aes: Avoid illegal read and don't generate more key than we use.

13 years ago · c9e5ac3380
parent 88b2436911
commit c9e5ac3380
1 changed files with 4 additions and 4 deletions
--- a/libavutil/aes.c
+++ b/libavutil/aes.c
@ -222,11 +222,9 @@ int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt)
    a->rounds = rounds;

    memcpy(tk, key, KC * 4);
+    memcpy(a->round_key[0].u8, key, KC * 4);

-    for (t = 0; t < (rounds + 1) * 16;) {
-        memcpy(a->round_key[0].u8 + t, tk, KC * 4);
-        t += KC * 4;
-
+    for (t = KC * 4; t < (rounds + 1) * 16; t += KC * 4) {
        for (i = 0; i < 4; i++)
            tk[0][i] ^= sbox[tk[KC - 1][(i + 1) & 3]];
        tk[0][0] ^= rcon[rconpointer++];
@ -239,6 +237,8 @@ int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt)
                for (i = 0; i < 4; i++)
                    tk[j][i] ^= sbox[tk[j - 1][i]];
        }
+
+        memcpy(a->round_key[0].u8 + t, tk, KC * 4);
    }

    if (decrypt) {