1 files changed, 73 insertions, 0 deletions
diff --git a/source/a/pam/fedora-patches/pam-1.3.1-unix-checksalt_syslog.patch b/source/a/pam/fedora-patches/pam-1.3.1-unix-checksalt_syslog.patch
new file mode 100644
index 000000000..5cbc35b03
--- /dev/null
+++ b/source/a/pam/fedora-patches/pam-1.3.1-unix-checksalt_syslog.patch
@@ -0,0 +1,73 @@
+From 86eed7ca01864b9fd17099e57f10f2b9b6b568a1 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Bj=C3=B6rn=20Esser?= <besser82@fedoraproject.org>
+Date: Mon, 26 Nov 2018 22:33:17 +0100
+Subject: [PATCH] pam_unix: Report unusable hashes found by checksalt to
+ syslog.
+
+libxcrypt can be build-time configured to support (or not support)
+various hashing methods.  Future versions will also have support for
+runtime configuration by the system's vendor and/or administrator.
+
+For that reason adminstrator should be notified by pam if users cannot
+log into their account anymore because of such a change in the system's
+configuration of libxcrypt.
+
+Also check for malformed hashes, like descrypt hashes starting with
+"$2...", which might have been generated by unsafe base64 encoding
+functions as used in glibc <= 2.16.
+Such hashes are likely to be rejected by many recent implementations
+of libcrypt.
+
+* modules/pam_unix/passverify.c (verify_pwd_hash): Report unusable
+hashes found by checksalt to syslog.
+---
+ modules/pam_unix/passverify.c | 36 +++++++++++++++++++++++++++++++++++
+ 1 file changed, 36 insertions(+)
+
+diff --git a/modules/pam_unix/passverify.c b/modules/pam_unix/passverify.c
+index eb2444bb..2c808eb5 100644
+--- a/modules/pam_unix/passverify.c
++++ b/modules/pam_unix/passverify.c
+@@ -103,6 +103,42 @@ verify_pwd_hash(const char *p, char *hash, unsigned int nullok)
+ 			 * Ok, we don't know the crypt algorithm, but maybe
+ 			 * libcrypt knows about it? We should try it.
+ 			 */
++#if defined(CRYPT_CHECKSALT_AVAILABLE) && CRYPT_CHECKSALT_AVAILABLE
++			/* Get the status of the hash from checksalt */
++			int retval_checksalt = crypt_checksalt(hash);
++
++			/*
++			 * Check for hashing methods that are disabled by
++			 * libcrypt configuration and/or system preset.
++			 */
++			if (retval_checksalt == CRYPT_SALT_METHOD_DISABLED) {
++				/*
++				 * pam_syslog() needs a pam handle,
++				 * but that's not available here.
++				 */
++				helper_log_err(LOG_ERR,
++				  "pam_unix(verify_pwd_hash): The method "
++				  "for computing the hash \"%.6s\" has been "
++				  "disabled in libcrypt by the preset from "
++				  "the system's vendor and/or administrator.",
++				  hash);
++			}
++			/*
++			 * Check for malformed hashes, like descrypt hashes
++			 * starting with "$2...", which might have been
++			 * generated by unsafe base64 encoding functions
++			 * as used in glibc <= 2.16.
++			 * Such hashes are likely to be rejected by many
++			 * recent implementations of libcrypt.
++			 */
++			if (retval_checksalt == CRYPT_SALT_INVALID) {
++				helper_log_err(LOG_ERR,
++				  "pam_unix(verify_pwd_hash): The hash \"%.6s\""
++				  "does not use a method known by the version "
++				  "of libcrypt this system is supplied with.",
++				  hash);
++			}
++#endif
+ #ifdef HAVE_CRYPT_R
+ 			struct crypt_data *cdata;
+ 			cdata = malloc(sizeof(*cdata));