Compare string lengths when parsing the snapshot mask

We used to rely on the result from strncmp() without comparing the length of
the strings involved. Even worse, any single-character format specifier would
enable zip-format due to the optional '.'-prefix since the length of the
mask then would become zero.

Noticed-by: Evan Martin <sys@neugierig.org>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/ui-snapshot.c b/ui-snapshot.c
index 4d1aa88..dfedd8f 100644
--- a/ui-snapshot.c
+++ b/ui-snapshot.c
@@ -101,56 +101,57 @@ void cgit_print_snapshot(struct cacheitem *item, const char *head,
                 args.tree = commit->tree;
                 args.time = commit->date;
                 cgit_print_snapshot_start(sat->mimetype, filename, item);
                 (*sat->write_func)(&args);
                 return;
         }
         cgit_print_error(fmt("Unsupported snapshot format: %s", filename));
 }
 
 void cgit_print_snapshot_links(const char *repo, const char *head,
                                const char *hex, int snapshots)
 {
         const struct snapshot_archive_t* sat;
             char *filename;
         int f;
 
         for(f=0; f<snapshot_archives_len; f++) {
                 sat = &snapshot_archives[f];
                 if(!(snapshots & sat->bit))
                         continue;
                 filename = fmt("%s-%s%s", cgit_repobasename(repo), hex,
                                sat->suffix);
                 cgit_snapshot_link(filename, NULL, NULL, (char *)head,
                                    (char *)hex, filename);
                 html("<br/>");
         }
 }
 
 int cgit_parse_snapshots_mask(const char *str)
 {
         const struct snapshot_archive_t* sat;
         static const char *delim = " \t,:/|;";
-        int f, tl, rv = 0;
+        int f, tl, sl, rv = 0;
 
         /* favor legacy setting */
         if(atoi(str))
                 return 1;
         for(;;) {
                 str += strspn(str,delim);
                 tl = strcspn(str,delim);
                 if(!tl)
                         break;
                 for(f=0; f<snapshot_archives_len; f++) {
                         sat = &snapshot_archives[f];
-                        if(!(strncmp(sat->suffix, str, tl) &&
-                             strncmp(sat->suffix+1, str, tl-1))) {
+                        sl = strlen(sat->suffix);
+                        if((tl == sl && !strncmp(sat->suffix, str, tl)) ||
+                           (tl == sl-1 && !strncmp(sat->suffix+1, str, tl-1))) {
                                 rv |= sat->bit;
                                 break;
                         }
                 }
                 str += tl;
         }
         return rv;
 }
 
 /* vim:set sw=8: */