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-rw-r--r--kernel/bpf/verifier.c137
1 files changed, 82 insertions, 55 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f0dca726ebfd..b532f1058d35 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -240,12 +240,6 @@ static bool bpf_pseudo_kfunc_call(const struct bpf_insn *insn)
insn->src_reg == BPF_PSEUDO_KFUNC_CALL;
}
-static bool bpf_pseudo_func(const struct bpf_insn *insn)
-{
- return insn->code == (BPF_LD | BPF_IMM | BPF_DW) &&
- insn->src_reg == BPF_PSEUDO_FUNC;
-}
-
struct bpf_call_arg_meta {
struct bpf_map *map_ptr;
bool raw_mode;
@@ -1157,7 +1151,8 @@ static void mark_ptr_not_null_reg(struct bpf_reg_state *reg)
/* transfer reg's id which is unique for every map_lookup_elem
* as UID of the inner map.
*/
- reg->map_uid = reg->id;
+ if (map_value_has_timer(map->inner_map_meta))
+ reg->map_uid = reg->id;
} else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {
reg->type = PTR_TO_XDP_SOCK;
} else if (map->map_type == BPF_MAP_TYPE_SOCKMAP ||
@@ -1371,22 +1366,28 @@ static void __reg_bound_offset(struct bpf_reg_state *reg)
reg->var_off = tnum_or(tnum_clear_subreg(var64_off), var32_off);
}
+static bool __reg32_bound_s64(s32 a)
+{
+ return a >= 0 && a <= S32_MAX;
+}
+
static void __reg_assign_32_into_64(struct bpf_reg_state *reg)
{
reg->umin_value = reg->u32_min_value;
reg->umax_value = reg->u32_max_value;
- /* Attempt to pull 32-bit signed bounds into 64-bit bounds
- * but must be positive otherwise set to worse case bounds
- * and refine later from tnum.
+
+ /* Attempt to pull 32-bit signed bounds into 64-bit bounds but must
+ * be positive otherwise set to worse case bounds and refine later
+ * from tnum.
*/
- if (reg->s32_min_value >= 0 && reg->s32_max_value >= 0)
- reg->smax_value = reg->s32_max_value;
- else
- reg->smax_value = U32_MAX;
- if (reg->s32_min_value >= 0)
+ if (__reg32_bound_s64(reg->s32_min_value) &&
+ __reg32_bound_s64(reg->s32_max_value)) {
reg->smin_value = reg->s32_min_value;
- else
+ reg->smax_value = reg->s32_max_value;
+ } else {
reg->smin_value = 0;
+ reg->smax_value = U32_MAX;
+ }
}
static void __reg_combine_32_into_64(struct bpf_reg_state *reg)
@@ -1960,16 +1961,10 @@ static int add_subprog_and_kfunc(struct bpf_verifier_env *env)
return -EPERM;
}
- if (bpf_pseudo_func(insn)) {
- ret = add_subprog(env, i + insn->imm + 1);
- if (ret >= 0)
- /* remember subprog */
- insn[1].imm = ret;
- } else if (bpf_pseudo_call(insn)) {
+ if (bpf_pseudo_func(insn) || bpf_pseudo_call(insn))
ret = add_subprog(env, i + insn->imm + 1);
- } else {
+ else
ret = add_kfunc_call(env, insn->imm, insn->off);
- }
if (ret < 0)
return ret;
@@ -2390,8 +2385,6 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx,
*/
if (insn->src_reg != BPF_REG_FP)
return 0;
- if (BPF_SIZE(insn->code) != BPF_DW)
- return 0;
/* dreg = *(u64 *)[fp - off] was a fill from the stack.
* that [fp - off] slot contains scalar that needs to be
@@ -2414,8 +2407,6 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx,
/* scalars can only be spilled into stack */
if (insn->dst_reg != BPF_REG_FP)
return 0;
- if (BPF_SIZE(insn->code) != BPF_DW)
- return 0;
spi = (-insn->off - 1) / BPF_REG_SIZE;
if (spi >= 64) {
verbose(env, "BUG spi %d\n", spi);
@@ -3088,9 +3079,12 @@ static int check_stack_read_fixed_off(struct bpf_verifier_env *env,
reg = &reg_state->stack[spi].spilled_ptr;
if (is_spilled_reg(&reg_state->stack[spi])) {
- if (size != BPF_REG_SIZE) {
- u8 scalar_size = 0;
+ u8 spill_size = 1;
+
+ for (i = BPF_REG_SIZE - 1; i > 0 && stype[i - 1] == STACK_SPILL; i--)
+ spill_size++;
+ if (size != BPF_REG_SIZE || spill_size != BPF_REG_SIZE) {
if (reg->type != SCALAR_VALUE) {
verbose_linfo(env, env->insn_idx, "; ");
verbose(env, "invalid size of register fill\n");
@@ -3101,10 +3095,7 @@ static int check_stack_read_fixed_off(struct bpf_verifier_env *env,
if (dst_regno < 0)
return 0;
- for (i = BPF_REG_SIZE; i > 0 && stype[i - 1] == STACK_SPILL; i--)
- scalar_size++;
-
- if (!(off % BPF_REG_SIZE) && size == scalar_size) {
+ if (!(off % BPF_REG_SIZE) && size == spill_size) {
/* The earlier check_reg_arg() has decided the
* subreg_def for this insn. Save it first.
*/
@@ -3128,12 +3119,6 @@ static int check_stack_read_fixed_off(struct bpf_verifier_env *env,
state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
return 0;
}
- for (i = 1; i < BPF_REG_SIZE; i++) {
- if (stype[(slot - i) % BPF_REG_SIZE] != STACK_SPILL) {
- verbose(env, "corrupted spill memory\n");
- return -EACCES;
- }
- }
if (dst_regno >= 0) {
/* restore register state from stack */
@@ -4073,7 +4058,22 @@ static void coerce_reg_to_size(struct bpf_reg_state *reg, int size)
static bool bpf_map_is_rdonly(const struct bpf_map *map)
{
- return (map->map_flags & BPF_F_RDONLY_PROG) && map->frozen;
+ /* A map is considered read-only if the following condition are true:
+ *
+ * 1) BPF program side cannot change any of the map content. The
+ * BPF_F_RDONLY_PROG flag is throughout the lifetime of a map
+ * and was set at map creation time.
+ * 2) The map value(s) have been initialized from user space by a
+ * loader and then "frozen", such that no new map update/delete
+ * operations from syscall side are possible for the rest of
+ * the map's lifetime from that point onwards.
+ * 3) Any parallel/pending map update/delete operations from syscall
+ * side have been completed. Only after that point, it's safe to
+ * assume that map value(s) are immutable.
+ */
+ return (map->map_flags & BPF_F_RDONLY_PROG) &&
+ READ_ONCE(map->frozen) &&
+ !bpf_map_write_active(map);
}
static int bpf_map_direct_read(struct bpf_map *map, int off, int size, u64 *val)
@@ -4553,9 +4553,16 @@ static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_i
if (insn->imm == BPF_CMPXCHG) {
/* Check comparison of R0 with memory location */
- err = check_reg_arg(env, BPF_REG_0, SRC_OP);
+ const u32 aux_reg = BPF_REG_0;
+
+ err = check_reg_arg(env, aux_reg, SRC_OP);
if (err)
return err;
+
+ if (is_pointer_value(env, aux_reg)) {
+ verbose(env, "R%d leaks addr into mem\n", aux_reg);
+ return -EACCES;
+ }
}
if (is_pointer_value(env, insn->src_reg)) {
@@ -4590,13 +4597,19 @@ static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_i
load_reg = -1;
}
- /* check whether we can read the memory */
+ /* Check whether we can read the memory, with second call for fetch
+ * case to simulate the register fill.
+ */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
- BPF_SIZE(insn->code), BPF_READ, load_reg, true);
+ BPF_SIZE(insn->code), BPF_READ, -1, true);
+ if (!err && load_reg >= 0)
+ err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
+ BPF_SIZE(insn->code), BPF_READ, load_reg,
+ true);
if (err)
return err;
- /* check whether we can write into the same memory */
+ /* Check whether we can write into the same memory. */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_WRITE, -1, true);
if (err)
@@ -8310,6 +8323,10 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
insn->dst_reg);
}
zext_32_to_64(dst_reg);
+
+ __update_reg_bounds(dst_reg);
+ __reg_deduce_bounds(dst_reg);
+ __reg_bound_offset(dst_reg);
}
} else {
/* case: R = imm
@@ -8424,7 +8441,7 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
new_range = dst_reg->off;
if (range_right_open)
- new_range--;
+ new_range++;
/* Examples for register markings:
*
@@ -9393,7 +9410,8 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
if (insn->src_reg == BPF_PSEUDO_FUNC) {
struct bpf_prog_aux *aux = env->prog->aux;
- u32 subprogno = insn[1].imm;
+ u32 subprogno = find_subprog(env,
+ env->insn_idx + insn->imm + 1);
if (!aux->func_info) {
verbose(env, "missing btf func_info\n");
@@ -11648,6 +11666,13 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env,
}
}
+ if (map_value_has_timer(map)) {
+ if (is_tracing_prog_type(prog_type)) {
+ verbose(env, "tracing progs cannot use bpf_timer yet\n");
+ return -EINVAL;
+ }
+ }
+
if ((bpf_prog_is_dev_bound(prog->aux) || bpf_map_is_dev_bound(map)) &&
!bpf_offload_prog_map_match(prog, map)) {
verbose(env, "offload device mismatch between prog and map\n");
@@ -12563,14 +12588,9 @@ static int jit_subprogs(struct bpf_verifier_env *env)
return 0;
for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
- if (bpf_pseudo_func(insn)) {
- env->insn_aux_data[i].call_imm = insn->imm;
- /* subprog is encoded in insn[1].imm */
+ if (!bpf_pseudo_func(insn) && !bpf_pseudo_call(insn))
continue;
- }
- if (!bpf_pseudo_call(insn))
- continue;
/* Upon error here we cannot fall back to interpreter but
* need a hard reject of the program. Thus -EFAULT is
* propagated in any case.
@@ -12591,6 +12611,12 @@ static int jit_subprogs(struct bpf_verifier_env *env)
env->insn_aux_data[i].call_imm = insn->imm;
/* point imm to __bpf_call_base+1 from JITs point of view */
insn->imm = 1;
+ if (bpf_pseudo_func(insn))
+ /* jit (e.g. x86_64) may emit fewer instructions
+ * if it learns a u32 imm is the same as a u64 imm.
+ * Force a non zero here.
+ */
+ insn[1].imm = 1;
}
err = bpf_prog_alloc_jited_linfo(prog);
@@ -12675,7 +12701,7 @@ static int jit_subprogs(struct bpf_verifier_env *env)
insn = func[i]->insnsi;
for (j = 0; j < func[i]->len; j++, insn++) {
if (bpf_pseudo_func(insn)) {
- subprog = insn[1].imm;
+ subprog = insn->off;
insn[0].imm = (u32)(long)func[subprog]->bpf_func;
insn[1].imm = ((u64)(long)func[subprog]->bpf_func) >> 32;
continue;
@@ -12726,7 +12752,8 @@ static int jit_subprogs(struct bpf_verifier_env *env)
for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
if (bpf_pseudo_func(insn)) {
insn[0].imm = env->insn_aux_data[i].call_imm;
- insn[1].imm = find_subprog(env, i + insn[0].imm + 1);
+ insn[1].imm = insn->off;
+ insn->off = 0;
continue;
}
if (!bpf_pseudo_call(insn))
generated by cgit v1.2.3 (git 2.46.0) at 2025-04-25 22:29:25 +0000