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authorHugh Dickins <hughd@google.com>2012-10-07 20:32:51 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-10-21 09:27:57 -0700
commit530258fceacd8c17075906c648c1ba20928c940b (patch)
tree6adac17cf54efdc5e000c5c2b22fee2a59b4e6a8 /mm
parentfb2ca533f518dabf814c6aab3b7ce3c236959a68 (diff)
downloadlinux-linaro-stable-530258fceacd8c17075906c648c1ba20928c940b.tar.gz
tmpfs,ceph,gfs2,isofs,reiserfs,xfs: fix fh_len checking
commit 35c2a7f4908d404c9124c2efc6ada4640ca4d5d5 upstream. Fuzzing with trinity oopsed on the 1st instruction of shmem_fh_to_dentry(), u64 inum = fid->raw[2]; which is unhelpfully reported as at the end of shmem_alloc_inode(): BUG: unable to handle kernel paging request at ffff880061cd3000 IP: [<ffffffff812190d0>] shmem_alloc_inode+0x40/0x40 Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC Call Trace: [<ffffffff81488649>] ? exportfs_decode_fh+0x79/0x2d0 [<ffffffff812d77c3>] do_handle_open+0x163/0x2c0 [<ffffffff812d792c>] sys_open_by_handle_at+0xc/0x10 [<ffffffff83a5f3f8>] tracesys+0xe1/0xe6 Right, tmpfs is being stupid to access fid->raw[2] before validating that fh_len includes it: the buffer kmalloc'ed by do_sys_name_to_handle() may fall at the end of a page, and the next page not be present. But some other filesystems (ceph, gfs2, isofs, reiserfs, xfs) are being careless about fh_len too, in fh_to_dentry() and/or fh_to_parent(), and could oops in the same way: add the missing fh_len checks to those. Reported-by: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Sage Weil <sage@inktank.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/shmem.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index 9d65a02a8799..40383cddc916 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2018,12 +2018,14 @@ static struct dentry *shmem_fh_to_dentry(struct super_block *sb,
{
struct inode *inode;
struct dentry *dentry = NULL;
- u64 inum = fid->raw[2];
- inum = (inum << 32) | fid->raw[1];
+ u64 inum;
if (fh_len < 3)
return NULL;
+ inum = fid->raw[2];
+ inum = (inum << 32) | fid->raw[1];
+
inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]),
shmem_match, fid->raw);
if (inode) {