From: Tim Kientzle <kientzle@acm.org>
Date: Sun, 11 Sep 2016 21:33:30 +0000 (-0700)
Subject: Use O_NOFOLLOW to avoid traversing symlinks when restoring data-carrying hardlinks.
X-Git-Tag: v3.2.2~15
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9f0dee226163de2490510fd258fbd9547a032f16;p=thirdparty%2Flibarchive.git

Use O_NOFOLLOW to avoid traversing symlinks when restoring data-carrying hardlinks.

TODO: Consider using this flag in other situations as well.

Thanks to Pavel Raiskup.
---

diff --git a/libarchive/archive_write_disk_posix.c b/libarchive/archive_write_disk_posix.c
index 3a8eaf602..17c23b004 100644
--- a/libarchive/archive_write_disk_posix.c
+++ b/libarchive/archive_write_disk_posix.c
@@ -140,7 +140,17 @@ __FBSDID("$FreeBSD$");
 #define O_BINARY 0
 #endif
 #ifndef O_CLOEXEC
-#define O_CLOEXEC	0
+#define O_CLOEXEC 0
+#endif
+
+/* Ignore non-int O_NOFOLLOW constant. */
+/* gnulib's fcntl.h does this on AIX, but it seems practical everywhere */
+#if defined O_NOFOLLOW && !(INT_MIN <= O_NOFOLLOW && O_NOFOLLOW <= INT_MAX)
+#undef O_NOFOLLOW
+#endif
+
+#ifndef O_NOFOLLOW
+#define O_NOFOLLOW 0
 #endif
 
 struct fixup_entry {
@@ -2067,7 +2077,7 @@ create_filesystem_object(struct archive_write_disk *a)
 			a->deferred = 0;
 		} else if (r == 0 && a->filesize > 0) {
 			a->fd = open(a->name,
-				     O_WRONLY | O_TRUNC | O_BINARY | O_CLOEXEC);
+				     O_WRONLY | O_TRUNC | O_BINARY | O_CLOEXEC | O_NOFOLLOW);
 			__archive_ensure_cloexec_flag(a->fd);
 			if (a->fd < 0)
 				r = errno;