Resolve some UNSAFE_TODO() in AES
In particular, convert the local `keysched` to span.
Change-Id: Id417752949a5e94b21b5a7ccccee7b8eb7513a71
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/132930
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
diff --git a/core/fdrm/fx_crypt_aes.cpp b/core/fdrm/fx_crypt_aes.cpp
index 74d2fdf..d8b012a 100644
--- a/core/fdrm/fx_crypt_aes.cpp
+++ b/core/fdrm/fx_crypt_aes.cpp
@@ -6,6 +6,8 @@
#include "core/fdrm/fx_crypt_aes.h"
+#include <array>
+
#include "core/fxcrt/byteorder.h"
#include "core/fxcrt/check.h"
#include "core/fxcrt/check_op.h"
@@ -431,29 +433,28 @@
0xcb84617b, 0x32b670d5, 0x6c5c7448, 0xb85742d0,
}};
-#define ADD_ROUND_KEY_4() \
- UNSAFE_TODO((block[0] ^= *keysched++, block[1] ^= *keysched++, \
- block[2] ^= *keysched++, block[3] ^= *keysched++))
-#define MOVEWORD(i) UNSAFE_TODO((block[i] = newstate[i]))
-#define FMAKEWORD(i) \
- UNSAFE_TODO((newstate[i] = (E0[(block[i] >> 24) & 0xFF] ^ \
- E1[(block[(i + C1) % Nb] >> 16) & 0xFF] ^ \
- E2[(block[(i + C2) % Nb] >> 8) & 0xFF] ^ \
- E3[block[(i + C3) % Nb] & 0xFF])))
-#define LASTWORD(i) \
- UNSAFE_TODO( \
- (newstate[i] = (Sbox[(block[i] >> 24) & 0xFF] << 24) | \
- (Sbox[(block[(i + C1) % Nb] >> 16) & 0xFF] << 16) | \
- (Sbox[(block[(i + C2) % Nb] >> 8) & 0xFF] << 8) | \
- (Sbox[(block[(i + C3) % Nb]) & 0xFF])))
+#define ADD_ROUND_KEY_4() \
+ (block[0] ^= keysched[0], block[1] ^= keysched[1], block[2] ^= keysched[2], \
+ block[3] ^= keysched[3], keysched = keysched.subspan<4u>())
+#define MOVEWORD(i) (block[i] = newstate[i])
+#define FMAKEWORD(i) \
+ (newstate[i] = (E0[(block[i] >> 24) & 0xFF] ^ \
+ E1[(block[(i + C1) % Nb] >> 16) & 0xFF] ^ \
+ E2[(block[(i + C2) % Nb] >> 8) & 0xFF] ^ \
+ E3[block[(i + C3) % Nb] & 0xFF]))
+#define LASTWORD(i) \
+ (newstate[i] = (Sbox[(block[i] >> 24) & 0xFF] << 24) | \
+ (Sbox[(block[(i + C1) % Nb] >> 16) & 0xFF] << 16) | \
+ (Sbox[(block[(i + C2) % Nb] >> 8) & 0xFF] << 8) | \
+ (Sbox[(block[(i + C3) % Nb]) & 0xFF]))
-void aes_encrypt_nb_4(CRYPT_aes_context* ctx, uint32_t* block) {
+void aes_encrypt_nb_4(CRYPT_aes_context* ctx, pdfium::span<uint32_t, 4> block) {
const int C1 = 1;
const int C2 = 2;
const int C3 = 3;
const int Nb = 4;
- uint32_t* keysched = ctx->keysched.data();
- uint32_t newstate[4];
+ pdfium::span<uint32_t> keysched(ctx->keysched);
+ std::array<uint32_t, 4> newstate;
CHECK_NE(ctx->Nr, 0u);
for (size_t i = 0; i < ctx->Nr - 1; i++) {
ADD_ROUND_KEY_4();
@@ -480,25 +481,24 @@
#undef FMAKEWORD
#undef LASTWORD
-#define FMAKEWORD(i) \
- UNSAFE_TODO((newstate[i] = (D0[(block[i] >> 24) & 0xFF] ^ \
- D1[(block[(i + C1) % Nb] >> 16) & 0xFF] ^ \
- D2[(block[(i + C2) % Nb] >> 8) & 0xFF] ^ \
- D3[block[(i + C3) % Nb] & 0xFF])))
-#define LASTWORD(i) \
- UNSAFE_TODO( \
- (newstate[i] = (Sboxinv[(block[i] >> 24) & 0xFF] << 24) | \
- (Sboxinv[(block[(i + C1) % Nb] >> 16) & 0xFF] << 16) | \
- (Sboxinv[(block[(i + C2) % Nb] >> 8) & 0xFF] << 8) | \
- (Sboxinv[(block[(i + C3) % Nb]) & 0xFF])))
+#define FMAKEWORD(i) \
+ (newstate[i] = (D0[(block[i] >> 24) & 0xFF] ^ \
+ D1[(block[(i + C1) % Nb] >> 16) & 0xFF] ^ \
+ D2[(block[(i + C2) % Nb] >> 8) & 0xFF] ^ \
+ D3[block[(i + C3) % Nb] & 0xFF]))
+#define LASTWORD(i) \
+ (newstate[i] = (Sboxinv[(block[i] >> 24) & 0xFF] << 24) | \
+ (Sboxinv[(block[(i + C1) % Nb] >> 16) & 0xFF] << 16) | \
+ (Sboxinv[(block[(i + C2) % Nb] >> 8) & 0xFF] << 8) | \
+ (Sboxinv[(block[(i + C3) % Nb]) & 0xFF]))
-void aes_decrypt_nb_4(CRYPT_aes_context* ctx, uint32_t* block) {
+void aes_decrypt_nb_4(CRYPT_aes_context* ctx, pdfium::span<uint32_t, 4> block) {
const int C1 = 4 - 1;
const int C2 = 4 - 2;
const int C3 = 4 - 3;
const int Nb = 4;
- uint32_t* keysched = ctx->invkeysched.data();
- uint32_t newstate[4];
+ pdfium::span<uint32_t> keysched(ctx->invkeysched);
+ std::array<uint32_t, 4> newstate;
CHECK_NE(ctx->Nr, 0);
for (size_t i = 0; i < ctx->Nr - 1; i++) {
ADD_ROUND_KEY_4();
@@ -623,7 +623,7 @@
iv_element ^= fxcrt::GetUInt32MSBFirst(src.first<4u>());
src = src.subspan(4u);
}
- aes_encrypt_nb_4(ctx, ctx_iv.data());
+ aes_encrypt_nb_4(ctx, ctx_iv);
for (auto& iv_element : ctx_iv) {
fxcrt::PutUInt32MSBFirst(iv_element, dest.first<4u>());
dest = dest.subspan(4u);
