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From 05aa693b7db6b818d31e41f0cab1d5fb4f49600e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Esser?= <besser82@fedoraproject.org>
Date: Thu, 15 Nov 2018 15:58:56 +0100
Subject: [PATCH] pam_unix: Prefer a gensalt function, that supports auto
entropy.
* modules/pam_unix/pam_unix_passwd.c: Initialize rounds parameter to 0.
* modules/pam_unix/passverify.c: Prefer gensalt with auto entropy.
* modules/pam_unix/support.c: Fix sanitizing of rounds parameter.
---
modules/pam_unix/pam_unix_passwd.c | 2 +-
modules/pam_unix/passverify.c | 13 +++++++++++++
modules/pam_unix/support.c | 7 +++++--
3 files changed, 19 insertions(+), 3 deletions(-)
Index: Linux-PAM-1.3.1/modules/pam_unix/pam_unix_passwd.c
===================================================================
--- Linux-PAM-1.3.1.orig/modules/pam_unix/pam_unix_passwd.c
+++ Linux-PAM-1.3.1/modules/pam_unix/pam_unix_passwd.c
@@ -607,7 +607,7 @@ pam_sm_chauthtok(pam_handle_t *pamh, int
unsigned int ctrl, lctrl;
int retval;
int remember = -1;
- int rounds = -1;
+ int rounds = 0;
int pass_min_len = 0;
/* <DO NOT free() THESE> */
Index: Linux-PAM-1.3.1/modules/pam_unix/passverify.c
===================================================================
--- Linux-PAM-1.3.1.orig/modules/pam_unix/passverify.c
+++ Linux-PAM-1.3.1/modules/pam_unix/passverify.c
@@ -375,7 +375,12 @@ PAMH_ARG_DECL(char * create_password_has
const char *password, unsigned int ctrl, int rounds)
{
const char *algoid;
+#if defined(CRYPT_GENSALT_OUTPUT_SIZE) && CRYPT_GENSALT_OUTPUT_SIZE > 64
+ /* Strings returned by crypt_gensalt_rn will be no longer than this. */
+ char salt[CRYPT_GENSALT_OUTPUT_SIZE];
+#else
char salt[64]; /* contains rounds number + max 16 bytes of salt + algo id */
+#endif
char *sp;
#ifdef HAVE_CRYPT_R
struct crypt_data *cdata = NULL;
@@ -406,6 +411,13 @@ PAMH_ARG_DECL(char * create_password_has
return crypted;
}
+#if defined(CRYPT_GENSALT_IMPLEMENTS_AUTO_ENTROPY) && CRYPT_GENSALT_IMPLEMENTS_AUTO_ENTROPY
+ /*
+ * Any version of libcrypt supporting auto entropy is
+ * guaranteed to have crypt_gensalt_rn().
+ */
+ sp = crypt_gensalt_rn(algoid, rounds, NULL, 0, salt, sizeof(salt));
+#else
#ifdef HAVE_CRYPT_GENSALT_R
if (on(UNIX_BLOWFISH_PASS, ctrl)) {
char entropy[17];
@@ -423,6 +435,7 @@ PAMH_ARG_DECL(char * create_password_has
#ifdef HAVE_CRYPT_GENSALT_R
}
#endif
+#endif /* CRYPT_GENSALT_IMPLEMENTS_AUTO_ENTROPY */
#ifdef HAVE_CRYPT_R
sp = NULL;
cdata = malloc(sizeof(*cdata));
Index: Linux-PAM-1.3.1/modules/pam_unix/support.c
===================================================================
--- Linux-PAM-1.3.1.orig/modules/pam_unix/support.c
+++ Linux-PAM-1.3.1/modules/pam_unix/support.c
@@ -175,6 +175,7 @@ int _set_ctrl(pam_handle_t *pamh, int fl
if (val) {
*rounds = strtol(val, NULL, 10);
+ set(UNIX_ALGO_ROUNDS, ctrl);
free (val);
}
}
@@ -254,11 +255,13 @@ int _set_ctrl(pam_handle_t *pamh, int fl
if (*rounds < 4 || *rounds > 31)
*rounds = 5;
} else if (on(UNIX_SHA256_PASS, ctrl) || on(UNIX_SHA512_PASS, ctrl)) {
- if ((*rounds < 1000) || (*rounds == INT_MAX))
+ if ((*rounds < 1000) || (*rounds == INT_MAX)) {
/* don't care about bogus values */
+ *rounds = 0;
unset(UNIX_ALGO_ROUNDS, ctrl);
- if (*rounds >= 10000000)
+ } else if (*rounds >= 10000000) {
*rounds = 9999999;
+ }
}
}
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