sunrpc: fix use-after-free in __rpc_clnt_handle_event and __rpc_clnt_remove_pipedir

Browse source

Normal client creation goes through rpc_setup_pipedir(), which records
clnt->pipefs_sb, but the mount-event path in __rpc_clnt_handle_event()
calls rpc_setup_pipedir_sb() directly and never refreshes that field.
The umount path also removes the directory without clearing
clnt->pipefs_sb.

After a late pipefs mount or any remount, rpc_clnt_remove_pipedir()
compares the current superblock against a stale pipefs_sb pointer and
skips cleanup, leaving pipefs dentries whose inode private data still
points at a freed rpc_clnt, leading to a potential use-after-free during
subsequent rpc_info_open() or rpc_show_info() calls.

Fix this by properly updating clnt->pipefs_sb upon mount events and
clearing it during unmount or failure paths.

Fixes: bfca5fb4e9 ("SUNRPC: Fix RPC client cleaned up the freed pipefs dentries")
Cc: stable@vger.kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Xin Liu <dstsmallbird@foxmail.com>
Reviewed-by: Ren Wei <enjou1224z@gmail.com>
Assisted-by: Codex:gpt-5.4
Signed-off-by: Luxiao Xu <rakukuip@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

...

This commit is contained in:

Luxiao Xu 2026-07-07 13:20:47 +08:00 • committed by Trond Myklebust

parent 3e05a62a97

commit 932a8cf6ab

1 changed files with 17 additions and 5 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

22

net/sunrpc/clnt.c

View file