@@ -2269,6 +2269,9 @@ EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
};
+
+#define MAX_INTERPRETERS_CALLBACK (sizeof(interpreters) / sizeof(*interpreters))
+
#undef PROG_NAME_LIST
#define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size),
static __maybe_unused
@@ -2290,17 +2293,18 @@ void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
insn->code = BPF_JMP | BPF_CALL_ARGS;
}
#endif
-#else
+#endif
+
static unsigned int __bpf_prog_ret0_warn(const void *ctx,
const struct bpf_insn *insn)
{
/* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON
- * is not working properly, so warn about it!
+ * is not working properly, or interpreter is being used when
+ * prog->jit_requested is not 0, so warn about it!
*/
WARN_ON_ONCE(1);
return 0;
}
-#endif
bool bpf_prog_map_compatible(struct bpf_map *map,
const struct bpf_prog *fp)
@@ -2380,8 +2384,14 @@ static void bpf_prog_select_func(struct bpf_prog *fp)
{
#ifndef CONFIG_BPF_JIT_ALWAYS_ON
u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
+ u32 idx = (round_up(stack_depth, 32) / 32) - 1;
- fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
+ if (!fp->jit_requested) {
+ WARN_ON_ONCE(idx >= MAX_INTERPRETERS_CALLBACK);
+ fp->bpf_func = interpreters[idx];
+ } else {
+ fp->bpf_func = __bpf_prog_ret0_warn;
+ }
#else
fp->bpf_func = __bpf_prog_ret0_warn;
#endif
@@ -21882,6 +21882,13 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
if (subprogs[cur_subprog + 1].start == i + delta + 1) {
subprogs[cur_subprog].stack_depth += stack_depth_extra;
subprogs[cur_subprog].stack_extra = stack_depth_extra;
+
+ stack_depth = subprogs[cur_subprog].stack_depth;
+ if (stack_depth > MAX_BPF_STACK && !prog->jit_requested) {
+ verbose(env, "stack size %d(extra %d) is too large\n",
+ stack_depth, stack_depth_extra);
+ return -EINVAL;
+ }
cur_subprog++;
stack_depth = subprogs[cur_subprog].stack_depth;
stack_depth_extra = 0;
may_goto uses an additional 8 bytes on the stack, which causes the interpreters[] array to go out of bounds when calculating index by stack_size. 1. If a BPF program is rewritten, re-evaluate the stack size. For non-JIT cases, reject loading directly. 2. For non-JIT cases, calculating interpreters[idx] may still cause out-of-bounds array access, and just warn about it. 3. For jit_requested cases, the execution of bpf_func also needs to be warned. So Move the definition of function __bpf_prog_ret0_warn out of the macro definition CONFIG_BPF_JIT_ALWAYS_ON Reported-by: syzbot+d2a2c639d03ac200a4f1@syzkaller.appspotmail.com Closes: https://lore.kernel.org/bpf/0000000000000f823606139faa5d@google.com/ Fixes: 011832b97b311 ("bpf: Introduce may_goto instruction") Signed-off-by: Jiayuan Chen <mrpre@163.com> --- kernel/bpf/core.c | 18 ++++++++++++++---- kernel/bpf/verifier.c | 7 +++++++ 2 files changed, 21 insertions(+), 4 deletions(-)