From: Dan Carpenter <dan.carpenter@oracle.com>
To: Ben Myers <bpm@sgi.com>
Cc: Fabian Yamaguchi <fabs@goesec.de>,
security@kernel.org, Alex Elder <elder@kernel.org>,
Nico Golde <nico@ngolde.de>,
xfs@oss.sgi.com
Subject: [patch] xfs: underflow bug in xfs_attrlist_by_handle()
Date: Thu, 31 Oct 2013 21:00:10 +0300 [thread overview]
Message-ID: <20131031180010.GA24839@longonot.mountain> (raw)
In-Reply-To: <20131025144452.GA28451@ngolde.de>
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>
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 4d61340..33ad9a7 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -442,7 +442,8 @@ 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 e8fb123..a7992f8 100644
--- a/fs/xfs/xfs_ioctl32.c
+++ b/fs/xfs/xfs_ioctl32.c
@@ -356,7 +356,8 @@ 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);
/*
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next parent reply other threads:[~2013-10-31 18:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20131025144452.GA28451@ngolde.de>
2013-10-31 18:00 ` Dan Carpenter [this message]
2013-10-31 21:34 ` [patch] xfs: underflow bug in xfs_attrlist_by_handle() Dave Chinner
2013-12-04 21:53 ` Ben Myers
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