Make the crc32 hash provider correctly chain multiple input buffers,

so that it returns the same result if you pass it one big buffer or
many small buffers containing the same data.  To do this, change the
contract of mit_crc32 so that the cksum parameter is in-out.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@23386 dc483132-0cff-0310-8789-dd5450dbe970

diff --git a/src/lib/crypto/builtin/hash_provider/hash_crc32.c b/src/lib/crypto/builtin/hash_provider/hash_crc32.c
index e748c98cfe9ab98fef7b16c4e3dd620ec3f12938..58efffe4f3422ac212f61623a5d1680e68e75c44 100644 (file)
--- a/src/lib/crypto/builtin/hash_provider/hash_crc32.c
+++ b/src/lib/crypto/builtin/hash_provider/hash_crc32.c
@@ -33,17 +33,15 @@ static krb5_error_code
 k5_crc32_hash(unsigned int icount, const krb5_data *input,
               krb5_data *output)
 {
-    unsigned long c, cn;
+    unsigned long c;
     unsigned int i;
 
     if (output->length != CRC32_CKSUM_LENGTH)
         return(KRB5_CRYPTO_INTERNAL);
 
     c = 0;
-    for (i=0; i<icount; i++) {
-        mit_crc32(input[i].data, input[i].length, &cn);
-        c ^= cn;
-    }
+    for (i=0; i<icount; i++)
+        mit_crc32(input[i].data, input[i].length, &c);
 
     store_32_le(c, output->data);
     return(0);

diff --git a/src/lib/crypto/crypto_tests/t_crc.c b/src/lib/crypto/crypto_tests/t_crc.c
index 6d06334dd7f74a133e92fd70ea18937c7bde33f5..69a6468053dda30e3a283ac56953a5a9db62ec33 100644 (file)
--- a/src/lib/crypto/crypto_tests/t_crc.c
+++ b/src/lib/crypto/crypto_tests/t_crc.c
@@ -121,6 +121,7 @@ timetest(unsigned int nblk, unsigned int blksiz)
         block[i] = i % 256;
     times(&before);
     for (i = 0; i < nblk; i++) {
+        cksum = 0;
         mit_crc32(block + i * blksiz, blksiz, &cksum);
     }
 
@@ -136,6 +137,7 @@ timetest(unsigned int nblk, unsigned int blksiz)
 #ifdef CRC32_SHIFT4
     times(&before);
     for (i = 0; i < nblk; i++) {
+        cksum = 0;
         mit_crc32_shift4(block + i * blksiz, blksiz, &cksum);
     }
     times(&after);
@@ -185,11 +187,13 @@ verify(void)
         case STR:
             len = strlen(trial.data);
             typestr = "STR";
+            cksum = 0;
             mit_crc32(trial.data, len, &cksum);
             break;
         case HEX:
             typestr = "HEX";
             gethexstr(trial.data, &len, buf, 4);
+            cksum = 0;
             mit_crc32(buf, len, &cksum);
             break;
         default:

diff --git a/src/lib/crypto/krb/crc32/crc-32.h b/src/lib/crypto/krb/crc32/crc-32.h
index 95001f59d3108d44a3114de48cc6952d6ee72434..5c28b8b790288e4fe2a43c11233b365adc10bba1 100644 (file)
--- a/src/lib/crypto/krb/crc32/crc-32.h
+++ b/src/lib/crypto/krb/crc32/crc-32.h
@@ -60,6 +60,7 @@
 
 #define CRC32_CKSUM_LENGTH      4
 
+/* c is in-out to allow chaining; initialize to 0. */
 void
 mit_crc32 (krb5_pointer in, size_t in_length, unsigned long *c);
 

diff --git a/src/lib/crypto/krb/crc32/crc32.c b/src/lib/crypto/krb/crc32/crc32.c
index 490979803143995a4d629bd19145df9dbba6ebab..ef364f3ed9bbcf33874ba9d240d55b5a1b2d3ccf 100644 (file)
--- a/src/lib/crypto/krb/crc32/crc32.c
+++ b/src/lib/crypto/krb/crc32/crc32.c
@@ -151,7 +151,7 @@ void
 mit_crc32(krb5_pointer in, size_t in_length, unsigned long *cksum)
 {
     register u_char *data;
-    register u_long c = 0;
+    register u_long c = *cksum;
     register int idx;
     size_t i;
 
@@ -178,7 +178,7 @@ void
 mit_crc32_shift4(krb5_pointer in, size_t in_length, unsigned long *cksum)
 {
     register unsigned char *data, b;
-    register unsigned long c = 0;
+    register unsigned long c = *cksum;
     size_t i;
 
     data = (u_char *)in;

diff --git a/src/lib/crypto/openssl/hash_provider/hash_crc32.c b/src/lib/crypto/openssl/hash_provider/hash_crc32.c
index e748c98cfe9ab98fef7b16c4e3dd620ec3f12938..58efffe4f3422ac212f61623a5d1680e68e75c44 100644 (file)
--- a/src/lib/crypto/openssl/hash_provider/hash_crc32.c
+++ b/src/lib/crypto/openssl/hash_provider/hash_crc32.c
@@ -33,17 +33,15 @@ static krb5_error_code
 k5_crc32_hash(unsigned int icount, const krb5_data *input,
               krb5_data *output)
 {
-    unsigned long c, cn;
+    unsigned long c;
     unsigned int i;
 
     if (output->length != CRC32_CKSUM_LENGTH)
         return(KRB5_CRYPTO_INTERNAL);
 
     c = 0;
-    for (i=0; i<icount; i++) {
-        mit_crc32(input[i].data, input[i].length, &cn);
-        c ^= cn;
-    }
+    for (i=0; i<icount; i++)
+        mit_crc32(input[i].data, input[i].length, &c);
 
     store_32_le(c, output->data);
     return(0);