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Diffstat (limited to 'kernel/bpf/btf.c')
-rw-r--r--kernel/bpf/btf.c65
1 files changed, 44 insertions, 21 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 6b2d508b33d4..7a19bf5bfe97 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -1524,6 +1524,11 @@ static void btf_free_rcu(struct rcu_head *rcu)
btf_free(btf);
}
+void btf_get(struct btf *btf)
+{
+ refcount_inc(&btf->refcnt);
+}
+
void btf_put(struct btf *btf)
{
if (btf && refcount_dec_and_test(&btf->refcnt)) {
@@ -4555,11 +4560,10 @@ struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
{
struct bpf_prog *tgt_prog = prog->aux->dst_prog;
- if (tgt_prog) {
+ if (tgt_prog)
return tgt_prog->aux->btf;
- } else {
- return btf_vmlinux;
- }
+ else
+ return prog->aux->attach_btf;
}
static bool is_string_ptr(struct btf *btf, const struct btf_type *t)
@@ -4700,6 +4704,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
if (ctx_arg_info->offset == off) {
info->reg_type = ctx_arg_info->reg_type;
+ info->btf = btf_vmlinux;
info->btf_id = ctx_arg_info->btf_id;
return true;
}
@@ -4716,6 +4721,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
if (ret > 0) {
+ info->btf = btf_vmlinux;
info->btf_id = ret;
return true;
} else {
@@ -4723,6 +4729,7 @@ 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);
/* skip modifiers */
@@ -4749,7 +4756,7 @@ enum bpf_struct_walk_result {
WALK_STRUCT,
};
-static int btf_struct_walk(struct bpf_verifier_log *log,
+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)
{
@@ -4760,7 +4767,7 @@ static int btf_struct_walk(struct bpf_verifier_log *log,
u32 vlen, elem_id, mid;
again:
- tname = __btf_name_by_offset(btf_vmlinux, t->name_off);
+ tname = __btf_name_by_offset(btf, t->name_off);
if (!btf_type_is_struct(t)) {
bpf_log(log, "Type '%s' is not a struct\n", tname);
return -EINVAL;
@@ -4777,7 +4784,7 @@ again:
goto error;
member = btf_type_member(t) + vlen - 1;
- mtype = btf_type_skip_modifiers(btf_vmlinux, member->type,
+ mtype = btf_type_skip_modifiers(btf, member->type,
NULL);
if (!btf_type_is_array(mtype))
goto error;
@@ -4793,7 +4800,7 @@ again:
/* Only allow structure for now, can be relaxed for
* other types later.
*/
- t = btf_type_skip_modifiers(btf_vmlinux, array_elem->type,
+ t = btf_type_skip_modifiers(btf, array_elem->type,
NULL);
if (!btf_type_is_struct(t))
goto error;
@@ -4851,10 +4858,10 @@ error:
/* type of the field */
mid = member->type;
- mtype = btf_type_by_id(btf_vmlinux, member->type);
- mname = __btf_name_by_offset(btf_vmlinux, member->name_off);
+ mtype = btf_type_by_id(btf, member->type);
+ mname = __btf_name_by_offset(btf, member->name_off);
- mtype = __btf_resolve_size(btf_vmlinux, mtype, &msize,
+ mtype = __btf_resolve_size(btf, mtype, &msize,
&elem_type, &elem_id, &total_nelems,
&mid);
if (IS_ERR(mtype)) {
@@ -4949,7 +4956,7 @@ error:
mname, moff, tname, off, size);
return -EACCES;
}
- stype = btf_type_skip_modifiers(btf_vmlinux, mtype->type, &id);
+ stype = btf_type_skip_modifiers(btf, mtype->type, &id);
if (btf_type_is_struct(stype)) {
*next_btf_id = id;
return WALK_PTR;
@@ -4975,7 +4982,7 @@ error:
return -EINVAL;
}
-int btf_struct_access(struct bpf_verifier_log *log,
+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)
@@ -4984,7 +4991,7 @@ int btf_struct_access(struct bpf_verifier_log *log,
u32 id;
do {
- err = btf_struct_walk(log, t, off, size, &id);
+ err = btf_struct_walk(log, btf, t, off, size, &id);
switch (err) {
case WALK_PTR:
@@ -5000,7 +5007,7 @@ int btf_struct_access(struct bpf_verifier_log *log,
* by diving in it. At this point the offset is
* aligned with the new type, so set it to 0.
*/
- t = btf_type_by_id(btf_vmlinux, id);
+ t = btf_type_by_id(btf, id);
off = 0;
break;
default:
@@ -5016,21 +5023,37 @@ int btf_struct_access(struct bpf_verifier_log *log,
return -EINVAL;
}
+/* Check that two BTF types, each specified as an BTF object + id, are exactly
+ * the same. Trivial ID check is not enough due to module BTFs, because we can
+ * end up with two different module BTFs, but IDs point to the common type in
+ * vmlinux BTF.
+ */
+static bool btf_types_are_same(const struct btf *btf1, u32 id1,
+ const struct btf *btf2, u32 id2)
+{
+ if (id1 != id2)
+ return false;
+ if (btf1 == btf2)
+ return true;
+ return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
+}
+
bool btf_struct_ids_match(struct bpf_verifier_log *log,
- int off, u32 id, u32 need_type_id)
+ const struct btf *btf, u32 id, int off,
+ const struct btf *need_btf, u32 need_type_id)
{
const struct btf_type *type;
int err;
/* Are we already done? */
- if (need_type_id == id && off == 0)
+ if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
return true;
again:
- type = btf_type_by_id(btf_vmlinux, id);
+ type = btf_type_by_id(btf, id);
if (!type)
return false;
- err = btf_struct_walk(log, type, off, 1, &id);
+ err = btf_struct_walk(log, btf, type, off, 1, &id);
if (err != WALK_STRUCT)
return false;
@@ -5039,7 +5062,7 @@ again:
* continue the search with offset 0 in the new
* type.
*/
- if (need_type_id != id) {
+ if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
off = 0;
goto again;
}
@@ -5710,7 +5733,7 @@ int btf_get_fd_by_id(u32 id)
return fd;
}
-u32 btf_id(const struct btf *btf)
+u32 btf_obj_id(const struct btf *btf)
{
return btf->id;
}
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-01 17:26:47 +0100