Hi Luis, On Tue, May 13, 2014 at 12:08:12PM +0100, Luis Henriques wrote: > > diff --git a/fs/xfs/linux-2.6/xfs_ioctl32.c b/fs/xfs/linux-2.6/xfs_ioctl32.c > > index bad485a..782d03d 100644 > > --- a/fs/xfs/linux-2.6/xfs_ioctl32.c > > +++ b/fs/xfs/linux-2.6/xfs_ioctl32.c > > @@ -361,8 +361,8 @@ 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) > > - return -XFS_ERROR(EINVAL); > > Am I missing something or was the above return statement deleted by > mistake? > > > + if (al_hreq.buflen < sizeof(struct attrlist) || > > + al_hreq.buflen > XATTR_LIST_MAX) Ouch! You're absolutely right, thanks a lot for spotting this! Here's an updated patch. Dann, Moritz, you want to use this one as well instead! thanks, Willy
>From 2282cff50cb9c2205d92b31257d894a4eda4ed86 Mon Sep 17 00:00:00 2001 From: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Date: Thu, 31 Oct 2013 21:00:10 +0300 Subject: xfs: underflow bug in xfs_attrlist_by_handle() 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@xxxxxxxxx> Reported-by: Fabian Yamaguchi <fabs@xxxxxxxxx> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx> Signed-off-by: Ben Myers <bpm@xxxxxxx> (cherry picked from commit 071c529eb672648ee8ca3f90944bcbcc730b4c06) [dannf: backported to Debian's 2.6.32] Signed-off-by: Willy Tarreau <w@xxxxxx> --- fs/xfs/linux-2.6/xfs_ioctl.c | 3 ++- fs/xfs/linux-2.6/xfs_ioctl32.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/xfs/linux-2.6/xfs_ioctl.c b/fs/xfs/linux-2.6/xfs_ioctl.c index 942362f..5663351 100644 --- a/fs/xfs/linux-2.6/xfs_ioctl.c +++ b/fs/xfs/linux-2.6/xfs_ioctl.c @@ -410,7 +410,8 @@ 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/linux-2.6/xfs_ioctl32.c b/fs/xfs/linux-2.6/xfs_ioctl32.c index bad485a..e671047 100644 --- a/fs/xfs/linux-2.6/xfs_ioctl32.c +++ b/fs/xfs/linux-2.6/xfs_ioctl32.c @@ -361,7 +361,8 @@ 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); /* -- 1.7.12.2.21.g234cd45.dirty