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: f569ca164751 ("crypto: arm64/poly1305 - incorporate OpenSSL/CRYPTOGAMS ...")
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
---
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 6e5576d19af8..cbc980fb02e3 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 8d1c4e420ccd..fb2822abf63a 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
--
2.17.1
