Fix missing error on --import on bogus key file (RhBug:869667)

- When the "BEGIN PGP" marker is not found at all, we would silently
  exit with success when trying to import utter garbage, such as
  rpmkeys --import /bin/bash (not that I consider bash as gargabe ;)
(cherry picked from commit 0b9c93ed18a11818a2f3645431a338bdc3f1fc81)

1 files changed, 5 insertions, 4 deletions

diff --git a/lib/rpmchecksig.c b/lib/rpmchecksig.c
index 42e2e6095..0d3e95ad7 100644
--- a/lib/rpmchecksig.c
+++ b/lib/rpmchecksig.c
@@ -32,8 +32,8 @@ static int doImport(rpmts ts, const char *fn, char *buf, ssize_t blen)
     int res = 0;
     int keyno = 1;
     char *start = strstr(buf, pgpmark);
-    
-    while (start) {
+
+    do {
 	uint8_t *pkt = NULL;
 	size_t pktlen = 0;
 	
@@ -51,7 +51,7 @@ static int doImport(rpmts ts, const char *fn, char *buf, ssize_t blen)
 	}
 	
 	/* See if there are more keys in the buffer */
-	if (start + marklen < buf + blen) {
+	if (start && start + marklen < buf + blen) {
 	    start = strstr(start + marklen, pgpmark);
 	} else {
 	    start = NULL;
@@ -59,7 +59,8 @@ static int doImport(rpmts ts, const char *fn, char *buf, ssize_t blen)
 
 	keyno++;
 	free(pkt);
-    }
+    } while (start != NULL);
+
     return res;
 }