diff options
| author |   Will Deacon <will.deacon@arm.com> | 2013-08-21 18:24:47 +0100 |
|---|---|---|
| committer |   Eric Van Hensbergen <ericvh@gmail.com> | 2013-08-26 10:28:46 -0500 |
| commit | 50192abe02929586111fb33f216060a9341875f1 (patch) | |
| tree | c766629c78fc8410eb452e018b0ba4b629141a3e /fs/9p | |
| parent | 9p: send uevent after adding/removing mount_tag attribute (diff) | |
| download | linux-dev-50192abe02929586111fb33f216060a9341875f1.tar.xz linux-dev-50192abe02929586111fb33f216060a9341875f1.zip | |
fs/9p: avoid accessing utsname after namespace has been torn down
During trinity fuzzing in a kvmtool guest, I stumbled across the
following:
Unable to handle kernel NULL pointer dereference at virtual address 00000004
PC is at v9fs_file_do_lock+0xc8/0x1a0
LR is at v9fs_file_do_lock+0x48/0x1a0
[<c01e2ed0>] (v9fs_file_do_lock+0xc8/0x1a0) from [<c0119154>] (locks_remove_flock+0x8c/0x124)
[<c0119154>] (locks_remove_flock+0x8c/0x124) from [<c00d9bf0>] (__fput+0x58/0x1e4)
[<c00d9bf0>] (__fput+0x58/0x1e4) from [<c0044340>] (task_work_run+0xac/0xe8)
[<c0044340>] (task_work_run+0xac/0xe8) from [<c002e36c>] (do_exit+0x6bc/0x8d8)
[<c002e36c>] (do_exit+0x6bc/0x8d8) from [<c002e674>] (do_group_exit+0x3c/0xb0)
[<c002e674>] (do_group_exit+0x3c/0xb0) from [<c002e6f8>] (__wake_up_parent+0x0/0x18)
I believe this is due to an attempt to access utsname()->nodename, after
exit_task_namespaces() has been called, leaving current->nsproxy->uts_ns
as NULL and causing the above dereference.
A similar issue was fixed for lockd in 9a1b6bf818e7 ("LOCKD: Don't call
utsname()->nodename from nlmclnt_setlockargs"), so this patch attempts
something similar for 9pfs.
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Diffstat (limited to 'fs/9p')
| -rw-r--r-- | fs/9p/vfs_file.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c index d384a8b77ee8..aa5ecf479a57 100644 --- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -183,7 +183,7 @@ static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl) else flock.length = fl->fl_end - fl->fl_start + 1; flock.proc_id = fl->fl_pid; - flock.client_id = utsname()->nodename; + flock.client_id = fid->clnt->name; if (IS_SETLKW(cmd)) flock.flags = P9_LOCK_FLAGS_BLOCK; @@ -260,7 +260,7 @@ static int v9fs_file_getlock(struct file *filp, struct file_lock *fl) else glock.length = fl->fl_end - fl->fl_start + 1; glock.proc_id = fl->fl_pid; - glock.client_id = utsname()->nodename; + glock.client_id = fid->clnt->name; res = p9_client_getlock_dotl(fid, &glock); if (res < 0) |