From aea6650cfca5836ab52b48de9f141c2d1a93c8ab Mon Sep 17 00:00:00 2001
From: Marco d'Itri <md@linux.it>
Date: Tue, 31 Dec 2019 02:36:51 +0100
Subject: [PATCH] mkpasswd: support raw $salt$ prefixes

If the salt provided to the program starts with '$' then it will be
passed straight to crypt(3) without any checks.
---
 mkpasswd.1 | 7 +++++--
 mkpasswd.c | 4 +++-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/mkpasswd.1 b/mkpasswd.1
index 06ab223..e35fac4 100644
--- a/mkpasswd.1
+++ b/mkpasswd.1
@@ -16,8 +16,11 @@ libc function, using the given salt.
 .BI \-\-salt= STRING
 Use the
 .I STRING
-as salt. It must not contain prefixes such as
-.IR $1$ .
+as salt. If it begins with
+.I $
+then it will be passed straight to
+.BR crypt (3)
+without any checks.
 .TP
 .BR \-R ", "\c
 .BI \-\-rounds= NUMBER
diff --git a/mkpasswd.c b/mkpasswd.c
index 6b98a1f..9d05786 100644
--- a/mkpasswd.c
+++ b/mkpasswd.c
@@ -282,7 +282,9 @@ int main(int argc, char *argv[])
     else
 	rounds_str[0] = '\0';
 
-    if (salt_arg && salt_arg[0] != '\0') {
+    if (salt_arg && salt_arg[0] == '$')
+	salt = NOFAIL(strdup(salt_arg));
+    else if (salt_arg && salt_arg[0] != '\0') {
 	unsigned int c = strlen(salt_arg);
 	if (c < salt_minlen || c > salt_maxlen) {
 	    if (salt_minlen == salt_maxlen)