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tmpfs,ceph,gfs2,isofs,reiserfs,xfs: fix fh_len checking

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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>
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Hugh Dickins
2012-10-07 20:32:51 -07:00
committed by Al Viro
parent 8e22cc88d6
commit 35c2a7f490
6 changed files with 31 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
fs/ceph/export.c
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@@ -99,7 +99,7 @@ static int ceph_encode_fh(struct inode *inode, u32 *rawfh, int *max_len,
* FIXME: we should try harder by querying the mds for the ino.
*/
static struct dentry *__fh_to_dentry(struct super_block *sb,
struct ceph_nfs_fh *fh)
struct ceph_nfs_fh *fh, int fh_len)
{
struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
struct inode *inode;
@@ -107,6 +107,9 @@ static struct dentry *__fh_to_dentry(struct super_block *sb,
struct ceph_vino vino;
int err;
if (fh_len < sizeof(*fh) / 4)
return ERR_PTR(-ESTALE);
dout("__fh_to_dentry %llx\n", fh->ino);
vino.ino = fh->ino;
vino.snap = CEPH_NOSNAP;
@@ -150,7 +153,7 @@ static struct dentry *__fh_to_dentry(struct super_block *sb,
* convert connectable fh to dentry
*/
static struct dentry *__cfh_to_dentry(struct super_block *sb,
struct ceph_nfs_confh *cfh)
struct ceph_nfs_confh *cfh, int fh_len)
{
struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
struct inode *inode;
@@ -158,6 +161,9 @@ static struct dentry *__cfh_to_dentry(struct super_block *sb,
struct ceph_vino vino;
int err;
if (fh_len < sizeof(*cfh) / 4)
return ERR_PTR(-ESTALE);
dout("__cfh_to_dentry %llx (%llx/%x)\n",
cfh->ino, cfh->parent_ino, cfh->parent_name_hash);
@@ -207,9 +213,11 @@ static struct dentry *ceph_fh_to_dentry(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type)
{
if (fh_type == 1)
return __fh_to_dentry(sb, (struct ceph_nfs_fh *)fid->raw);
return __fh_to_dentry(sb, (struct ceph_nfs_fh *)fid->raw,
fh_len);
else
return __cfh_to_dentry(sb, (struct ceph_nfs_confh *)fid->raw);
return __cfh_to_dentry(sb, (struct ceph_nfs_confh *)fid->raw,
fh_len);
}
/*
@@ -230,6 +238,8 @@ static struct dentry *ceph_fh_to_parent(struct super_block *sb,
if (fh_type == 1)
return ERR_PTR(-ESTALE);
if (fh_len < sizeof(*cfh) / 4)
return ERR_PTR(-ESTALE);
pr_debug("fh_to_parent %llx/%d\n", cfh->parent_ino,
cfh->parent_name_hash);