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Use an sbuf to generate the output of the net.inet.tcp.hostcache.list

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sysctl to avoid a possible buffer overflow if the cache grows while the
text is being generated.

PR:		172675
MFC after:	2 weeks
This commit is contained in:
John Baldwin 2015-01-25 19:45:44 +00:00
parent 4fa545cb14
commit 002d455873
1 changed files with 11 additions and 13 deletions
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24
sys/netinet/tcp_hostcache.c
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@ -73,6 +73,7 @@ __FBSDID("$FreeBSD$");
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/malloc.h>
#include <sys/sbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
@ -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);
}