const char *func_name,
struct btf_func_model *m);
-struct bpf_kfunc_arg_meta {
- u64 r0_size;
- bool r0_rdonly;
- int ref_obj_id;
- u32 flags;
-};
-
struct bpf_reg_state;
int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
struct bpf_reg_state *regs);
int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog,
struct bpf_reg_state *regs);
-int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
- const struct btf *btf, u32 func_id,
- struct bpf_reg_state *regs,
- struct bpf_kfunc_arg_meta *meta);
int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
struct bpf_reg_state *reg);
int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
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);
-int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
- u32 regno);
int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
u32 regno, u32 mem_size);
bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env,
return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
}
+static inline bool __btf_type_is_struct(const struct btf_type *t)
+{
+ return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
+}
+
+static inline bool btf_type_is_array(const struct btf_type *t)
+{
+ return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
+}
+
static inline u16 btf_type_vlen(const struct btf_type *t)
{
return BTF_INFO_VLEN(t->info);
return bsearch(&id, set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func);
}
-#ifdef CONFIG_BPF_SYSCALL
struct bpf_prog;
+struct bpf_verifier_log;
+#ifdef CONFIG_BPF_SYSCALL
const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);
const char *btf_name_by_offset(const struct btf *btf, u32 offset);
struct btf *btf_parse_vmlinux(void);
int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
struct module *owner);
struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id);
+const struct btf_member *
+btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
+ const struct btf_type *t, enum bpf_prog_type prog_type,
+ int arg);
+bool btf_types_are_same(const struct btf *btf1, u32 id1,
+ const struct btf *btf2, u32 id2);
#else
static inline const struct btf_type *btf_type_by_id(const struct btf *btf,
u32 type_id)
{
return NULL;
}
+static inline const struct btf_member *
+btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
+ const struct btf_type *t, enum bpf_prog_type prog_type,
+ int arg)
+{
+ return NULL;
+}
+static inline bool btf_types_are_same(const struct btf *btf1, u32 id1,
+ const struct btf *btf2, u32 id2)
+{
+ return false;
+}
#endif
static inline bool btf_type_is_struct_ptr(struct btf *btf, const struct btf_type *t)
return !t || btf_type_nosize(t);
}
-static bool __btf_type_is_struct(const struct btf_type *t)
-{
- return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
-}
-
-static bool btf_type_is_array(const struct btf_type *t)
-{
- return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
-}
-
static bool btf_type_is_datasec(const struct btf_type *t)
{
return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
#undef BPF_MAP_TYPE
#undef BPF_LINK_TYPE
-static const struct btf_member *
+const struct btf_member *
btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
const struct btf_type *t, enum bpf_prog_type prog_type,
int arg)
* 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)
+bool btf_types_are_same(const struct btf *btf1, u32 id1,
+ const struct btf *btf2, u32 id2)
{
if (id1 != id2)
return false;
return btf_check_func_type_match(log, btf1, t1, btf2, t2);
}
-static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
-#ifdef CONFIG_NET
- [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
- [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
- [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
-#endif
-};
-
-/* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
-static bool __btf_type_is_scalar_struct(struct bpf_verifier_log *log,
- const struct btf *btf,
- const struct btf_type *t, int rec)
-{
- const struct btf_type *member_type;
- const struct btf_member *member;
- u32 i;
-
- if (!btf_type_is_struct(t))
- return false;
-
- for_each_member(i, t, member) {
- const struct btf_array *array;
-
- member_type = btf_type_skip_modifiers(btf, member->type, NULL);
- if (btf_type_is_struct(member_type)) {
- if (rec >= 3) {
- bpf_log(log, "max struct nesting depth exceeded\n");
- return false;
- }
- if (!__btf_type_is_scalar_struct(log, btf, member_type, rec + 1))
- return false;
- continue;
- }
- if (btf_type_is_array(member_type)) {
- array = btf_type_array(member_type);
- if (!array->nelems)
- return false;
- member_type = btf_type_skip_modifiers(btf, array->type, NULL);
- if (!btf_type_is_scalar(member_type))
- return false;
- continue;
- }
- if (!btf_type_is_scalar(member_type))
- return false;
- }
- return true;
-}
-
-static bool is_kfunc_arg_mem_size(const struct btf *btf,
- const struct btf_param *arg,
- const struct bpf_reg_state *reg)
-{
- int len, sfx_len = sizeof("__sz") - 1;
- const struct btf_type *t;
- const char *param_name;
-
- t = btf_type_skip_modifiers(btf, arg->type, NULL);
- if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
- return false;
-
- /* In the future, this can be ported to use BTF tagging */
- param_name = btf_name_by_offset(btf, arg->name_off);
- if (str_is_empty(param_name))
- return false;
- len = strlen(param_name);
- if (len < sfx_len)
- return false;
- param_name += len - sfx_len;
- if (strncmp(param_name, "__sz", sfx_len))
- return false;
-
- return true;
-}
-
-static bool btf_is_kfunc_arg_mem_size(const struct btf *btf,
- const struct btf_param *arg,
- const struct bpf_reg_state *reg,
- const char *name)
-{
- int len, target_len = strlen(name);
- const struct btf_type *t;
- const char *param_name;
-
- t = btf_type_skip_modifiers(btf, arg->type, NULL);
- if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
- return false;
-
- param_name = btf_name_by_offset(btf, arg->name_off);
- if (str_is_empty(param_name))
- return false;
- len = strlen(param_name);
- if (len != target_len)
- return false;
- if (strcmp(param_name, name))
- return false;
-
- return true;
-}
-
static int btf_check_func_arg_match(struct bpf_verifier_env *env,
const struct btf *btf, u32 func_id,
struct bpf_reg_state *regs,
bool ptr_to_mem_ok,
- struct bpf_kfunc_arg_meta *kfunc_meta,
bool processing_call)
{
enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
- bool rel = false, kptr_get = false, trusted_args = false;
- bool sleepable = false;
struct bpf_verifier_log *log = &env->log;
- u32 i, nargs, ref_id, ref_obj_id = 0;
- bool is_kfunc = btf_is_kernel(btf);
const char *func_name, *ref_tname;
const struct btf_type *t, *ref_t;
const struct btf_param *args;
- int ref_regno = 0, ret;
+ u32 i, nargs, ref_id;
+ int ret;
t = btf_type_by_id(btf, func_id);
if (!t || !btf_type_is_func(t)) {
return -EINVAL;
}
- if (is_kfunc && kfunc_meta) {
- /* Only kfunc can be release func */
- rel = kfunc_meta->flags & KF_RELEASE;
- kptr_get = kfunc_meta->flags & KF_KPTR_GET;
- trusted_args = kfunc_meta->flags & KF_TRUSTED_ARGS;
- sleepable = kfunc_meta->flags & KF_SLEEPABLE;
- }
-
/* check that BTF function arguments match actual types that the
* verifier sees.
*/
enum bpf_arg_type arg_type = ARG_DONTCARE;
u32 regno = i + 1;
struct bpf_reg_state *reg = ®s[regno];
- bool obj_ptr = false;
t = btf_type_skip_modifiers(btf, args[i].type, NULL);
if (btf_type_is_scalar(t)) {
- if (is_kfunc && kfunc_meta) {
- bool is_buf_size = false;
-
- /* check for any const scalar parameter of name "rdonly_buf_size"
- * or "rdwr_buf_size"
- */
- if (btf_is_kfunc_arg_mem_size(btf, &args[i], reg,
- "rdonly_buf_size")) {
- kfunc_meta->r0_rdonly = true;
- is_buf_size = true;
- } else if (btf_is_kfunc_arg_mem_size(btf, &args[i], reg,
- "rdwr_buf_size"))
- is_buf_size = true;
-
- if (is_buf_size) {
- if (kfunc_meta->r0_size) {
- bpf_log(log, "2 or more rdonly/rdwr_buf_size parameters for kfunc");
- return -EINVAL;
- }
-
- if (!tnum_is_const(reg->var_off)) {
- bpf_log(log, "R%d is not a const\n", regno);
- return -EINVAL;
- }
-
- kfunc_meta->r0_size = reg->var_off.value;
- ret = mark_chain_precision(env, regno);
- if (ret)
- return ret;
- }
- }
-
if (reg->type == SCALAR_VALUE)
continue;
bpf_log(log, "R%d is not a scalar\n", regno);
return -EINVAL;
}
- /* These register types have special constraints wrt ref_obj_id
- * and offset checks. The rest of trusted args don't.
- */
- obj_ptr = reg->type == PTR_TO_CTX || reg->type == PTR_TO_BTF_ID ||
- reg2btf_ids[base_type(reg->type)];
-
- /* Check if argument must be a referenced pointer, args + i has
- * been verified to be a pointer (after skipping modifiers).
- * PTR_TO_CTX is ok without having non-zero ref_obj_id.
- */
- if (is_kfunc && trusted_args && (obj_ptr && reg->type != PTR_TO_CTX) && !reg->ref_obj_id) {
- bpf_log(log, "R%d must be referenced\n", regno);
- return -EINVAL;
- }
-
ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
ref_tname = btf_name_by_offset(btf, ref_t->name_off);
- /* Trusted args have the same offset checks as release arguments */
- if ((trusted_args && obj_ptr) || (rel && reg->ref_obj_id))
- arg_type |= OBJ_RELEASE;
ret = check_func_arg_reg_off(env, reg, regno, arg_type);
if (ret < 0)
return ret;
- if (is_kfunc && reg->ref_obj_id) {
- /* Ensure only one argument is referenced PTR_TO_BTF_ID */
- if (ref_obj_id) {
- bpf_log(log, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
- regno, reg->ref_obj_id, ref_obj_id);
- return -EFAULT;
- }
- ref_regno = regno;
- ref_obj_id = reg->ref_obj_id;
- }
-
- /* kptr_get is only true for kfunc */
- if (i == 0 && kptr_get) {
- struct btf_field *kptr_field;
-
- if (reg->type != PTR_TO_MAP_VALUE) {
- bpf_log(log, "arg#0 expected pointer to map value\n");
- return -EINVAL;
- }
-
- /* check_func_arg_reg_off allows var_off for
- * PTR_TO_MAP_VALUE, but we need fixed offset to find
- * off_desc.
- */
- if (!tnum_is_const(reg->var_off)) {
- bpf_log(log, "arg#0 must have constant offset\n");
- return -EINVAL;
- }
-
- kptr_field = btf_record_find(reg->map_ptr->record, reg->off + reg->var_off.value, BPF_KPTR);
- if (!kptr_field || kptr_field->type != BPF_KPTR_REF) {
- bpf_log(log, "arg#0 no referenced kptr at map value offset=%llu\n",
- reg->off + reg->var_off.value);
- return -EINVAL;
- }
-
- if (!btf_type_is_ptr(ref_t)) {
- bpf_log(log, "arg#0 BTF type must be a double pointer\n");
- return -EINVAL;
- }
-
- ref_t = btf_type_skip_modifiers(btf, ref_t->type, &ref_id);
- ref_tname = btf_name_by_offset(btf, ref_t->name_off);
-
- if (!btf_type_is_struct(ref_t)) {
- bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n",
- func_name, i, btf_type_str(ref_t), ref_tname);
- return -EINVAL;
- }
- if (!btf_struct_ids_match(log, btf, ref_id, 0, kptr_field->kptr.btf,
- kptr_field->kptr.btf_id, true)) {
- bpf_log(log, "kernel function %s args#%d expected pointer to %s %s\n",
- func_name, i, btf_type_str(ref_t), ref_tname);
- return -EINVAL;
- }
- /* rest of the arguments can be anything, like normal kfunc */
- } else if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
+ if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
/* If function expects ctx type in BTF check that caller
* is passing PTR_TO_CTX.
*/
i, btf_type_str(t));
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;
- const struct btf *reg_btf;
- const char *reg_ref_tname;
- u32 reg_ref_id;
-
- if (!btf_type_is_struct(ref_t)) {
- bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n",
- func_name, i, btf_type_str(ref_t),
- ref_tname);
- return -EINVAL;
- }
-
- if (reg->type == PTR_TO_BTF_ID) {
- reg_btf = reg->btf;
- reg_ref_id = reg->btf_id;
- } else {
- reg_btf = btf_vmlinux;
- reg_ref_id = *reg2btf_ids[base_type(reg->type)];
- }
-
- reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id,
- ®_ref_id);
- reg_ref_tname = btf_name_by_offset(reg_btf,
- reg_ref_t->name_off);
- if (!btf_struct_ids_match(log, reg_btf, reg_ref_id,
- reg->off, btf, ref_id,
- trusted_args || (rel && reg->ref_obj_id))) {
- bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
- func_name, i,
- btf_type_str(ref_t), ref_tname,
- regno, btf_type_str(reg_ref_t),
- reg_ref_tname);
- return -EINVAL;
- }
} else if (ptr_to_mem_ok && processing_call) {
const struct btf_type *resolve_ret;
u32 type_size;
- if (is_kfunc) {
- bool arg_mem_size = i + 1 < nargs && is_kfunc_arg_mem_size(btf, &args[i + 1], ®s[regno + 1]);
- bool arg_dynptr = btf_type_is_struct(ref_t) &&
- !strcmp(ref_tname,
- stringify_struct(bpf_dynptr_kern));
-
- /* Permit pointer to mem, but only when argument
- * type is pointer to scalar, or struct composed
- * (recursively) of scalars.
- * When arg_mem_size is true, the pointer can be
- * void *.
- * Also permit initialized local dynamic pointers.
- */
- if (!btf_type_is_scalar(ref_t) &&
- !__btf_type_is_scalar_struct(log, btf, ref_t, 0) &&
- !arg_dynptr &&
- (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) {
- bpf_log(log,
- "arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n",
- i, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : "");
- return -EINVAL;
- }
-
- if (arg_dynptr) {
- if (reg->type != PTR_TO_STACK) {
- bpf_log(log, "arg#%d pointer type %s %s not to stack\n",
- i, btf_type_str(ref_t),
- ref_tname);
- return -EINVAL;
- }
-
- if (!is_dynptr_reg_valid_init(env, reg)) {
- bpf_log(log,
- "arg#%d pointer type %s %s must be valid and initialized\n",
- i, btf_type_str(ref_t),
- ref_tname);
- return -EINVAL;
- }
-
- if (!is_dynptr_type_expected(env, reg,
- ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL)) {
- bpf_log(log,
- "arg#%d pointer type %s %s points to unsupported dynamic pointer type\n",
- i, btf_type_str(ref_t),
- ref_tname);
- return -EINVAL;
- }
-
- continue;
- }
-
- /* Check for mem, len pair */
- if (arg_mem_size) {
- if (check_kfunc_mem_size_reg(env, ®s[regno + 1], regno + 1)) {
- bpf_log(log, "arg#%d arg#%d memory, len pair leads to invalid memory access\n",
- i, i + 1);
- return -EINVAL;
- }
- i++;
- continue;
- }
- }
-
resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
if (IS_ERR(resolve_ret)) {
bpf_log(log,
if (check_mem_reg(env, reg, regno, type_size))
return -EINVAL;
} else {
- bpf_log(log, "reg type unsupported for arg#%d %sfunction %s#%d\n", i,
- is_kfunc ? "kernel " : "", func_name, func_id);
+ bpf_log(log, "reg type unsupported for arg#%d function %s#%d\n", i,
+ func_name, func_id);
return -EINVAL;
}
}
- /* Either both are set, or neither */
- WARN_ON_ONCE((ref_obj_id && !ref_regno) || (!ref_obj_id && ref_regno));
- /* 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;
- }
-
- if (sleepable && !env->prog->aux->sleepable) {
- bpf_log(log, "kernel function %s is sleepable but the program is not\n",
- func_name);
- return -EINVAL;
- }
-
- if (kfunc_meta && ref_obj_id)
- kfunc_meta->ref_obj_id = ref_obj_id;
-
- /* returns argument register number > 0 in case of reference release kfunc */
- return rel ? ref_regno : 0;
+ return 0;
}
/* Compare BTF of a function declaration with given bpf_reg_state.
return -EINVAL;
is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
- err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, NULL, false);
+ err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, false);
/* Compiler optimizations can remove arguments from static functions
* or mismatched type can be passed into a global function.
return -EINVAL;
is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
- err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, NULL, true);
+ err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, true);
/* Compiler optimizations can remove arguments from static functions
* or mismatched type can be passed into a global function.
return err;
}
-int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
- const struct btf *btf, u32 func_id,
- struct bpf_reg_state *regs,
- struct bpf_kfunc_arg_meta *meta)
-{
- return btf_check_func_arg_match(env, btf, func_id, regs, true, meta, true);
-}
-
/* Convert BTF of a function into bpf_reg_state if possible
* Returns:
* EFAULT - there is a verifier bug. Abort verification.
return err;
}
-int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
- u32 regno)
+static int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+ u32 regno)
{
struct bpf_reg_state *mem_reg = &cur_regs(env)[regno - 1];
bool may_be_null = type_may_be_null(mem_reg->type);
}
}
+struct bpf_kfunc_call_arg_meta {
+ /* In parameters */
+ struct btf *btf;
+ u32 func_id;
+ u32 kfunc_flags;
+ const struct btf_type *func_proto;
+ const char *func_name;
+ /* Out parameters */
+ u32 ref_obj_id;
+ u8 release_regno;
+ bool r0_rdonly;
+ u64 r0_size;
+};
+
+static bool is_kfunc_acquire(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_ACQUIRE;
+}
+
+static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_RET_NULL;
+}
+
+static bool is_kfunc_release(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_RELEASE;
+}
+
+static bool is_kfunc_trusted_args(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_TRUSTED_ARGS;
+}
+
+static bool is_kfunc_sleepable(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_SLEEPABLE;
+}
+
+static bool is_kfunc_destructive(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_DESTRUCTIVE;
+}
+
+static bool is_kfunc_arg_kptr_get(struct bpf_kfunc_call_arg_meta *meta, int arg)
+{
+ return arg == 0 && (meta->kfunc_flags & KF_KPTR_GET);
+}
+
+static bool is_kfunc_arg_mem_size(const struct btf *btf,
+ const struct btf_param *arg,
+ const struct bpf_reg_state *reg)
+{
+ int len, sfx_len = sizeof("__sz") - 1;
+ const struct btf_type *t;
+ const char *param_name;
+
+ t = btf_type_skip_modifiers(btf, arg->type, NULL);
+ if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
+ return false;
+
+ /* In the future, this can be ported to use BTF tagging */
+ param_name = btf_name_by_offset(btf, arg->name_off);
+ if (str_is_empty(param_name))
+ return false;
+ len = strlen(param_name);
+ if (len < sfx_len)
+ return false;
+ param_name += len - sfx_len;
+ if (strncmp(param_name, "__sz", sfx_len))
+ return false;
+
+ return true;
+}
+
+static bool is_kfunc_arg_scalar_with_name(const struct btf *btf,
+ const struct btf_param *arg,
+ const char *name)
+{
+ int len, target_len = strlen(name);
+ const char *param_name;
+
+ param_name = btf_name_by_offset(btf, arg->name_off);
+ if (str_is_empty(param_name))
+ return false;
+ len = strlen(param_name);
+ if (len != target_len)
+ return false;
+ if (strcmp(param_name, name))
+ return false;
+
+ return true;
+}
+
+enum {
+ KF_ARG_DYNPTR_ID,
+};
+
+BTF_ID_LIST(kf_arg_btf_ids)
+BTF_ID(struct, bpf_dynptr_kern)
+
+static bool is_kfunc_arg_dynptr(const struct btf *btf,
+ const struct btf_param *arg)
+{
+ const struct btf_type *t;
+ u32 res_id;
+
+ t = btf_type_skip_modifiers(btf, arg->type, NULL);
+ if (!t)
+ return false;
+ if (!btf_type_is_ptr(t))
+ return false;
+ t = btf_type_skip_modifiers(btf, t->type, &res_id);
+ if (!t)
+ return false;
+ return btf_types_are_same(btf, res_id, btf_vmlinux, kf_arg_btf_ids[KF_ARG_DYNPTR_ID]);
+}
+
+/* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
+static bool __btf_type_is_scalar_struct(struct bpf_verifier_env *env,
+ const struct btf *btf,
+ const struct btf_type *t, int rec)
+{
+ const struct btf_type *member_type;
+ const struct btf_member *member;
+ u32 i;
+
+ if (!btf_type_is_struct(t))
+ return false;
+
+ for_each_member(i, t, member) {
+ const struct btf_array *array;
+
+ member_type = btf_type_skip_modifiers(btf, member->type, NULL);
+ if (btf_type_is_struct(member_type)) {
+ if (rec >= 3) {
+ verbose(env, "max struct nesting depth exceeded\n");
+ return false;
+ }
+ if (!__btf_type_is_scalar_struct(env, btf, member_type, rec + 1))
+ return false;
+ continue;
+ }
+ if (btf_type_is_array(member_type)) {
+ array = btf_array(member_type);
+ if (!array->nelems)
+ return false;
+ member_type = btf_type_skip_modifiers(btf, array->type, NULL);
+ if (!btf_type_is_scalar(member_type))
+ return false;
+ continue;
+ }
+ if (!btf_type_is_scalar(member_type))
+ return false;
+ }
+ return true;
+}
+
+
+static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
+#ifdef CONFIG_NET
+ [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
+ [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
+ [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
+#endif
+};
+
+enum kfunc_ptr_arg_type {
+ KF_ARG_PTR_TO_CTX,
+ KF_ARG_PTR_TO_KPTR, /* PTR_TO_KPTR but type specific */
+ KF_ARG_PTR_TO_DYNPTR,
+ KF_ARG_PTR_TO_BTF_ID, /* Also covers reg2btf_ids conversions */
+ KF_ARG_PTR_TO_MEM,
+ KF_ARG_PTR_TO_MEM_SIZE, /* Size derived from next argument, skip it */
+};
+
+static enum kfunc_ptr_arg_type
+get_kfunc_ptr_arg_type(struct bpf_verifier_env *env,
+ struct bpf_kfunc_call_arg_meta *meta,
+ const struct btf_type *t, const struct btf_type *ref_t,
+ const char *ref_tname, const struct btf_param *args,
+ int argno, int nargs)
+{
+ u32 regno = argno + 1;
+ struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_reg_state *reg = ®s[regno];
+ bool arg_mem_size = false;
+
+ /* In this function, we verify the kfunc's BTF as per the argument type,
+ * leaving the rest of the verification with respect to the register
+ * type to our caller. When a set of conditions hold in the BTF type of
+ * arguments, we resolve it to a known kfunc_ptr_arg_type.
+ */
+ if (btf_get_prog_ctx_type(&env->log, meta->btf, t, resolve_prog_type(env->prog), argno))
+ return KF_ARG_PTR_TO_CTX;
+
+ if (is_kfunc_arg_kptr_get(meta, argno)) {
+ if (!btf_type_is_ptr(ref_t)) {
+ verbose(env, "arg#0 BTF type must be a double pointer for kptr_get kfunc\n");
+ return -EINVAL;
+ }
+ ref_t = btf_type_by_id(meta->btf, ref_t->type);
+ ref_tname = btf_name_by_offset(meta->btf, ref_t->name_off);
+ if (!btf_type_is_struct(ref_t)) {
+ verbose(env, "kernel function %s args#0 pointer type %s %s is not supported\n",
+ meta->func_name, btf_type_str(ref_t), ref_tname);
+ return -EINVAL;
+ }
+ return KF_ARG_PTR_TO_KPTR;
+ }
+
+ if (is_kfunc_arg_dynptr(meta->btf, &args[argno]))
+ return KF_ARG_PTR_TO_DYNPTR;
+
+ if ((base_type(reg->type) == PTR_TO_BTF_ID || reg2btf_ids[base_type(reg->type)])) {
+ if (!btf_type_is_struct(ref_t)) {
+ verbose(env, "kernel function %s args#%d pointer type %s %s is not supported\n",
+ meta->func_name, argno, btf_type_str(ref_t), ref_tname);
+ return -EINVAL;
+ }
+ return KF_ARG_PTR_TO_BTF_ID;
+ }
+
+ if (argno + 1 < nargs && is_kfunc_arg_mem_size(meta->btf, &args[argno + 1], ®s[regno + 1]))
+ arg_mem_size = true;
+
+ /* This is the catch all argument type of register types supported by
+ * check_helper_mem_access. However, we only allow when argument type is
+ * pointer to scalar, or struct composed (recursively) of scalars. When
+ * arg_mem_size is true, the pointer can be void *.
+ */
+ if (!btf_type_is_scalar(ref_t) && !__btf_type_is_scalar_struct(env, meta->btf, ref_t, 0) &&
+ (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) {
+ verbose(env, "arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n",
+ argno, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : "");
+ return -EINVAL;
+ }
+ return arg_mem_size ? KF_ARG_PTR_TO_MEM_SIZE : KF_ARG_PTR_TO_MEM;
+}
+
+static int process_kf_arg_ptr_to_btf_id(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg,
+ const struct btf_type *ref_t,
+ const char *ref_tname, u32 ref_id,
+ struct bpf_kfunc_call_arg_meta *meta,
+ int argno)
+{
+ const struct btf_type *reg_ref_t;
+ bool strict_type_match = false;
+ const struct btf *reg_btf;
+ const char *reg_ref_tname;
+ u32 reg_ref_id;
+
+ if (reg->type == PTR_TO_BTF_ID) {
+ reg_btf = reg->btf;
+ reg_ref_id = reg->btf_id;
+ } else {
+ reg_btf = btf_vmlinux;
+ reg_ref_id = *reg2btf_ids[base_type(reg->type)];
+ }
+
+ if (is_kfunc_trusted_args(meta) || (is_kfunc_release(meta) && reg->ref_obj_id))
+ strict_type_match = true;
+
+ reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id, ®_ref_id);
+ reg_ref_tname = btf_name_by_offset(reg_btf, reg_ref_t->name_off);
+ if (!btf_struct_ids_match(&env->log, reg_btf, reg_ref_id, reg->off, meta->btf, ref_id, strict_type_match)) {
+ verbose(env, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
+ meta->func_name, argno, btf_type_str(ref_t), ref_tname, argno + 1,
+ btf_type_str(reg_ref_t), reg_ref_tname);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int process_kf_arg_ptr_to_kptr(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg,
+ const struct btf_type *ref_t,
+ const char *ref_tname,
+ struct bpf_kfunc_call_arg_meta *meta,
+ int argno)
+{
+ struct btf_field *kptr_field;
+
+ /* check_func_arg_reg_off allows var_off for
+ * PTR_TO_MAP_VALUE, but we need fixed offset to find
+ * off_desc.
+ */
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env, "arg#0 must have constant offset\n");
+ return -EINVAL;
+ }
+
+ kptr_field = btf_record_find(reg->map_ptr->record, reg->off + reg->var_off.value, BPF_KPTR);
+ if (!kptr_field || kptr_field->type != BPF_KPTR_REF) {
+ verbose(env, "arg#0 no referenced kptr at map value offset=%llu\n",
+ reg->off + reg->var_off.value);
+ return -EINVAL;
+ }
+
+ if (!btf_struct_ids_match(&env->log, meta->btf, ref_t->type, 0, kptr_field->kptr.btf,
+ kptr_field->kptr.btf_id, true)) {
+ verbose(env, "kernel function %s args#%d expected pointer to %s %s\n",
+ meta->func_name, argno, btf_type_str(ref_t), ref_tname);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta)
+{
+ const char *func_name = meta->func_name, *ref_tname;
+ const struct btf *btf = meta->btf;
+ const struct btf_param *args;
+ u32 i, nargs;
+ int ret;
+
+ args = (const struct btf_param *)(meta->func_proto + 1);
+ nargs = btf_type_vlen(meta->func_proto);
+ if (nargs > MAX_BPF_FUNC_REG_ARGS) {
+ verbose(env, "Function %s has %d > %d args\n", func_name, nargs,
+ MAX_BPF_FUNC_REG_ARGS);
+ return -EINVAL;
+ }
+
+ /* Check that BTF function arguments match actual types that the
+ * verifier sees.
+ */
+ for (i = 0; i < nargs; i++) {
+ struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[i + 1];
+ const struct btf_type *t, *ref_t, *resolve_ret;
+ enum bpf_arg_type arg_type = ARG_DONTCARE;
+ u32 regno = i + 1, ref_id, type_size;
+ bool is_ret_buf_sz = false;
+ int kf_arg_type;
+
+ t = btf_type_skip_modifiers(btf, args[i].type, NULL);
+ if (btf_type_is_scalar(t)) {
+ if (reg->type != SCALAR_VALUE) {
+ verbose(env, "R%d is not a scalar\n", regno);
+ return -EINVAL;
+ }
+ if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdonly_buf_size")) {
+ meta->r0_rdonly = true;
+ is_ret_buf_sz = true;
+ } else if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdwr_buf_size")) {
+ is_ret_buf_sz = true;
+ }
+
+ if (is_ret_buf_sz) {
+ if (meta->r0_size) {
+ verbose(env, "2 or more rdonly/rdwr_buf_size parameters for kfunc");
+ return -EINVAL;
+ }
+
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env, "R%d is not a const\n", regno);
+ return -EINVAL;
+ }
+
+ meta->r0_size = reg->var_off.value;
+ ret = mark_chain_precision(env, regno);
+ if (ret)
+ return ret;
+ }
+ continue;
+ }
+
+ if (!btf_type_is_ptr(t)) {
+ verbose(env, "Unrecognized arg#%d type %s\n", i, btf_type_str(t));
+ return -EINVAL;
+ }
+
+ if (reg->ref_obj_id) {
+ if (is_kfunc_release(meta) && meta->ref_obj_id) {
+ verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
+ regno, reg->ref_obj_id,
+ meta->ref_obj_id);
+ return -EFAULT;
+ }
+ meta->ref_obj_id = reg->ref_obj_id;
+ if (is_kfunc_release(meta))
+ meta->release_regno = regno;
+ }
+
+ ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
+ ref_tname = btf_name_by_offset(btf, ref_t->name_off);
+
+ kf_arg_type = get_kfunc_ptr_arg_type(env, meta, t, ref_t, ref_tname, args, i, nargs);
+ if (kf_arg_type < 0)
+ return kf_arg_type;
+
+ switch (kf_arg_type) {
+ case KF_ARG_PTR_TO_BTF_ID:
+ if (!is_kfunc_trusted_args(meta))
+ break;
+ if (!reg->ref_obj_id) {
+ verbose(env, "R%d must be referenced\n", regno);
+ return -EINVAL;
+ }
+ fallthrough;
+ case KF_ARG_PTR_TO_CTX:
+ /* Trusted arguments have the same offset checks as release arguments */
+ arg_type |= OBJ_RELEASE;
+ break;
+ case KF_ARG_PTR_TO_KPTR:
+ case KF_ARG_PTR_TO_DYNPTR:
+ case KF_ARG_PTR_TO_MEM:
+ case KF_ARG_PTR_TO_MEM_SIZE:
+ /* Trusted by default */
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return -EFAULT;
+ }
+
+ if (is_kfunc_release(meta) && reg->ref_obj_id)
+ arg_type |= OBJ_RELEASE;
+ ret = check_func_arg_reg_off(env, reg, regno, arg_type);
+ if (ret < 0)
+ return ret;
+
+ switch (kf_arg_type) {
+ case KF_ARG_PTR_TO_CTX:
+ if (reg->type != PTR_TO_CTX) {
+ verbose(env, "arg#%d expected pointer to ctx, but got %s\n", i, btf_type_str(t));
+ return -EINVAL;
+ }
+ break;
+ case KF_ARG_PTR_TO_KPTR:
+ if (reg->type != PTR_TO_MAP_VALUE) {
+ verbose(env, "arg#0 expected pointer to map value\n");
+ return -EINVAL;
+ }
+ ret = process_kf_arg_ptr_to_kptr(env, reg, ref_t, ref_tname, meta, i);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_DYNPTR:
+ if (reg->type != PTR_TO_STACK) {
+ verbose(env, "arg#%d expected pointer to stack\n", i);
+ return -EINVAL;
+ }
+
+ if (!is_dynptr_reg_valid_init(env, reg)) {
+ verbose(env, "arg#%d pointer type %s %s must be valid and initialized\n",
+ i, btf_type_str(ref_t), ref_tname);
+ return -EINVAL;
+ }
+
+ if (!is_dynptr_type_expected(env, reg, ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL)) {
+ verbose(env, "arg#%d pointer type %s %s points to unsupported dynamic pointer type\n",
+ i, btf_type_str(ref_t), ref_tname);
+ return -EINVAL;
+ }
+ break;
+ case KF_ARG_PTR_TO_BTF_ID:
+ /* Only base_type is checked, further checks are done here */
+ if (reg->type != PTR_TO_BTF_ID &&
+ (!reg2btf_ids[base_type(reg->type)] || type_flag(reg->type))) {
+ verbose(env, "arg#%d expected pointer to btf or socket\n", i);
+ return -EINVAL;
+ }
+ ret = process_kf_arg_ptr_to_btf_id(env, reg, ref_t, ref_tname, ref_id, meta, i);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_MEM:
+ resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
+ if (IS_ERR(resolve_ret)) {
+ verbose(env, "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
+ i, btf_type_str(ref_t), ref_tname, PTR_ERR(resolve_ret));
+ return -EINVAL;
+ }
+ ret = check_mem_reg(env, reg, regno, type_size);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_MEM_SIZE:
+ ret = check_kfunc_mem_size_reg(env, ®s[regno + 1], regno + 1);
+ if (ret < 0) {
+ verbose(env, "arg#%d arg#%d memory, len pair leads to invalid memory access\n", i, i + 1);
+ return ret;
+ }
+ /* Skip next '__sz' argument */
+ i++;
+ break;
+ }
+ }
+
+ if (is_kfunc_release(meta) && !meta->release_regno) {
+ verbose(env, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n",
+ func_name);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
int *insn_idx_p)
{
const struct btf_type *t, *func, *func_proto, *ptr_type;
struct bpf_reg_state *regs = cur_regs(env);
- struct bpf_kfunc_arg_meta meta = { 0 };
const char *func_name, *ptr_type_name;
+ struct bpf_kfunc_call_arg_meta meta;
u32 i, nargs, func_id, ptr_type_id;
int err, insn_idx = *insn_idx_p;
const struct btf_param *args;
struct btf *desc_btf;
u32 *kfunc_flags;
- bool acq;
/* skip for now, but return error when we find this in fixup_kfunc_call */
if (!insn->imm)
func_name);
return -EACCES;
}
- if (*kfunc_flags & KF_DESTRUCTIVE && !capable(CAP_SYS_BOOT)) {
- verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capabilities\n");
+
+ /* Prepare kfunc call metadata */
+ memset(&meta, 0, sizeof(meta));
+ meta.btf = desc_btf;
+ meta.func_id = func_id;
+ meta.kfunc_flags = *kfunc_flags;
+ meta.func_proto = func_proto;
+ meta.func_name = func_name;
+
+ if (is_kfunc_destructive(&meta) && !capable(CAP_SYS_BOOT)) {
+ verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capability\n");
return -EACCES;
}
- acq = *kfunc_flags & KF_ACQUIRE;
-
- meta.flags = *kfunc_flags;
+ if (is_kfunc_sleepable(&meta) && !env->prog->aux->sleepable) {
+ verbose(env, "program must be sleepable to call sleepable kfunc %s\n", func_name);
+ return -EACCES;
+ }
/* Check the arguments */
- err = btf_check_kfunc_arg_match(env, desc_btf, func_id, regs, &meta);
+ err = check_kfunc_args(env, &meta);
if (err < 0)
return err;
/* In case of release function, we get register number of refcounted
- * PTR_TO_BTF_ID back from btf_check_kfunc_arg_match, do the release now
+ * PTR_TO_BTF_ID in bpf_kfunc_arg_meta, do the release now.
*/
- if (err) {
- err = release_reference(env, regs[err].ref_obj_id);
+ if (meta.release_regno) {
+ err = release_reference(env, regs[meta.release_regno].ref_obj_id);
if (err) {
verbose(env, "kfunc %s#%d reference has not been acquired before\n",
func_name, func_id);
/* Check return type */
t = btf_type_skip_modifiers(desc_btf, func_proto->type, NULL);
- if (acq && !btf_type_is_struct_ptr(desc_btf, t)) {
+ if (is_kfunc_acquire(&meta) && !btf_type_is_struct_ptr(meta.btf, t)) {
verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n");
return -EINVAL;
}
regs[BPF_REG_0].type = PTR_TO_BTF_ID;
regs[BPF_REG_0].btf_id = ptr_type_id;
}
- if (*kfunc_flags & KF_RET_NULL) {
+ if (is_kfunc_ret_null(&meta)) {
regs[BPF_REG_0].type |= PTR_MAYBE_NULL;
/* For mark_ptr_or_null_reg, see 93c230e3f5bd6 */
regs[BPF_REG_0].id = ++env->id_gen;
}
mark_btf_func_reg_size(env, BPF_REG_0, sizeof(void *));
- if (acq) {
+ if (is_kfunc_acquire(&meta)) {
int id = acquire_reference_state(env, insn_idx);
if (id < 0)
return id;
- regs[BPF_REG_0].id = id;
+ if (is_kfunc_ret_null(&meta))
+ regs[BPF_REG_0].id = id;
regs[BPF_REG_0].ref_obj_id = id;
}
+ if (reg_may_point_to_spin_lock(®s[BPF_REG_0]) && !regs[BPF_REG_0].id)
+ regs[BPF_REG_0].id = ++env->id_gen;
} /* else { add_kfunc_call() ensures it is btf_type_is_void(t) } */
nargs = btf_type_vlen(func_proto);
"arg#0 pointer type STRUCT bpf_dynptr_kern points to unsupported dynamic pointer type", 0},
{"not_valid_dynptr",
"arg#0 pointer type STRUCT bpf_dynptr_kern must be valid and initialized", 0},
- {"not_ptr_to_stack", "arg#0 pointer type STRUCT bpf_dynptr_kern not to stack", 0},
+ {"not_ptr_to_stack", "arg#0 expected pointer to stack", 0},
{"dynptr_data_null", NULL, -EBADMSG},
};
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
- .errstr = "arg#0 pointer type STRUCT prog_test_ref_kfunc must point",
+ .errstr = "arg#0 expected pointer to btf or socket",
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_acquire", 3 },
{ "bpf_kfunc_call_test_release", 5 },
.kfunc = "bpf",
.expected_attach_type = BPF_LSM_MAC,
.flags = BPF_F_SLEEPABLE,
- .errstr = "arg#0 pointer type STRUCT bpf_key must point to scalar, or struct with scalar",
+ .errstr = "arg#0 expected pointer to btf or socket",
.fixup_kfunc_btf_id = {
{ "bpf_lookup_user_key", 2 },
{ "bpf_key_put", 4 },
.kfunc = "bpf",
.expected_attach_type = BPF_LSM_MAC,
.flags = BPF_F_SLEEPABLE,
- .errstr = "arg#0 pointer type STRUCT bpf_key must point to scalar, or struct with scalar",
+ .errstr = "arg#0 expected pointer to btf or socket",
.fixup_kfunc_btf_id = {
{ "bpf_lookup_system_key", 1 },
{ "bpf_key_put", 3 },
projects / users / hch / xfs.git / commitdiff