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-rw-r--r--include/linux/bpf.h9
-rw-r--r--include/linux/bpf_verifier.h2
-rw-r--r--include/linux/btf.h10
-rw-r--r--kernel/bpf/btf.c101
-rw-r--r--kernel/bpf/verifier.c45
5 files changed, 133 insertions, 34 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 3cf161cfd396..79883f883ff3 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1944,6 +1944,13 @@ int btf_distill_func_proto(struct bpf_verifier_log *log,
const char *func_name,
struct btf_func_model *m);
+struct bpf_kfunc_arg_meta {
+ u64 r0_size;
+ bool r0_rdonly;
+ int ref_obj_id;
+ u32 flags;
+};
+
struct bpf_reg_state;
int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
struct bpf_reg_state *regs);
@@ -1952,7 +1959,7 @@ int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog,
int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
const struct btf *btf, u32 func_id,
struct bpf_reg_state *regs,
- u32 kfunc_flags);
+ struct bpf_kfunc_arg_meta *meta);
int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
struct bpf_reg_state *reg);
int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 1fdddbf3546b..8fbc1d05281e 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -598,6 +598,8 @@ int bpf_check_attach_target(struct bpf_verifier_log *log,
struct bpf_attach_target_info *tgt_info);
void bpf_free_kfunc_btf_tab(struct bpf_kfunc_btf_tab *tab);
+int mark_chain_precision(struct bpf_verifier_env *env, int regno);
+
#define BPF_BASE_TYPE_MASK GENMASK(BPF_BASE_TYPE_BITS - 1, 0)
/* extract base type from bpf_{arg, return, reg}_type. */
diff --git a/include/linux/btf.h b/include/linux/btf.h
index ad93c2d9cc1c..1fcc833a8690 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -441,4 +441,14 @@ static inline int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dt
}
#endif
+static inline bool btf_type_is_struct_ptr(struct btf *btf, const struct btf_type *t)
+{
+ if (!btf_type_is_ptr(t))
+ return false;
+
+ t = btf_type_skip_modifiers(btf, t->type, NULL);
+
+ return btf_type_is_struct(t);
+}
+
#endif
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 2c2d8190ca4a..9d12212fcd61 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -6199,11 +6199,36 @@ static bool is_kfunc_arg_mem_size(const struct btf *btf,
return true;
}
+static bool btf_is_kfunc_arg_mem_size(const struct btf *btf,
+ const struct btf_param *arg,
+ const struct bpf_reg_state *reg,
+ const char *name)
+{
+ int len, target_len = strlen(name);
+ const struct btf_type *t;
+ const char *param_name;
+
+ t = btf_type_skip_modifiers(btf, arg->type, NULL);
+ if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
+ return false;
+
+ param_name = btf_name_by_offset(btf, arg->name_off);
+ if (str_is_empty(param_name))
+ return false;
+ len = strlen(param_name);
+ if (len != target_len)
+ return false;
+ if (strcmp(param_name, name))
+ return false;
+
+ return true;
+}
+
static int btf_check_func_arg_match(struct bpf_verifier_env *env,
const struct btf *btf, u32 func_id,
struct bpf_reg_state *regs,
bool ptr_to_mem_ok,
- u32 kfunc_flags,
+ struct bpf_kfunc_arg_meta *kfunc_meta,
bool processing_call)
{
enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
@@ -6241,12 +6266,12 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
return -EINVAL;
}
- if (is_kfunc) {
+ if (is_kfunc && kfunc_meta) {
/* Only kfunc can be release func */
- rel = kfunc_flags & KF_RELEASE;
- kptr_get = kfunc_flags & KF_KPTR_GET;
- trusted_arg = kfunc_flags & KF_TRUSTED_ARGS;
- sleepable = kfunc_flags & KF_SLEEPABLE;
+ rel = kfunc_meta->flags & KF_RELEASE;
+ kptr_get = kfunc_meta->flags & KF_KPTR_GET;
+ trusted_arg = kfunc_meta->flags & KF_TRUSTED_ARGS;
+ sleepable = kfunc_meta->flags & KF_SLEEPABLE;
}
/* check that BTF function arguments match actual types that the
@@ -6259,6 +6284,38 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
t = btf_type_skip_modifiers(btf, args[i].type, NULL);
if (btf_type_is_scalar(t)) {
+ if (is_kfunc && kfunc_meta) {
+ bool is_buf_size = false;
+
+ /* check for any const scalar parameter of name "rdonly_buf_size"
+ * or "rdwr_buf_size"
+ */
+ if (btf_is_kfunc_arg_mem_size(btf, &args[i], reg,
+ "rdonly_buf_size")) {
+ kfunc_meta->r0_rdonly = true;
+ is_buf_size = true;
+ } else if (btf_is_kfunc_arg_mem_size(btf, &args[i], reg,
+ "rdwr_buf_size"))
+ is_buf_size = true;
+
+ if (is_buf_size) {
+ if (kfunc_meta->r0_size) {
+ bpf_log(log, "2 or more rdonly/rdwr_buf_size parameters for kfunc");
+ return -EINVAL;
+ }
+
+ if (!tnum_is_const(reg->var_off)) {
+ bpf_log(log, "R%d is not a const\n", regno);
+ return -EINVAL;
+ }
+
+ kfunc_meta->r0_size = reg->var_off.value;
+ ret = mark_chain_precision(env, regno);
+ if (ret)
+ return ret;
+ }
+ }
+
if (reg->type == SCALAR_VALUE)
continue;
bpf_log(log, "R%d is not a scalar\n", regno);
@@ -6289,6 +6346,17 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
if (ret < 0)
return ret;
+ if (is_kfunc && reg->ref_obj_id) {
+ /* Ensure only one argument is referenced PTR_TO_BTF_ID */
+ if (ref_obj_id) {
+ bpf_log(log, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
+ regno, reg->ref_obj_id, ref_obj_id);
+ return -EFAULT;
+ }
+ ref_regno = regno;
+ ref_obj_id = reg->ref_obj_id;
+ }
+
/* kptr_get is only true for kfunc */
if (i == 0 && kptr_get) {
struct bpf_map_value_off_desc *off_desc;
@@ -6361,16 +6429,6 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
if (reg->type == PTR_TO_BTF_ID) {
reg_btf = reg->btf;
reg_ref_id = reg->btf_id;
- /* Ensure only one argument is referenced PTR_TO_BTF_ID */
- if (reg->ref_obj_id) {
- if (ref_obj_id) {
- bpf_log(log, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
- regno, reg->ref_obj_id, ref_obj_id);
- return -EFAULT;
- }
- ref_regno = regno;
- ref_obj_id = reg->ref_obj_id;
- }
} else {
reg_btf = btf_vmlinux;
reg_ref_id = *reg2btf_ids[base_type(reg->type)];
@@ -6461,6 +6519,9 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
return -EINVAL;
}
+ if (kfunc_meta && ref_obj_id)
+ kfunc_meta->ref_obj_id = ref_obj_id;
+
/* returns argument register number > 0 in case of reference release kfunc */
return rel ? ref_regno : 0;
}
@@ -6492,7 +6553,7 @@ int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
return -EINVAL;
is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
- err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, 0, false);
+ err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, NULL, false);
/* Compiler optimizations can remove arguments from static functions
* or mismatched type can be passed into a global function.
@@ -6535,7 +6596,7 @@ int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog,
return -EINVAL;
is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
- err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, 0, true);
+ err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, NULL, true);
/* Compiler optimizations can remove arguments from static functions
* or mismatched type can be passed into a global function.
@@ -6549,9 +6610,9 @@ int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog,
int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
const struct btf *btf, u32 func_id,
struct bpf_reg_state *regs,
- u32 kfunc_flags)
+ struct bpf_kfunc_arg_meta *meta)
{
- return btf_check_func_arg_match(env, btf, func_id, regs, true, kfunc_flags, true);
+ return btf_check_func_arg_match(env, btf, func_id, regs, true, meta, true);
}
/* Convert BTF of a function into bpf_reg_state if possible
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 3cfe60206de6..f3344a86d88d 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2908,7 +2908,7 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno,
return 0;
}
-static int mark_chain_precision(struct bpf_verifier_env *env, int regno)
+int mark_chain_precision(struct bpf_verifier_env *env, int regno)
{
return __mark_chain_precision(env, regno, -1);
}
@@ -7595,6 +7595,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
{
const struct btf_type *t, *func, *func_proto, *ptr_type;
struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_kfunc_arg_meta meta = { 0 };
const char *func_name, *ptr_type_name;
u32 i, nargs, func_id, ptr_type_id;
int err, insn_idx = *insn_idx_p;
@@ -7629,8 +7630,10 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
acq = *kfunc_flags & KF_ACQUIRE;
+ meta.flags = *kfunc_flags;
+
/* Check the arguments */
- err = btf_check_kfunc_arg_match(env, desc_btf, func_id, regs, *kfunc_flags);
+ err = btf_check_kfunc_arg_match(env, desc_btf, func_id, regs, &meta);
if (err < 0)
return err;
/* In case of release function, we get register number of refcounted
@@ -7651,7 +7654,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
/* Check return type */
t = btf_type_skip_modifiers(desc_btf, func_proto->type, NULL);
- if (acq && !btf_type_is_ptr(t)) {
+ if (acq && !btf_type_is_struct_ptr(desc_btf, t)) {
verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n");
return -EINVAL;
}
@@ -7663,17 +7666,33 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
ptr_type = btf_type_skip_modifiers(desc_btf, t->type,
&ptr_type_id);
if (!btf_type_is_struct(ptr_type)) {
- ptr_type_name = btf_name_by_offset(desc_btf,
- ptr_type->name_off);
- verbose(env, "kernel function %s returns pointer type %s %s is not supported\n",
- func_name, btf_type_str(ptr_type),
- ptr_type_name);
- return -EINVAL;
+ if (!meta.r0_size) {
+ ptr_type_name = btf_name_by_offset(desc_btf,
+ ptr_type->name_off);
+ verbose(env,
+ "kernel function %s returns pointer type %s %s is not supported\n",
+ func_name,
+ btf_type_str(ptr_type),
+ ptr_type_name);
+ return -EINVAL;
+ }
+
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_MEM;
+ regs[BPF_REG_0].mem_size = meta.r0_size;
+
+ if (meta.r0_rdonly)
+ regs[BPF_REG_0].type |= MEM_RDONLY;
+
+ /* Ensures we don't access the memory after a release_reference() */
+ if (meta.ref_obj_id)
+ regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id;
+ } else {
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].btf = desc_btf;
+ regs[BPF_REG_0].type = PTR_TO_BTF_ID;
+ regs[BPF_REG_0].btf_id = ptr_type_id;
}
- mark_reg_known_zero(env, regs, BPF_REG_0);
- regs[BPF_REG_0].btf = desc_btf;
- regs[BPF_REG_0].type = PTR_TO_BTF_ID;
- regs[BPF_REG_0].btf_id = ptr_type_id;
if (*kfunc_flags & KF_RET_NULL) {
regs[BPF_REG_0].type |= PTR_MAYBE_NULL;
/* For mark_ptr_or_null_reg, see 93c230e3f5bd6 */
generated by cgit v1.2.3-70-g09d2 (git 2.47.1) at 2024-12-28 18:39:47 +0000