Introduce a helper to add btfs to the env->used_maps array. Use it
to simplify the check_pseudo_btf_id() function. This new helper will
also be re-used in a consequent patch.
Signed-off-by: Anton Protopopov <aspsk@xxxxxxxxxxxxx>
---
kernel/bpf/verifier.c | 132 ++++++++++++++++++++++++------------------
1 file changed, 76 insertions(+), 56 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 89bba0de853f..296765ffbdc5 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -19218,50 +19218,68 @@ static int find_btf_percpu_datasec(struct btf *btf)
return -ENOENT;
}
+/*
+ * Add btf to the used_btfs array and return the index. (If the btf was
+ * already added, then just return the index.) Upon successful insertion
+ * increase btf refcnt, and, if present, also refcount the corresponding
+ * kernel module.
+ */
+static int __add_used_btf(struct bpf_verifier_env *env, struct btf *btf)
+{
+ struct btf_mod_pair *btf_mod;
+ int i;
+
+ /* check whether we recorded this BTF (and maybe module) already */
+ for (i = 0; i < env->used_btf_cnt; i++)
+ if (env->used_btfs[i].btf == btf)
+ return i;
+
+ if (env->used_btf_cnt >= MAX_USED_BTFS)
+ return -E2BIG;
+
+ btf_get(btf);
+
+ btf_mod = &env->used_btfs[env->used_btf_cnt];
+ btf_mod->btf = btf;
+ btf_mod->module = NULL;
+
+ /* if we reference variables from kernel module, bump its refcount */
+ if (btf_is_module(btf)) {
+ btf_mod->module = btf_try_get_module(btf);
+ if (!btf_mod->module) {
+ btf_put(btf);
+ return -ENXIO;
+ }
+ }
+
+ return env->used_btf_cnt++;
+}
+
/* replace pseudo btf_id with kernel symbol address */
-static int check_pseudo_btf_id(struct bpf_verifier_env *env,
- struct bpf_insn *insn,
- struct bpf_insn_aux_data *aux)
+static int __check_pseudo_btf_id(struct bpf_verifier_env *env,
+ struct bpf_insn *insn,
+ struct bpf_insn_aux_data *aux,
+ struct btf *btf)
{
const struct btf_var_secinfo *vsi;
const struct btf_type *datasec;
- struct btf_mod_pair *btf_mod;
const struct btf_type *t;
const char *sym_name;
bool percpu = false;
u32 type, id = insn->imm;
- struct btf *btf;
s32 datasec_id;
u64 addr;
- int i, btf_fd, err;
-
- btf_fd = insn[1].imm;
- if (btf_fd) {
- btf = btf_get_by_fd(btf_fd);
- if (IS_ERR(btf)) {
- verbose(env, "invalid module BTF object FD specified.\n");
- return -EINVAL;
- }
- } else {
- if (!btf_vmlinux) {
- verbose(env, "kernel is missing BTF, make sure CONFIG_DEBUG_INFO_BTF=y is specified in Kconfig.\n");
- return -EINVAL;
- }
- btf = btf_vmlinux;
- btf_get(btf);
- }
+ int i;
t = btf_type_by_id(btf, id);
if (!t) {
verbose(env, "ldimm64 insn specifies invalid btf_id %d.\n", id);
- err = -ENOENT;
- goto err_put;
+ return -ENOENT;
}
if (!btf_type_is_var(t) && !btf_type_is_func(t)) {
verbose(env, "pseudo btf_id %d in ldimm64 isn't KIND_VAR or KIND_FUNC\n", id);
- err = -EINVAL;
- goto err_put;
+ return -EINVAL;
}
sym_name = btf_name_by_offset(btf, t->name_off);
@@ -19269,8 +19287,7 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env,
if (!addr) {
verbose(env, "ldimm64 failed to find the address for kernel symbol '%s'.\n",
sym_name);
- err = -ENOENT;
- goto err_put;
+ return -ENOENT;
}
insn[0].imm = (u32)addr;
insn[1].imm = addr >> 32;
@@ -19278,7 +19295,7 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env,
if (btf_type_is_func(t)) {
aux->btf_var.reg_type = PTR_TO_MEM | MEM_RDONLY;
aux->btf_var.mem_size = 0;
- goto check_btf;
+ return 0;
}
datasec_id = find_btf_percpu_datasec(btf);
@@ -19309,8 +19326,7 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env,
tname = btf_name_by_offset(btf, t->name_off);
verbose(env, "ldimm64 unable to resolve the size of type '%s': %ld\n",
tname, PTR_ERR(ret));
- err = -EINVAL;
- goto err_put;
+ return -EINVAL;
}
aux->btf_var.reg_type = PTR_TO_MEM | MEM_RDONLY;
aux->btf_var.mem_size = tsize;
@@ -19319,39 +19335,43 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env,
aux->btf_var.btf = btf;
aux->btf_var.btf_id = type;
}
-check_btf:
- /* check whether we recorded this BTF (and maybe module) already */
- for (i = 0; i < env->used_btf_cnt; i++) {
- if (env->used_btfs[i].btf == btf) {
- btf_put(btf);
- return 0;
- }
- }
- if (env->used_btf_cnt >= MAX_USED_BTFS) {
- err = -E2BIG;
- goto err_put;
- }
+ return 0;
+}
- btf_mod = &env->used_btfs[env->used_btf_cnt];
- btf_mod->btf = btf;
- btf_mod->module = NULL;
+static int check_pseudo_btf_id(struct bpf_verifier_env *env,
+ struct bpf_insn *insn,
+ struct bpf_insn_aux_data *aux)
+{
+ struct btf *btf;
+ int btf_fd;
+ int err;
- /* if we reference variables from kernel module, bump its refcount */
- if (btf_is_module(btf)) {
- btf_mod->module = btf_try_get_module(btf);
- if (!btf_mod->module) {
- err = -ENXIO;
- goto err_put;
+ btf_fd = insn[1].imm;
+ if (btf_fd) {
+ CLASS(fd, f)(btf_fd);
+
+ btf = __btf_get_by_fd(f);
+ if (IS_ERR(btf)) {
+ verbose(env, "invalid module BTF object FD specified.\n");
+ return -EINVAL;
}
+ } else {
+ if (!btf_vmlinux) {
+ verbose(env, "kernel is missing BTF, make sure CONFIG_DEBUG_INFO_BTF=y is specified in Kconfig.\n");
+ return -EINVAL;
+ }
+ btf = btf_vmlinux;
}
- env->used_btf_cnt++;
+ err = __check_pseudo_btf_id(env, insn, aux, btf);
+ if (err)
+ return err;
+ err = __add_used_btf(env, btf);
+ if (err < 0)
+ return err;
return 0;
-err_put:
- btf_put(btf);
- return err;
}
static bool is_tracing_prog_type(enum bpf_prog_type type)
--
2.34.1
