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-rw-r--r--kernel/bpf/verifier.c86
1 files changed, 64 insertions, 22 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 5dd1dcb902bf..dcebf3f7365c 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -156,7 +156,29 @@ struct bpf_verifier_stack_elem {
#define BPF_COMPLEXITY_LIMIT_INSNS 131072
#define BPF_COMPLEXITY_LIMIT_STACK 1024
-#define BPF_MAP_PTR_POISON ((void *)0xeB9F + POISON_POINTER_DELTA)
+#define BPF_MAP_PTR_UNPRIV 1UL
+#define BPF_MAP_PTR_POISON ((void *)((0xeB9FUL << 1) + \
+ POISON_POINTER_DELTA))
+#define BPF_MAP_PTR(X) ((struct bpf_map *)((X) & ~BPF_MAP_PTR_UNPRIV))
+
+static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data *aux)
+{
+ return BPF_MAP_PTR(aux->map_state) == BPF_MAP_PTR_POISON;
+}
+
+static bool bpf_map_ptr_unpriv(const struct bpf_insn_aux_data *aux)
+{
+ return aux->map_state & BPF_MAP_PTR_UNPRIV;
+}
+
+static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux,
+ const struct bpf_map *map, bool unpriv)
+{
+ BUILD_BUG_ON((unsigned long)BPF_MAP_PTR_POISON & BPF_MAP_PTR_UNPRIV);
+ unpriv |= bpf_map_ptr_unpriv(aux);
+ aux->map_state = (unsigned long)map |
+ (unpriv ? BPF_MAP_PTR_UNPRIV : 0UL);
+}
struct bpf_call_arg_meta {
struct bpf_map *map_ptr;
@@ -2333,6 +2355,29 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
return 0;
}
+static int
+record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
+ int func_id, int insn_idx)
+{
+ struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
+
+ if (func_id != BPF_FUNC_tail_call &&
+ func_id != BPF_FUNC_map_lookup_elem)
+ return 0;
+ if (meta->map_ptr == NULL) {
+ verbose(env, "kernel subsystem misconfigured verifier\n");
+ return -EINVAL;
+ }
+
+ if (!BPF_MAP_PTR(aux->map_state))
+ bpf_map_ptr_store(aux, meta->map_ptr,
+ meta->map_ptr->unpriv_array);
+ else if (BPF_MAP_PTR(aux->map_state) != meta->map_ptr)
+ bpf_map_ptr_store(aux, BPF_MAP_PTR_POISON,
+ meta->map_ptr->unpriv_array);
+ return 0;
+}
+
static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn_idx)
{
const struct bpf_func_proto *fn = NULL;
@@ -2387,13 +2432,6 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
err = check_func_arg(env, BPF_REG_2, fn->arg2_type, &meta);
if (err)
return err;
- if (func_id == BPF_FUNC_tail_call) {
- if (meta.map_ptr == NULL) {
- verbose(env, "verifier bug\n");
- return -EINVAL;
- }
- env->insn_aux_data[insn_idx].map_ptr = meta.map_ptr;
- }
err = check_func_arg(env, BPF_REG_3, fn->arg3_type, &meta);
if (err)
return err;
@@ -2404,6 +2442,10 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
if (err)
return err;
+ err = record_func_map(env, &meta, func_id, insn_idx);
+ if (err)
+ return err;
+
/* Mark slots with STACK_MISC in case of raw mode, stack offset
* is inferred from register state.
*/
@@ -2428,8 +2470,6 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
} else if (fn->ret_type == RET_VOID) {
regs[BPF_REG_0].type = NOT_INIT;
} else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL) {
- struct bpf_insn_aux_data *insn_aux;
-
regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
/* There is no offset yet applied, variable or fixed */
mark_reg_known_zero(env, regs, BPF_REG_0);
@@ -2445,11 +2485,6 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
}
regs[BPF_REG_0].map_ptr = meta.map_ptr;
regs[BPF_REG_0].id = ++env->id_gen;
- insn_aux = &env->insn_aux_data[insn_idx];
- if (!insn_aux->map_ptr)
- insn_aux->map_ptr = meta.map_ptr;
- else if (insn_aux->map_ptr != meta.map_ptr)
- insn_aux->map_ptr = BPF_MAP_PTR_POISON;
} else {
verbose(env, "unknown return type %d of func %s#%d\n",
fn->ret_type, func_id_name(func_id), func_id);
@@ -5417,6 +5452,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
struct bpf_insn *insn = prog->insnsi;
const struct bpf_func_proto *fn;
const int insn_cnt = prog->len;
+ struct bpf_insn_aux_data *aux;
struct bpf_insn insn_buf[16];
struct bpf_prog *new_prog;
struct bpf_map *map_ptr;
@@ -5491,19 +5527,22 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
insn->imm = 0;
insn->code = BPF_JMP | BPF_TAIL_CALL;
+ aux = &env->insn_aux_data[i + delta];
+ if (!bpf_map_ptr_unpriv(aux))
+ continue;
+
/* instead of changing every JIT dealing with tail_call
* emit two extra insns:
* if (index >= max_entries) goto out;
* index &= array->index_mask;
* to avoid out-of-bounds cpu speculation
*/
- map_ptr = env->insn_aux_data[i + delta].map_ptr;
- if (map_ptr == BPF_MAP_PTR_POISON) {
+ if (bpf_map_ptr_poisoned(aux)) {
verbose(env, "tail_call abusing map_ptr\n");
return -EINVAL;
}
- if (!map_ptr->unpriv_array)
- continue;
+
+ map_ptr = BPF_MAP_PTR(aux->map_state);
insn_buf[0] = BPF_JMP_IMM(BPF_JGE, BPF_REG_3,
map_ptr->max_entries, 2);
insn_buf[1] = BPF_ALU32_IMM(BPF_AND, BPF_REG_3,
@@ -5527,9 +5566,12 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
*/
if (prog->jit_requested && BITS_PER_LONG == 64 &&
insn->imm == BPF_FUNC_map_lookup_elem) {
- map_ptr = env->insn_aux_data[i + delta].map_ptr;
- if (map_ptr == BPF_MAP_PTR_POISON ||
- !map_ptr->ops->map_gen_lookup)
+ aux = &env->insn_aux_data[i + delta];
+ if (bpf_map_ptr_poisoned(aux))
+ goto patch_call_imm;
+
+ map_ptr = BPF_MAP_PTR(aux->map_state);
+ if (!map_ptr->ops->map_gen_lookup)
goto patch_call_imm;
cnt = map_ptr->ops->map_gen_lookup(map_ptr, insn_buf);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-14 11:37:19 +0100