From: Ard Biesheuvel <ardb@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: Ard Biesheuvel <ardb@kernel.org>, Marc Zyngier <maz@kernel.org>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Kees Cook <keescook@chromium.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Mark Brown <broonie@kernel.org>
Subject: [PATCH 1/4] arm64: assembler: Force error on misuse of .Lframe_local_offset
Date: Tue, 29 Nov 2022 15:18:00 +0100 [thread overview]
Message-ID: <20221129141803.1746898-2-ardb@kernel.org> (raw)
In-Reply-To: <20221129141803.1746898-1-ardb@kernel.org>
The frame_push macro sets a local symbol .Lframe_local_offset to the
offset where the local variable area resides in the stack frame.
However, while we take care not to nest frame_push and frame_pop
sequences, .Lframe_local_offset retains its most recent value, allowing
it to be referenced erroneously from outside a frame_push/frame_pop
pair. So set it to an obviously wrong value that is guaranteed to
trigger a link error in frame_pop.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm64/include/asm/assembler.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 30eee6473cf0c0ea..3d1714a7eb6411ba 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -752,6 +752,7 @@ alternative_endif
.endif
ldp x29, x30, [sp], #.Lframe_local_offset + .Lframe_extra
.set .Lframe_regcount, -1
+ .set .Lframe_local_offset, frame_local_offset_error
.endif
.endm
--
2.35.1
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next prev parent reply other threads:[~2022-11-29 14:19 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-29 14:17 [PATCH 0/4] arm64: Add return address protection to asm code Ard Biesheuvel
2022-11-29 14:18 ` Ard Biesheuvel [this message]
2022-11-29 14:18 ` [PATCH 2/4] arm64: assembler: Add macros for return address protection Ard Biesheuvel
2022-11-30 14:15 ` Mark Rutland
2022-11-30 14:33 ` Ard Biesheuvel
2022-11-29 14:18 ` [PATCH 3/4] arm64: efi: Add return address protection to runtime wrapper Ard Biesheuvel
2022-11-29 14:18 ` [PATCH 4/4] arm64: ftrace: Add return address protection Ard Biesheuvel
2022-11-30 14:04 ` Mark Rutland
2022-11-30 14:26 ` Ard Biesheuvel
2022-11-30 17:45 ` Mark Rutland
2022-12-01 13:09 ` Ard Biesheuvel
2022-12-01 14:40 ` Mark Rutland
2022-12-01 15:05 ` Ard Biesheuvel
2022-12-01 15:48 ` Mark Rutland
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