From 0bc8e0bdfd6f3065e2d40e6955510e43930133ba 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 1e4659b6..65c3e793 100644
--- a/src/libsodium/crypto_scalarmult/curve25519/sandy2x/sandy2x.S
+++ b/src/libsodium/crypto_scalarmult/curve25519/sandy2x/sandy2x.S
@@ -9,6 +9,24 @@
 #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 a5289615..7bc0c119 100644
--- a/src/libsodium/crypto_stream/salsa20/xmm6/salsa20_xmm6-asm.S
+++ b/src/libsodium/crypto_stream/salsa20/xmm6/salsa20_xmm6-asm.S
@@ -958,5 +958,23 @@ 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