From 78b8ebb89afe6230ab4e1c4297666216a545c425 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Sat, 30 Dec 2006 18:29:13 -0500 Subject: hfs_fill_super returns success even if no root inode (CVE-2006-6056) http://kernelfun.blogspot.com/2006/11/mokb-14-11-2006-linux-26x-selinux.html mount that image... fs: filesystem was not cleanly unmounted, running fsck.hfs is recommended. mounting read-only. hfs: get root inode failed. BUG: unable to handle kernel NULL pointer dereference at virtual address 00000018 printing eip ... EIP is at superblock_doinit+0x21/0x767 ... [] selinux_sb_kern_mount+0xc/0x4b [] vfs_kern_mount+0x99/0xf6 [] do_kern_mount+0x2d/0x3e [] do_mount+0x5fa/0x66d [] sys_mount+0x77/0xae [] syscall_call+0x7/0xb DWARF2 unwinder stuck at syscall_call+0x7/0xb hfs_fill_super() returns success even if root_inode = hfs_iget(sb, &fd.search_key->cat, &rec); or sb->s_root = d_alloc_root(root_inode); fails. This superblock finds its way to superblock_doinit() which does: struct dentry *root = sb->s_root; struct inode *inode = root->d_inode; and boom. Need to make sure the error cases return an error, I think. [akpm@osdl.org: return -ENOMEM on oom] Signed-off-by: Eric Sandeen Cc: Roman Zippel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Chris Wright Signed-off-by: Greg Kroah-Hartman --- fs/hfs/super.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/hfs/super.c b/fs/hfs/super.c index 34937ee83ab1..9882a9050695 100644 --- a/fs/hfs/super.c +++ b/fs/hfs/super.c @@ -391,11 +391,13 @@ static int hfs_fill_super(struct super_block *sb, void *data, int silent) hfs_find_exit(&fd); goto bail_no_root; } + res = -EINVAL; root_inode = hfs_iget(sb, &fd.search_key->cat, &rec); hfs_find_exit(&fd); if (!root_inode) goto bail_no_root; + res = -ENOMEM; sb->s_root = d_alloc_root(root_inode); if (!sb->s_root) goto bail_iput; -- cgit v1.2.3