compat: Add simplified merge sort implementation from glibc

diff --git a/commit.c b/commit.c
index f074811edc8c5ba41351f50c48a6cda7614e8f8e..8b8fb04d1f6107da15cb142485d80cabe7a3828e 100644 (file)
--- a/commit.c
+++ b/commit.c
@@ -48,19 +48,32 @@ struct commit *lookup_commit(const unsigned char *sha1)
        return check_commit(obj, sha1, 0);
 }
 
-static unsigned long parse_commit_date(const char *buf)
+static unsigned long parse_commit_date(const char *buf, const char *tail)
 {
        unsigned long date;
+       const char *dateptr;
 
+       if (buf + 6 >= tail)
+               return 0;
        if (memcmp(buf, "author", 6))
                return 0;
-       while (*buf++ != '\n')
+       while (buf < tail && *buf++ != '\n')
                /* nada */;
+       if (buf + 9 >= tail)
+               return 0;
        if (memcmp(buf, "committer", 9))
                return 0;
-       while (*buf++ != '>')
+       while (buf < tail && *buf++ != '>')
                /* nada */;
-       date = strtoul(buf, NULL, 10);
+       if (buf >= tail)
+               return 0;
+       dateptr = buf;
+       while (buf < tail && *buf++ != '\n')
+               /* nada */;
+       if (buf >= tail)
+               return 0;
+       /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
+       date = strtoul(dateptr, NULL, 10);
        if (date == ULONG_MAX)
                date = 0;
        return date;
@@ -236,9 +249,9 @@ int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
                return 0;
        item->object.parsed = 1;
        tail += size;
-       if (tail <= bufptr + 5 || memcmp(bufptr, "tree ", 5))
+       if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
-       if (tail <= bufptr + 45 || get_sha1_hex(bufptr + 5, parent) < 0)
+       if (get_sha1_hex(bufptr + 5, parent) < 0)
                return error("bad tree pointer in commit %s",
                             sha1_to_hex(item->object.sha1));
        item->tree = lookup_tree(parent);
@@ -275,7 +288,7 @@ int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
                        n_refs++;
                }
        }
-       item->date = parse_commit_date(bufptr);
+       item->date = parse_commit_date(bufptr, tail);
 
        if (track_object_refs) {
                unsigned i = 0;