svn commit: r193043 - head/contrib/ipfilter/lib
Stanislav Sedov
stas at FreeBSD.org
Fri May 29 16:24:24 UTC 2009
Author: stas
Date: Fri May 29 16:24:23 2009
New Revision: 193043
URL: http://svn.freebsd.org/changeset/base/193043
Log:
- Prevent buffer overflow in IPFilter's load_http function used to load
ipfilter tables via http by the user-level ippool utility. Previously
the 1024-byte buffer used to store a http request coudld easily overflow
if the length of the hostname part of the url passes exceeded 496 bytes. [1]
- Use snprintf to prevent possieble buffer overflows in future. [2]
- Do not try to close the descriptor twice on failure. [2]
Reported by: Maksymilian Arciemowicz <cxib at securityreason.com> [1]
Obtained from: NetBSD CVS [2]
MFC after: 2 weeks
Modified:
head/contrib/ipfilter/lib/load_http.c
Modified: head/contrib/ipfilter/lib/load_http.c
==============================================================================
--- head/contrib/ipfilter/lib/load_http.c Fri May 29 16:15:56 2009 (r193042)
+++ head/contrib/ipfilter/lib/load_http.c Fri May 29 16:24:23 2009 (r193043)
@@ -14,11 +14,13 @@
alist_t *
load_http(char *url)
{
- int fd, len, left, port, endhdr, removed;
- char *s, *t, *u, buffer[1024], *myurl;
+ char *s, *t, *u, buffer[1044], *myurl;
alist_t *a, *rtop, *rbot;
struct sockaddr_in sin;
struct hostent *host;
+ size_t avail;
+ int fd, len, left, port, endhdr, removed;
+ int error;
/*
* More than this would just be absurd.
@@ -32,7 +34,14 @@ load_http(char *url)
rtop = NULL;
rbot = NULL;
- sprintf(buffer, "GET %s HTTP/1.0\r\n", url);
+ avail = sizeof(buffer);
+ error = snprintf(buffer, avail, "GET %s HTTP/1.0\r\n", url);
+
+ /*
+ * error is always less then avail due to the constraint on
+ * the url length above.
+ */
+ avail -= error;
myurl = strdup(url);
if (myurl == NULL)
@@ -51,7 +60,11 @@ load_http(char *url)
if (u != NULL)
s = u + 1; /* AUTH */
- sprintf(buffer + strlen(buffer), "Host: %s\r\n\r\n", s);
+ error = snprintf(buffer + strlen(buffer), avail, "Host: %s\r\n\r\n", s);
+ if (error >= avail) {
+ fprintf(stderr, "URL is too large: %s\n", url);
+ goto done;
+ }
u = strchr(s, ':');
if (u != NULL) {
@@ -83,16 +96,12 @@ load_http(char *url)
if (fd == -1)
goto done;
- if (connect(fd, (struct sockaddr *)&sin, sizeof(sin)) == -1) {
- close(fd);
+ if (connect(fd, (struct sockaddr *)&sin, sizeof(sin)) == -1)
goto done;
- }
len = strlen(buffer);
- if (write(fd, buffer, len) != len) {
- close(fd);
+ if (write(fd, buffer, len) != len)
goto done;
- }
s = buffer;
endhdr = 0;
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