From c886bef63a4820d12fbc956f62747840fba8a88e Mon Sep 17 00:00:00 2001

From: Greg Hudson <ghudson@mit.edu>

Date: Sat, 3 Feb 2018 20:53:42 -0500

Subject: [PATCH] Add vector support to k5_sha256()

Add a length argument so that multiple krb5_data values can be passed

to k5_sha256(), for efficient computation of SHA-256 hashes over

concatenations of data values.

(cherry picked from commit 4f3373e8c55b3e9bdfb5b065e07214c5816c85fa)

---

 src/include/k5-int.h                 | 4 ++--

 src/lib/crypto/builtin/sha2/sha256.c | 6 ++++--

 src/lib/crypto/crypto_tests/t_sha2.c | 2 +-

 src/lib/crypto/openssl/sha256.c      | 6 ++++--

 src/lib/krb5/rcache/rc_conv.c        | 2 +-

 5 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/include/k5-int.h b/src/include/k5-int.h

index 10b034037..7c549bce2 100644

--- a/src/include/k5-int.h

+++ b/src/include/k5-int.h

@@ -634,9 +634,9 @@ krb5int_arcfour_gsscrypt(const krb5_keyblock *keyblock, krb5_keyusage usage,

 #define K5_SHA256_HASHLEN (256 / 8)

-/* Write the SHA-256 hash of in to out. */

+/* Write the SHA-256 hash of in (containing n elements) to out. */

 krb5_error_code

-k5_sha256(const krb5_data *in, uint8_t out[K5_SHA256_HASHLEN]);

+k5_sha256(const krb5_data *in, size_t n, uint8_t out[K5_SHA256_HASHLEN]);

 /*

  * Attempt to zero memory in a way that compilers won't optimize out.

diff --git a/src/lib/crypto/builtin/sha2/sha256.c b/src/lib/crypto/builtin/sha2/sha256.c

index e34bed575..4b5fe10a3 100644

--- a/src/lib/crypto/builtin/sha2/sha256.c

+++ b/src/lib/crypto/builtin/sha2/sha256.c

@@ -257,12 +257,14 @@ k5_sha256_final(void *res, SHA256_CTX *m)

 }

 krb5_error_code

-k5_sha256(const krb5_data *in, uint8_t out[K5_SHA256_HASHLEN])

+k5_sha256(const krb5_data *in, size_t n, uint8_t out[K5_SHA256_HASHLEN])

 {

     SHA256_CTX ctx;

+    size_t i;

     k5_sha256_init(&ctx;;

-    k5_sha256_update(&ctx, in->data, in->length);

+    for (i = 0; i < n; i++)

+        k5_sha256_update(&ctx, in[i].data, in[i].length);

     k5_sha256_final(out, &ctx;;

     return 0;

 }

diff --git a/src/lib/crypto/crypto_tests/t_sha2.c b/src/lib/crypto/crypto_tests/t_sha2.c

index 12f32869b..e6fa58498 100644

--- a/src/lib/crypto/crypto_tests/t_sha2.c

+++ b/src/lib/crypto/crypto_tests/t_sha2.c

@@ -125,7 +125,7 @@ hash_test(const struct krb5_hash_provider *hash, struct test *tests)

 	    if (hash == &krb5int_hash_sha256) {

 		/* Try again using k5_sha256(). */

-		if (k5_sha256(&iov.data, (uint8_t *)hval.data) != 0)

+		if (k5_sha256(&iov.data, 1, (uint8_t *)hval.data) != 0)

 		    abort();

 		if (memcmp(hval.data, t->hash, hval.length) != 0)

 		    abort();

diff --git a/src/lib/crypto/openssl/sha256.c b/src/lib/crypto/openssl/sha256.c

index fa095d472..0edd8b7ba 100644

--- a/src/lib/crypto/openssl/sha256.c

+++ b/src/lib/crypto/openssl/sha256.c

@@ -34,16 +34,18 @@

 #include <openssl/evp.h>

 krb5_error_code

-k5_sha256(const krb5_data *in, uint8_t out[K5_SHA256_HASHLEN])

+k5_sha256(const krb5_data *in, size_t n, uint8_t out[K5_SHA256_HASHLEN])

 {

     EVP_MD_CTX *ctx;

+    size_t i;

     int ok;

     ctx = EVP_MD_CTX_new();

     if (ctx == NULL)

         return ENOMEM;

     ok = EVP_DigestInit_ex(ctx, EVP_sha256(), NULL);

-    ok = ok && EVP_DigestUpdate(ctx, in->data, in->length);

+    for (i = 0; i < n; i++)

+        ok = ok && EVP_DigestUpdate(ctx, in[i].data, in[i].length);

     ok = ok && EVP_DigestFinal_ex(ctx, out, NULL);

     EVP_MD_CTX_free(ctx);

     return ok ? 0 : ENOMEM;

diff --git a/src/lib/krb5/rcache/rc_conv.c b/src/lib/krb5/rcache/rc_conv.c

index 0e021f5d8..f2fe528ac 100644

--- a/src/lib/krb5/rcache/rc_conv.c

+++ b/src/lib/krb5/rcache/rc_conv.c

@@ -58,7 +58,7 @@ krb5_rc_hash_message(krb5_context context, const krb5_data *message,

     *out = NULL;

     /* Calculate the binary checksum. */

-    retval = k5_sha256(message, cksum);

+    retval = k5_sha256(message, 1, cksum);

     if (retval)

         return retval;