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-rw-r--r--include/linux/bpf.h3
-rw-r--r--kernel/bpf/bpf_struct_ops.c27
-rw-r--r--kernel/bpf/btf.c1
-rw-r--r--kernel/bpf/verifier.c35
4 files changed, 57 insertions, 9 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index f4df39e8c735..15164787ce7f 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -968,6 +968,7 @@ struct bpf_insn_access_aux {
struct {
struct btf *btf;
u32 btf_id;
+ u32 ref_obj_id;
};
};
struct bpf_verifier_log *log; /* for verbose logs */
@@ -1481,6 +1482,8 @@ struct bpf_ctx_arg_aux {
enum bpf_reg_type reg_type;
struct btf *btf;
u32 btf_id;
+ u32 ref_obj_id;
+ bool refcounted;
};
struct btf_mod_pair {
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index 9b7f3b9c5262..0ef00f7f64c9 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -146,6 +146,7 @@ void bpf_struct_ops_image_free(void *image)
}
#define MAYBE_NULL_SUFFIX "__nullable"
+#define REFCOUNTED_SUFFIX "__ref"
/* Prepare argument info for every nullable argument of a member of a
* struct_ops type.
@@ -174,11 +175,13 @@ static int prepare_arg_info(struct btf *btf,
struct bpf_struct_ops_arg_info *arg_info)
{
const struct btf_type *stub_func_proto, *pointed_type;
+ bool is_nullable = false, is_refcounted = false;
const struct btf_param *stub_args, *args;
struct bpf_ctx_arg_aux *info, *info_buf;
u32 nargs, arg_no, info_cnt = 0;
char ksym[KSYM_SYMBOL_LEN];
const char *stub_fname;
+ const char *suffix;
s32 stub_func_id;
u32 arg_btf_id;
int offset;
@@ -223,10 +226,18 @@ static int prepare_arg_info(struct btf *btf,
info = info_buf;
for (arg_no = 0; arg_no < nargs; arg_no++) {
/* Skip arguments that is not suffixed with
- * "__nullable".
+ * "__nullable or __ref".
*/
- if (!btf_param_match_suffix(btf, &stub_args[arg_no],
- MAYBE_NULL_SUFFIX))
+ is_nullable = btf_param_match_suffix(btf, &stub_args[arg_no],
+ MAYBE_NULL_SUFFIX);
+ is_refcounted = btf_param_match_suffix(btf, &stub_args[arg_no],
+ REFCOUNTED_SUFFIX);
+
+ if (is_nullable)
+ suffix = MAYBE_NULL_SUFFIX;
+ else if (is_refcounted)
+ suffix = REFCOUNTED_SUFFIX;
+ else
continue;
/* Should be a pointer to struct */
@@ -236,7 +247,7 @@ static int prepare_arg_info(struct btf *btf,
if (!pointed_type ||
!btf_type_is_struct(pointed_type)) {
pr_warn("stub function %s has %s tagging to an unsupported type\n",
- stub_fname, MAYBE_NULL_SUFFIX);
+ stub_fname, suffix);
goto err_out;
}
@@ -254,11 +265,15 @@ static int prepare_arg_info(struct btf *btf,
}
/* Fill the information of the new argument */
- info->reg_type =
- PTR_TRUSTED | PTR_TO_BTF_ID | PTR_MAYBE_NULL;
info->btf_id = arg_btf_id;
info->btf = btf;
info->offset = offset;
+ if (is_nullable) {
+ info->reg_type = PTR_TRUSTED | PTR_TO_BTF_ID | PTR_MAYBE_NULL;
+ } else if (is_refcounted) {
+ info->reg_type = PTR_TRUSTED | PTR_TO_BTF_ID;
+ info->refcounted = true;
+ }
info++;
info_cnt++;
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index f8335bdc8bf8..69f5752e880b 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -6774,6 +6774,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
info->reg_type = ctx_arg_info->reg_type;
info->btf = ctx_arg_info->btf ? : btf_vmlinux;
info->btf_id = ctx_arg_info->btf_id;
+ info->ref_obj_id = ctx_arg_info->ref_obj_id;
return true;
}
}
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index a231223d985b..c2762b56e604 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1543,6 +1543,17 @@ static void release_reference_state(struct bpf_verifier_state *state, int idx)
return;
}
+static bool find_reference_state(struct bpf_verifier_state *state, int ptr_id)
+{
+ int i;
+
+ for (i = 0; i < state->acquired_refs; i++)
+ if (state->refs[i].id == ptr_id)
+ return true;
+
+ return false;
+}
+
static int release_lock_state(struct bpf_verifier_state *state, int type, int id, void *ptr)
{
int i;
@@ -5981,7 +5992,8 @@ static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off,
/* check access to 'struct bpf_context' fields. Supports fixed offsets only */
static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size,
enum bpf_access_type t, enum bpf_reg_type *reg_type,
- struct btf **btf, u32 *btf_id, bool *is_retval, bool is_ldsx)
+ struct btf **btf, u32 *btf_id, bool *is_retval, bool is_ldsx,
+ u32 *ref_obj_id)
{
struct bpf_insn_access_aux info = {
.reg_type = *reg_type,
@@ -6003,8 +6015,16 @@ static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off,
*is_retval = info.is_retval;
if (base_type(*reg_type) == PTR_TO_BTF_ID) {
+ if (info.ref_obj_id &&
+ !find_reference_state(env->cur_state, info.ref_obj_id)) {
+ verbose(env, "invalid bpf_context access off=%d. Reference may already be released\n",
+ off);
+ return -EACCES;
+ }
+
*btf = info.btf;
*btf_id = info.btf_id;
+ *ref_obj_id = info.ref_obj_id;
} else {
env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size;
}
@@ -7367,7 +7387,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
struct bpf_retval_range range;
enum bpf_reg_type reg_type = SCALAR_VALUE;
struct btf *btf = NULL;
- u32 btf_id = 0;
+ u32 btf_id = 0, ref_obj_id = 0;
if (t == BPF_WRITE && value_regno >= 0 &&
is_pointer_value(env, value_regno)) {
@@ -7380,7 +7400,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
return err;
err = check_ctx_access(env, insn_idx, off, size, t, &reg_type, &btf,
- &btf_id, &is_retval, is_ldsx);
+ &btf_id, &is_retval, is_ldsx, &ref_obj_id);
if (err)
verbose_linfo(env, insn_idx, "; ");
if (!err && t == BPF_READ && value_regno >= 0) {
@@ -7411,6 +7431,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
if (base_type(reg_type) == PTR_TO_BTF_ID) {
regs[value_regno].btf = btf;
regs[value_regno].btf_id = btf_id;
+ regs[value_regno].ref_obj_id = ref_obj_id;
}
}
regs[value_regno].type = reg_type;
@@ -22176,6 +22197,7 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog)
{
bool pop_log = !(env->log.level & BPF_LOG_LEVEL2);
struct bpf_subprog_info *sub = subprog_info(env, subprog);
+ struct bpf_prog_aux *aux = env->prog->aux;
struct bpf_verifier_state *state;
struct bpf_reg_state *regs;
int ret, i;
@@ -22283,6 +22305,13 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog)
mark_reg_known_zero(env, regs, BPF_REG_1);
}
+ /* Acquire references for struct_ops program arguments tagged with "__ref" */
+ if (!subprog && env->prog->type == BPF_PROG_TYPE_STRUCT_OPS) {
+ for (i = 0; i < aux->ctx_arg_info_size; i++)
+ aux->ctx_arg_info[i].ref_obj_id = aux->ctx_arg_info[i].refcounted ?
+ acquire_reference(env, 0) : 0;
+ }
+
ret = do_check(env);
out:
/* check for NULL is necessary, since cur_state can be freed inside
generated by cgit (git 2.34.1) at 2025-06-18 00:24:51 +0000