zebra: Allow ns delete to happen after under/over flow checks

[mirror_frr.git] / pimd / mtracebis.c

diff --git a/pimd/mtracebis.c b/pimd/mtracebis.c
index 731fdb1beb5c5e71f9d382820e30439549a41c0d..65c495eff04502a6f0ca35e74be2d362f4d0aa30 100644 (file)
--- a/pimd/mtracebis.c
+++ b/pimd/mtracebis.c
@@ -17,6 +17,10 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
 #ifdef __linux__
 
 #include "pim_igmp_mtrace.h"
@@ -266,6 +270,8 @@ static int recv_response(int fd, int *hops, struct igmp_mtrace *mtracer)
        int mtrace_len;
        int responses;
        unsigned short sum;
+       size_t mtrace_off;
+       size_t ip_len;
 
        recvd = recvfrom(fd, mtrace_buf, IP_AND_MTRACE_BUF_LEN, 0, NULL, 0);
 
@@ -292,17 +298,20 @@ static int recv_response(int fd, int *hops, struct igmp_mtrace *mtracer)
        if (sum != in_cksum(ip, ip->ip_hl * 4))
                return -1;
 
-       mtrace = (struct igmp_mtrace *)(mtrace_buf + (4 * ip->ip_hl));
-
-       mtrace_len = ntohs(ip->ip_len) - ip->ip_hl * 4;
-
-       if ((char *)mtrace + mtrace_len
-           > (char *)mtrace_buf + IP_AND_MTRACE_BUF_LEN)
+       /* Header overflow check */
+       mtrace_off = 4 * ip->ip_hl;
+       if (mtrace_off > MTRACE_BUF_LEN)
                return -1;
 
-       if (mtrace_len < (int)MTRACE_HDR_SIZE)
+       /* Underflow/overflow check */
+       ip_len = ntohs(ip->ip_len);
+       if (ip_len < mtrace_off || ip_len < MTRACE_HDR_SIZE
+           || ip_len > MTRACE_BUF_LEN)
                return -1;
 
+       mtrace_len = ip_len - mtrace_off;
+       mtrace = (struct igmp_mtrace *)(mtrace_buf + mtrace_off);
+
        sum = mtrace->checksum;
        mtrace->checksum = 0;
        if (sum != in_cksum(mtrace, mtrace_len)) {
@@ -336,7 +345,7 @@ static int wait_for_response(int fd, int *hops, struct igmp_mtrace *mtrace,
 {
        fd_set readfds;
        struct timeval timeout;
-       int ret = -1;
+       int ret;
        long msec, rmsec, tmsec;
 
        FD_ZERO(&readfds);