summaryrefslogtreecommitdiff
path: root/kernel/bpf/verifier.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/bpf/verifier.c')
-rw-r--r--kernel/bpf/verifier.c71
1 files changed, 59 insertions, 12 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 401d6c4960ec..f108c01ff6d0 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2511,6 +2511,30 @@ static void __reg32_deduce_bounds(struct bpf_reg_state *reg)
if ((u32)reg->s32_min_value <= (u32)reg->s32_max_value) {
reg->u32_min_value = max_t(u32, reg->s32_min_value, reg->u32_min_value);
reg->u32_max_value = min_t(u32, reg->s32_max_value, reg->u32_max_value);
+ } else {
+ if (reg->u32_max_value < (u32)reg->s32_min_value) {
+ /* See __reg64_deduce_bounds() for detailed explanation.
+ * Refine ranges in the following situation:
+ *
+ * 0 U32_MAX
+ * | [xxxxxxxxxxxxxx u32 range xxxxxxxxxxxxxx] |
+ * |----------------------------|----------------------------|
+ * |xxxxx s32 range xxxxxxxxx] [xxxxxxx|
+ * 0 S32_MAX S32_MIN -1
+ */
+ reg->s32_min_value = (s32)reg->u32_min_value;
+ reg->u32_max_value = min_t(u32, reg->u32_max_value, reg->s32_max_value);
+ } else if ((u32)reg->s32_max_value < reg->u32_min_value) {
+ /*
+ * 0 U32_MAX
+ * | [xxxxxxxxxxxxxx u32 range xxxxxxxxxxxxxx] |
+ * |----------------------------|----------------------------|
+ * |xxxxxxxxx] [xxxxxxxxxxxx s32 range |
+ * 0 S32_MAX S32_MIN -1
+ */
+ reg->s32_max_value = (s32)reg->u32_max_value;
+ reg->u32_min_value = max_t(u32, reg->u32_min_value, reg->s32_min_value);
+ }
}
}
@@ -15886,6 +15910,13 @@ static void scalar_byte_swap(struct bpf_reg_state *dst_reg, struct bpf_insn *ins
/* Apply bswap if alu64 or switch between big-endian and little-endian machines */
bool need_bswap = alu64 || (to_le == is_big_endian);
+ /*
+ * If the register is mutated, manually reset its scalar ID to break
+ * any existing ties and avoid incorrect bounds propagation.
+ */
+ if (need_bswap || insn->imm == 16 || insn->imm == 32)
+ dst_reg->id = 0;
+
if (need_bswap) {
if (insn->imm == 16)
dst_reg->var_off = tnum_bswap16(dst_reg->var_off);
@@ -15968,7 +15999,7 @@ static int maybe_fork_scalars(struct bpf_verifier_env *env, struct bpf_insn *ins
else
return 0;
- branch = push_stack(env, env->insn_idx + 1, env->insn_idx, false);
+ branch = push_stack(env, env->insn_idx, env->insn_idx, false);
if (IS_ERR(branch))
return PTR_ERR(branch);
@@ -17335,17 +17366,24 @@ static void __collect_linked_regs(struct linked_regs *reg_set, struct bpf_reg_st
* in verifier state, save R in linked_regs if R->id == id.
* If there are too many Rs sharing same id, reset id for leftover Rs.
*/
-static void collect_linked_regs(struct bpf_verifier_state *vstate, u32 id,
+static void collect_linked_regs(struct bpf_verifier_env *env,
+ struct bpf_verifier_state *vstate,
+ u32 id,
struct linked_regs *linked_regs)
{
+ struct bpf_insn_aux_data *aux = env->insn_aux_data;
struct bpf_func_state *func;
struct bpf_reg_state *reg;
+ u16 live_regs;
int i, j;
id = id & ~BPF_ADD_CONST;
for (i = vstate->curframe; i >= 0; i--) {
+ live_regs = aux[frame_insn_idx(vstate, i)].live_regs_before;
func = vstate->frame[i];
for (j = 0; j < BPF_REG_FP; j++) {
+ if (!(live_regs & BIT(j)))
+ continue;
reg = &func->regs[j];
__collect_linked_regs(linked_regs, reg, id, i, j, true);
}
@@ -17377,6 +17415,12 @@ static void sync_linked_regs(struct bpf_verifier_env *env, struct bpf_verifier_s
continue;
if ((reg->id & ~BPF_ADD_CONST) != (known_reg->id & ~BPF_ADD_CONST))
continue;
+ /*
+ * Skip mixed 32/64-bit links: the delta relationship doesn't
+ * hold across different ALU widths.
+ */
+ if (((reg->id ^ known_reg->id) & BPF_ADD_CONST) == BPF_ADD_CONST)
+ continue;
if ((!(reg->id & BPF_ADD_CONST) && !(known_reg->id & BPF_ADD_CONST)) ||
reg->off == known_reg->off) {
s32 saved_subreg_def = reg->subreg_def;
@@ -17404,7 +17448,7 @@ static void sync_linked_regs(struct bpf_verifier_env *env, struct bpf_verifier_s
scalar32_min_max_add(reg, &fake_reg);
scalar_min_max_add(reg, &fake_reg);
reg->var_off = tnum_add(reg->var_off, fake_reg.var_off);
- if (known_reg->id & BPF_ADD_CONST32)
+ if ((reg->id | known_reg->id) & BPF_ADD_CONST32)
zext_32_to_64(reg);
reg_bounds_sync(reg);
}
@@ -17560,9 +17604,9 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
* if parent state is created.
*/
if (BPF_SRC(insn->code) == BPF_X && src_reg->type == SCALAR_VALUE && src_reg->id)
- collect_linked_regs(this_branch, src_reg->id, &linked_regs);
+ collect_linked_regs(env, this_branch, src_reg->id, &linked_regs);
if (dst_reg->type == SCALAR_VALUE && dst_reg->id)
- collect_linked_regs(this_branch, dst_reg->id, &linked_regs);
+ collect_linked_regs(env, this_branch, dst_reg->id, &linked_regs);
if (linked_regs.cnt > 1) {
err = push_jmp_history(env, this_branch, 0, linked_regs_pack(&linked_regs));
if (err)
@@ -19832,11 +19876,14 @@ static bool regsafe(struct bpf_verifier_env *env, struct bpf_reg_state *rold,
* Also verify that new value satisfies old value range knowledge.
*/
- /* ADD_CONST mismatch: different linking semantics */
- if ((rold->id & BPF_ADD_CONST) && !(rcur->id & BPF_ADD_CONST))
- return false;
-
- if (rold->id && !(rold->id & BPF_ADD_CONST) && (rcur->id & BPF_ADD_CONST))
+ /*
+ * ADD_CONST flags must match exactly: BPF_ADD_CONST32 and
+ * BPF_ADD_CONST64 have different linking semantics in
+ * sync_linked_regs() (alu32 zero-extends, alu64 does not),
+ * so pruning across different flag types is unsafe.
+ */
+ if (rold->id &&
+ (rold->id & BPF_ADD_CONST) != (rcur->id & BPF_ADD_CONST))
return false;
/* Both have offset linkage: offsets must match */
@@ -20873,7 +20920,8 @@ static int process_bpf_exit_full(struct bpf_verifier_env *env,
* state when it exits.
*/
int err = check_resource_leak(env, exception_exit,
- !env->cur_state->curframe,
+ exception_exit || !env->cur_state->curframe,
+ exception_exit ? "bpf_throw" :
"BPF_EXIT instruction in main prog");
if (err)
return err;
@@ -25261,7 +25309,6 @@ BTF_ID(func, __x64_sys_exit_group)
BTF_ID(func, do_exit)
BTF_ID(func, do_group_exit)
BTF_ID(func, kthread_complete_and_exit)
-BTF_ID(func, kthread_exit)
BTF_ID(func, make_task_dead)
BTF_SET_END(noreturn_deny)
generated by cgit v1.2.3 (git 2.46.0) at 2026-04-02 18:58:29 +0000