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/isofs/export.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/isofs') diff --git a/fs/isofs/export.c b/fs/isofs/export.c index 1d3804492aa7..2b4f2358eadb 100644 --- a/fs/isofs/export.c +++ b/fs/isofs/export.c @@ -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, -- cgit v1.2.3