From a2e806255fd9df10e263e939f8556eb4d0c8b958 Mon Sep 17 00:00:00 2001
From: Julian Arevalo <julian.arevalo@ledger.fr>
Date: Mon, 7 Oct 2024 18:06:44 +0200
Subject: [PATCH] cx_aes_siv: Add new function to reset AES hw copro

---
 include/cx_stubs.h             |  1 +
 lib_cxng/cx.export             |  1 +
 lib_cxng/include/lcx_aes_siv.h | 11 +++++++++++
 lib_cxng/src/cx_aes_siv.c      | 17 ++++++++++++++++-
 src/cx_stubs.S                 |  1 +
 5 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/include/cx_stubs.h b/include/cx_stubs.h
index b0d5a5e7e..40ec737dd 100644
--- a/include/cx_stubs.h
+++ b/include/cx_stubs.h
@@ -145,3 +145,4 @@
 #define _NR_cx_cmac_start                        0x8d
 #define _NR_cx_cmac_update                       0x8e
 #define _NR_cx_cmac_finish                       0x8f
+#define _NR_cx_aes_siv_reset                     0x90
diff --git a/lib_cxng/cx.export b/lib_cxng/cx.export
index 19d47e726..b935b75ff 100644
--- a/lib_cxng/cx.export
+++ b/lib_cxng/cx.export
@@ -148,3 +148,4 @@ cx_cipher_reset
 cx_cmac_start
 cx_cmac_update
 cx_cmac_finish
+cx_aes_siv_reset
diff --git a/lib_cxng/include/lcx_aes_siv.h b/lib_cxng/include/lcx_aes_siv.h
index 06905dc69..b4db323b2 100644
--- a/lib_cxng/include/lcx_aes_siv.h
+++ b/lib_cxng/include/lcx_aes_siv.h
@@ -55,6 +55,17 @@ typedef struct _cx_aes_siv_context {
  */
 WARN_UNUSED_RESULT cx_err_t cx_aes_siv_init(cx_aes_siv_context_t *ctx);
 
+/**
+ * @brief   Reset the AES-SIV context and HW used.
+ * @details The cipher context must be initialized beforehand.
+ *          This function must be called after calls to #cx_aes_siv_finish or
+ *          #cx_aes_siv_update.
+ *
+ * @param[in] ctx Pointer to the AES-SIV context.
+ * @return        Error code.
+ */
+WARN_UNUSED_RESULT cx_err_t cx_aes_siv_reset(cx_aes_siv_context_t *ctx);
+
 /**
  * @brief   Sets the key to compute AES-SIV.
  *
diff --git a/lib_cxng/src/cx_aes_siv.c b/lib_cxng/src/cx_aes_siv.c
index ed106d3dd..13d59e119 100644
--- a/lib_cxng/src/cx_aes_siv.c
+++ b/lib_cxng/src/cx_aes_siv.c
@@ -22,6 +22,19 @@ cx_err_t cx_aes_siv_init(cx_aes_siv_context_t *ctx)
     return error;
 }
 
+cx_err_t cx_aes_siv_reset(cx_aes_siv_context_t *ctx)
+{
+    cx_err_t error = CX_INVALID_PARAMETER_VALUE;
+    if (ctx->cipher_ctx == NULL) {
+        goto end;
+    }
+    CX_CHECK(ctx->cipher_ctx->cipher_info->base->ctx_reset());
+    cx_cipher_reset(ctx->cipher_ctx);
+
+end:
+    return error;
+}
+
 cx_err_t cx_aes_siv_set_key(cx_aes_siv_context_t *ctx, const uint8_t *key, size_t key_bitlen)
 {
     // AES SIV uses two keys of either 128, 192 or 256 bits each
@@ -161,6 +174,7 @@ cx_err_t cx_aes_siv_encrypt(cx_aes_siv_context_t *ctx,
     CX_CHECK(cx_aes_siv_finish(ctx, input, in_len, tag));
     CX_CHECK(cx_aes_siv_update(ctx, input, output, in_len));
 end:
+    error = cx_aes_siv_reset(ctx);
     return error;
 }
 
@@ -175,11 +189,12 @@ cx_err_t cx_aes_siv_decrypt(cx_aes_siv_context_t *ctx,
     cx_err_t error;
     CX_CHECK(cx_aes_siv_start(ctx, CX_DECRYPT, tag, CX_AES_BLOCK_SIZE));
     CX_CHECK(cx_aes_siv_update(ctx, input, output, in_len));
-    cx_cipher_reset(ctx->cipher_ctx);
+    CX_CHECK(cx_aes_siv_reset(ctx));
     CX_CHECK(cx_aes_siv_update_aad(ctx, aad, aad_len));
     CX_CHECK(cx_aes_siv_finish(ctx, output, in_len, tag));
 
 end:
+    error = cx_aes_siv_reset(ctx);
     return error;
 }
 
diff --git a/src/cx_stubs.S b/src/cx_stubs.S
index 49d1ade68..c4ab57a23 100644
--- a/src/cx_stubs.S
+++ b/src/cx_stubs.S
@@ -160,6 +160,7 @@ CX_TRAMPOLINE _NR_cx_cipher_reset                          cx_cipher_reset
 CX_TRAMPOLINE _NR_cx_cmac_start                            cx_cmac_start
 CX_TRAMPOLINE _NR_cx_cmac_update                           cx_cmac_update
 CX_TRAMPOLINE _NR_cx_cmac_finish                           cx_cmac_finish
+CX_TRAMPOLINE _NR_cx_aes_siv_reset                         cx_aes_siv_reset
 
 .thumb_func
 cx_trampoline_helper: