From: Tommi Hirvola <tommi@hirvola.fi>
Date: Tue, 19 Feb 2019 15:45:54 +0000 (+0200)
Subject: crypto: x86/poly1305 - Clear key material from stack in SSE2 variant
X-Git-Tag: v5.1-rc1~177^2~7
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7748168c66404a3ee732972a3a55b5332245eb25;p=thirdparty%2Fkernel%2Flinux.git

crypto: x86/poly1305 - Clear key material from stack in SSE2 variant

1-block SSE2 variant of poly1305 stores variables s1..s4 containing key
material on the stack. This commit adds missing zeroing of the stack
memory. Benchmarks show negligible performance hit (tested on i7-3770).

Signed-off-by: Tommi Hirvola <tommi@hirvola.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

diff --git a/arch/x86/crypto/poly1305-sse2-x86_64.S b/arch/x86/crypto/poly1305-sse2-x86_64.S
index c88c670cb5fc6..e6add74d78a59 100644
--- a/arch/x86/crypto/poly1305-sse2-x86_64.S
+++ b/arch/x86/crypto/poly1305-sse2-x86_64.S
@@ -272,6 +272,10 @@ ENTRY(poly1305_block_sse2)
 	dec		%rcx
 	jnz		.Ldoblock
 
+	# Zeroing of key material
+	mov		%rcx,0x00(%rsp)
+	mov		%rcx,0x08(%rsp)
+
 	add		$0x10,%rsp
 	pop		%r12
 	pop		%rbx