[PATCH] modechange: avoid memory leaks for invalid octal modes

[Bernhard Voelker]

* lib/modechange.c (mode_compile): During the parsing of
notations like +40, free the 'mc' buffer for invalid mode
strings like +17777 (greater than the maximum octal mode),
=18 (bad octal mode characters) or u=1 ('affected' with
octal modes).
Reproducer, e.g.:

    $ valgrind --leak-check=full chmod +17777 file

Introduced via the 2012-03-09 commit, 4730c3e3, "modechange:
add notations +40, 00440, etc.".
Spotted by coverity (RESOURCE_LEAK).
---
 ChangeLog        | 14 ++++++++++++++
 lib/modechange.c |  4 ++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 8fa880d..30b364b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2014-03-26  Bernhard Voelker  <address@hidden>
+
+       modechange: avoid memory leaks for invalid octal modes
+       * lib/modechange.c (mode_compile): During the parsing of
+       notations like +40, free the 'mc' buffer for invalid mode
+       strings like +17777 (greater than the maximum octal mode),
+       =18 (bad octal mode characters) or u=1 ('affected' with
+       octal modes).
+       Reproducer, e.g.:
+           $ valgrind --leak-check=full chmod +17777 file
+       Introduced via the 2012-03-09 commit, 4730c3e3, "modechange:
+       add notations +40, 00440, etc.".
+       Spotted by coverity (RESOURCE_LEAK).
+
 2014-03-24  Paul Eggert  <address@hidden>
 
        gitlog-to-changelog: include a dummy git-log-fix file
diff --git a/lib/modechange.c b/lib/modechange.c
index 8ac1879..412fe1d 100644
--- a/lib/modechange.c
+++ b/lib/modechange.c
@@ -220,12 +220,12 @@ mode_compile (char const *mode_string)
                   {
                     octal_mode = 8 * octal_mode + *p++ - '0';
                     if (ALLM < octal_mode)
-                      return NULL;
+                      goto invalid;
                   }
                 while ('0' <= *p && *p < '8');
 
                 if (affected || (*p && *p != ','))
-                  return NULL;
+                  goto invalid;
                 affected = mentioned = CHMOD_MODE_BITS;
                 value = octal_to_mode (octal_mode);
                 flag = MODE_ORDINARY_CHANGE;
-- 
1.8.4.5