From 002d455873f5f94749ba3b60c47cdb0ecf5e48c6 Mon Sep 17 00:00:00 2001 From: John Baldwin Date: Sun, 25 Jan 2015 19:45:44 +0000 Subject: [PATCH] Use an sbuf to generate the output of the net.inet.tcp.hostcache.list sysctl to avoid a possible buffer overflow if the cache grows while the text is being generated. PR: 172675 MFC after: 2 weeks --- sys/netinet/tcp_hostcache.c | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-) diff --git a/sys/netinet/tcp_hostcache.c b/sys/netinet/tcp_hostcache.c index cbe24985a701..b03556ff67e0 100644 --- a/sys/netinet/tcp_hostcache.c +++ b/sys/netinet/tcp_hostcache.c @@ -73,6 +73,7 @@ __FBSDID("$FreeBSD$"); #include #include #include +#include #include #include #include @@ -595,30 +596,27 @@ tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml) static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS) { - int bufsize; int linesize = 128; - char *p, *buf; - int len, i, error; + struct sbuf sb; + int i, error; struct hc_metrics *hc_entry; #ifdef INET6 char ip6buf[INET6_ADDRSTRLEN]; #endif - bufsize = linesize * (V_tcp_hostcache.cache_count + 1); + sbuf_new(&sb, NULL, linesize * (V_tcp_hostcache.cache_count + 1), + SBUF_FIXEDLEN); - p = buf = (char *)malloc(bufsize, M_TEMP, M_WAITOK|M_ZERO); - - len = snprintf(p, linesize, - "\nIP address MTU SSTRESH RTT RTTVAR BANDWIDTH " + sbuf_printf(&sb, + "\nIP address MTU SSTRESH RTT RTTVAR BANDWIDTH " " CWND SENDPIPE RECVPIPE HITS UPD EXP\n"); - p += len; #define msec(u) (((u) + 500) / 1000) for (i = 0; i < V_tcp_hostcache.hashsize; i++) { THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx); TAILQ_FOREACH(hc_entry, &V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q) { - len = snprintf(p, linesize, + sbuf_printf(&sb, "%-15s %5lu %8lu %6lums %6lums %9lu %8lu %8lu %8lu " "%4lu %4lu %4i\n", hc_entry->ip4.s_addr ? inet_ntoa(hc_entry->ip4) : @@ -640,13 +638,13 @@ sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS) hc_entry->rmx_hits, hc_entry->rmx_updates, hc_entry->rmx_expire); - p += len; } THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx); } #undef msec - error = SYSCTL_OUT(req, buf, p - buf); - free(buf, M_TEMP); + sbuf_finish(&sb); + error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb)); + sbuf_delete(&sb); return(error); }