chpasswd: support -c argument and respect DEFAULT_PASSWD_ALGO

Signed-off-by: Pascal Bach <pascal.bach@siemens.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 23 insertions, 18 deletions

diff --git a/libbb/pw_encrypt.c b/libbb/pw_encrypt.c
index bfc7030a8..dbc15e5fc 100644
--- a/libbb/pw_encrypt.c
+++ b/libbb/pw_encrypt.c
@@ -52,14 +52,18 @@ char* FAST_FUNC crypt_make_pw_salt(char salt[MAX_PW_SALT_LEN], const char *algo)
 {
         int len = 2/2;
         char *salt_ptr = salt;
-        if (algo[0] != 'd') { /* not des */
+
+        /* Standard chpasswd uses uppercase algos ("MD5", not "md5").
+         * Need to be case-insensitive in the code below.
+         */
+        if ((algo[0]|0x20) != 'd') { /* not des */
                 len = 8/2; /* so far assuming md5 */
                 *salt_ptr++ = '$';
                 *salt_ptr++ = '1';
                 *salt_ptr++ = '$';
 #if !ENABLE_USE_BB_CRYPT || ENABLE_USE_BB_CRYPT_SHA
-                if (algo[0] == 's') { /* sha */
-                        salt[1] = '5' + (strcmp(algo, "sha512") == 0);
+                if ((algo[0]|0x20) == 's') { /* sha */
+                        salt[1] = '5' + (strcasecmp(algo, "sha512") == 0);
                         len = 16/2;
                 }
 #endif
diff --git a/loginutils/chpasswd.c b/loginutils/chpasswd.c
index 6c41d17be..a022a42d6 100644
--- a/loginutils/chpasswd.c
+++ b/loginutils/chpasswd.c
@@ -24,26 +24,27 @@
 //kbuild:lib-$(CONFIG_CHPASSWD) += chpasswd.o
 
 //usage:#define chpasswd_trivial_usage
-//usage:        IF_LONG_OPTS("[--md5|--encrypted]") IF_NOT_LONG_OPTS("[-m|-e]")
+//usage:        IF_LONG_OPTS("[--md5|--encrypted|--crypt-method]") IF_NOT_LONG_OPTS("[-m|-e|-c]")
 //usage:#define chpasswd_full_usage "\n\n"
 //usage:       "Read user:password from stdin and update /etc/passwd\n"
 //usage:        IF_LONG_OPTS(
-//usage:     "\n        -e,--encrypted  Supplied passwords are in encrypted form"
-//usage:     "\n        -m,--md5        Use MD5 encryption instead of DES"
+//usage:     "\n        -e,--encrypted          Supplied passwords are in encrypted form"
+//usage:     "\n        -m,--md5                Use MD5 encryption instead of DES"
+//usage:     "\n        -c,--crypt-method       Use the specified method to encrypt the passwords"
 //usage:        )
 //usage:        IF_NOT_LONG_OPTS(
 //usage:     "\n        -e      Supplied passwords are in encrypted form"
 //usage:     "\n        -m      Use MD5 encryption instead of DES"
+//usage:     "\n        -c      Use the specified method to encrypt the passwords"
 //usage:        )
 
-//TODO: implement -c ALGO
-
 #include "libbb.h"
 
 #if ENABLE_LONG_OPTS
 static const char chpasswd_longopts[] ALIGN1 =
-        "encrypted\0" No_argument "e"
-        "md5\0"       No_argument "m"
+        "encrypted\0"    No_argument       "e"
+        "md5\0"          No_argument       "m"
+        "crypt-method\0" Required_argument "c"
         ;
 #endif
 
@@ -54,14 +55,15 @@ int chpasswd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int chpasswd_main(int argc UNUSED_PARAM, char **argv)
 {
         char *name;
+        const char *algo = CONFIG_FEATURE_DEFAULT_PASSWD_ALGO;
         int opt;
 
         if (getuid() != 0)
                 bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
 
-        opt_complementary = "m--e:e--m";
+        opt_complementary = "m--ec:e--mc:c--em";
         IF_LONG_OPTS(applet_long_options = chpasswd_longopts;)
-        opt = getopt32(argv, "em");
+        opt = getopt32(argv, "emc:", &algo);
 
         while ((name = xmalloc_fgetline(stdin)) != NULL) {
                 char *free_me;
@@ -77,15 +79,14 @@ int chpasswd_main(int argc UNUSED_PARAM, char **argv)
 
                 free_me = NULL;
                 if (!(opt & OPT_ENC)) {
-                        char salt[sizeof("$N$XXXXXXXX")];
+                        char salt[MAX_PW_SALT_LEN];
 
-                        crypt_make_salt(salt, 1);
                         if (opt & OPT_MD5) {
-                                salt[0] = '$';
-                                salt[1] = '1';
-                                salt[2] = '$';
-                                crypt_make_salt(salt + 3, 4);
+                                /* Force MD5 if the -m flag is set */
+                                algo = "md5";
                         }
+
+                        crypt_make_pw_salt(salt, algo);
                         free_me = pass = pw_encrypt(pass, salt, 0);
                 }