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

(From OE-Core rev: a7f7e6da8383b4bde6d8ce951e5c3c955073c0bd)

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

1 files changed, 63 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 0000000000..7cd45afebb
--- /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