make prefix_path() never return NULL

There are 9 places where prefix_path is called, and only in one of
them the returned pointer was checked to be non-zero and only to
call exit(128) as it is usually done by die(). In other 8 places,
the returned value was not checked and it caused SIGSEGV when a
path outside of the working tree was used. For instance, running
  git update-index --add /some/path/outside
caused SIGSEGV.

This patch changes prefix_path() to die if the path is outside of
the repository, so it never returns NULL.

Signed-off-by: Dmitry Potapov <dpotapov@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

diff --git a/setup.c b/setup.c
index 2e3248a0c4958f31001213470a88d1154b5947fc..78a8041ff0d17a5220133549880ccbc507b1890d 100644 (file)
--- a/setup.c
+++ b/setup.c
@@ -110,9 +110,7 @@ const char *prefix_path(const char *prefix, int len, const char *path)
                if (strncmp(sanitized, work_tree, len) ||
                    (sanitized[len] != '\0' && sanitized[len] != '/')) {
                error_out:
-                       error("'%s' is outside repository", orig);
-                       free(sanitized);
-                       return NULL;
+                       die("'%s' is outside repository", orig);
                }
                if (sanitized[len] == '/')
                        len++;
@@ -216,10 +214,7 @@ const char **get_pathspec(const char *prefix, const char **pathspec)
        prefixlen = prefix ? strlen(prefix) : 0;
        while (*src) {
                const char *p = prefix_path(prefix, prefixlen, *src);
-               if (p)
-                       *(dst++) = p;
-               else
-                       exit(128); /* error message already given */
+               *(dst++) = p;
                src++;
        }
        *dst = NULL;