shadow: add patch to fix crypt: Invalid Argument

This patch came from Slackware and address a change in crypt()'s handling
of an invalid seed, which in the past returned an encrypted string and now
returns a NULL.

[YOCTO #4097] related to tinylogin segfault

Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 64 insertions, 0 deletions

diff --git a/meta/recipes-extended/shadow/files/slackware_fix_for_glib-2.17_crypt.patch b/meta/recipes-extended/shadow/files/slackware_fix_for_glib-2.17_crypt.patch
new file mode 100644
index 00000000000..7cd45afebb7
--- /dev/null
+++ b/meta/recipes-extended/shadow/files/slackware_fix_for_glib-2.17_crypt.patch
@@ -0,0 +1,63 @@
+
+This patch is from Slackware, I tried to find the actual
+author to add that attribution.  The comment below is the
+best summary, I will not repeat it here.
+
+Upstream-Status: Backport from slackware
+
+Signed-off-by: Saul Wold <sgw@linux.intel.com>
+
+Index: shadow-4.1.4.3/lib/encrypt.c
+===================================================================
+--- shadow-4.1.4.3.orig/lib/encrypt.c
++++ shadow-4.1.4.3/lib/encrypt.c
+@@ -45,15 +45,40 @@ char *pw_encrypt (const char *clear, con
+ 	static char cipher[128];
+ 	char *cp;
+ 
+-	cp = crypt (clear, salt);
+-	if (!cp) {
+-		/*
+-		 * Single Unix Spec: crypt() may return a null pointer,
+-		 * and set errno to indicate an error.  The caller doesn't
+-		 * expect us to return NULL, so...
+-		 */
+-		perror ("crypt");
+-		exit (EXIT_FAILURE);
++ 	cp = crypt (clear, salt);
++ 	if (!cp) {
++ 		/*
++		 * In glibc-2.17 and newer, crypt() will return NULL if
++		 * it was called using an invalid salt format.  Previous
++		 * versions of glibc would go ahead and compute a DES hash
++		 * using the invalid salt.  The salt value in this case was
++		 * always '!'.  We might arrive at this place if either the
++		 * user does not exist, or if the hash in /etc/shadow doesn't
++		 * have the proper magic for one of the supported hash
++		 * formats (for example, if the account was locked using
++		 * "passwd -l".  To handle this situation, we will recompute
++		 * the hash using a hardcoded salt as was previously done
++		 * by glibc.  The hash returned by the old glibc function
++		 * always began with "!!", which would ensure that it could
++		 * never match an otherwise valid hash in /etc/shadow that
++		 * was disabled with a "!" at the beginning (since the second
++		 * character would never be "!" as well), so we will also
++		 * prepend the resulting hash with "!!".  Finally, in case
++		 * crypt() failed for some other reason we will check to see
++		 * if we still get NULL from crypt even with the valid salt
++		 * and will fail if that's the case.
++ 		 */
++
++		/* Recalculate hash using a hardcoded, valid SHA512 salt: */
++		cp = crypt (clear, "$6$8IIcy/1EPOk/");
++
++		if (!cp) {
++			perror ("crypt");
++			exit (EXIT_FAILURE);
++		} else {
++			sprintf (cipher, "!!%s", cp);
++			return cipher;
++		}
+ 	}
+ 
+ 	/* The GNU crypt does not return NULL if the algorithm is not
diff --git a/meta/recipes-extended/shadow/shadow_4.1.4.3.bb b/meta/recipes-extended/shadow/shadow_4.1.4.3.bb
index 8226a6e3b39..caf24c06aff 100644
--- a/meta/recipes-extended/shadow/shadow_4.1.4.3.bb
+++ b/meta/recipes-extended/shadow/shadow_4.1.4.3.bb
@@ -23,6 +23,7 @@ SRC_URI = "http://pkg-shadow.alioth.debian.org/releases/${BPN}-${PV}.tar.bz2 \
            file://shadow-4.1.4.2-su_no_sanitize_env.patch \
            file://shadow-update-pam-conf.patch \
            file://shadow_fix_for_automake-1.12.patch \
+           file://slackware_fix_for_glib-2.17_crypt.patch \
            "
 
 SRC_URI[md5sum] = "b8608d8294ac88974f27b20f991c0e79"