X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavutil%2Fxtea.c;h=f3357ce544af9fcb3e502708ff1e590af0fef222;hb=92281850a2d878dae1d50e271886ba87013b6ff3;hp=07a66e56666a5d3a2882c06ee4eab69eac482b45;hpb=f6687bf5f8989d397cdef6d9d05bcb13a7ef8c4f;p=ffmpeg

diff --git a/libavutil/xtea.c b/libavutil/xtea.c
index 07a66e56666..f3357ce544a 100644
--- a/libavutil/xtea.c
+++ b/libavutil/xtea.c
@@ -36,7 +36,7 @@ void av_xtea_init(AVXTEA *ctx, const uint8_t key[16])
 }
 
 static void xtea_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
-                           int decrypt)
+                           int decrypt, uint8_t *iv)
 {
     uint32_t v0, v1;
     int i;
@@ -52,6 +52,11 @@ static void xtea_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
             sum -= delta;
             v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
         }
+        if (iv) {
+            v0 ^= AV_RB32(iv);
+            v1 ^= AV_RB32(iv + 4);
+            memcpy(iv, src, 8);
+        }
     } else {
         uint32_t sum = 0, delta = 0x9E3779B9;
 
@@ -72,32 +77,24 @@ void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
     int i;
 
     if (decrypt) {
-        while (count > 0) {
-            xtea_crypt_ecb(ctx, dst, src, decrypt);
-
-            if (iv) {
-                for (i = 0; i < 8; i++)
-                    dst[i] = dst[i] ^ iv[i];
-                memcpy(iv, src, 8);
-            }
+        while (count--) {
+            xtea_crypt_ecb(ctx, dst, src, decrypt, iv);
 
             src   += 8;
             dst   += 8;
-            count -= 8;
         }
     } else {
-        while (count > 0) {
+        while (count--) {
             if (iv) {
                 for (i = 0; i < 8; i++)
                     dst[i] = src[i] ^ iv[i];
-                xtea_crypt_ecb(ctx, dst, dst, decrypt);
+                xtea_crypt_ecb(ctx, dst, dst, decrypt, NULL);
                 memcpy(iv, dst, 8);
             } else {
-                xtea_crypt_ecb(ctx, dst, src, decrypt);
+                xtea_crypt_ecb(ctx, dst, src, decrypt, NULL);
             }
             src   += 8;
             dst   += 8;
-            count -= 8;
         }
     }
 }
@@ -141,26 +138,50 @@ static const uint8_t xtea_test_ct[XTEA_NUM_TESTS][8] = {
     { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
 };
 
+#undef exit
+static void test_xtea(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
+                      const uint8_t *ref, int len, uint8_t *iv, int dir,
+                      const char *test)
+{
+    av_xtea_crypt(ctx, dst, src, len, iv, dir);
+    if (memcmp(dst, ref, 8*len)) {
+        int i;
+        printf("%s failed\ngot      ", test);
+        for (i = 0; i < 8*len; i++)
+            printf("%02x ", dst[i]);
+        printf("\nexpected ");
+        for (i = 0; i < 8*len; i++)
+            printf("%02x ", ref[i]);
+        printf("\n");
+        exit(1);
+    }
+}
+
 int main(void)
 {
     AVXTEA ctx;
-    uint8_t buf[8];
+    uint8_t buf[8], iv[8];
     int i;
+    const uint8_t src[32] = "HelloWorldHelloWorldHelloWorld";
+    uint8_t ct[32];
+    uint8_t pl[32];
 
     for (i = 0; i < XTEA_NUM_TESTS; i++) {
         av_xtea_init(&ctx, xtea_test_key[i]);
 
-        av_xtea_crypt(&ctx, buf, xtea_test_pt[i], 1, NULL, 0);
-        if (memcmp(buf, xtea_test_ct[i], 8)) {
-            printf("Test encryption failed.\n");
-            return 1;
-        }
+        test_xtea(&ctx, buf, xtea_test_pt[i], xtea_test_ct[i], 1, NULL, 0, "encryption");
+        test_xtea(&ctx, buf, xtea_test_ct[i], xtea_test_pt[i], 1, NULL, 1, "decryption");
 
-        av_xtea_crypt(&ctx, buf, xtea_test_ct[i], 1, NULL, 1);
-        if (memcmp(buf, xtea_test_pt[i], 8)) {
-            printf("Test decryption failed.\n");
-            return 1;
-        }
+        /* encrypt */
+        memcpy(iv, "HALLO123", 8);
+        av_xtea_crypt(&ctx, ct, src, 4, iv, 0);
+
+        /* decrypt into pl */
+        memcpy(iv, "HALLO123", 8);
+        test_xtea(&ctx, pl, ct, src, 4, iv, 1, "CBC decryption");
+
+        memcpy(iv, "HALLO123", 8);
+        test_xtea(&ctx, ct, ct, src, 4, iv, 1, "CBC inplace decryption");
     }
     printf("Test encryption/decryption success.\n");