From: Wenwen Wang <wang6495@umn.edu>
To: wang6495@umn.edu
Cc: kjlu@umn.edu, Oleg Drokin <oleg.drokin@intel.com>,
Andreas Dilger <andreas.dilger@intel.com>,
James Simmons <jsimmons@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Ben Evans <bevans@cray.com>,
Aastha Gupta <aastha.gupta4104@gmail.com>,
NeilBrown <neilb@suse.com>, Jeff Layton <jlayton@redhat.com>,
Luis de Bethencourt <luisbg@kernel.org>,
lustre-devel@lists.lustre.org, devel@driverdev.osuosl.org,
linux-kernel@vger.kernel.org
Subject: [PATCH] staging: luster: llite: fix a potential missing-check bug when copying lumv
Date: Fri, 27 Apr 2018 18:45:02 -0500 [thread overview]
Message-ID: <1524872704-13391-1-git-send-email-wang6495@umn.edu> (raw)
In ll_dir_ioctl(), the object lumv3 is firstly copied from the user space
using Its address, i.e., lumv1 = &lumv3. If the lmm_magic field of lumv3 is
LOV_USER_MAGIV_V3, lumv3 will be modified by the second copy from the user
space. The second copy is necessary, because the two versions (i.e.,
lov_user_md_v1 and lov_user_md_v3) have different data formats and lengths.
However, given that the user data resides in the user space, a malicious
user-space process can race to change the data between the two copies. By
doing so, the attacker can provide a data with an inconsistent version,
e.g., v1 version + v3 data. This can lead to logical errors in the
following execution in ll_dir_setstripe(), which performs different actions
according to the version specified by the field lmm_magic.
This patch rechecks the version field lmm_magic in the second copy. If the
version is not as expected, i.e., LOV_USER_MAGIC_V3, an error code will be
returned: -EINVAL.
Signed-off-by: Wenwen Wang <wang6495@umn.edu>
---
drivers/staging/lustre/lustre/llite/dir.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/staging/lustre/lustre/llite/dir.c b/drivers/staging/lustre/lustre/llite/dir.c
index d10d272..80d44ca 100644
--- a/drivers/staging/lustre/lustre/llite/dir.c
+++ b/drivers/staging/lustre/lustre/llite/dir.c
@@ -1185,6 +1185,8 @@ static long ll_dir_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
if (lumv1->lmm_magic == LOV_USER_MAGIC_V3) {
if (copy_from_user(&lumv3, lumv3p, sizeof(lumv3)))
return -EFAULT;
+ if (lumv3.lmm_magic != LOV_USER_MAGIC_V3)
+ return -EINVAL;
}
if (is_root_inode(inode))
--
2.7.4
next reply other threads:[~2018-04-27 23:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-27 23:45 Wenwen Wang [this message]
2018-04-28 16:04 ` [PATCH] staging: luster: llite: fix a potential missing-check bug when copying lumv Dilger, Andreas
2018-04-29 13:20 ` Greg Kroah-Hartman
2018-04-29 20:58 ` Wenwen Wang
2018-04-30 11:15 ` Dan Carpenter
2018-04-30 22:38 ` Dilger, Andreas
2018-04-30 22:43 ` Wenwen Wang
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