md5 passwords: reduce static usage

    text           data     bss     dec     hex filename
-   1875              0     120    1995     7cb libcrypt/md5.o
+   1855              0      35    1890     762 libcrypt/md5.o

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/libcrypt/md5.c b/libcrypt/md5.c
index ab5548c..1af11ed 100644 (file)
--- a/libcrypt/md5.c
+++ b/libcrypt/md5.c
@@ -531,7 +531,8 @@ static void __md5_to64( char *s, unsigned long v, int n)
 char *__md5_crypt(const unsigned char *pw, const unsigned char *salt)
 {
        /* Static stuff */
-       static char passwd[120];
+       /* "$1$" + salt_up_to_8_chars + "$" + 22_bytes_of_hash + NUL */
+       static char passwd[3 + 8 + 1 + 22 + 1];
 
        const unsigned char *sp, *ep;
        char *p;
@@ -584,9 +585,9 @@ char *__md5_crypt(const unsigned char *pw, const unsigned char *salt)
        }
 
        /* Now make the output string */
-       strcpy(passwd,__md5__magic);
-       strncat(passwd,sp,sl);
-       strcat(passwd,"$");
+       strcpy(passwd,__md5__magic); /* 3 bytes */
+       strncpy(passwd+MD5_MAGIC_LEN,(char*)sp,sl); /* 8 or less */
+       passwd[MD5_MAGIC_LEN+sl] = '$';
 
        __md5_Final(final,&ctx);
 
@@ -615,15 +616,17 @@ char *__md5_crypt(const unsigned char *pw, const unsigned char *salt)
                __md5_Final(final,&ctx1);
        }
 
-       p = passwd + strlen(passwd);
-
+       /* Add 5*4+2 = 22 bytes of hash, + NUL byte. */
+       p = passwd + MD5_MAGIC_LEN + sl + 1;
        final[16] = final[5];
        for ( i=0 ; i < 5 ; i++ ) {
                l = (final[i]<<16) | (final[i+6]<<8) | final[i+12];
-               __md5_to64(p,l,4); p += 4;
+               __md5_to64(p,l,4);
+               p += 4;
        }
        l = final[11];
-       __md5_to64(p,l,2); p += 2;
+       __md5_to64(p,l,2);
+       p += 2;
        *p = '\0';
 
        /* Don't leave anything around in vm they could use. */