[10/35] crypto: Add aesdec_ISB_ISR

Commit Message

Richard Henderson June 3, 2023, 2:34 a.m. UTC

Add a primitive for InvSubBytes + InvShiftRows.

Signed-off-by: Richard Henderson <[e-mail]>
---
 host/include/generic/host/aes-round.h |  3 ++
 include/crypto/aes-round.h            | 18 +++++++++++
 crypto/aes.c                          | 46 +++++++++++++++++++++++++++
 3 files changed, 67 insertions(+)

Patch

diff --git a/host/include/generic/host/aes-round.h b/host/include/generic/host/aes-round.h
index 598242c603..cb4fed61fe 100644
--- a/host/include/generic/host/aes-round.h
+++ b/host/include/generic/host/aes-round.h
@@ -12,4 +12,7 @@ 
 void aesenc_SB_SR_accel(AESState *, const AESState *, bool)
     QEMU_ERROR("unsupported accel");
 
+void aesdec_ISB_ISR_accel(AESState *, const AESState *, bool)
+    QEMU_ERROR("unsupported accel");
+
 #endif
diff --git a/include/crypto/aes-round.h b/include/crypto/aes-round.h
index 784e1daee6..ff1914bd63 100644
--- a/include/crypto/aes-round.h
+++ b/include/crypto/aes-round.h
@@ -38,4 +38,22 @@  static inline void aesenc_SB_SR(AESState *r, const AESState *st, bool be)
     }
 }
 
+/*
+ * Perform InvSubBytes + InvShiftRows.
+ */
+
+void aesdec_ISB_ISR_gen(AESState *ret, const AESState *st);
+void aesdec_ISB_ISR_genrev(AESState *ret, const AESState *st);
+
+static inline void aesdec_ISB_ISR(AESState *r, const AESState *st, bool be)
+{
+    if (HAVE_AES_ACCEL) {
+        aesdec_ISB_ISR_accel(r, st, be);
+    } else if (HOST_BIG_ENDIAN == be) {
+        aesdec_ISB_ISR_gen(r, st);
+    } else {
+        aesdec_ISB_ISR_genrev(r, st);
+    }
+}
+
 #endif /* CRYPTO_AES_ROUND_H */
diff --git a/crypto/aes.c b/crypto/aes.c
index 708838315a..937377647f 100644
--- a/crypto/aes.c
+++ b/crypto/aes.c
@@ -1298,6 +1298,52 @@  void aesenc_SB_SR_genrev(AESState *r, const AESState *st)
     aesenc_SB_SR_swap(r, st, true);
 }
 
+/* Perform InvSubBytes + InvShiftRows. */
+static inline void
+aesdec_ISB_ISR_swap(AESState *r, const AESState *st, bool swap)
+{
+    const int swap_b = swap ? 15 : 0;
+    uint8_t t;
+
+    /* These four indexes are not swizzled. */
+    r->b[swap_b ^ 0x0] = AES_isbox[st->b[swap_b ^ AES_ISH_0]];
+    r->b[swap_b ^ 0x4] = AES_isbox[st->b[swap_b ^ AES_ISH_4]];
+    r->b[swap_b ^ 0x8] = AES_isbox[st->b[swap_b ^ AES_ISH_8]];
+    r->b[swap_b ^ 0xc] = AES_isbox[st->b[swap_b ^ AES_ISH_C]];
+
+    /* Otherwise, break cycles. */
+
+    t = AES_isbox[st->b[swap_b ^ AES_ISH_5]];
+    r->b[swap_b ^ 0x1] = AES_isbox[st->b[swap_b ^ AES_ISH_1]];
+    r->b[swap_b ^ 0xd] = AES_isbox[st->b[swap_b ^ AES_ISH_D]];
+    r->b[swap_b ^ 0x9] = AES_isbox[st->b[swap_b ^ AES_ISH_9]];
+    r->b[swap_b ^ 0x5] = t;
+
+    t = AES_isbox[st->b[swap_b ^ AES_ISH_A]];
+    r->b[swap_b ^ 0x2] = AES_isbox[st->b[swap_b ^ AES_ISH_2]];
+    r->b[swap_b ^ 0xa] = t;
+
+    t = AES_isbox[st->b[swap_b ^ AES_ISH_E]];
+    r->b[swap_b ^ 0x6] = AES_isbox[st->b[swap_b ^ AES_ISH_6]];
+    r->b[swap_b ^ 0xe] = t;
+
+    t = AES_isbox[st->b[swap_b ^ AES_ISH_F]];
+    r->b[swap_b ^ 0x3] = AES_isbox[st->b[swap_b ^ AES_ISH_3]];
+    r->b[swap_b ^ 0x7] = AES_isbox[st->b[swap_b ^ AES_ISH_7]];
+    r->b[swap_b ^ 0xb] = AES_isbox[st->b[swap_b ^ AES_ISH_B]];
+    r->b[swap_b ^ 0xf] = t;
+}
+
+void aesdec_ISB_ISR_gen(AESState *r, const AESState *st)
+{
+    aesdec_ISB_ISR_swap(r, st, false);
+}
+
+void aesdec_ISB_ISR_genrev(AESState *r, const AESState *st)
+{
+    aesdec_ISB_ISR_swap(r, st, true);
+}
+
 /**
  * Expand the cipher key into the encryption key schedule.
  */