From f795e90a11c683d64bacc260fb7feab705b220b1 Mon Sep 17 00:00:00 2001 From: Andrew Turner Date: Tue, 3 Oct 2023 23:12:36 +0100 Subject: [PATCH] Add BTI landing pads to the AArch64 SHA2 assembly The Arm Branch Target Identification (BTI) extension guards against branching to an unintended instruction. To support BTI add the landing pad instructions to the SHA2 functions. These are from the hint space so are a nop on hardware that lacks BTI support or if BTI isn't enabled. Reviewed-by: Allan Jude Reviewed-by: Brian Behlendorf Reviewed-by: Tino Reichardt Signed-off-by: Andrew Turner Closes #14862 Closes #15339 --- module/icp/asm-aarch64/sha2/sha256-armv8.S | 3 +++ module/icp/asm-aarch64/sha2/sha512-armv8.S | 2 ++ 2 files changed, 5 insertions(+) diff --git a/module/icp/asm-aarch64/sha2/sha256-armv8.S b/module/icp/asm-aarch64/sha2/sha256-armv8.S index fa50c4e74d..7ae486e4e2 100644 --- a/module/icp/asm-aarch64/sha2/sha256-armv8.S +++ b/module/icp/asm-aarch64/sha2/sha256-armv8.S @@ -49,6 +49,7 @@ .type zfs_sha256_block_armv7,%function .align 6 zfs_sha256_block_armv7: + hint #34 // bti c stp x29,x30,[sp,#-128]! add x29,sp,#0 @@ -1015,6 +1016,7 @@ zfs_sha256_block_armv7: .type zfs_sha256_block_armv8,%function .align 6 zfs_sha256_block_armv8: + hint #34 // bti c .Lv8_entry: stp x29,x30,[sp,#-16]! add x29,sp,#0 @@ -1155,6 +1157,7 @@ zfs_sha256_block_armv8: .type zfs_sha256_block_neon,%function .align 4 zfs_sha256_block_neon: + hint #34 // bti c .Lneon_entry: stp x29, x30, [sp, #-16]! mov x29, sp diff --git a/module/icp/asm-aarch64/sha2/sha512-armv8.S b/module/icp/asm-aarch64/sha2/sha512-armv8.S index 1683fc1ca5..9c61eeee4d 100644 --- a/module/icp/asm-aarch64/sha2/sha512-armv8.S +++ b/module/icp/asm-aarch64/sha2/sha512-armv8.S @@ -73,6 +73,7 @@ .type zfs_sha512_block_armv7,%function .align 6 zfs_sha512_block_armv7: + hint #34 // bti c stp x29,x30,[sp,#-128]! add x29,sp,#0 @@ -1040,6 +1041,7 @@ zfs_sha512_block_armv7: .type zfs_sha512_block_armv8,%function .align 6 zfs_sha512_block_armv8: + hint #34 // bti c .Lv8_entry: // Armv8.3-A PAuth: even though x30 is pushed to stack it is not popped later stp x29,x30,[sp,#-16]!