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authorWill Deacon <will.deacon@arm.com>2013-08-21 21:24:47 +0400
committerEric Van Hensbergen <ericvh@gmail.com>2013-08-26 19:28:46 +0400
commit50192abe02929586111fb33f216060a9341875f1 (patch)
treec766629c78fc8410eb452e018b0ba4b629141a3e /fs/9p
parente0d6cb9cd3a3ac8a3b8e5b22b83c4f8619786f22 (diff)
downloadlinux-50192abe02929586111fb33f216060a9341875f1.tar.xz
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.c4
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)