From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2154) id D0C1C39B1C43; Fri, 23 Jul 2021 17:06:55 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org D0C1C39B1C43 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Stan Shebs To: glibc-cvs@sourceware.org Subject: [glibc/google/grte/v5-2.27/master] Fix use-after-free in glob when expanding ~user (bug 25414) X-Act-Checkin: glibc X-Git-Author: Andreas Schwab X-Git-Refname: refs/heads/google/grte/v5-2.27/master X-Git-Oldrev: 4bb48f1b3aec652651b2fe45d5dac90cd7812453 X-Git-Newrev: 1ebb784472433f069e4c735efbbd738860e55bd0 Message-Id: <20210723170655.D0C1C39B1C43@sourceware.org> Date: Fri, 23 Jul 2021 17:06:55 +0000 (GMT) X-BeenThere: glibc-cvs@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Glibc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 23 Jul 2021 17:06:55 -0000 https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=1ebb784472433f069e4c735efbbd738860e55bd0 commit 1ebb784472433f069e4c735efbbd738860e55bd0 Author: Andreas Schwab Date: Wed Feb 19 17:21:46 2020 +0100 Fix use-after-free in glob when expanding ~user (bug 25414) The value of `end_name' points into the value of `dirname', thus don't deallocate the latter before the last use of the former. Diff: --- posix/glob.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/posix/glob.c b/posix/glob.c index 8444b2f79e..1b389d2da1 100644 --- a/posix/glob.c +++ b/posix/glob.c @@ -827,31 +827,32 @@ __glob (const char *pattern, int flags, int (*errfunc) (const char *, int), { size_t home_len = strlen (p->pw_dir); size_t rest_len = end_name == NULL ? 0 : strlen (end_name); - char *d; + char *d, *newp; + bool use_alloca = glob_use_alloca (alloca_used, + home_len + rest_len + 1); - if (__glibc_unlikely (malloc_dirname)) - free (dirname); - malloc_dirname = 0; - - if (glob_use_alloca (alloca_used, home_len + rest_len + 1)) - dirname = alloca_account (home_len + rest_len + 1, - alloca_used); + if (use_alloca) + newp = alloca_account (home_len + rest_len + 1, alloca_used); else { - dirname = malloc (home_len + rest_len + 1); - if (dirname == NULL) + newp = malloc (home_len + rest_len + 1); + if (newp == NULL) { scratch_buffer_free (&pwtmpbuf); retval = GLOB_NOSPACE; goto out; } - malloc_dirname = 1; } - d = mempcpy (dirname, p->pw_dir, home_len); + d = mempcpy (newp, p->pw_dir, home_len); if (end_name != NULL) d = mempcpy (d, end_name, rest_len); *d = '\0'; + if (__glibc_unlikely (malloc_dirname)) + free (dirname); + dirname = newp; + malloc_dirname = !use_alloca; + dirlen = home_len + rest_len; dirname_modified = 1; }