lkml.org 
[lkml]   [2014]   [Oct]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH v2 1/3] tools: hv: fcopy_daemon: Check buffer limits
From: Matej Mužila <mmuzila@redhat.com>

Check if cpmsg->size is in limits of DATA_FRAGMENT

Signed-off-by: Matej Mužila <mmuzila@redhat.com>
---

If corrupted data are read from /dev/vmbus/hv_fcopy, pwrite can
read from memory outside of the buffer (defined at line 138).
Added check.

Changes made since v1:
* max value of cmesg->size is now derived from structure
definition in sources/include/uapi/linux/hyperv.h
* Fixed comments


diff --git a/tools/hv/hv_fcopy_daemon.c b/tools/hv/hv_fcopy_daemon.c
index 6f27e2f..1fc2dc2 100644
--- a/tools/hv/hv_fcopy_daemon.c
+++ b/tools/hv/hv_fcopy_daemon.c
@@ -104,6 +104,10 @@ static int hv_copy_data(struct hv_do_fcopy *cpmsg)
{
ssize_t bytes_written;

+ /* Check if the cpmsg->size is in limits of DATA_FRAGMENT */
+ if (cpmsg->size > sizeof(cpmsg->data))
+ return HV_E_FAIL;
+
bytes_written = pwrite(target_fd, cpmsg->data, cpmsg->size,
cpmsg->offset);

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2014-10-21 17:21    [W:0.101 / U:1.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site