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-rw-r--r--kernel/bpf/btf.c31
-rw-r--r--kernel/bpf/core.c23
-rw-r--r--kernel/bpf/verifier.c154
3 files changed, 178 insertions, 30 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 8d6bdb4f4d61..7ccc0133723a 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -458,7 +458,7 @@ static bool btf_type_is_datasec(const struct btf_type *t)
return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
}
-static u32 btf_nr_types_total(const struct btf *btf)
+u32 btf_nr_types(const struct btf *btf)
{
u32 total = 0;
@@ -476,7 +476,7 @@ s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
const char *tname;
u32 i, total;
- total = btf_nr_types_total(btf);
+ total = btf_nr_types(btf);
for (i = 1; i < total; i++) {
t = btf_type_by_id(btf, i);
if (BTF_INFO_KIND(t->info) != kind)
@@ -5743,6 +5743,11 @@ bool btf_is_kernel(const struct btf *btf)
return btf->kernel_btf;
}
+bool btf_is_module(const struct btf *btf)
+{
+ return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
+}
+
static int btf_id_cmp_func(const void *a, const void *b)
{
const int *pa = a, *pb = b;
@@ -5877,3 +5882,25 @@ static int __init btf_module_init(void)
fs_initcall(btf_module_init);
#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
+
+struct module *btf_try_get_module(const struct btf *btf)
+{
+ struct module *res = NULL;
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+ struct btf_module *btf_mod, *tmp;
+
+ mutex_lock(&btf_module_mutex);
+ list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
+ if (btf_mod->btf != btf)
+ continue;
+
+ if (try_module_get(btf_mod->module))
+ res = btf_mod->module;
+
+ break;
+ }
+ mutex_unlock(&btf_module_mutex);
+#endif
+
+ return res;
+}
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 261f8692d0d2..69c3c308de5e 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2119,6 +2119,28 @@ static void bpf_free_used_maps(struct bpf_prog_aux *aux)
kfree(aux->used_maps);
}
+void __bpf_free_used_btfs(struct bpf_prog_aux *aux,
+ struct btf_mod_pair *used_btfs, u32 len)
+{
+#ifdef CONFIG_BPF_SYSCALL
+ struct btf_mod_pair *btf_mod;
+ u32 i;
+
+ for (i = 0; i < len; i++) {
+ btf_mod = &used_btfs[i];
+ if (btf_mod->module)
+ module_put(btf_mod->module);
+ btf_put(btf_mod->btf);
+ }
+#endif
+}
+
+static void bpf_free_used_btfs(struct bpf_prog_aux *aux)
+{
+ __bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt);
+ kfree(aux->used_btfs);
+}
+
static void bpf_prog_free_deferred(struct work_struct *work)
{
struct bpf_prog_aux *aux;
@@ -2126,6 +2148,7 @@ static void bpf_prog_free_deferred(struct work_struct *work)
aux = container_of(work, struct bpf_prog_aux, work);
bpf_free_used_maps(aux);
+ bpf_free_used_btfs(aux);
if (bpf_prog_is_dev_bound(aux))
bpf_prog_offload_destroy(aux->prog);
#ifdef CONFIG_PERF_EVENTS
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 5534e667bdb1..ae2aee48cf82 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -9703,6 +9703,36 @@ process_bpf_exit:
return 0;
}
+static int find_btf_percpu_datasec(struct btf *btf)
+{
+ const struct btf_type *t;
+ const char *tname;
+ int i, n;
+
+ /*
+ * Both vmlinux and module each have their own ".data..percpu"
+ * DATASECs in BTF. So for module's case, we need to skip vmlinux BTF
+ * types to look at only module's own BTF types.
+ */
+ n = btf_nr_types(btf);
+ if (btf_is_module(btf))
+ i = btf_nr_types(btf_vmlinux);
+ else
+ i = 1;
+
+ for(; i < n; i++) {
+ t = btf_type_by_id(btf, i);
+ if (BTF_INFO_KIND(t->info) != BTF_KIND_DATASEC)
+ continue;
+
+ tname = btf_name_by_offset(btf, t->name_off);
+ if (!strcmp(tname, ".data..percpu"))
+ return i;
+ }
+
+ return -ENOENT;
+}
+
/* replace pseudo btf_id with kernel symbol address */
static int check_pseudo_btf_id(struct bpf_verifier_env *env,
struct bpf_insn *insn,
@@ -9710,48 +9740,57 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env,
{
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;
-
- if (!btf_vmlinux) {
- verbose(env, "kernel is missing BTF, make sure CONFIG_DEBUG_INFO_BTF=y is specified in Kconfig.\n");
- return -EINVAL;
- }
+ int i, btf_fd, err;
- if (insn[1].imm != 0) {
- verbose(env, "reserved field (insn[1].imm) is used in pseudo_btf_id ldimm64 insn.\n");
- return -EINVAL;
+ 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);
}
- t = btf_type_by_id(btf_vmlinux, id);
+ t = btf_type_by_id(btf, id);
if (!t) {
verbose(env, "ldimm64 insn specifies invalid btf_id %d.\n", id);
- return -ENOENT;
+ err = -ENOENT;
+ goto err_put;
}
if (!btf_type_is_var(t)) {
- verbose(env, "pseudo btf_id %d in ldimm64 isn't KIND_VAR.\n",
- id);
- return -EINVAL;
+ verbose(env, "pseudo btf_id %d in ldimm64 isn't KIND_VAR.\n", id);
+ err = -EINVAL;
+ goto err_put;
}
- sym_name = btf_name_by_offset(btf_vmlinux, t->name_off);
+ sym_name = btf_name_by_offset(btf, t->name_off);
addr = kallsyms_lookup_name(sym_name);
if (!addr) {
verbose(env, "ldimm64 failed to find the address for kernel symbol '%s'.\n",
sym_name);
- return -ENOENT;
+ err = -ENOENT;
+ goto err_put;
}
- datasec_id = btf_find_by_name_kind(btf_vmlinux, ".data..percpu",
- BTF_KIND_DATASEC);
+ datasec_id = find_btf_percpu_datasec(btf);
if (datasec_id > 0) {
- datasec = btf_type_by_id(btf_vmlinux, datasec_id);
+ datasec = btf_type_by_id(btf, datasec_id);
for_each_vsi(i, datasec, vsi) {
if (vsi->type == id) {
percpu = true;
@@ -9764,10 +9803,10 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env,
insn[1].imm = addr >> 32;
type = t->type;
- t = btf_type_skip_modifiers(btf_vmlinux, type, NULL);
+ t = btf_type_skip_modifiers(btf, type, NULL);
if (percpu) {
aux->btf_var.reg_type = PTR_TO_PERCPU_BTF_ID;
- aux->btf_var.btf = btf_vmlinux;
+ aux->btf_var.btf = btf;
aux->btf_var.btf_id = type;
} else if (!btf_type_is_struct(t)) {
const struct btf_type *ret;
@@ -9775,21 +9814,54 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env,
u32 tsize;
/* resolve the type size of ksym. */
- ret = btf_resolve_size(btf_vmlinux, t, &tsize);
+ ret = btf_resolve_size(btf, t, &tsize);
if (IS_ERR(ret)) {
- tname = btf_name_by_offset(btf_vmlinux, t->name_off);
+ 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));
- return -EINVAL;
+ err = -EINVAL;
+ goto err_put;
}
aux->btf_var.reg_type = PTR_TO_MEM;
aux->btf_var.mem_size = tsize;
} else {
aux->btf_var.reg_type = PTR_TO_BTF_ID;
- aux->btf_var.btf = btf_vmlinux;
+ aux->btf_var.btf = btf;
aux->btf_var.btf_id = type;
}
+
+ /* 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;
+ }
+
+ 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) {
+ err = -ENXIO;
+ goto err_put;
+ }
+ }
+
+ env->used_btf_cnt++;
+
return 0;
+err_put:
+ btf_put(btf);
+ return err;
}
static int check_map_prealloc(struct bpf_map *map)
@@ -10086,6 +10158,13 @@ static void release_maps(struct bpf_verifier_env *env)
env->used_map_cnt);
}
+/* drop refcnt of maps used by the rejected program */
+static void release_btfs(struct bpf_verifier_env *env)
+{
+ __bpf_free_used_btfs(env->prog->aux, env->used_btfs,
+ env->used_btf_cnt);
+}
+
/* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */
static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env)
{
@@ -12098,7 +12177,10 @@ skip_full_check:
goto err_release_maps;
}
- if (ret == 0 && env->used_map_cnt) {
+ if (ret)
+ goto err_release_maps;
+
+ if (env->used_map_cnt) {
/* if program passed verifier, update used_maps in bpf_prog_info */
env->prog->aux->used_maps = kmalloc_array(env->used_map_cnt,
sizeof(env->used_maps[0]),
@@ -12112,15 +12194,29 @@ skip_full_check:
memcpy(env->prog->aux->used_maps, env->used_maps,
sizeof(env->used_maps[0]) * env->used_map_cnt);
env->prog->aux->used_map_cnt = env->used_map_cnt;
+ }
+ if (env->used_btf_cnt) {
+ /* if program passed verifier, update used_btfs in bpf_prog_aux */
+ env->prog->aux->used_btfs = kmalloc_array(env->used_btf_cnt,
+ sizeof(env->used_btfs[0]),
+ GFP_KERNEL);
+ if (!env->prog->aux->used_btfs) {
+ ret = -ENOMEM;
+ goto err_release_maps;
+ }
+ memcpy(env->prog->aux->used_btfs, env->used_btfs,
+ sizeof(env->used_btfs[0]) * env->used_btf_cnt);
+ env->prog->aux->used_btf_cnt = env->used_btf_cnt;
+ }
+ if (env->used_map_cnt || env->used_btf_cnt) {
/* program is valid. Convert pseudo bpf_ld_imm64 into generic
* bpf_ld_imm64 instructions
*/
convert_pseudo_ld_imm64(env);
}
- if (ret == 0)
- adjust_btf_func(env);
+ adjust_btf_func(env);
err_release_maps:
if (!env->prog->aux->used_maps)
@@ -12128,6 +12224,8 @@ err_release_maps:
* them now. Otherwise free_used_maps() will release them.
*/
release_maps(env);
+ if (!env->prog->aux->used_btfs)
+ release_btfs(env);
/* extension progs temporarily inherit the attach_type of their targets
for verification purposes, so set it back to zero before returning
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-26 11:39:24 +0000