6.14-stable review patch. If anyone has any objections, please let me know.
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From: Amery Hung ameryhung@gmail.com
[ Upstream commit 432051806f614ca512da401b80257b95b2a2241e ]
Currently, ctx_arg_info is read-only in the view of the verifier since it is shared among programs of the same attach type. Make each program have their own copy of ctx_arg_info so that we can use it to store program specific information.
In the next patch where we support acquiring a referenced kptr through a struct_ops argument tagged with "__ref", ctx_arg_info->ref_obj_id will be used to store the unique reference object id of the argument. This avoids creating a requirement in the verifier that "__ref" tagged arguments must be the first set of references acquired [0].
[0] https://lore.kernel.org/bpf/20241220195619.2022866-2-amery.hung@gmail.com/
Signed-off-by: Amery Hung ameryhung@gmail.com Acked-by: Eduard Zingerman eddyz87@gmail.com Acked-by: Martin KaFai Lau martin.lau@kernel.org Link: https://lore.kernel.org/r/20250217190640.1748177-2-ameryhung@gmail.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/bpf.h | 7 +++++-- kernel/bpf/bpf_iter.c | 13 ++++++------- kernel/bpf/syscall.c | 1 + kernel/bpf/verifier.c | 22 ++++++++++++---------- 4 files changed, 24 insertions(+), 19 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index f3f50e29d6392..f4df39e8c7357 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1507,7 +1507,7 @@ struct bpf_prog_aux { u32 max_rdonly_access; u32 max_rdwr_access; struct btf *attach_btf; - const struct bpf_ctx_arg_aux *ctx_arg_info; + struct bpf_ctx_arg_aux *ctx_arg_info; void __percpu *priv_stack_ptr; struct mutex dst_mutex; /* protects dst_* pointers below, *after* prog becomes visible */ struct bpf_prog *dst_prog; @@ -1945,6 +1945,9 @@ static inline void bpf_struct_ops_desc_release(struct bpf_struct_ops_desc *st_op
#endif
+int bpf_prog_ctx_arg_info_init(struct bpf_prog *prog, + const struct bpf_ctx_arg_aux *info, u32 cnt); + #if defined(CONFIG_CGROUP_BPF) && defined(CONFIG_BPF_LSM) int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog, int cgroup_atype); @@ -2546,7 +2549,7 @@ struct bpf_iter__bpf_map_elem {
int bpf_iter_reg_target(const struct bpf_iter_reg *reg_info); void bpf_iter_unreg_target(const struct bpf_iter_reg *reg_info); -bool bpf_iter_prog_supported(struct bpf_prog *prog); +int bpf_iter_prog_supported(struct bpf_prog *prog); const struct bpf_func_proto * bpf_iter_get_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog); int bpf_iter_link_attach(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_prog *prog); diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index 106735145948b..380e9a7cac75d 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -335,7 +335,7 @@ static void cache_btf_id(struct bpf_iter_target_info *tinfo, tinfo->btf_id = prog->aux->attach_btf_id; }
-bool bpf_iter_prog_supported(struct bpf_prog *prog) +int bpf_iter_prog_supported(struct bpf_prog *prog) { const char *attach_fname = prog->aux->attach_func_name; struct bpf_iter_target_info *tinfo = NULL, *iter; @@ -344,7 +344,7 @@ bool bpf_iter_prog_supported(struct bpf_prog *prog) int prefix_len = strlen(prefix);
if (strncmp(attach_fname, prefix, prefix_len)) - return false; + return -EINVAL;
mutex_lock(&targets_mutex); list_for_each_entry(iter, &targets, list) { @@ -360,12 +360,11 @@ bool bpf_iter_prog_supported(struct bpf_prog *prog) } mutex_unlock(&targets_mutex);
- if (tinfo) { - prog->aux->ctx_arg_info_size = tinfo->reg_info->ctx_arg_info_size; - prog->aux->ctx_arg_info = tinfo->reg_info->ctx_arg_info; - } + if (!tinfo) + return -EINVAL;
- return tinfo != NULL; + return bpf_prog_ctx_arg_info_init(prog, tinfo->reg_info->ctx_arg_info, + tinfo->reg_info->ctx_arg_info_size); }
const struct bpf_func_proto * diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 8c42c094f0d1e..32a8d5fd98612 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2314,6 +2314,7 @@ static void __bpf_prog_put_noref(struct bpf_prog *prog, bool deferred) kvfree(prog->aux->jited_linfo); kvfree(prog->aux->linfo); kfree(prog->aux->kfunc_tab); + kfree(prog->aux->ctx_arg_info); if (prog->aux->attach_btf) btf_put(prog->aux->attach_btf);
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 0752e8e556389..4392436ba7511 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -22429,6 +22429,15 @@ static void print_verification_stats(struct bpf_verifier_env *env) env->peak_states, env->longest_mark_read_walk); }
+int bpf_prog_ctx_arg_info_init(struct bpf_prog *prog, + const struct bpf_ctx_arg_aux *info, u32 cnt) +{ + prog->aux->ctx_arg_info = kmemdup_array(info, cnt, sizeof(*info), GFP_KERNEL); + prog->aux->ctx_arg_info_size = cnt; + + return prog->aux->ctx_arg_info ? 0 : -ENOMEM; +} + static int check_struct_ops_btf_id(struct bpf_verifier_env *env) { const struct btf_type *t, *func_proto; @@ -22509,17 +22518,12 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env) return -EACCES; }
- /* btf_ctx_access() used this to provide argument type info */ - prog->aux->ctx_arg_info = - st_ops_desc->arg_info[member_idx].info; - prog->aux->ctx_arg_info_size = - st_ops_desc->arg_info[member_idx].cnt; - prog->aux->attach_func_proto = func_proto; prog->aux->attach_func_name = mname; env->ops = st_ops->verifier_ops;
- return 0; + return bpf_prog_ctx_arg_info_init(prog, st_ops_desc->arg_info[member_idx].info, + st_ops_desc->arg_info[member_idx].cnt); } #define SECURITY_PREFIX "security_"
@@ -22996,9 +23000,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) prog->aux->attach_btf_trace = true; return 0; } else if (prog->expected_attach_type == BPF_TRACE_ITER) { - if (!bpf_iter_prog_supported(prog)) - return -EINVAL; - return 0; + return bpf_iter_prog_supported(prog); }
if (prog->type == BPF_PROG_TYPE_LSM) {