summaryrefslogtreecommitdiff
path: root/kernel
diff options
context:
space:
mode:
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/btf.c40
-rw-r--r--kernel/bpf/verifier.c94
2 files changed, 90 insertions, 44 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index b472cf0c8fdb..162807e3b4a5 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -5726,7 +5726,7 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
const char *func_name, *ref_tname;
const struct btf_type *t, *ref_t;
const struct btf_param *args;
- int ref_regno = 0;
+ int ref_regno = 0, ret;
bool rel = false;
t = btf_type_by_id(btf, func_id);
@@ -5753,6 +5753,10 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
return -EINVAL;
}
+ /* Only kfunc can be release func */
+ if (is_kfunc)
+ rel = btf_kfunc_id_set_contains(btf, resolve_prog_type(env->prog),
+ BTF_KFUNC_TYPE_RELEASE, func_id);
/* check that BTF function arguments match actual types that the
* verifier sees.
*/
@@ -5776,6 +5780,11 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
ref_tname = btf_name_by_offset(btf, ref_t->name_off);
+
+ ret = check_func_arg_reg_off(env, reg, regno, ARG_DONTCARE, rel);
+ if (ret < 0)
+ return ret;
+
if (btf_get_prog_ctx_type(log, btf, t,
env->prog->type, i)) {
/* If function expects ctx type in BTF check that caller
@@ -5787,8 +5796,6 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
i, btf_type_str(t));
return -EINVAL;
}
- if (check_ptr_off_reg(env, reg, regno))
- return -EINVAL;
} else if (is_kfunc && (reg->type == PTR_TO_BTF_ID ||
(reg2btf_ids[base_type(reg->type)] && !type_flag(reg->type)))) {
const struct btf_type *reg_ref_t;
@@ -5806,7 +5813,11 @@ 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 */
+ /* Ensure only one argument is referenced
+ * PTR_TO_BTF_ID, check_func_arg_reg_off relies
+ * on only one referenced register being allowed
+ * for kfuncs.
+ */
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",
@@ -5888,18 +5899,15 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
/* Either both are set, or neither */
WARN_ON_ONCE((ref_obj_id && !ref_regno) || (!ref_obj_id && ref_regno));
- if (is_kfunc) {
- rel = btf_kfunc_id_set_contains(btf, resolve_prog_type(env->prog),
- BTF_KFUNC_TYPE_RELEASE, func_id);
- /* We already made sure ref_obj_id is set only for one argument */
- if (rel && !ref_obj_id) {
- bpf_log(log, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n",
- func_name);
- return -EINVAL;
- }
- /* Allow (!rel && ref_obj_id), so that passing such referenced PTR_TO_BTF_ID to
- * other kfuncs works
- */
+ /* We already made sure ref_obj_id is set only for one argument. We do
+ * allow (!rel && ref_obj_id), so that passing such referenced
+ * PTR_TO_BTF_ID to other kfuncs works. Note that rel is only true when
+ * is_kfunc is true.
+ */
+ if (rel && !ref_obj_id) {
+ bpf_log(log, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n",
+ func_name);
+ return -EINVAL;
}
/* returns argument register number > 0 in case of reference release kfunc */
return rel ? ref_regno : 0;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index a57db4b2803c..fe9a513e2314 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3990,6 +3990,12 @@ static int __check_ptr_off_reg(struct bpf_verifier_env *env,
* is only allowed in its original, unmodified form.
*/
+ if (reg->off < 0) {
+ verbose(env, "negative offset %s ptr R%d off=%d disallowed\n",
+ reg_type_str(env, reg->type), regno, reg->off);
+ return -EACCES;
+ }
+
if (!fixed_off_ok && reg->off) {
verbose(env, "dereference of modified %s ptr R%d off=%d disallowed\n",
reg_type_str(env, reg->type), regno, reg->off);
@@ -5359,6 +5365,60 @@ found:
return 0;
}
+int check_func_arg_reg_off(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg, int regno,
+ enum bpf_arg_type arg_type,
+ bool is_release_func)
+{
+ bool fixed_off_ok = false, release_reg;
+ enum bpf_reg_type type = reg->type;
+
+ switch ((u32)type) {
+ case SCALAR_VALUE:
+ /* Pointer types where reg offset is explicitly allowed: */
+ case PTR_TO_PACKET:
+ case PTR_TO_PACKET_META:
+ case PTR_TO_MAP_KEY:
+ case PTR_TO_MAP_VALUE:
+ case PTR_TO_MEM:
+ case PTR_TO_MEM | MEM_RDONLY:
+ case PTR_TO_MEM | MEM_ALLOC:
+ case PTR_TO_BUF:
+ case PTR_TO_BUF | MEM_RDONLY:
+ case PTR_TO_STACK:
+ /* Some of the argument types nevertheless require a
+ * zero register offset.
+ */
+ if (arg_type != ARG_PTR_TO_ALLOC_MEM)
+ return 0;
+ break;
+ /* All the rest must be rejected, except PTR_TO_BTF_ID which allows
+ * fixed offset.
+ */
+ case PTR_TO_BTF_ID:
+ /* When referenced PTR_TO_BTF_ID is passed to release function,
+ * it's fixed offset must be 0. We rely on the property that
+ * only one referenced register can be passed to BPF helpers and
+ * kfuncs. In the other cases, fixed offset can be non-zero.
+ */
+ release_reg = is_release_func && reg->ref_obj_id;
+ if (release_reg && reg->off) {
+ verbose(env, "R%d must have zero offset when passed to release func\n",
+ regno);
+ return -EINVAL;
+ }
+ /* For release_reg == true, fixed_off_ok must be false, but we
+ * already checked and rejected reg->off != 0 above, so set to
+ * true to allow fixed offset for all other cases.
+ */
+ fixed_off_ok = true;
+ break;
+ default:
+ break;
+ }
+ return __check_ptr_off_reg(env, reg, regno, fixed_off_ok);
+}
+
static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
struct bpf_call_arg_meta *meta,
const struct bpf_func_proto *fn)
@@ -5408,36 +5468,14 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
if (err)
return err;
- switch ((u32)type) {
- case SCALAR_VALUE:
- /* Pointer types where reg offset is explicitly allowed: */
- case PTR_TO_PACKET:
- case PTR_TO_PACKET_META:
- case PTR_TO_MAP_KEY:
- case PTR_TO_MAP_VALUE:
- case PTR_TO_MEM:
- case PTR_TO_MEM | MEM_RDONLY:
- case PTR_TO_MEM | MEM_ALLOC:
- case PTR_TO_BUF:
- case PTR_TO_BUF | MEM_RDONLY:
- case PTR_TO_STACK:
- /* Some of the argument types nevertheless require a
- * zero register offset.
- */
- if (arg_type == ARG_PTR_TO_ALLOC_MEM)
- goto force_off_check;
- break;
- /* All the rest must be rejected: */
- default:
-force_off_check:
- err = __check_ptr_off_reg(env, reg, regno,
- type == PTR_TO_BTF_ID);
- if (err < 0)
- return err;
- break;
- }
+ err = check_func_arg_reg_off(env, reg, regno, arg_type, is_release_function(meta->func_id));
+ if (err)
+ return err;
skip_type_check:
+ /* check_func_arg_reg_off relies on only one referenced register being
+ * allowed for BPF helpers.
+ */
if (reg->ref_obj_id) {
if (meta->ref_obj_id) {
verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
generated by cgit v1.2.3 (git 2.46.0) at 2025-09-28 20:02:17 +0000