may produce incorrect result. For such cases,
bpf_probe_read_user() will be the correct way to read p->m1.
To support encoding __user information in BTF, a new attribute
__attribute__((btf_type_tag("<arbitrary_string>")))
is implemented in clang ([4]). For example, if we have
#define __user __attribute__((btf_type_tag("user")))
during kernel compilation, the attribute "user" information will
be preserved in dwarf. After pahole converting dwarf to BTF, __user
information will be available in vmlinux BTF and such information
can be used by bpf verifier, perf/probe or other use cases.
Currently btf_type_tag is only supported in clang (>= clang14) and
pahole (>= 1.23). gcc support is also proposed and under development ([5]).
In the rest of patch set, Patch 1 added support of __user btf_type_tag
during compilation. Patch 2 added bpf verifier support to utilize __user
tag information to reject bpf programs not using proper helper to access
user memories. Patches 3-5 are for bpf selftests which demonstrate verifier
can reject direct user memory accesses.
[1] http://lkml.kernel.org/r/155789874562.26965.10836126971405890891.stgit@devnote2
[2] http://lkml.kernel.org/r/155789872187.26965.4468456816590888687.stgit@devnote2
[3] http://lkml.kernel.org/r/155789871009.26965.14167558859557329331.stgit@devnote2
[4] https://reviews.llvm.org/D111199
[5] https://lore.kernel.org/bpf/0cbeb2fb-1a18-f690-e360-24b1c90c2a91@fb.com/
Changelog:
v2 -> v3:
- remove FLAG_DONTCARE enumerator and just use 0 as dontcare flag.
- explain how btf type_tag is encoded in btf type chain.
v1 -> v2:
- use MEM_USER flag for PTR_TO_BTF_ID reg type instead of a separate
field to encode __user tag.
- add a test with kernel function __sys_getsockname which has __user tagged
argument.
Yonghong Song (6):
compiler_types: define __user as __attribute__((btf_type_tag("user")))
bpf: reject program if a __user tagged memory accessed in kernel way
selftests/bpf: rename btf_decl_tag.c to test_btf_decl_tag.c
selftests/bpf: add a selftest with __user tag
selftests/bpf: specify pahole version requirement for btf_tag test
docs/bpf: clarify how btf_type_tag gets encoded in the type chain
Documentation/bpf/btf.rst | 13 +++
include/linux/bpf.h | 9 +-
include/linux/btf.h | 5 +
include/linux/compiler_types.h | 3 +
kernel/bpf/btf.c | 34 ++++--
kernel/bpf/verifier.c | 35 ++++--
lib/Kconfig.debug | 8 ++
net/bpf/bpf_dummy_struct_ops.c | 6 +-
net/ipv4/bpf_tcp_ca.c | 6 +-
tools/testing/selftests/bpf/README.rst | 2 +
.../selftests/bpf/bpf_testmod/bpf_testmod.c | 18 ++++
.../selftests/bpf/prog_tests/btf_tag.c | 101 +++++++++++++++++-
.../selftests/bpf/progs/btf_type_tag_user.c | 40 +++++++
.../{btf_decl_tag.c => test_btf_decl_tag.c} | 0
14 files changed, 252 insertions(+), 28 deletions(-)
create mode 100644 tools/testing/selftests/bpf/progs/btf_type_tag_user.c
rename tools/testing/selftests/bpf/progs/{btf_decl_tag.c => test_btf_decl_tag.c} (100%)
--
2.30.2
^ permalink raw reply [flat|nested] 8+ messages in thread* [PATCH bpf-next v3 1/6] compiler_types: define __user as __attribute__((btf_type_tag("user"))) 2022-01-27 15:45 [PATCH bpf-next v3 0/6] bpf: add __user tagging support in vmlinux BTF Yonghong Song @ 2022-01-27 15:46 ` Yonghong Song 2022-01-27 15:46 ` [PATCH bpf-next v3 2/6] bpf: reject program if a __user tagged memory accessed in kernel way Yonghong Song ` (5 subsequent siblings) 6 siblings, 0 replies; 8+ messages in thread From: Yonghong Song @ 2022-01-27 15:46 UTC (permalink / raw) To: Alexei Starovoitov, Andrii Nakryiko, bpf, Daniel Borkmann, Linus Torvalds Cc: Arnaldo Carvalho de Melo, Jose E . Marchesi, kernel-team, Masami Hiramatsu The __user attribute is currently mainly used by sparse for type checking. The attribute indicates whether a memory access is in user memory address space or not. Such information is important during tracing kernel internal functions or data structures as accessing user memory often has different mechanisms compared to accessing kernel memory. For example, the perf-probe needs explicit command line specification to indicate a particular argument or string in user-space memory ([1], [2], [3]). Currently, vmlinux BTF is available in kernel with many distributions. If __user attribute information is available in vmlinux BTF, the explicit user memory access information from users will not be necessary as the kernel can figure it out by itself with vmlinux BTF. Besides the above possible use for perf/probe, another use case is for bpf verifier. Currently, for bpf BPF_PROG_TYPE_TRACING type of bpf programs, users can write direct code like p->m1->m2 and "p" could be a function parameter. Without __user information in BTF, the verifier will assume p->m1 accessing kernel memory and will generate normal loads. Let us say "p" actually tagged with __user in the source code. In such cases, p->m1 is actually accessing user memory and direct load is not right and may produce incorrect result. For such cases, bpf_probe_read_user() will be the correct way to read p->m1. To support encoding __user information in BTF, a new attribute __attribute__((btf_type_tag("<arbitrary_string>"))) is implemented in clang ([4]). For example, if we have #define __user __attribute__((btf_type_tag("user"))) during kernel compilation, the attribute "user" information will be preserved in dwarf. After pahole converting dwarf to BTF, __user information will be available in vmlinux BTF. The following is an example with latest upstream clang (clang14) and pahole 1.23: [$ ~] cat test.c #define __user __attribute__((btf_type_tag("user"))) int foo(int __user *arg) { return *arg; } [$ ~] clang -O2 -g -c test.c [$ ~] pahole -JV test.o ... [1] INT int size=4 nr_bits=32 encoding=SIGNED [2] TYPE_TAG user type_id=1 [3] PTR (anon) type_id=2 [4] FUNC_PROTO (anon) return=1 args=(3 arg) [5] FUNC foo type_id=4 [$ ~] You can see for the function argument "int __user *arg", its type is described as PTR -> TYPE_TAG(user) -> INT The kernel can use this information for bpf verification or other use cases. Current btf_type_tag is only supported in clang (>= clang14) and pahole (>= 1.23). gcc support is also proposed and under development ([5]). [1] http://lkml.kernel.org/r/155789874562.26965.10836126971405890891.stgit@devnote2 [2] http://lkml.kernel.org/r/155789872187.26965.4468456816590888687.stgit@devnote2 [3] http://lkml.kernel.org/r/155789871009.26965.14167558859557329331.stgit@devnote2 [4] https://reviews.llvm.org/D111199 [5] https://lore.kernel.org/bpf/0cbeb2fb-1a18-f690-e360-24b1c90c2a91@fb.com/ Signed-off-by: Yonghong Song <yhs@fb.com> --- include/linux/compiler_types.h | 3 +++ lib/Kconfig.debug | 8 ++++++++ 2 files changed, 11 insertions(+) diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 3c1795fdb568..3f31ff400432 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -31,6 +31,9 @@ static inline void __chk_io_ptr(const volatile void __iomem *ptr) { } # define __kernel # ifdef STRUCTLEAK_PLUGIN # define __user __attribute__((user)) +# elif defined(CONFIG_DEBUG_INFO_BTF) && defined(CONFIG_PAHOLE_HAS_BTF_TAG) && \ + __has_attribute(btf_type_tag) +# define __user __attribute__((btf_type_tag("user"))) # else # define __user # endif diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 14b89aa37c5c..6159859769fa 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -325,6 +325,14 @@ config DEBUG_INFO_BTF config PAHOLE_HAS_SPLIT_BTF def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "119") +config PAHOLE_HAS_BTF_TAG + def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "123") + depends on CC_IS_CLANG + help + Decide whether pahole emits btf_tag attributes (btf_type_tag and + btf_decl_tag) or not. Currently only clang compiler implements + these attributes, so make the config depend on CC_IS_CLANG. + config DEBUG_INFO_BTF_MODULES def_bool y depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF -- 2.30.2 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH bpf-next v3 2/6] bpf: reject program if a __user tagged memory accessed in kernel way 2022-01-27 15:45 [PATCH bpf-next v3 0/6] bpf: add __user tagging support in vmlinux BTF Yonghong Song 2022-01-27 15:46 ` [PATCH bpf-next v3 1/6] compiler_types: define __user as __attribute__((btf_type_tag("user"))) Yonghong Song @ 2022-01-27 15:46 ` Yonghong Song 2022-01-27 15:46 ` [PATCH bpf-next v3 3/6] selftests/bpf: rename btf_decl_tag.c to test_btf_decl_tag.c Yonghong Song ` (4 subsequent siblings) 6 siblings, 0 replies; 8+ messages in thread From: Yonghong Song @ 2022-01-27 15:46 UTC (permalink / raw) To: Alexei Starovoitov, Andrii Nakryiko, bpf, Daniel Borkmann, Linus Torvalds Cc: Arnaldo Carvalho de Melo, Jose E . Marchesi, kernel-team, Masami Hiramatsu BPF verifier supports direct memory access for BPF_PROG_TYPE_TRACING type of bpf programs, e.g., a->b. If "a" is a pointer pointing to kernel memory, bpf verifier will allow user to write code in C like a->b and the verifier will translate it to a kernel load properly. If "a" is a pointer to user memory, it is expected that bpf developer should be bpf_probe_read_user() helper to get the value a->b. Without utilizing BTF __user tagging information, current verifier will assume that a->b is a kernel memory access and this may generate incorrect result. Now BTF contains __user information, it can check whether the pointer points to a user memory or not. If it is, the verifier can reject the program and force users to use bpf_probe_read_user() helper explicitly. In the future, we can easily extend btf_add_space for other address space tagging, for example, rcu/percpu etc. Signed-off-by: Yonghong Song <yhs@fb.com> --- include/linux/bpf.h | 9 ++++++--- include/linux/btf.h | 5 +++++ kernel/bpf/btf.c | 34 +++++++++++++++++++++++++++------ kernel/bpf/verifier.c | 35 +++++++++++++++++++++++----------- net/bpf/bpf_dummy_struct_ops.c | 6 ++++-- net/ipv4/bpf_tcp_ca.c | 6 ++++-- 6 files changed, 71 insertions(+), 24 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 2344f793c4dc..d518bcbc42bc 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -332,7 +332,10 @@ enum bpf_type_flag { */ MEM_ALLOC = BIT(2 + BPF_BASE_TYPE_BITS), - __BPF_TYPE_LAST_FLAG = MEM_ALLOC, + /* MEM is in user address space. */ + MEM_USER = BIT(3 + BPF_BASE_TYPE_BITS), + + __BPF_TYPE_LAST_FLAG = MEM_USER, }; /* Max number of base types. */ @@ -588,7 +591,7 @@ struct bpf_verifier_ops { const struct btf *btf, const struct btf_type *t, int off, int size, enum bpf_access_type atype, - u32 *next_btf_id); + u32 *next_btf_id, enum bpf_type_flag *flag); }; struct bpf_prog_offload_ops { @@ -1767,7 +1770,7 @@ static inline bool bpf_tracing_btf_ctx_access(int off, int size, int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, int off, int size, enum bpf_access_type atype, - u32 *next_btf_id); + u32 *next_btf_id, enum bpf_type_flag *flag); bool btf_struct_ids_match(struct bpf_verifier_log *log, const struct btf *btf, u32 id, int off, const struct btf *need_btf, u32 need_type_id); diff --git a/include/linux/btf.h b/include/linux/btf.h index b12cfe3b12bb..f6c43dd513fa 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -238,6 +238,11 @@ static inline bool btf_type_is_var(const struct btf_type *t) return BTF_INFO_KIND(t->info) == BTF_KIND_VAR; } +static inline bool btf_type_is_type_tag(const struct btf_type *t) +{ + return BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG; +} + /* union is only a special case of struct: * all its offsetof(member) == 0 */ diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index b2a248956100..b983cee8d196 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -4886,6 +4886,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, const char *tname = prog->aux->attach_func_name; struct bpf_verifier_log *log = info->log; const struct btf_param *args; + const char *tag_value; u32 nr_args, arg; int i, ret; @@ -5038,6 +5039,13 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, info->btf = btf; info->btf_id = t->type; t = btf_type_by_id(btf, t->type); + + if (btf_type_is_type_tag(t)) { + tag_value = __btf_name_by_offset(btf, t->name_off); + if (strcmp(tag_value, "user") == 0) + info->reg_type |= MEM_USER; + } + /* skip modifiers */ while (btf_type_is_modifier(t)) { info->btf_id = t->type; @@ -5064,12 +5072,12 @@ enum bpf_struct_walk_result { static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, int off, int size, - u32 *next_btf_id) + u32 *next_btf_id, enum bpf_type_flag *flag) { u32 i, moff, mtrue_end, msize = 0, total_nelems = 0; const struct btf_type *mtype, *elem_type = NULL; const struct btf_member *member; - const char *tname, *mname; + const char *tname, *mname, *tag_value; u32 vlen, elem_id, mid; again: @@ -5253,7 +5261,8 @@ static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf, } if (btf_type_is_ptr(mtype)) { - const struct btf_type *stype; + const struct btf_type *stype, *t; + enum bpf_type_flag tmp_flag = 0; u32 id; if (msize != size || off != moff) { @@ -5262,9 +5271,19 @@ static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf, mname, moff, tname, off, size); return -EACCES; } + + /* check __user tag */ + t = btf_type_by_id(btf, mtype->type); + if (btf_type_is_type_tag(t)) { + tag_value = __btf_name_by_offset(btf, t->name_off); + if (strcmp(tag_value, "user") == 0) + tmp_flag = MEM_USER; + } + stype = btf_type_skip_modifiers(btf, mtype->type, &id); if (btf_type_is_struct(stype)) { *next_btf_id = id; + *flag = tmp_flag; return WALK_PTR; } } @@ -5291,13 +5310,14 @@ static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf, int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, int off, int size, enum bpf_access_type atype __maybe_unused, - u32 *next_btf_id) + u32 *next_btf_id, enum bpf_type_flag *flag) { + enum bpf_type_flag tmp_flag = 0; int err; u32 id; do { - err = btf_struct_walk(log, btf, t, off, size, &id); + err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag); switch (err) { case WALK_PTR: @@ -5305,6 +5325,7 @@ int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, * we're done. */ *next_btf_id = id; + *flag = tmp_flag; return PTR_TO_BTF_ID; case WALK_SCALAR: return SCALAR_VALUE; @@ -5349,6 +5370,7 @@ bool btf_struct_ids_match(struct bpf_verifier_log *log, const struct btf *need_btf, u32 need_type_id) { const struct btf_type *type; + enum bpf_type_flag flag; int err; /* Are we already done? */ @@ -5359,7 +5381,7 @@ bool btf_struct_ids_match(struct bpf_verifier_log *log, type = btf_type_by_id(btf, id); if (!type) return false; - err = btf_struct_walk(log, btf, type, off, 1, &id); + err = btf_struct_walk(log, btf, type, off, 1, &id, &flag); if (err != WALK_STRUCT) return false; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index dcf065ec2774..1ae41d0cf96c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -536,7 +536,7 @@ static bool is_cmpxchg_insn(const struct bpf_insn *insn) static const char *reg_type_str(struct bpf_verifier_env *env, enum bpf_reg_type type) { - char postfix[16] = {0}, prefix[16] = {0}; + char postfix[16] = {0}, prefix[32] = {0}; static const char * const str[] = { [NOT_INIT] = "?", [SCALAR_VALUE] = "inv", @@ -570,9 +570,11 @@ static const char *reg_type_str(struct bpf_verifier_env *env, } if (type & MEM_RDONLY) - strncpy(prefix, "rdonly_", 16); + strncpy(prefix, "rdonly_", 32); if (type & MEM_ALLOC) - strncpy(prefix, "alloc_", 16); + strncpy(prefix, "alloc_", 32); + if (type & MEM_USER) + strncpy(prefix, "user_", 32); snprintf(env->type_str_buf, TYPE_STR_BUF_LEN, "%s%s%s", prefix, str[base_type(type)], postfix); @@ -1547,14 +1549,15 @@ static void mark_reg_not_init(struct bpf_verifier_env *env, static void mark_btf_ld_reg(struct bpf_verifier_env *env, struct bpf_reg_state *regs, u32 regno, enum bpf_reg_type reg_type, - struct btf *btf, u32 btf_id) + struct btf *btf, u32 btf_id, + enum bpf_type_flag flag) { if (reg_type == SCALAR_VALUE) { mark_reg_unknown(env, regs, regno); return; } mark_reg_known_zero(env, regs, regno); - regs[regno].type = PTR_TO_BTF_ID; + regs[regno].type = PTR_TO_BTF_ID | flag; regs[regno].btf = btf; regs[regno].btf_id = btf_id; } @@ -4152,6 +4155,7 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env, struct bpf_reg_state *reg = regs + regno; const struct btf_type *t = btf_type_by_id(reg->btf, reg->btf_id); const char *tname = btf_name_by_offset(reg->btf, t->name_off); + enum bpf_type_flag flag = 0; u32 btf_id; int ret; @@ -4171,9 +4175,16 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env, return -EACCES; } + if (reg->type & MEM_USER) { + verbose(env, + "R%d is ptr_%s access user memory: off=%d\n", + regno, tname, off); + return -EACCES; + } + if (env->ops->btf_struct_access) { ret = env->ops->btf_struct_access(&env->log, reg->btf, t, - off, size, atype, &btf_id); + off, size, atype, &btf_id, &flag); } else { if (atype != BPF_READ) { verbose(env, "only read is supported\n"); @@ -4181,14 +4192,14 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env, } ret = btf_struct_access(&env->log, reg->btf, t, off, size, - atype, &btf_id); + atype, &btf_id, &flag); } if (ret < 0) return ret; if (atype == BPF_READ && value_regno >= 0) - mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id); + mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id, flag); return 0; } @@ -4201,6 +4212,7 @@ static int check_ptr_to_map_access(struct bpf_verifier_env *env, { struct bpf_reg_state *reg = regs + regno; struct bpf_map *map = reg->map_ptr; + enum bpf_type_flag flag = 0; const struct btf_type *t; const char *tname; u32 btf_id; @@ -4238,12 +4250,12 @@ static int check_ptr_to_map_access(struct bpf_verifier_env *env, return -EACCES; } - ret = btf_struct_access(&env->log, btf_vmlinux, t, off, size, atype, &btf_id); + ret = btf_struct_access(&env->log, btf_vmlinux, t, off, size, atype, &btf_id, &flag); if (ret < 0) return ret; if (value_regno >= 0) - mark_btf_ld_reg(env, regs, value_regno, ret, btf_vmlinux, btf_id); + mark_btf_ld_reg(env, regs, value_regno, ret, btf_vmlinux, btf_id, flag); return 0; } @@ -4444,7 +4456,8 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn if (err < 0) return err; - err = check_ctx_access(env, insn_idx, off, size, t, ®_type, &btf, &btf_id); + err = check_ctx_access(env, insn_idx, off, size, t, ®_type, &btf, + &btf_id); if (err) verbose_linfo(env, insn_idx, "; "); if (!err && t == BPF_READ && value_regno >= 0) { diff --git a/net/bpf/bpf_dummy_struct_ops.c b/net/bpf/bpf_dummy_struct_ops.c index fbc896323bec..d0e54e30658a 100644 --- a/net/bpf/bpf_dummy_struct_ops.c +++ b/net/bpf/bpf_dummy_struct_ops.c @@ -145,7 +145,8 @@ static int bpf_dummy_ops_btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, int off, int size, enum bpf_access_type atype, - u32 *next_btf_id) + u32 *next_btf_id, + enum bpf_type_flag *flag) { const struct btf_type *state; s32 type_id; @@ -162,7 +163,8 @@ static int bpf_dummy_ops_btf_struct_access(struct bpf_verifier_log *log, return -EACCES; } - err = btf_struct_access(log, btf, t, off, size, atype, next_btf_id); + err = btf_struct_access(log, btf, t, off, size, atype, next_btf_id, + flag); if (err < 0) return err; diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c index b60c9fd7147e..f79ab942f03b 100644 --- a/net/ipv4/bpf_tcp_ca.c +++ b/net/ipv4/bpf_tcp_ca.c @@ -96,12 +96,14 @@ static int bpf_tcp_ca_btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, int off, int size, enum bpf_access_type atype, - u32 *next_btf_id) + u32 *next_btf_id, + enum bpf_type_flag *flag) { size_t end; if (atype == BPF_READ) - return btf_struct_access(log, btf, t, off, size, atype, next_btf_id); + return btf_struct_access(log, btf, t, off, size, atype, next_btf_id, + flag); if (t != tcp_sock_type) { bpf_log(log, "only read is supported\n"); -- 2.30.2 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH bpf-next v3 3/6] selftests/bpf: rename btf_decl_tag.c to test_btf_decl_tag.c 2022-01-27 15:45 [PATCH bpf-next v3 0/6] bpf: add __user tagging support in vmlinux BTF Yonghong Song 2022-01-27 15:46 ` [PATCH bpf-next v3 1/6] compiler_types: define __user as __attribute__((btf_type_tag("user"))) Yonghong Song 2022-01-27 15:46 ` [PATCH bpf-next v3 2/6] bpf: reject program if a __user tagged memory accessed in kernel way Yonghong Song @ 2022-01-27 15:46 ` Yonghong Song 2022-01-27 15:46 ` [PATCH bpf-next v3 4/6] selftests/bpf: add a selftest with __user tag Yonghong Song ` (3 subsequent siblings) 6 siblings, 0 replies; 8+ messages in thread From: Yonghong Song @ 2022-01-27 15:46 UTC (permalink / raw) To: Alexei Starovoitov, Andrii Nakryiko, bpf, Daniel Borkmann, Linus Torvalds Cc: Arnaldo Carvalho de Melo, Jose E . Marchesi, kernel-team, Masami Hiramatsu The uapi btf.h contains the following declaration: struct btf_decl_tag { __s32 component_idx; }; The skeleton will also generate a struct with name "btf_decl_tag" for bpf program btf_decl_tag.c. Rename btf_decl_tag.c to test_btf_decl_tag.c so the corresponding skeleton struct name becomes "test_btf_decl_tag". This way, we could include uapi btf.h in prog_tests/btf_tag.c. There is no functionality change for this patch. Signed-off-by: Yonghong Song <yhs@fb.com> --- tools/testing/selftests/bpf/prog_tests/btf_tag.c | 8 ++++---- .../bpf/progs/{btf_decl_tag.c => test_btf_decl_tag.c} | 0 2 files changed, 4 insertions(+), 4 deletions(-) rename tools/testing/selftests/bpf/progs/{btf_decl_tag.c => test_btf_decl_tag.c} (100%) diff --git a/tools/testing/selftests/bpf/prog_tests/btf_tag.c b/tools/testing/selftests/bpf/prog_tests/btf_tag.c index 88d63e23e35f..c4cf27777ff7 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf_tag.c +++ b/tools/testing/selftests/bpf/prog_tests/btf_tag.c @@ -1,7 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 /* Copyright (c) 2021 Facebook */ #include <test_progs.h> -#include "btf_decl_tag.skel.h" +#include "test_btf_decl_tag.skel.h" /* struct btf_type_tag_test is referenced in btf_type_tag.skel.h */ struct btf_type_tag_test { @@ -11,9 +11,9 @@ struct btf_type_tag_test { static void test_btf_decl_tag(void) { - struct btf_decl_tag *skel; + struct test_btf_decl_tag *skel; - skel = btf_decl_tag__open_and_load(); + skel = test_btf_decl_tag__open_and_load(); if (!ASSERT_OK_PTR(skel, "btf_decl_tag")) return; @@ -22,7 +22,7 @@ static void test_btf_decl_tag(void) test__skip(); } - btf_decl_tag__destroy(skel); + test_btf_decl_tag__destroy(skel); } static void test_btf_type_tag(void) diff --git a/tools/testing/selftests/bpf/progs/btf_decl_tag.c b/tools/testing/selftests/bpf/progs/test_btf_decl_tag.c similarity index 100% rename from tools/testing/selftests/bpf/progs/btf_decl_tag.c rename to tools/testing/selftests/bpf/progs/test_btf_decl_tag.c -- 2.30.2 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH bpf-next v3 4/6] selftests/bpf: add a selftest with __user tag 2022-01-27 15:45 [PATCH bpf-next v3 0/6] bpf: add __user tagging support in vmlinux BTF Yonghong Song ` (2 preceding siblings ...) 2022-01-27 15:46 ` [PATCH bpf-next v3 3/6] selftests/bpf: rename btf_decl_tag.c to test_btf_decl_tag.c Yonghong Song @ 2022-01-27 15:46 ` Yonghong Song 2022-01-27 15:46 ` [PATCH bpf-next v3 5/6] selftests/bpf: specify pahole version requirement for btf_tag test Yonghong Song ` (2 subsequent siblings) 6 siblings, 0 replies; 8+ messages in thread From: Yonghong Song @ 2022-01-27 15:46 UTC (permalink / raw) To: Alexei Starovoitov, Andrii Nakryiko, bpf, Daniel Borkmann, Linus Torvalds Cc: Arnaldo Carvalho de Melo, Jose E . Marchesi, kernel-team, Masami Hiramatsu Added a selftest with three__user usages: a __user pointer-type argument in bpf_testmod, a __user pointer-type struct member in bpf_testmod, and a __user pointer-type struct member in vmlinux. In all cases, directly accessing the user memory will result verification failure. $ ./test_progs -v -n 22/3 ... libbpf: prog 'test_user1': BPF program load failed: Permission denied libbpf: prog 'test_user1': -- BEGIN PROG LOAD LOG -- R1 type=ctx expected=fp 0: R1=ctx(id=0,off=0,imm=0) R10=fp0 ; int BPF_PROG(test_user1, struct bpf_testmod_btf_type_tag_1 *arg) 0: (79) r1 = *(u64 *)(r1 +0) func 'bpf_testmod_test_btf_type_tag_user_1' arg0 has btf_id 136561 type STRUCT 'bpf_testmod_btf_type_tag_1' 1: R1_w=user_ptr_bpf_testmod_btf_type_tag_1(id=0,off=0,imm=0) ; g = arg->a; 1: (61) r1 = *(u32 *)(r1 +0) R1 invalid mem access 'user_ptr_' ... #22/3 btf_tag/btf_type_tag_user_mod1:OK $ ./test_progs -v -n 22/4 ... libbpf: prog 'test_user2': BPF program load failed: Permission denied libbpf: prog 'test_user2': -- BEGIN PROG LOAD LOG -- R1 type=ctx expected=fp 0: R1=ctx(id=0,off=0,imm=0) R10=fp0 ; int BPF_PROG(test_user2, struct bpf_testmod_btf_type_tag_2 *arg) 0: (79) r1 = *(u64 *)(r1 +0) func 'bpf_testmod_test_btf_type_tag_user_2' arg0 has btf_id 136563 type STRUCT 'bpf_testmod_btf_type_tag_2' 1: R1_w=ptr_bpf_testmod_btf_type_tag_2(id=0,off=0,imm=0) ; g = arg->p->a; 1: (79) r1 = *(u64 *)(r1 +0) ; R1_w=user_ptr_bpf_testmod_btf_type_tag_1(id=0,off=0,imm=0) ; g = arg->p->a; 2: (61) r1 = *(u32 *)(r1 +0) R1 invalid mem access 'user_ptr_' ... #22/4 btf_tag/btf_type_tag_user_mod2:OK $ ./test_progs -v -n 22/5 ... libbpf: prog 'test_sys_getsockname': BPF program load failed: Permission denied libbpf: prog 'test_sys_getsockname': -- BEGIN PROG LOAD LOG -- R1 type=ctx expected=fp 0: R1=ctx(id=0,off=0,imm=0) R10=fp0 ; int BPF_PROG(test_sys_getsockname, int fd, struct sockaddr *usockaddr, 0: (79) r1 = *(u64 *)(r1 +8) func '__sys_getsockname' arg1 has btf_id 2319 type STRUCT 'sockaddr' 1: R1_w=user_ptr_sockaddr(id=0,off=0,imm=0) ; g = usockaddr->sa_family; 1: (69) r1 = *(u16 *)(r1 +0) R1 invalid mem access 'user_ptr_' ... #22/5 btf_tag/btf_type_tag_user_vmlinux:OK Signed-off-by: Yonghong Song <yhs@fb.com> --- .../selftests/bpf/bpf_testmod/bpf_testmod.c | 18 ++++ .../selftests/bpf/prog_tests/btf_tag.c | 93 +++++++++++++++++++ .../selftests/bpf/progs/btf_type_tag_user.c | 40 ++++++++ 3 files changed, 151 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/btf_type_tag_user.c diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c index bdbacf5adcd2..595d32ab285a 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c @@ -21,6 +21,24 @@ bpf_testmod_test_mod_kfunc(int i) *(int *)this_cpu_ptr(&bpf_testmod_ksym_percpu) = i; } +struct bpf_testmod_btf_type_tag_1 { + int a; +}; + +struct bpf_testmod_btf_type_tag_2 { + struct bpf_testmod_btf_type_tag_1 __user *p; +}; + +noinline int +bpf_testmod_test_btf_type_tag_user_1(struct bpf_testmod_btf_type_tag_1 __user *arg) { + return arg->a; +} + +noinline int +bpf_testmod_test_btf_type_tag_user_2(struct bpf_testmod_btf_type_tag_2 *arg) { + return arg->p->a; +} + noinline int bpf_testmod_loop_test(int n) { int i, sum = 0; diff --git a/tools/testing/selftests/bpf/prog_tests/btf_tag.c b/tools/testing/selftests/bpf/prog_tests/btf_tag.c index c4cf27777ff7..f7560b54a6bb 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf_tag.c +++ b/tools/testing/selftests/bpf/prog_tests/btf_tag.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 /* Copyright (c) 2021 Facebook */ #include <test_progs.h> +#include <bpf/btf.h> #include "test_btf_decl_tag.skel.h" /* struct btf_type_tag_test is referenced in btf_type_tag.skel.h */ @@ -8,6 +9,7 @@ struct btf_type_tag_test { int **p; }; #include "btf_type_tag.skel.h" +#include "btf_type_tag_user.skel.h" static void test_btf_decl_tag(void) { @@ -41,10 +43,101 @@ static void test_btf_type_tag(void) btf_type_tag__destroy(skel); } +static void test_btf_type_tag_mod_user(bool load_test_user1) +{ + const char *module_name = "bpf_testmod"; + struct btf *vmlinux_btf, *module_btf; + struct btf_type_tag_user *skel; + __s32 type_id; + int err; + + if (!env.has_testmod) { + test__skip(); + return; + } + + /* skip the test if the module does not have __user tags */ + vmlinux_btf = btf__load_vmlinux_btf(); + if (!ASSERT_OK_PTR(vmlinux_btf, "could not load vmlinux BTF")) + return; + + module_btf = btf__load_module_btf(module_name, vmlinux_btf); + if (!ASSERT_OK_PTR(module_btf, "could not load module BTF")) + goto free_vmlinux_btf; + + type_id = btf__find_by_name_kind(module_btf, "user", BTF_KIND_TYPE_TAG); + if (type_id <= 0) { + printf("%s:SKIP: btf_type_tag attribute not in %s", __func__, module_name); + test__skip(); + goto free_module_btf; + } + + skel = btf_type_tag_user__open(); + if (!ASSERT_OK_PTR(skel, "btf_type_tag_user")) + goto free_module_btf; + + bpf_program__set_autoload(skel->progs.test_sys_getsockname, false); + if (load_test_user1) + bpf_program__set_autoload(skel->progs.test_user2, false); + else + bpf_program__set_autoload(skel->progs.test_user1, false); + + err = btf_type_tag_user__load(skel); + ASSERT_ERR(err, "btf_type_tag_user"); + + btf_type_tag_user__destroy(skel); + +free_module_btf: + btf__free(module_btf); +free_vmlinux_btf: + btf__free(vmlinux_btf); +} + +static void test_btf_type_tag_vmlinux_user(void) +{ + struct btf_type_tag_user *skel; + struct btf *vmlinux_btf; + __s32 type_id; + int err; + + /* skip the test if the vmlinux does not have __user tags */ + vmlinux_btf = btf__load_vmlinux_btf(); + if (!ASSERT_OK_PTR(vmlinux_btf, "could not load vmlinux BTF")) + return; + + type_id = btf__find_by_name_kind(vmlinux_btf, "user", BTF_KIND_TYPE_TAG); + if (type_id <= 0) { + printf("%s:SKIP: btf_type_tag attribute not in vmlinux btf", __func__); + test__skip(); + goto free_vmlinux_btf; + } + + skel = btf_type_tag_user__open(); + if (!ASSERT_OK_PTR(skel, "btf_type_tag_user")) + goto free_vmlinux_btf; + + bpf_program__set_autoload(skel->progs.test_user2, false); + bpf_program__set_autoload(skel->progs.test_user1, false); + + err = btf_type_tag_user__load(skel); + ASSERT_ERR(err, "btf_type_tag_user"); + + btf_type_tag_user__destroy(skel); + +free_vmlinux_btf: + btf__free(vmlinux_btf); +} + void test_btf_tag(void) { if (test__start_subtest("btf_decl_tag")) test_btf_decl_tag(); if (test__start_subtest("btf_type_tag")) test_btf_type_tag(); + if (test__start_subtest("btf_type_tag_user_mod1")) + test_btf_type_tag_mod_user(true); + if (test__start_subtest("btf_type_tag_user_mod2")) + test_btf_type_tag_mod_user(false); + if (test__start_subtest("btf_type_tag_sys_user_vmlinux")) + test_btf_type_tag_vmlinux_user(); } diff --git a/tools/testing/selftests/bpf/progs/btf_type_tag_user.c b/tools/testing/selftests/bpf/progs/btf_type_tag_user.c new file mode 100644 index 000000000000..5523f77c5a44 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/btf_type_tag_user.c @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Facebook */ +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +struct bpf_testmod_btf_type_tag_1 { + int a; +}; + +struct bpf_testmod_btf_type_tag_2 { + struct bpf_testmod_btf_type_tag_1 *p; +}; + +int g; + +SEC("fentry/bpf_testmod_test_btf_type_tag_user_1") +int BPF_PROG(test_user1, struct bpf_testmod_btf_type_tag_1 *arg) +{ + g = arg->a; + return 0; +} + +SEC("fentry/bpf_testmod_test_btf_type_tag_user_2") +int BPF_PROG(test_user2, struct bpf_testmod_btf_type_tag_2 *arg) +{ + g = arg->p->a; + return 0; +} + +/* int __sys_getsockname(int fd, struct sockaddr __user *usockaddr, + * int __user *usockaddr_len); + */ +SEC("fentry/__sys_getsockname") +int BPF_PROG(test_sys_getsockname, int fd, struct sockaddr *usockaddr, + int *usockaddr_len) +{ + g = usockaddr->sa_family; + return 0; +} -- 2.30.2 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH bpf-next v3 5/6] selftests/bpf: specify pahole version requirement for btf_tag test 2022-01-27 15:45 [PATCH bpf-next v3 0/6] bpf: add __user tagging support in vmlinux BTF Yonghong Song ` (3 preceding siblings ...) 2022-01-27 15:46 ` [PATCH bpf-next v3 4/6] selftests/bpf: add a selftest with __user tag Yonghong Song @ 2022-01-27 15:46 ` Yonghong Song 2022-01-27 15:46 ` [PATCH bpf-next v3 6/6] docs/bpf: clarify how btf_type_tag gets encoded in the type chain Yonghong Song 2022-01-27 20:17 ` [PATCH bpf-next v3 0/6] bpf: add __user tagging support in vmlinux BTF Alexei Starovoitov 6 siblings, 0 replies; 8+ messages in thread From: Yonghong Song @ 2022-01-27 15:46 UTC (permalink / raw) To: Alexei Starovoitov, Andrii Nakryiko, bpf, Daniel Borkmann, Linus Torvalds Cc: Arnaldo Carvalho de Melo, Jose E . Marchesi, kernel-team, Masami Hiramatsu Specify pahole version requirement (1.23) for btf_tag subtests btf_type_tag_user_{mod1, mod2, vmlinux}. Signed-off-by: Yonghong Song <yhs@fb.com> --- tools/testing/selftests/bpf/README.rst | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/testing/selftests/bpf/README.rst b/tools/testing/selftests/bpf/README.rst index 42ef250c7acc..d099d91adc3b 100644 --- a/tools/testing/selftests/bpf/README.rst +++ b/tools/testing/selftests/bpf/README.rst @@ -206,6 +206,8 @@ btf_tag test and Clang version The btf_tag selftest requires LLVM support to recognize the btf_decl_tag and btf_type_tag attributes. They are introduced in `Clang 14` [0_, 1_]. +The subtests ``btf_type_tag_user_{mod1, mod2, vmlinux}`` also requires +pahole version ``1.23``. Without them, the btf_tag selftest will be skipped and you will observe: -- 2.30.2 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH bpf-next v3 6/6] docs/bpf: clarify how btf_type_tag gets encoded in the type chain 2022-01-27 15:45 [PATCH bpf-next v3 0/6] bpf: add __user tagging support in vmlinux BTF Yonghong Song ` (4 preceding siblings ...) 2022-01-27 15:46 ` [PATCH bpf-next v3 5/6] selftests/bpf: specify pahole version requirement for btf_tag test Yonghong Song @ 2022-01-27 15:46 ` Yonghong Song 2022-01-27 20:17 ` [PATCH bpf-next v3 0/6] bpf: add __user tagging support in vmlinux BTF Alexei Starovoitov 6 siblings, 0 replies; 8+ messages in thread From: Yonghong Song @ 2022-01-27 15:46 UTC (permalink / raw) To: Alexei Starovoitov, Andrii Nakryiko, bpf, Daniel Borkmann, Linus Torvalds Cc: Arnaldo Carvalho de Melo, Jose E . Marchesi, kernel-team, Masami Hiramatsu Clarify where the BTF_KIND_TYPE_TAG gets encoded in the type chain, so applications and kernel can properly parse them. Signed-off-by: Yonghong Song <yhs@fb.com> --- Documentation/bpf/btf.rst | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst index ab08852e53ae..7940da9bc6c1 100644 --- a/Documentation/bpf/btf.rst +++ b/Documentation/bpf/btf.rst @@ -503,6 +503,19 @@ valid index (starting from 0) pointing to a member or an argument. * ``info.vlen``: 0 * ``type``: the type with ``btf_type_tag`` attribute +Currently, ``BTF_KIND_TYPE_TAG`` is only emitted for pointer types. +It has the following btf type chain: +:: + + ptr -> [type_tag]* + -> [const | volatile | restrict | typedef]* + -> base_type + +Basically, a pointer type points to zero or more +type_tag, then zero or more const/volatile/restrict/typedef +and finally the base type. The base type is one of +int, ptr, array, struct, union, enum, func_proto and float types. + 3. BTF Kernel API ================= -- 2.30.2 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH bpf-next v3 0/6] bpf: add __user tagging support in vmlinux BTF 2022-01-27 15:45 [PATCH bpf-next v3 0/6] bpf: add __user tagging support in vmlinux BTF Yonghong Song ` (5 preceding siblings ...) 2022-01-27 15:46 ` [PATCH bpf-next v3 6/6] docs/bpf: clarify how btf_type_tag gets encoded in the type chain Yonghong Song @ 2022-01-27 20:17 ` Alexei Starovoitov 6 siblings, 0 replies; 8+ messages in thread From: Alexei Starovoitov @ 2022-01-27 20:17 UTC (permalink / raw) To: Yonghong Song Cc: Alexei Starovoitov, Andrii Nakryiko, bpf, Daniel Borkmann, Linus Torvalds, Arnaldo Carvalho de Melo, Jose E . Marchesi, Kernel Team, Masami Hiramatsu On Thu, Jan 27, 2022 at 7:46 AM Yonghong Song <yhs@fb.com> wrote: > > The __user attribute is currently mainly used by sparse for type checking. > The attribute indicates whether a memory access is in user memory address > space or not. Such information is important during tracing kernel > internal functions or data structures as accessing user memory often > has different mechanisms compared to accessing kernel memory. For example, > the perf-probe needs explicit command line specification to indicate a > particular argument or string in user-space memory ([1], [2], [3]). > Currently, vmlinux BTF is available in kernel with many distributions. > If __user attribute information is available in vmlinux BTF, the explicit > user memory access information from users will not be necessary as > the kernel can figure it out by itself with vmlinux BTF. > > Besides the above possible use for perf/probe, another use case is > for bpf verifier. Currently, for bpf BPF_PROG_TYPE_TRACING type of bpf > programs, users can write direct code like > p->m1->m2 > and "p" could be a function parameter. Without __user information in BTF, > the verifier will assume p->m1 accessing kernel memory and will generate > normal loads. Let us say "p" actually tagged with __user in the source > code. In such cases, p->m1 is actually accessing user memory and direct > load is not right and may produce incorrect result. For such cases, > bpf_probe_read_user() will be the correct way to read p->m1. > > To support encoding __user information in BTF, a new attribute > __attribute__((btf_type_tag("<arbitrary_string>"))) > is implemented in clang ([4]). For example, if we have > #define __user __attribute__((btf_type_tag("user"))) > during kernel compilation, the attribute "user" information will > be preserved in dwarf. After pahole converting dwarf to BTF, __user > information will be available in vmlinux BTF and such information > can be used by bpf verifier, perf/probe or other use cases. > > Currently btf_type_tag is only supported in clang (>= clang14) and > pahole (>= 1.23). gcc support is also proposed and under development ([5]). > > In the rest of patch set, Patch 1 added support of __user btf_type_tag > during compilation. Patch 2 added bpf verifier support to utilize __user > tag information to reject bpf programs not using proper helper to access > user memories. Patches 3-5 are for bpf selftests which demonstrate verifier > can reject direct user memory accesses. > > [1] http://lkml.kernel.org/r/155789874562.26965.10836126971405890891.stgit@devnote2 > [2] http://lkml.kernel.org/r/155789872187.26965.4468456816590888687.stgit@devnote2 > [3] http://lkml.kernel.org/r/155789871009.26965.14167558859557329331.stgit@devnote2 > [4] https://reviews.llvm.org/D111199 > [5] https://lore.kernel.org/bpf/0cbeb2fb-1a18-f690-e360-24b1c90c2a91@fb.com/ > > Changelog: > v2 -> v3: > - remove FLAG_DONTCARE enumerator and just use 0 as dontcare flag. > - explain how btf type_tag is encoded in btf type chain. Applied. Thanks ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2022-01-27 20:18 UTC | newest]
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2022-01-27 15:45 [PATCH bpf-next v3 0/6] bpf: add __user tagging support in vmlinux BTF Yonghong Song
2022-01-27 15:46 ` [PATCH bpf-next v3 1/6] compiler_types: define __user as __attribute__((btf_type_tag("user"))) Yonghong Song
2022-01-27 15:46 ` [PATCH bpf-next v3 2/6] bpf: reject program if a __user tagged memory accessed in kernel way Yonghong Song
2022-01-27 15:46 ` [PATCH bpf-next v3 3/6] selftests/bpf: rename btf_decl_tag.c to test_btf_decl_tag.c Yonghong Song
2022-01-27 15:46 ` [PATCH bpf-next v3 4/6] selftests/bpf: add a selftest with __user tag Yonghong Song
2022-01-27 15:46 ` [PATCH bpf-next v3 5/6] selftests/bpf: specify pahole version requirement for btf_tag test Yonghong Song
2022-01-27 15:46 ` [PATCH bpf-next v3 6/6] docs/bpf: clarify how btf_type_tag gets encoded in the type chain Yonghong Song
2022-01-27 20:17 ` [PATCH bpf-next v3 0/6] bpf: add __user tagging support in vmlinux BTF Alexei Starovoitov
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