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Commit 35c2a7f4 authored by Hugh Dickins's avatar Hugh Dickins Committed by Al Viro
Browse files

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



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: default avatarSasha Levin <levinsasha928@gmail.com>
Signed-off-by: default avatarHugh 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: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 8e22cc88

fs/ceph/export.c

+14 −4
Original line number Diff line number Diff line
@@ -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);

fs/gfs2/export.c

+4 −0
Original line number Diff line number Diff line
@@ -161,6 +161,8 @@ static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid, 
	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(struct super_block *sb, struct fid *fid, 
	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;

fs/isofs/export.c

+1 −1
Original line number Diff line number Diff line
@@ -175,7 +175,7 @@ static struct dentry *isofs_fh_to_parent(struct super_block *sb, 
{

	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,

fs/reiserfs/inode.c

+5 −1
Original line number Diff line number Diff line
@@ -1573,8 +1573,10 @@ struct dentry *reiserfs_fh_to_dentry(struct super_block *sb, struct fid *fid, 
			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(struct super_block *sb, struct fid *fid, 
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;

fs/xfs/xfs_export.c

+3 −0
Original line number Diff line number Diff line
@@ -189,6 +189,9 @@ xfs_fs_fh_to_parent(struct super_block *sb, struct fid *fid, 
	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,