diff options
| author | Hou Tao <houtao1@huawei.com> | 2022-08-31 12:26:28 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-10-26 12:34:40 +0200 |
| commit | 0e13425104903970a5ede853082d3bbb4edec6f3 (patch) | |
| tree | d5a93b15e8fba1bdaa46ccd3dc69456d76e5face /kernel | |
| parent | 0b00c6130c1aad1518327f07de811b8d68116015 (diff) | |
bpf: Propagate error from htab_lock_bucket() to userspace
[ Upstream commit 66a7a92e4d0d091e79148a4c6ec15d1da65f4280 ]
In __htab_map_lookup_and_delete_batch() if htab_lock_bucket() returns
-EBUSY, it will go to next bucket. Going to next bucket may not only
skip the elements in current bucket silently, but also incur
out-of-bound memory access or expose kernel memory to userspace if
current bucket_cnt is greater than bucket_size or zero.
Fixing it by stopping batch operation and returning -EBUSY when
htab_lock_bucket() fails, and the application can retry or skip the busy
batch as needed.
Fixes: 20b6cc34ea74 ("bpf: Avoid hashtab deadlock with map_locked")
Reported-by: Hao Sun <sunhao.th@gmail.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20220831042629.130006-3-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/hashtab.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index cae858985f0c..e7f45a966e6b 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -1671,8 +1671,11 @@ again_nocopy: /* do not grab the lock unless need it (bucket_cnt > 0). */ if (locked) { ret = htab_lock_bucket(htab, b, batch, &flags); - if (ret) - goto next_batch; + if (ret) { + rcu_read_unlock(); + bpf_enable_instrumentation(); + goto after_loop; + } } bucket_cnt = 0; |