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From 1b33867fa996034deb50819ae54640be501f8d20 Mon Sep 17 00:00:00 2001
From: Alan Coopersmith <alan.coopersmith@oracle.com>
Date: Thu, 02 May 2013 00:59:31 +0000
Subject: integer overflow in read_packet() [CVE-2013-2064]
Ensure that when calculating the size of the incoming response from the
Xserver, we don't overflow the integer used in the calculations when we
multiply the int32_t length by 4 and add it to the default response size.
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
---
diff --git a/src/xcb_in.c b/src/xcb_in.c
index b810783..8a7af92 100644
--- a/src/xcb_in.c
+++ b/src/xcb_in.c
@@ -93,8 +93,9 @@ static void remove_finished_readers(reader_list **prev_reader, uint64_t complete
static int read_packet(xcb_connection_t *c)
{
xcb_generic_reply_t genrep;
- int length = 32;
- int eventlength = 0; /* length after first 32 bytes for GenericEvents */
+ uint64_t length = 32;
+ uint64_t eventlength = 0; /* length after first 32 bytes for GenericEvents */
+ uint64_t bufsize;
void *buf;
pending_reply *pend = 0;
struct event_list *event;
@@ -169,8 +170,12 @@ static int read_packet(xcb_connection_t *c)
if ((genrep.response_type & 0x7f) == XCB_XGE_EVENT)
eventlength = genrep.length * 4;
- buf = malloc(length + eventlength +
- (genrep.response_type == XCB_REPLY ? 0 : sizeof(uint32_t)));
+ bufsize = length + eventlength +
+ (genrep.response_type == XCB_REPLY ? 0 : sizeof(uint32_t));
+ if (bufsize < INT32_MAX)
+ buf = malloc((size_t) bufsize);
+ else
+ buf = NULL;
if(!buf)
{
_xcb_conn_shutdown(c, XCB_CONN_CLOSED_MEM_INSUFFICIENT);
--
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