[ 17/76] tmpfs,ceph,gfs2,isofs,reiserfs,xfs: fix fh_len checking

Greg Kroah-Hartman
2012-10-19T02:48:42Z

From: Hugh Dickins <hughd@google.com>

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>

---
fs/ceph/export.c | 18 ++++++++++++++----
fs/gfs2/export.c | 4 ++++
fs/isofs/export.c | 2 +-
fs/reiserfs/inode.c | 6 +++++-
fs/xfs/xfs_export.c | 3 +++
mm/shmem.c | 6 ++++--
6 files changed, 31 insertions(+), 8 deletions(-)

--- a/fs/ceph/export.c
+++ b/fs/ceph/export.c
@@ -99,7 +99,7 @@ static int ceph_encode_fh(struct inode *
* 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(str
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(str
* 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(st
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(
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(

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);
--- a/fs/gfs2/export.c
+++ b/fs/gfs2/export.c
@@ -161,6 +161,8 @@ static struct dentry *gfs2_fh_to_dentry(
case GFS2_SMALL_FH_SIZE:
case GFS2_LARGE_FH_SIZE:
case GFS2_OLD_FH_SIZE:
+ if (fh_len < GFS2_SMALL_FH_SIZE)
+ return NULL;
this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
this.no_formal_ino |= be32_to_cpu(fh[1]);
this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
@@ -180,6 +182,8 @@ static struct dentry *gfs2_fh_to_parent(
switch (fh_type) {
case GFS2_LARGE_FH_SIZE:
case GFS2_OLD_FH_SIZE:
+ if (fh_len < GFS2_LARGE_FH_SIZE)
+ return NULL;
parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
parent.no_formal_ino |= be32_to_cpu(fh[5]);
parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
--- a/fs/isofs/export.c
+++ b/fs/isofs/export.c
@@ -175,7 +175,7 @@ static struct dentry *isofs_fh_to_parent
{
struct isofs_fid *ifid = (struct isofs_fid *)fid;

- if (fh_type != 2)
+ if (fh_len < 2 || fh_type != 2)
return NULL;

return isofs_export_iget(sb,
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -1573,8 +1573,10 @@ struct dentry *reiserfs_fh_to_dentry(str
reiserfs_warning(sb, "reiserfs-13077",
"nfsd/reiserfs, fhtype=%d, len=%d - odd",
fh_type, fh_len);
- fh_type = 5;
+ fh_type = fh_len;
}
+ if (fh_len < 2)
+ return NULL;

return reiserfs_get_dentry(sb, fid->raw[0], fid->raw[1],
(fh_type == 3 || fh_type >= 5) ? fid->raw[2] : 0);
@@ -1583,6 +1585,8 @@ struct dentry *reiserfs_fh_to_dentry(str
struct dentry *reiserfs_fh_to_parent(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type)
{
+ if (fh_type > fh_len)
+ fh_type = fh_len;
if (fh_type < 4)
return NULL;

--- a/fs/xfs/xfs_export.c
+++ b/fs/xfs/xfs_export.c
@@ -189,6 +189,9 @@ xfs_fs_fh_to_parent(struct super_block *
struct xfs_fid64 *fid64 = (struct xfs_fid64 *)fid;
struct inode *inode = NULL;

+ if (fh_len < xfs_fileid_length(fileid_type))
+ return NULL;
+
switch (fileid_type) {
case FILEID_INO32_GEN_PARENT:
inode = xfs_nfs_get_inode(sb, fid->i32.parent_ino,
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2366,12 +2366,14 @@ static struct dentry *shmem_fh_to_dentry
{
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) {