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-rw-r--r--include/linux/bpf_verifier.h3
-rw-r--r--kernel/bpf/verifier.c120
2 files changed, 113 insertions, 10 deletions
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index cdd08bf0ec06..26e40de9ef55 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -293,7 +293,7 @@ struct bpf_verifier_state_list {
struct bpf_insn_aux_data {
union {
enum bpf_reg_type ptr_type; /* pointer type for load/store insns */
- unsigned long map_state; /* pointer/poison value for maps */
+ unsigned long map_ptr_state; /* pointer/poison value for maps */
s32 call_imm; /* saved imm field of call insn */
u32 alu_limit; /* limit for add/sub register with pointer */
struct {
@@ -301,6 +301,7 @@ struct bpf_insn_aux_data {
u32 map_off; /* offset from value base address */
};
};
+ u64 map_key_state; /* constant (32 bit) key tracking for maps */
int ctx_field_size; /* the ctx field size for load insn, maybe 0 */
int sanitize_stack_off; /* stack slot to be cleared */
bool seen; /* this insn was processed by the verifier */
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index fc85714428c7..a0482e1c4a77 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -171,6 +171,9 @@ struct bpf_verifier_stack_elem {
#define BPF_COMPLEXITY_LIMIT_JMP_SEQ 8192
#define BPF_COMPLEXITY_LIMIT_STATES 64
+#define BPF_MAP_KEY_POISON (1ULL << 63)
+#define BPF_MAP_KEY_SEEN (1ULL << 62)
+
#define BPF_MAP_PTR_UNPRIV 1UL
#define BPF_MAP_PTR_POISON ((void *)((0xeB9FUL << 1) + \
POISON_POINTER_DELTA))
@@ -178,12 +181,12 @@ struct bpf_verifier_stack_elem {
static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data *aux)
{
- return BPF_MAP_PTR(aux->map_state) == BPF_MAP_PTR_POISON;
+ return BPF_MAP_PTR(aux->map_ptr_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;
+ return aux->map_ptr_state & BPF_MAP_PTR_UNPRIV;
}
static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux,
@@ -191,8 +194,31 @@ static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux,
{
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);
+ aux->map_ptr_state = (unsigned long)map |
+ (unpriv ? BPF_MAP_PTR_UNPRIV : 0UL);
+}
+
+static bool bpf_map_key_poisoned(const struct bpf_insn_aux_data *aux)
+{
+ return aux->map_key_state & BPF_MAP_KEY_POISON;
+}
+
+static bool bpf_map_key_unseen(const struct bpf_insn_aux_data *aux)
+{
+ return !(aux->map_key_state & BPF_MAP_KEY_SEEN);
+}
+
+static u64 bpf_map_key_immediate(const struct bpf_insn_aux_data *aux)
+{
+ return aux->map_key_state & ~(BPF_MAP_KEY_SEEN | BPF_MAP_KEY_POISON);
+}
+
+static void bpf_map_key_store(struct bpf_insn_aux_data *aux, u64 state)
+{
+ bool poisoned = bpf_map_key_poisoned(aux);
+
+ aux->map_key_state = state | BPF_MAP_KEY_SEEN |
+ (poisoned ? BPF_MAP_KEY_POISON : 0ULL);
}
struct bpf_call_arg_meta {
@@ -4090,15 +4116,49 @@ record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
return -EACCES;
}
- if (!BPF_MAP_PTR(aux->map_state))
+ if (!BPF_MAP_PTR(aux->map_ptr_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)
+ else if (BPF_MAP_PTR(aux->map_ptr_state) != meta->map_ptr)
bpf_map_ptr_store(aux, BPF_MAP_PTR_POISON,
meta->map_ptr->unpriv_array);
return 0;
}
+static int
+record_func_key(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];
+ struct bpf_reg_state *regs = cur_regs(env), *reg;
+ struct bpf_map *map = meta->map_ptr;
+ struct tnum range;
+ u64 val;
+
+ if (func_id != BPF_FUNC_tail_call)
+ return 0;
+ if (!map || map->map_type != BPF_MAP_TYPE_PROG_ARRAY) {
+ verbose(env, "kernel subsystem misconfigured verifier\n");
+ return -EINVAL;
+ }
+
+ range = tnum_range(0, map->max_entries - 1);
+ reg = &regs[BPF_REG_3];
+
+ if (!register_is_const(reg) || !tnum_in(range, reg->var_off)) {
+ bpf_map_key_store(aux, BPF_MAP_KEY_POISON);
+ return 0;
+ }
+
+ val = reg->var_off.value;
+ if (bpf_map_key_unseen(aux))
+ bpf_map_key_store(aux, val);
+ else if (!bpf_map_key_poisoned(aux) &&
+ bpf_map_key_immediate(aux) != val)
+ bpf_map_key_store(aux, BPF_MAP_KEY_POISON);
+ return 0;
+}
+
static int check_reference_leak(struct bpf_verifier_env *env)
{
struct bpf_func_state *state = cur_func(env);
@@ -4173,6 +4233,10 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
if (err)
return err;
+ err = record_func_key(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.
*/
@@ -9065,6 +9129,7 @@ static int fixup_call_args(struct bpf_verifier_env *env)
static int fixup_bpf_calls(struct bpf_verifier_env *env)
{
struct bpf_prog *prog = env->prog;
+ bool expect_blinding = bpf_jit_blinding_enabled(prog);
struct bpf_insn *insn = prog->insnsi;
const struct bpf_func_proto *fn;
const int insn_cnt = prog->len;
@@ -9073,7 +9138,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
struct bpf_insn insn_buf[16];
struct bpf_prog *new_prog;
struct bpf_map *map_ptr;
- int i, cnt, delta = 0;
+ int i, ret, cnt, delta = 0;
for (i = 0; i < insn_cnt; i++, insn++) {
if (insn->code == (BPF_ALU64 | BPF_MOD | BPF_X) ||
@@ -9217,6 +9282,26 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
insn->code = BPF_JMP | BPF_TAIL_CALL;
aux = &env->insn_aux_data[i + delta];
+ if (prog->jit_requested && !expect_blinding &&
+ !bpf_map_key_poisoned(aux) &&
+ !bpf_map_ptr_poisoned(aux) &&
+ !bpf_map_ptr_unpriv(aux)) {
+ struct bpf_jit_poke_descriptor desc = {
+ .reason = BPF_POKE_REASON_TAIL_CALL,
+ .tail_call.map = BPF_MAP_PTR(aux->map_ptr_state),
+ .tail_call.key = bpf_map_key_immediate(aux),
+ };
+
+ ret = bpf_jit_add_poke_descriptor(prog, &desc);
+ if (ret < 0) {
+ verbose(env, "adding tail call poke descriptor failed\n");
+ return ret;
+ }
+
+ insn->imm = ret + 1;
+ continue;
+ }
+
if (!bpf_map_ptr_unpriv(aux))
continue;
@@ -9231,7 +9316,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
return -EINVAL;
}
- map_ptr = BPF_MAP_PTR(aux->map_state);
+ map_ptr = BPF_MAP_PTR(aux->map_ptr_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,
@@ -9265,7 +9350,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
if (bpf_map_ptr_poisoned(aux))
goto patch_call_imm;
- map_ptr = BPF_MAP_PTR(aux->map_state);
+ map_ptr = BPF_MAP_PTR(aux->map_ptr_state);
ops = map_ptr->ops;
if (insn->imm == BPF_FUNC_map_lookup_elem &&
ops->map_gen_lookup) {
@@ -9345,6 +9430,23 @@ patch_call_imm:
insn->imm = fn->func - __bpf_call_base;
}
+ /* Since poke tab is now finalized, publish aux to tracker. */
+ for (i = 0; i < prog->aux->size_poke_tab; i++) {
+ map_ptr = prog->aux->poke_tab[i].tail_call.map;
+ if (!map_ptr->ops->map_poke_track ||
+ !map_ptr->ops->map_poke_untrack ||
+ !map_ptr->ops->map_poke_run) {
+ verbose(env, "bpf verifier is misconfigured\n");
+ return -EINVAL;
+ }
+
+ ret = map_ptr->ops->map_poke_track(map_ptr, prog->aux);
+ if (ret < 0) {
+ verbose(env, "tracking tail call prog failed\n");
+ return ret;
+ }
+ }
+
return 0;
}
generated by cgit (git 2.34.1) at 2024-06-19 01:44:01 +0000