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-rw-r--r--kernel/bpf/verifier.c59
1 files changed, 54 insertions, 5 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 202f8f738542..9c843a5417da 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -207,6 +207,9 @@ struct verifier_env {
struct bpf_call_arg_meta {
struct bpf_map *map_ptr;
+ bool raw_mode;
+ int regno;
+ int access_size;
};
/* verbose verifier prints what it's seeing
@@ -789,7 +792,8 @@ static int check_xadd(struct verifier_env *env, struct bpf_insn *insn)
* and all elements of stack are initialized
*/
static int check_stack_boundary(struct verifier_env *env, int regno,
- int access_size, bool zero_size_allowed)
+ int access_size, bool zero_size_allowed,
+ struct bpf_call_arg_meta *meta)
{
struct verifier_state *state = &env->cur_state;
struct reg_state *regs = state->regs;
@@ -815,6 +819,12 @@ static int check_stack_boundary(struct verifier_env *env, int regno,
return -EACCES;
}
+ if (meta && meta->raw_mode) {
+ meta->access_size = access_size;
+ meta->regno = regno;
+ return 0;
+ }
+
for (i = 0; i < access_size; i++) {
if (state->stack_slot_type[MAX_BPF_STACK + off + i] != STACK_MISC) {
verbose("invalid indirect read from stack off %d+%d size %d\n",
@@ -859,7 +869,8 @@ static int check_func_arg(struct verifier_env *env, u32 regno,
expected_type = CONST_PTR_TO_MAP;
} else if (arg_type == ARG_PTR_TO_CTX) {
expected_type = PTR_TO_CTX;
- } else if (arg_type == ARG_PTR_TO_STACK) {
+ } else if (arg_type == ARG_PTR_TO_STACK ||
+ arg_type == ARG_PTR_TO_RAW_STACK) {
expected_type = PTR_TO_STACK;
/* One exception here. In case function allows for NULL to be
* passed in as argument, it's a CONST_IMM type. Final test
@@ -867,6 +878,7 @@ static int check_func_arg(struct verifier_env *env, u32 regno,
*/
if (reg->type == CONST_IMM && reg->imm == 0)
expected_type = CONST_IMM;
+ meta->raw_mode = arg_type == ARG_PTR_TO_RAW_STACK;
} else {
verbose("unsupported arg_type %d\n", arg_type);
return -EFAULT;
@@ -896,7 +908,7 @@ static int check_func_arg(struct verifier_env *env, u32 regno,
return -EACCES;
}
err = check_stack_boundary(env, regno, meta->map_ptr->key_size,
- false);
+ false, NULL);
} else if (arg_type == ARG_PTR_TO_MAP_VALUE) {
/* bpf_map_xxx(..., map_ptr, ..., value) call:
* check [value, value + map->value_size) validity
@@ -907,7 +919,8 @@ static int check_func_arg(struct verifier_env *env, u32 regno,
return -EACCES;
}
err = check_stack_boundary(env, regno,
- meta->map_ptr->value_size, false);
+ meta->map_ptr->value_size,
+ false, NULL);
} else if (arg_type == ARG_CONST_STACK_SIZE ||
arg_type == ARG_CONST_STACK_SIZE_OR_ZERO) {
bool zero_size_allowed = (arg_type == ARG_CONST_STACK_SIZE_OR_ZERO);
@@ -922,7 +935,7 @@ static int check_func_arg(struct verifier_env *env, u32 regno,
return -EACCES;
}
err = check_stack_boundary(env, regno - 1, reg->imm,
- zero_size_allowed);
+ zero_size_allowed, meta);
}
return err;
@@ -953,6 +966,24 @@ static int check_map_func_compatibility(struct bpf_map *map, int func_id)
return 0;
}
+static int check_raw_mode(const struct bpf_func_proto *fn)
+{
+ int count = 0;
+
+ if (fn->arg1_type == ARG_PTR_TO_RAW_STACK)
+ count++;
+ if (fn->arg2_type == ARG_PTR_TO_RAW_STACK)
+ count++;
+ if (fn->arg3_type == ARG_PTR_TO_RAW_STACK)
+ count++;
+ if (fn->arg4_type == ARG_PTR_TO_RAW_STACK)
+ count++;
+ if (fn->arg5_type == ARG_PTR_TO_RAW_STACK)
+ count++;
+
+ return count > 1 ? -EINVAL : 0;
+}
+
static int check_call(struct verifier_env *env, int func_id)
{
struct verifier_state *state = &env->cur_state;
@@ -984,6 +1015,15 @@ static int check_call(struct verifier_env *env, int func_id)
memset(&meta, 0, sizeof(meta));
+ /* We only support one arg being in raw mode at the moment, which
+ * is sufficient for the helper functions we have right now.
+ */
+ err = check_raw_mode(fn);
+ if (err) {
+ verbose("kernel subsystem misconfigured func %d\n", func_id);
+ return err;
+ }
+
/* check args */
err = check_func_arg(env, BPF_REG_1, fn->arg1_type, &meta);
if (err)
@@ -1001,6 +1041,15 @@ static int check_call(struct verifier_env *env, int func_id)
if (err)
return err;
+ /* Mark slots with STACK_MISC in case of raw mode, stack offset
+ * is inferred from register state.
+ */
+ for (i = 0; i < meta.access_size; i++) {
+ err = check_mem_access(env, meta.regno, i, BPF_B, BPF_WRITE, -1);
+ if (err)
+ return err;
+ }
+
/* reset caller saved regs */
for (i = 0; i < CALLER_SAVED_REGS; i++) {
reg = regs + caller_saved[i];