From c9e5ac3380c8a8cebea222dbb3c3d95a9a93ee17 Mon Sep 17 00:00:00 2001
From: Alex Converse <alex.converse@gmail.com>
Date: Thu, 3 Nov 2011 18:13:57 -0700
Subject: [PATCH] aes: Avoid illegal read and don't generate more key than we
use.
---
libavutil/aes.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/libavutil/aes.c b/libavutil/aes.c
index ace317f38ab..0301e0395c6 100644
--- 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) {
--
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