glob: Fix buffer overflow during GLOB_TILDE unescaping [BZ #22332]

(cherry picked from commit a159b53fa059947cc2548e3b0d5bdcf7b9630ba8)

diff --git a/ChangeLog b/ChangeLog
index c19862d829965049adb956909ee5a4999cf673e1..951fe6f882f60e75dc452b39ebedc2afc2040e40 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2017-10-22  Paul Eggert <eggert@cs.ucla.edu>
+
+       [BZ #22332]
+       * posix/glob.c (__glob): Fix buffer overflow during GLOB_TILDE
+       unescaping.
+
 2017-10-21  Florian Weimer  <fweimer@redhat.com>
 
        * posix/Makefile (tests): Add tst-glob-tilde.

diff --git a/NEWS b/NEWS
index c353ce6273eec4880d149f60eb9557696fe450be..40ecd30fc540f5ce8690529ec86852744805d86e 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,10 @@ Security related changes:
   processing, leading to a memory leak and, potentially, to a denial
   of service.
 
+  The glob function, when invoked with GLOB_TILDE and without
+  GLOB_NOESCAPE, could write past the end of a buffer while
+  unescaping user names.  Reported by Tim Rühsen.
+
 The following bugs are resolved with this release:
 
   [20257] sunrpc: clntudp_call does not enforce timeout when receiving data

diff --git a/posix/glob.c b/posix/glob.c
index c761c0861ddb49eab67a173938c2f541d6836673..b2273ea7bce40552f3d45d74214868dec8cf232d 100644 (file)
--- a/posix/glob.c
+++ b/posix/glob.c
@@ -850,11 +850,11 @@ glob (const char *pattern, int flags, int (*errfunc) (const char *, int),
                  char *p = mempcpy (newp, dirname + 1,
                                     unescape - dirname - 1);
                  char *q = unescape;
-                 while (*q != '\0')
+                 while (q != end_name)
                    {
                      if (*q == '\\')
                        {
-                         if (q[1] == '\0')
+                         if (q + 1 == end_name)
                            {
                              /* "~fo\\o\\" unescape to user_name "foo\\",
                                 but "~fo\\o\\/" unescape to user_name