1 files changed, 84 insertions, 78 deletions

diff --git a/md5crypt.c b/md5crypt.c
index ba98ccccc..e14d53ac1 100644
--- a/md5crypt.c
+++ b/md5crypt.c
@@ -1,159 +1,165 @@
 /*
  * ----------------------------------------------------------------------------
  * "THE BEER-WARE LICENSE" (Revision 42):
- * <phk@login.dknet.dk> wrote this file.  As long as you retain this notice you
- * can do whatever you want with this stuff. If we meet some day, and you think
- * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
+ * <phk@login.dknet.dk> wrote this file.  As long as you retain this 
+ * notice you can do whatever you want with this stuff. If we meet some 
+ * day, and you think this stuff is worth it, you can buy me a beer in 
+ * return.   Poul-Henning Kamp
  * ----------------------------------------------------------------------------
  */
 
-/*
- * Ported from FreeBSD to Linux, only minimal changes.  --marekm
- */
-
-/*
- * Adapted from shadow-19990607 by Tudor Bosman, tudorb@jm.nu
- */
-
 #include "includes.h"
 
-RCSID("$Id: md5crypt.c,v 1.5 2001/02/09 01:55:36 djm Exp $");
-
 #if defined(HAVE_MD5_PASSWORDS) && !defined(HAVE_MD5_CRYPT)
-
 #include <openssl/md5.h>
 
-static unsigned char itoa64[] =         /* 0 ... 63 => ascii - 64 */
-        "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+RCSID("$Id: md5crypt.c,v 1.7 2003/05/30 06:58:23 dtucker Exp $");
+
+/* 0 ... 63 => ascii - 64 */
+static unsigned char itoa64[] =
+    "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 
-static char     *magic = "$1$"; /*
-                                 * This string is magic for
-                                 * this algorithm.  Having
-                                 * it this way, we can get
-                                 * get better later on
-                                 */
+static char *magic = "$1$";
 
-static void
-to64(char *s, unsigned long v, int n)
+static char *
+to64(unsigned long v, int n)
 {
+        static char buf[5];
+        char *s = buf;
+
+        if (n > 4)
+                return (NULL);
+
+        memset(buf, '\0', sizeof(buf));
         while (--n >= 0) {
                 *s++ = itoa64[v&0x3f];
                 v >>= 6;
         }
+        
+        return (buf);
 }
 
 int
 is_md5_salt(const char *salt)
 {
-        return (!strncmp(salt, magic, strlen(magic)));
+        return (strncmp(salt, magic, strlen(magic)) == 0);
 }
 
-/*
- * UNIX password
- *
- * Use MD5 for what it is best at...
- */
-
 char *
 md5_crypt(const char *pw, const char *salt)
 {
-        static char     passwd[120], *p;
-        static const char *sp,*ep;
-        unsigned char   final[16];
-        int sl,pl,i,j;
-        MD5_CTX ctx,ctx1;
+        static char passwd[120], salt_copy[9], *p;
+        static const char *sp, *ep;
+        unsigned char final[16];
+        int sl, pl, i, j;
+        MD5_CTX ctx, ctx1;
         unsigned long l;
 
         /* Refine the Salt first */
         sp = salt;
 
         /* If it starts with the magic string, then skip that */
-        if(!strncmp(sp,magic,strlen(magic)))
+        if(strncmp(sp, magic, strlen(magic)) == 0)
                 sp += strlen(magic);
 
         /* It stops at the first '$', max 8 chars */
-        for(ep=sp;*ep && *ep != '$' && ep < (sp+8);ep++)
-                continue;
+        for (ep = sp; *ep != '$'; ep++) {
+                if (*ep == '\0' || ep >= (sp + 8))
+                        return (NULL);
+        }
 
         /* get the length of the true salt */
         sl = ep - sp;
 
+        /* Stash the salt */
+        memcpy(salt_copy, sp, sl);
+        salt_copy[sl] = '\0';
+
         MD5_Init(&ctx);
 
         /* The password first, since that is what is most unknown */
-        MD5_Update(&ctx,pw,strlen(pw));
+        MD5_Update(&ctx, pw, strlen(pw));
 
         /* Then our magic string */
-        MD5_Update(&ctx,magic,strlen(magic));
+        MD5_Update(&ctx, magic, strlen(magic));
 
         /* Then the raw salt */
-        MD5_Update(&ctx,sp,sl);
+        MD5_Update(&ctx, sp, sl);
 
-        /* Then just as many characters of the MD5(pw,salt,pw) */
+        /* Then just as many characters of the MD5(pw, salt, pw) */
         MD5_Init(&ctx1);
-        MD5_Update(&ctx1,pw,strlen(pw));
-        MD5_Update(&ctx1,sp,sl);
-        MD5_Update(&ctx1,pw,strlen(pw));
-        MD5_Final(final,&ctx1);
+        MD5_Update(&ctx1, pw, strlen(pw));
+        MD5_Update(&ctx1, sp, sl);
+        MD5_Update(&ctx1, pw, strlen(pw));
+        MD5_Final(final, &ctx1);
+
         for(pl = strlen(pw); pl > 0; pl -= 16)
-                MD5_Update(&ctx,final,pl>16 ? 16 : pl);
+                MD5_Update(&ctx, final, pl > 16 ? 16 : pl);
 
         /* Don't leave anything around in vm they could use. */
-        memset(final,0,sizeof final);
+        memset(final, '\0', sizeof final);
 
         /* Then something really weird... */
-        for (j=0,i = strlen(pw); i ; i >>= 1)
-                if(i&1)
-                    MD5_Update(&ctx, final+j, 1);
+        for (j = 0, i = strlen(pw); i != 0; i >>= 1)
+                if (i & 1)
+                        MD5_Update(&ctx, final + j, 1);
                 else
-                    MD5_Update(&ctx, pw+j, 1);
+                        MD5_Update(&ctx, pw + j, 1);
 
         /* Now make the output string */
-        strcpy(passwd,magic);
-        strncat(passwd,sp,sl);
-        strcat(passwd,"$");
+        snprintf(passwd, sizeof(passwd), "%s%s$", magic, salt_copy);
 
-        MD5_Final(final,&ctx);
+        MD5_Final(final, &ctx);
 
         /*
          * and now, just to make sure things don't run too fast
          * On a 60 Mhz Pentium this takes 34 msec, so you would
          * need 30 seconds to build a 1000 entry dictionary...
          */
-        for(i=0;i<1000;i++) {
+        for(i = 0; i < 1000; i++) {
                 MD5_Init(&ctx1);
-                if(i & 1)
-                        MD5_Update(&ctx1,pw,strlen(pw));
+                if (i & 1)
+                        MD5_Update(&ctx1, pw, strlen(pw));
                 else
-                        MD5_Update(&ctx1,final,16);
+                        MD5_Update(&ctx1, final, 16);
 
-                if(i % 3)
-                        MD5_Update(&ctx1,sp,sl);
+                if (i % 3)
+                        MD5_Update(&ctx1, sp, sl);
 
-                if(i % 7)
-                        MD5_Update(&ctx1,pw,strlen(pw));
+                if (i % 7)
+                        MD5_Update(&ctx1, pw, strlen(pw));
 
-                if(i & 1)
-                        MD5_Update(&ctx1,final,16);
+                if (i & 1)
+                        MD5_Update(&ctx1, final, 16);
                 else
-                        MD5_Update(&ctx1,pw,strlen(pw));
-                MD5_Final(final,&ctx1);
+                        MD5_Update(&ctx1, pw, strlen(pw));
+
+                MD5_Final(final, &ctx1);
         }
 
         p = passwd + strlen(passwd);
 
-        l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; to64(p,l,4); p += 4;
-        l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; to64(p,l,4); p += 4;
-        l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; to64(p,l,4); p += 4;
-        l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; to64(p,l,4); p += 4;
-        l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; to64(p,l,4); p += 4;
-        l =                    final[11]                ; to64(p,l,2); p += 2;
-        *p = '\0';
+        l = (final[ 0]<<16) | (final[ 6]<<8) | final[12];
+        strlcat(passwd, to64(l, 4), sizeof(passwd));
+        l = (final[ 1]<<16) | (final[ 7]<<8) | final[13];
+        strlcat(passwd, to64(l, 4), sizeof(passwd));
+        l = (final[ 2]<<16) | (final[ 8]<<8) | final[14];
+        strlcat(passwd, to64(l, 4), sizeof(passwd));
+        l = (final[ 3]<<16) | (final[ 9]<<8) | final[15];
+        strlcat(passwd, to64(l, 4), sizeof(passwd));
+        l = (final[ 4]<<16) | (final[10]<<8) | final[ 5];
+        strlcat(passwd, to64(l, 4), sizeof(passwd));
+        l =                    final[11]                ;
+        strlcat(passwd, to64(l, 2), sizeof(passwd));
 
         /* Don't leave anything around in vm they could use. */
-        memset(final,0,sizeof final);
+        memset(final, 0, sizeof(final));
+        memset(salt_copy, 0, sizeof(salt_copy));
+        memset(&ctx, 0, sizeof(ctx));
+        memset(&ctx1, 0, sizeof(ctx1));
+        (void)to64(0, 4);
 
-        return passwd;
+        return (passwd);
 }
 
 #endif /* defined(HAVE_MD5_PASSWORDS) && !defined(HAVE_MD5_CRYPT) */