pretty: fix memory leaks when parsing pretty formats

When parsing pretty formats from the config we leak the name and user
format whenever these are set multiple times. This is because we do not
free any already-set value in case there is one.

Plugging this leak for the name is trivial. For the user format we need
to be a bit more careful, because we may end up assigning a pointer into
the allocated region when the string is prefixed with either "format" or
"tformat:". In order to make it safe to unconditionally free the user
format we thus strdup the stripped string into the field instead of a
pointer into the string.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/pretty.c b/pretty.c
index 44222fb83c62a12f8d7c6a5e8e5ba5f35f11b536..5e162d7204d68b4411cd586047e1b152e020852c 100644 (file)
--- a/pretty.c
+++ b/pretty.c
@@ -63,7 +63,7 @@ static int git_pretty_formats_config(const char *var, const char *value,
                                     void *cb UNUSED)
 {
        struct cmt_fmt_map *commit_format = NULL;
-       const char *name;
+       const char *name, *stripped;
        char *fmt;
        int i;
 
@@ -90,15 +90,21 @@ static int git_pretty_formats_config(const char *var, const char *value,
                commit_formats_len++;
        }
 
+       free((char *)commit_format->name);
        commit_format->name = xstrdup(name);
        commit_format->format = CMIT_FMT_USERFORMAT;
        if (git_config_string(&fmt, var, value))
                return -1;
 
-       if (skip_prefix(fmt, "format:", &commit_format->user_format)) {
+       free((char *)commit_format->user_format);
+       if (skip_prefix(fmt, "format:", &stripped)) {
                commit_format->is_tformat = 0;
-       } else if (skip_prefix(fmt, "tformat:", &commit_format->user_format)) {
+               commit_format->user_format = xstrdup(stripped);
+               free(fmt);
+       } else if (skip_prefix(fmt, "tformat:", &stripped)) {
                commit_format->is_tformat = 1;
+               commit_format->user_format = xstrdup(stripped);
+               free(fmt);
        } else if (strchr(fmt, '%')) {
                commit_format->is_tformat = 1;
                commit_format->user_format = fmt;