From 35c2a7f4908d404c9124c2efc6ada4640ca4d5d5 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Sun, 7 Oct 2012 20:32:51 -0700 Subject: 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: [] shmem_alloc_inode+0x40/0x40 Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC Call Trace: [] ? exportfs_decode_fh+0x79/0x2d0 [] do_handle_open+0x163/0x2c0 [] sys_open_by_handle_at+0xc/0x10 [] 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 Signed-off-by: Hugh Dickins Cc: Al Viro Cc: Sage Weil Cc: Steven Whitehouse Cc: Christoph Hellwig Cc: stable@vger.kernel.org Signed-off-by: Al Viro --- fs/ceph/export.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) (limited to 'fs/ceph') diff --git a/fs/ceph/export.c b/fs/ceph/export.c index 8e1b60e557b..02ce90972d8 100644 --- a/fs/ceph/export.c +++ b/fs/ceph/export.c @@ -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); -- cgit v1.2.3