[prev in list] [next in list] [prev in thread] [next in thread]
List: openbsd-announce
Subject: libevent errata
From: Alexander Bluhm <bluhm () openbsd ! org>
Date: 2015-01-13 20:55:52
Message-ID: 201501132102.t0DL2d7J004270 () shear ! ucar ! edu
[Download RAW message or body]
Patches are now available for 5.5 and 5.6 which fix libevent.
5.5 errata 20 and 5.6 errata 15:
Fix CVE-2014-6272 in libevent 1.4 event buffer handling. OpenBSD
base uses it for the programs: cu tmux ftp-proxy httpd ldapd relayd
tftp-proxy tftpd
Links:
http://www.openbsd.org/errata55.html
http://ftp.openbsd.org/pub/OpenBSD/patches/5.5/common/020_libevent.patch.sig
and
http://www.openbsd.org/errata56.html
http://ftp.openbsd.org/pub/OpenBSD/patches/5.6/common/015_libevent.patch.sig
untrusted comment: signature from openbsd 5.6 base private key
RWR0EANmo9nqhpu5mEMdLuZ056ynwx+qvxaVbodk7LsWqC0UCch3P2Ll0uGzfyJl/FSN9KH7tQgwwjbPwyss35EQNAlUAULiYgU=
OpenBSD 5.6 errata 15, Jan 8, 2015
Fix CVE-2014-6272 in libevent 1.4 event buffer handling. OpenBSD
base uses it for the programs: cu tmux ftp-proxy httpd ldapd relayd
tftp-proxy tftpd
A defect in the Libevent evbuffer API leaves some programs that
pass insanely large inputs to evbuffers open to a possible heap
overflow or infinite loop.
Apply patch using:
signify -Vep /etc/signify/openbsd-56-base.pub -x 015_libevent.patch.sig \
-m - | (cd /usr/src && patch -p0)
Then build and install libevent
cd /usr/src/lib/libevent
make obj
make
make install
Index: lib/libevent/buffer.c
===================================================================
RCS file: /mount/cvsdev/cvs/openbsd/src/lib/libevent/buffer.c,v
retrieving revision 1.19
diff -u -p -r1.19 buffer.c
--- lib/libevent/buffer.c 17 Jul 2010 17:16:47 -0000 1.19
+++ lib/libevent/buffer.c 7 Jan 2015 19:11:19 -0000
@@ -53,6 +53,7 @@
#include <assert.h>
#include <errno.h>
+#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -145,7 +146,8 @@ evbuffer_add_vprintf(struct evbuffer *bu
va_list aq;
/* make sure that at least some space is available */
- evbuffer_expand(buf, 64);
+ if (evbuffer_expand(buf, 64) < 0)
+ return (-1);
for (;;) {
size_t used = buf->misalign + buf->off;
buffer = (char *)buf->buffer + buf->off;
@@ -351,26 +353,38 @@ evbuffer_align(struct evbuffer *buf)
int
evbuffer_expand(struct evbuffer *buf, size_t datlen)
{
- size_t need = buf->misalign + buf->off + datlen;
+ size_t used = buf->misalign + buf->off;
+
+ assert(buf->totallen >= used);
/* If we can fit all the data, then we don't have to do anything */
- if (buf->totallen >= need)
+ if (buf->totallen - used >= datlen)
return (0);
+ /* If we would need to overflow to fit this much data, we can't
+ * do anything. */
+ if (datlen > SIZE_MAX - buf->off)
+ return (-1);
/*
* If the misalignment fulfills our data needs, we just force an
* alignment to happen. Afterwards, we have enough space.
*/
- if (buf->misalign >= datlen) {
+ if (buf->totallen - buf->off >= datlen) {
evbuffer_align(buf);
} else {
void *newbuf;
size_t length = buf->totallen;
+ size_t need = buf->off + datlen;
if (length < 256)
length = 256;
- while (length < need)
- length <<= 1;
+ if (need < SIZE_MAX / 2) {
+ while (length < need) {
+ length <<= 1;
+ }
+ } else {
+ length = need;
+ }
if (buf->orig_buffer != buf->buffer)
evbuffer_align(buf);
@@ -387,10 +401,10 @@ evbuffer_expand(struct evbuffer *buf, si
int
evbuffer_add(struct evbuffer *buf, const void *data, size_t datlen)
{
- size_t need = buf->misalign + buf->off + datlen;
+ size_t used = buf->misalign + buf->off;
size_t oldoff = buf->off;
- if (buf->totallen < need) {
+ if (buf->totallen - used < datlen) {
if (evbuffer_expand(buf, datlen) == -1)
return (-1);
}
[prev in list] [next in list] [prev in thread] [next in thread]
Configure |
About |
News |
Add a list |
Sponsored by KoreLogic