From f75eb9d4085192dc58c30a9384cf4496194be851 Mon Sep 17 00:00:00 2001 From: Dan Carpenter <dan.carpenter@oracle.com> Date: Thu, 31 Oct 2013 21:00:10 +0300 Subject: [PATCH] xfs: underflow bug in xfs_attrlist_by_handle() commit 31978b5cc66b8ba8a7e8eef60b12395d41b7b890 upstream. If we allocate less than sizeof(struct attrlist) then we end up corrupting memory or doing a ZERO_PTR_SIZE dereference. This can only be triggered with CAP_SYS_ADMIN. Reported-by: Nico Golde <nico@ngolde.de> Reported-by: Fabian Yamaguchi <fabs@goesec.de> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- fs/xfs/xfs_ioctl.c | 3 ++- fs/xfs/xfs_ioctl32.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c index ca01d830e989..83dfe6e73235 100644 --- a/fs/xfs/xfs_ioctl.c +++ b/fs/xfs/xfs_ioctl.c @@ -409,7 +409,8 @@ xfs_attrlist_by_handle( return -XFS_ERROR(EPERM); if (copy_from_user(&al_hreq, arg, sizeof(xfs_fsop_attrlist_handlereq_t))) return -XFS_ERROR(EFAULT); - if (al_hreq.buflen > XATTR_LIST_MAX) + if (al_hreq.buflen < sizeof(struct attrlist) || + al_hreq.buflen > XATTR_LIST_MAX) return -XFS_ERROR(EINVAL); /* diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c index c0c66259cc91..68799d7f02cc 100644 --- a/fs/xfs/xfs_ioctl32.c +++ b/fs/xfs/xfs_ioctl32.c @@ -359,7 +359,8 @@ xfs_compat_attrlist_by_handle( if (copy_from_user(&al_hreq, arg, sizeof(compat_xfs_fsop_attrlist_handlereq_t))) return -XFS_ERROR(EFAULT); - if (al_hreq.buflen > XATTR_LIST_MAX) + if (al_hreq.buflen < sizeof(struct attrlist) || + al_hreq.buflen > XATTR_LIST_MAX) return -XFS_ERROR(EINVAL); /* -- 2.34.1