From 4f931136085e8dd42029e70e66816e638ee9db75 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Tue, 27 Oct 2020 00:00:27 +0100 Subject: [PATCH] crypto: arm64/poly1305-neon - reorder PAC authentication with SP update PAC pointer authentication signs the return address against the value of the stack pointer, to prevent stack overrun exploits from corrupting the control flow. However, this requires that the AUTIASP is issued with SP holding the same value as it held when the PAC value was generated. The Poly1305 NEON code got this wrong, resulting in crashes on PAC capable hardware. Fixes: ab79b01b5b21 ("crypto: arm64/poly1305 - incorporate OpenSSL/CRYPTOGAMS ...") Signed-off-by: Ard Biesheuvel Signed-off-by: Herbert Xu --- arch/arm64/crypto/poly1305-armv8.pl | 2 +- arch/arm64/crypto/poly1305-core.S_shipped | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/crypto/poly1305-armv8.pl b/arch/arm64/crypto/poly1305-armv8.pl index 6e5576d19af8f..cbc980fb02e33 100644 --- a/arch/arm64/crypto/poly1305-armv8.pl +++ b/arch/arm64/crypto/poly1305-armv8.pl @@ -840,7 +840,6 @@ poly1305_blocks_neon: ldp d14,d15,[sp,#64] addp $ACC2,$ACC2,$ACC2 ldr x30,[sp,#8] - .inst 0xd50323bf // autiasp //////////////////////////////////////////////////////////////// // lazy reduction, but without narrowing @@ -882,6 +881,7 @@ poly1305_blocks_neon: str x4,[$ctx,#8] // set is_base2_26 ldr x29,[sp],#80 + .inst 0xd50323bf // autiasp ret .size poly1305_blocks_neon,.-poly1305_blocks_neon diff --git a/arch/arm64/crypto/poly1305-core.S_shipped b/arch/arm64/crypto/poly1305-core.S_shipped index 8d1c4e420ccdc..fb2822abf63aa 100644 --- a/arch/arm64/crypto/poly1305-core.S_shipped +++ b/arch/arm64/crypto/poly1305-core.S_shipped @@ -779,7 +779,6 @@ poly1305_blocks_neon: ldp d14,d15,[sp,#64] addp v21.2d,v21.2d,v21.2d ldr x30,[sp,#8] - .inst 0xd50323bf // autiasp //////////////////////////////////////////////////////////////// // lazy reduction, but without narrowing @@ -821,6 +820,7 @@ poly1305_blocks_neon: str x4,[x0,#8] // set is_base2_26 ldr x29,[sp],#80 + .inst 0xd50323bf // autiasp ret .size poly1305_blocks_neon,.-poly1305_blocks_neon -- 2.39.5