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Message-Id: <20200821194310.3089815-19-keescook@chromium.org>
Date: Fri, 21 Aug 2020 12:42:59 -0700
From: Kees Cook <keescook@...omium.org>
To: Ingo Molnar <mingo@...nel.org>
Cc: Kees Cook <keescook@...omium.org>,
Catalin Marinas <catalin.marinas@....com>,
Mark Rutland <mark.rutland@....com>,
Ard Biesheuvel <ardb@...nel.org>,
Peter Collingbourne <pcc@...gle.com>,
James Morse <james.morse@....com>,
Borislav Petkov <bp@...e.de>, Ingo Molnar <mingo@...hat.com>,
Russell King <linux@...linux.org.uk>,
Masahiro Yamada <masahiroy@...nel.org>,
Arvind Sankar <nivedita@...m.mit.edu>,
Nick Desaulniers <ndesaulniers@...gle.com>,
Nathan Chancellor <natechancellor@...il.com>,
Arnd Bergmann <arnd@...db.de>, x86@...nel.org,
clang-built-linux@...glegroups.com, linux-arch@...r.kernel.org,
linux-efi@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v6 18/29] arm/build: Assert for unwanted sections
In preparation for warning on orphan sections, enforce
expected-to-be-zero-sized sections (since discarding them might hide
problems with them suddenly gaining unexpected entries).
Signed-off-by: Kees Cook <keescook@...omium.org>
---
arch/arm/include/asm/vmlinux.lds.h | 11 +++++++++++
arch/arm/kernel/vmlinux-xip.lds.S | 2 ++
arch/arm/kernel/vmlinux.lds.S | 2 ++
3 files changed, 15 insertions(+)
diff --git a/arch/arm/include/asm/vmlinux.lds.h b/arch/arm/include/asm/vmlinux.lds.h
index 6624dd97475c..4a91428c324d 100644
--- a/arch/arm/include/asm/vmlinux.lds.h
+++ b/arch/arm/include/asm/vmlinux.lds.h
@@ -52,6 +52,17 @@
ARM_MMU_DISCARD(*(__ex_table)) \
COMMON_DISCARDS
+/*
+ * Sections that should stay zero sized, which is safer to explicitly
+ * check instead of blindly discarding.
+ */
+#define ARM_ASSERTS \
+ .plt : { \
+ *(.iplt) *(.rel.iplt) *(.iplt) *(.igot.plt) \
+ } \
+ ASSERT(SIZEOF(.plt) == 0, \
+ "Unexpected run-time procedure linkages detected!")
+
#define ARM_DETAILS \
ELF_DETAILS \
.ARM.attributes 0 : { *(.ARM.attributes) }
diff --git a/arch/arm/kernel/vmlinux-xip.lds.S b/arch/arm/kernel/vmlinux-xip.lds.S
index 11ffa79751da..50136828f5b5 100644
--- a/arch/arm/kernel/vmlinux-xip.lds.S
+++ b/arch/arm/kernel/vmlinux-xip.lds.S
@@ -152,6 +152,8 @@ SECTIONS
STABS_DEBUG
DWARF_DEBUG
ARM_DETAILS
+
+ ARM_ASSERTS
}
/*
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index dc672fe35de3..5f4922e858d0 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -151,6 +151,8 @@ SECTIONS
STABS_DEBUG
DWARF_DEBUG
ARM_DETAILS
+
+ ARM_ASSERTS
}
#ifdef CONFIG_STRICT_KERNEL_RWX
--
2.25.1
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