plugins/check_ntp.c - Verify struct from response

Coverity 66524 - req.data is not neccessarily null terminated but still feed to printf statements. This both does that, and verifies the struct more so than before. - SR

1 files changed, 11 insertions, 2 deletions

diff --git a/plugins/check_ntp.c b/plugins/check_ntp.c
index 0a7640a7..09a923eb 100644
--- a/plugins/check_ntp.c
+++ b/plugins/check_ntp.c
@@ -517,13 +517,14 @@ setup_control_request(ntp_control_message *p, uint8_t opcode, uint16_t seq){
 double jitter_request(const char *host, int *status){
         int conn=-1, i, npeers=0, num_candidates=0, syncsource_found=0;
         int run=0, min_peer_sel=PEER_INCLUDED, num_selected=0, num_valid=0;
-        int peers_size=0, peer_offset=0;
+        int peers_size=0, peer_offset=0, bytes_read=0;
         ntp_assoc_status_pair *peers=NULL;
         ntp_control_message req;
         const char *getvar = "jitter";
         double rval = 0.0, jitter = -1.0;
         char *startofvalue=NULL, *nptr=NULL;
         void *tmp;
+        int ntp_cm_ints = sizeof(uint16_t) * 5 + sizeof(uint8_t) * 2;
 
         /* Long-winded explanation:
          * Getting the jitter requires a number of steps:
@@ -608,7 +609,15 @@ double jitter_request(const char *host, int *status){
 
                                 req.count = htons(MAX_CM_SIZE);
                                 DBG(printf("recieving READVAR response...\n"));
-                                read(conn, &req, SIZEOF_NTPCM(req));
+
+                                /* cov-66524 - req.data not null terminated before usage. Also covers verifying struct was returned correctly*/
+                                if ((bytes_read = read(conn, &req, SIZEOF_NTPCM(req))) == -1)
+                                        die(STATE_UNKNOWN, _("Cannot read from socket: %s"), strerror(errno));
+                                if (bytes_read != ntp_cm_ints + req.count)
+                                        die(STATE_UNKNOWN, _("Invalid NTP response: %d bytes read does not equal %d plus %d data segment"), bytes_read, ntp_cm_ints, req.count); 
+                                /* else null terminate */
+                                strncpy(req.data[req.count], "\0", 1);
+
                                 DBG(print_ntp_control_message(&req));
 
                                 if(req.op&REM_ERROR && strstr(getvar, "jitter")) {