diff options
| author | Kuniyuki Iwashima <kuniyu@google.com> | 2026-01-24 04:18:40 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-03-13 17:20:35 +0100 |
| commit | 41170716421c25cd20b39e83f0e0762e212b377b (patch) | |
| tree | e104a941b11f8342bbcf7c1094f67a3bdf9cdb44 | |
| parent | 78b8d2f55a564236435649fbd8bd6a103f30acf5 (diff) | |
nfsd: Fix cred ref leak in nfsd_nl_threads_set_doit().
commit 1cb968a2013ffa8112d52ebe605009ea1c6a582c upstream.
syzbot reported memory leak of struct cred. [0]
nfsd_nl_threads_set_doit() passes get_current_cred() to
nfsd_svc(), but put_cred() is not called after that.
The cred is finally passed down to _svc_xprt_create(),
which calls get_cred() with the cred for struct svc_xprt.
The ownership of the refcount by get_current_cred() is not
transferred to anywhere and is just leaked.
nfsd_svc() is also called from write_threads(), but it does
not bump file->f_cred there.
nfsd_nl_threads_set_doit() is called from sendmsg() and
current->cred does not go away.
Let's use current_cred() in nfsd_nl_threads_set_doit().
[0]:
BUG: memory leak
unreferenced object 0xffff888108b89480 (size 184):
comm "syz-executor", pid 5994, jiffies 4294943386
hex dump (first 32 bytes):
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc 369454a7):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4958 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x412/0x580 mm/slub.c:5270
prepare_creds+0x22/0x600 kernel/cred.c:185
copy_creds+0x44/0x290 kernel/cred.c:286
copy_process+0x7a7/0x2870 kernel/fork.c:2086
kernel_clone+0xac/0x6e0 kernel/fork.c:2651
__do_sys_clone+0x7f/0xb0 kernel/fork.c:2792
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Fixes: 924f4fb003ba ("NFSD: convert write_threads to netlink command")
Cc: stable@vger.kernel.org
Reported-by: syzbot+dd3b43aa0204089217ee@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/69744674.a00a0220.33ccc7.0000.GAE@google.com/
Tested-by: syzbot+dd3b43aa0204089217ee@syzkaller.appspotmail.com
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/nfsd/nfsctl.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index eb012f943912..d80be50dad76 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -1724,7 +1724,7 @@ int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info) scope = nla_data(attr); } - ret = nfsd_svc(nrpools, nthreads, net, get_current_cred(), scope); + ret = nfsd_svc(nrpools, nthreads, net, current_cred(), scope); if (ret > 0) ret = 0; out_unlock: |