diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/core.c | 55 | ||||
| -rw-r--r-- | kernel/bpf/syscall.c | 4 |
2 files changed, 49 insertions, 10 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 1061968adcc1..a9e6c04d0f4a 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -598,6 +598,8 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, bpf_fill_ill_insns(hdr, size); hdr->pages = size / PAGE_SIZE; + hdr->locked = 0; + hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), PAGE_SIZE - sizeof(*hdr)); start = (get_random_int() % hole) & ~(alignment - 1); @@ -1448,6 +1450,33 @@ static int bpf_check_tail_call(const struct bpf_prog *fp) return 0; } +static int bpf_prog_check_pages_ro_locked(const struct bpf_prog *fp) +{ +#ifdef CONFIG_ARCH_HAS_SET_MEMORY + int i, err; + + for (i = 0; i < fp->aux->func_cnt; i++) { + err = bpf_prog_check_pages_ro_single(fp->aux->func[i]); + if (err) + return err; + } + + return bpf_prog_check_pages_ro_single(fp); +#endif + return 0; +} + +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); + + fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; +#else + fp->bpf_func = __bpf_prog_ret0_warn; +#endif +} + /** * bpf_prog_select_runtime - select exec runtime for BPF program * @fp: bpf_prog populated with internal BPF program @@ -1458,13 +1487,13 @@ static int bpf_check_tail_call(const struct bpf_prog *fp) */ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) { -#ifndef CONFIG_BPF_JIT_ALWAYS_ON - u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); + /* In case of BPF to BPF calls, verifier did all the prep + * work with regards to JITing, etc. + */ + if (fp->bpf_func) + goto finalize; - fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; -#else - fp->bpf_func = __bpf_prog_ret0_warn; -#endif + bpf_prog_select_func(fp); /* eBPF JITs can rewrite the program in case constant * blinding is active. However, in case of error during @@ -1485,6 +1514,8 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) if (*err) return fp; } + +finalize: bpf_prog_lock_ro(fp); /* The tail call compatibility check can only be done at @@ -1493,7 +1524,17 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) * all eBPF JITs might immediately support all features. */ *err = bpf_check_tail_call(fp); - + if (*err) + return fp; + + /* Checkpoint: at this point onwards any cBPF -> eBPF or + * native eBPF program is read-only. If we failed to change + * the page attributes (e.g. allocation failure from + * splitting large pages), then reject the whole program + * in order to guarantee not ending up with any W+X pages + * from BPF side in kernel. + */ + *err = bpf_prog_check_pages_ro_locked(fp); return fp; } EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 0f62692fe635..35dc466641f2 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1353,9 +1353,7 @@ static int bpf_prog_load(union bpf_attr *attr) if (err < 0) goto free_used_maps; - /* eBPF program is ready to be JITed */ - if (!prog->bpf_func) - prog = bpf_prog_select_runtime(prog, &err); + prog = bpf_prog_select_runtime(prog, &err); if (err < 0) goto free_used_maps; |