Date: Thu, 9 Apr 2015 13:45:18 +0000 (UTC) From: Ed Maste <emaste@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r281311 - head/usr.bin/ar Message-ID: <201504091345.t39DjIIs016702@svn.freebsd.org>
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Author: emaste Date: Thu Apr 9 13:45:17 2015 New Revision: 281311 URL: https://svnweb.freebsd.org/changeset/base/281311 Log: ar: Disallow directory traversal Set ARCHIVE_EXTRACT_SECURE_SYMLINKS and ARCHIVE_EXTRACT_SECURE_NODOTDOT as in bsdtar to prevent extraction of archive entries whose pathnames contain .. or whose target directory would be altered by a symlink. Also disallow absolute pathnames. We don't currently provide an option to disable this behaviour (as bsdtar's -P does). It is unlikely to be a problem in practice for ar(1), but the -P option is not currently used and available if we want to consider it for this purpose. Differential Revision: https://reviews.freebsd.org/D1524 Reported by: Alexander Cherepanov <cherepan@mccme.ru> Approved by: delphij Obtained from: ELF tool chain ar, Ticket #474 MFC after: 1 week Relnotes: Yes Sponsored by: The FreeBSD Foundation Modified: head/usr.bin/ar/read.c Modified: head/usr.bin/ar/read.c ============================================================================== --- head/usr.bin/ar/read.c Thu Apr 9 13:09:05 2015 (r281310) +++ head/usr.bin/ar/read.c Thu Apr 9 13:45:17 2015 (r281311) @@ -187,7 +187,15 @@ read_archive(struct bsdar *bsdar, char m if (bsdar->options & AR_V) (void)fprintf(stdout, "x - %s\n", name); - flags = 0; + /* Disallow absolute paths. */ + if (name[0] == '/') { + bsdar_warnc(bsdar, 0, + "Absolute path '%s'", name); + continue; + } + /* Basic path security flags. */ + flags = ARCHIVE_EXTRACT_SECURE_SYMLINKS | \ + ARCHIVE_EXTRACT_SECURE_NODOTDOT; if (bsdar->options & AR_O) flags |= ARCHIVE_EXTRACT_TIME;
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