diff options
| author | Hou Tao <houtao1@huawei.com> | 2024-10-24 04:35:58 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-11-17 17:09:54 +0300 |
| commit | b3eb1b6a9f745d6941b345f0fae014dc8bb06d36 (patch) | |
| tree | 0df30d8bf978fdaad1261527c91d5e14d0a8eeef | |
| parent | bd965aba2ef089e6b7eab9aa66fbb82ac8839b68 (diff) | |
| download | linux-b3eb1b6a9f745d6941b345f0fae014dc8bb06d36.tar.xz | |
bpf: Check validity of link->type in bpf_link_show_fdinfo()
[ Upstream commit 8421d4c8762bd022cb491f2f0f7019ef51b4f0a7 ]
If a newly-added link type doesn't invoke BPF_LINK_TYPE(), accessing
bpf_link_type_strs[link->type] may result in an out-of-bounds access.
To spot such missed invocations early in the future, checking the
validity of link->type in bpf_link_show_fdinfo() and emitting a warning
when such invocations are missed.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241024013558.1135167-3-houtao@huaweicloud.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | kernel/bpf/syscall.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 19b590b5aaec..b282ed125035 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3136,13 +3136,17 @@ static void bpf_link_show_fdinfo(struct seq_file *m, struct file *filp) { const struct bpf_link *link = filp->private_data; const struct bpf_prog *prog = link->prog; + enum bpf_link_type type = link->type; char prog_tag[sizeof(prog->tag) * 2 + 1] = { }; - seq_printf(m, - "link_type:\t%s\n" - "link_id:\t%u\n", - bpf_link_type_strs[link->type], - link->id); + if (type < ARRAY_SIZE(bpf_link_type_strs) && bpf_link_type_strs[type]) { + seq_printf(m, "link_type:\t%s\n", bpf_link_type_strs[type]); + } else { + WARN_ONCE(1, "missing BPF_LINK_TYPE(...) for link type %u\n", type); + seq_printf(m, "link_type:\t<%u>\n", type); + } + seq_printf(m, "link_id:\t%u\n", link->id); + if (prog) { bin2hex(prog_tag, prog->tag, sizeof(prog->tag)); seq_printf(m, |