From 5fe02c89a7dc1d0ba78f69717d78de304b4a2021 Mon Sep 17 00:00:00 2001
From: Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
Date: Tue, 18 Jul 2023 11:56:18 -0400
Subject: [PATCH] Build correctly with IBT and Shadow Stack (#1289)

Add .gnu.property notes to indicate support for IBT and shadow stacks
when libsodium is built with it.  There's no stack switching code in
here, so this should not need any other codegen changes.
---
 .../curve25519/sandy2x/sandy2x.S               | 18 ++++++++++++++++++
 .../salsa20/xmm6/salsa20_xmm6-asm.S            | 18 ++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/src/libsodium/crypto_scalarmult/curve25519/sandy2x/sandy2x.S b/src/libsodium/crypto_scalarmult/curve25519/sandy2x/sandy2x.S
index 585804fb..eb4fe671 100644
--- a/src/libsodium/crypto_scalarmult/curve25519/sandy2x/sandy2x.S
+++ b/src/libsodium/crypto_scalarmult/curve25519/sandy2x/sandy2x.S
@@ -10,6 +10,24 @@
 #include "ladder.S"
 
 #if defined(__linux__) && defined(__ELF__)
+#if defined(__CET__)
+.section	.note.gnu.property,"a"
+.p2align 3
+.long	1f - 0f
+.long	4f - 1f
+.long	5
+0:
+.string	"GNU"
+1:
+.p2align 3
+.long	0xc0000002
+.long	3f - 2f
+2:
+.long	__CET__
+3:
+.p2align 3
+4:
+#endif
 .section .note.GNU-stack,"",%progbits
 #endif
 
diff --git a/src/libsodium/crypto_stream/salsa20/xmm6/salsa20_xmm6-asm.S b/src/libsodium/crypto_stream/salsa20/xmm6/salsa20_xmm6-asm.S
index 6d9f354e..b53a4f4a 100644
--- a/src/libsodium/crypto_stream/salsa20/xmm6/salsa20_xmm6-asm.S
+++ b/src/libsodium/crypto_stream/salsa20/xmm6/salsa20_xmm6-asm.S
@@ -956,5 +956,23 @@ jmp ._bytesbetween1and255
 #endif
 
 #if defined(__linux__) && defined(__ELF__)
+#if defined(__CET__)
+.section	.note.gnu.property,"a"
+.p2align 3
+.long	1f - 0f
+.long	4f - 1f
+.long	5
+0:
+.string	"GNU"
+1:
+.p2align 3
+.long	0xc0000002
+.long	3f - 2f
+2:
+.long	__CET__
+3:
+.p2align 3
+4:
+#endif
 .section .note.GNU-stack,"",%progbits
 #endif