libbb: make pw_encrypt() die if supplied salt is bad (e.g. emply)
Fished from 520-loginutils-handle-crypt-failures.patch in openwrt
function old new delta
pw_encrypt 913 927 +14
des_crypt 1327 1318 -9
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 14/-9) Total: 5 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/libbb/pw_encrypt_des.c b/libbb/pw_encrypt_des.c
index c6fc328..dcd3521 100644
--- a/libbb/pw_encrypt_des.c
+++ b/libbb/pw_encrypt_des.c
@@ -713,11 +713,15 @@
static char *
NOINLINE
des_crypt(struct des_ctx *ctx, char output[DES_OUT_BUFSIZE],
- const unsigned char *key, const unsigned char *setting)
+ const unsigned char *key, const unsigned char *salt_str)
{
uint32_t salt, r0, r1, keybuf[2];
uint8_t *q;
+ /* Bad salt? Mimic crypt() API - return NULL */
+ if (!salt_str[0] || !salt_str[1])
+ return NULL;
+
/*
* Copy the key, shifting each character up by one bit
* and padding with zeros.
@@ -732,22 +736,15 @@
des_setkey(ctx, (char *)keybuf);
/*
- * setting - 2 bytes of salt
+ * salt_str - 2 bytes of salt
* key - up to 8 characters
*/
- salt = (ascii_to_bin(setting[1]) << 6)
- | ascii_to_bin(setting[0]);
-
- output[0] = setting[0];
- /*
- * If the encrypted password that the salt was extracted from
- * is only 1 character long, the salt will be corrupted. We
- * need to ensure that the output string doesn't have an extra
- * NUL in it!
- */
- output[1] = setting[1] ? setting[1] : output[0];
-
+ output[0] = salt_str[0];
+ output[1] = salt_str[1];
+ salt = (ascii_to_bin(salt_str[1]) << 6)
+ | ascii_to_bin(salt_str[0]);
setup_salt(ctx, salt);
+
/* Do it. */
do_des(ctx, /*0, 0,*/ &r0, &r1, 25 /* count */);