From: James Morse <james.morse@arm.com>
Date: Wed, 17 Nov 2021 15:15:26 +0000
Subject: arm64: entry.S: Add ventry overflow sanity checks
Git-commit: 4330e2c5c04c27bebf89d34e0bc14e6943413067
Patch-mainline: v5.17 or v5.17-rc8 (next release)
References: bsc#1085308 CVE-2022-23960 CVE-2022-0001 CVE-2022-0002
Subsequent patches add even more code to the ventry slots.
Ensure kernels that overflow a ventry slot don't get built.
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>
---
arch/arm64/kernel/entry.S | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 772ec2ecf488..bd940b2254da 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -37,6 +37,7 @@
.macro kernel_ventry, el:req, ht:req, regsize:req, label:req
.align 7
+.Lventry_start\@:
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
.if \el == 0
alternative_if ARM64_UNMAP_KERNEL_AT_EL0
@@ -95,6 +96,7 @@ alternative_else_nop_endif
mrs x0, tpidrro_el0
#endif
b el\el\ht\()_\regsize\()_\label
+.org .Lventry_start\@ + 128 // Did we overflow the ventry slot?
.endm
.macro tramp_alias, dst, sym
@@ -662,6 +664,7 @@ alternative_else_nop_endif
add x30, x30, #(1b - tramp_vectors)
isb
ret
+.org 1b + 128 // Did we overflow the ventry slot?
.endm
.macro tramp_exit, regsize = 64
--
2.34.1