Messages in this thread Patch in this message | | | Date | Tue, 21 Oct 2014 16:46:58 +0200 | From | Matej Mužila <> | Subject | [PATCH v2 1/3] tools: hv: fcopy_daemon: Check buffer limits |
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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);
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