From: Kristen Carlson Accardi <kristen@linux.intel.com>
To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
hpa@zytor.com, arjan@linux.intel.com, keescook@chromium.org
Cc: rick.p.edgecombe@intel.com, x86@kernel.org,
linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com,
Kristen Carlson Accardi <kristen@linux.intel.com>
Subject: [RFC PATCH 06/11] x86: make sure _etext includes function sections
Date: Wed, 5 Feb 2020 14:39:45 -0800 [thread overview]
Message-ID: <20200205223950.1212394-7-kristen@linux.intel.com> (raw)
In-Reply-To: <20200205223950.1212394-1-kristen@linux.intel.com>
We will be using -ffunction-sections to place each function in
it's own text section so it can be randomized at load time. The
linker considers these .text.* sections "orphaned sections", and
will place them after the first similar section (.text). However,
we need to move _etext so that it is after both .text and .text.*
We also need to calculate text size to include .text AND .text.*
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
---
arch/x86/kernel/vmlinux.lds.S | 18 +++++++++++++++++-
include/asm-generic/vmlinux.lds.h | 2 +-
2 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 3a1a819da137..e54e9ac5b429 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -146,8 +146,24 @@ SECTIONS
#endif
} :text =0xcccc
- /* End of text section, which should occupy whole number of pages */
+#ifdef CONFIG_FG_KASLR
+ /*
+ * -ffunction-sections creates .text.* sections, which are considered
+ * "orphan sections" and added after the first similar section (.text).
+ * Adding this ALIGN statement causes the address of _etext
+ * to be below that of all the .text.* orphaned sections
+ */
+ . = ALIGN(PAGE_SIZE);
+#endif
_etext = .;
+
+ /*
+ * the size of the .text section is used to calculate the address
+ * range for orc lookups. If we just use SIZEOF(.text), we will
+ * miss all the .text.* sections. Calculate the size using _etext
+ * and _stext and save the value for later.
+ */
+ text_size = _etext - _stext;
. = ALIGN(PAGE_SIZE);
X86_ALIGN_RODATA_BEGIN
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index e00f41aa8ec4..edf19f4296e2 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -798,7 +798,7 @@
. = ALIGN(4); \
.orc_lookup : AT(ADDR(.orc_lookup) - LOAD_OFFSET) { \
orc_lookup = .; \
- . += (((SIZEOF(.text) + LOOKUP_BLOCK_SIZE - 1) / \
+ . += (((text_size + LOOKUP_BLOCK_SIZE - 1) / \
LOOKUP_BLOCK_SIZE) + 1) * 4; \
orc_lookup_end = .; \
}
--
2.24.1
next prev parent reply other threads:[~2020-02-05 22:39 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-05 22:39 [RFC PATCH 00/11] Finer grained kernel address space randomization Kristen Carlson Accardi
2020-02-05 22:39 ` [RFC PATCH 01/11] modpost: Support >64K sections Kristen Carlson Accardi
2020-02-06 12:38 ` Kees Cook
2020-02-05 22:39 ` [RFC PATCH 02/11] x86: tools/relocs: Support >64K section headers Kristen Carlson Accardi
2020-02-06 12:39 ` Kees Cook
2020-02-05 22:39 ` [RFC PATCH 03/11] x86/boot: Allow a "silent" kaslr random byte fetch Kristen Carlson Accardi
2020-02-06 1:08 ` Andy Lutomirski
2020-02-06 11:48 ` Kees Cook
2020-02-06 16:58 ` Kristen Carlson Accardi
2020-02-05 22:39 ` [RFC PATCH 04/11] x86/boot/KASLR: Introduce PRNG for faster shuffling Kristen Carlson Accardi
2020-02-06 1:11 ` Andy Lutomirski
2020-02-06 15:10 ` Jason A. Donenfeld
[not found] ` <CAGiyFdes26XnNeDfaz-vkm+bU7MBYQiK3xty2EigGjOXBGui2w@mail.gmail.com>
2020-02-07 9:05 ` Kees Cook
2020-02-07 16:52 ` Kristen Carlson Accardi
2020-02-05 22:39 ` [RFC PATCH 05/11] x86: Makefile: Add build and config option for CONFIG_FG_KASLR Kristen Carlson Accardi
2020-02-06 10:30 ` Peter Zijlstra
2020-02-06 11:52 ` Kees Cook
2020-02-25 17:55 ` Arvind Sankar
2020-02-26 19:13 ` Kristen Carlson Accardi
2020-03-24 21:24 ` Kristen Carlson Accardi
2020-03-25 15:34 ` Kees Cook
2020-02-05 22:39 ` Kristen Carlson Accardi [this message]
2020-02-06 12:26 ` [RFC PATCH 06/11] x86: make sure _etext includes function sections Kees Cook
2020-02-06 13:15 ` Jann Horn
2020-02-06 16:27 ` David Laight
2020-02-06 14:39 ` Arvind Sankar
2020-02-06 15:29 ` Arvind Sankar
2020-02-06 16:11 ` Andy Lutomirski
2020-02-06 14:57 ` Arvind Sankar
2020-02-06 15:45 ` Arvind Sankar
2020-02-06 19:41 ` Kristen Carlson Accardi
2020-02-06 20:02 ` Andy Lutomirski
2020-02-07 9:24 ` Peter Zijlstra
2020-02-10 1:43 ` Kees Cook
2020-02-10 10:51 ` Peter Zijlstra
2020-02-10 15:54 ` Arjan van de Ven
2020-02-10 16:36 ` Arvind Sankar
2020-02-21 19:50 ` Josh Poimboeuf
2020-02-21 23:05 ` Arvind Sankar
2020-02-05 22:39 ` [RFC PATCH 07/11] x86/tools: Adding relative relocs for randomized functions Kristen Carlson Accardi
2020-02-06 12:37 ` Kees Cook
2020-02-05 22:39 ` [RFC PATCH 08/11] x86: Add support for finer grained KASLR Kristen Carlson Accardi
2020-02-06 1:17 ` Andy Lutomirski
2020-02-06 11:56 ` Kees Cook
2020-02-06 17:36 ` Kristen Carlson Accardi
2020-02-06 10:38 ` Peter Zijlstra
2020-02-06 12:06 ` Kees Cook
2020-02-06 14:52 ` Peter Zijlstra
2020-02-06 17:25 ` Kristen Carlson Accardi
2020-02-06 17:35 ` Peter Zijlstra
2020-02-06 17:43 ` Kristen Carlson Accardi
2020-02-25 17:49 ` Arvind Sankar
2020-02-26 19:26 ` Kristen Carlson Accardi
2020-02-05 22:39 ` [RFC PATCH 09/11] kallsyms: hide layout and expose seed Kristen Carlson Accardi
2020-02-06 12:32 ` Kees Cook
2020-02-06 17:51 ` Kristen Carlson Accardi
2020-02-06 19:27 ` Jann Horn
2020-03-02 19:01 ` Kristen Carlson Accardi
2020-03-02 19:08 ` Kees Cook
2020-03-02 19:19 ` Kristen Carlson Accardi
2020-02-27 2:42 ` Baoquan He
2020-02-27 16:02 ` Kees Cook
2020-02-28 3:36 ` Baoquan He
2020-02-05 22:39 ` [RFC PATCH 10/11] module: Reorder functions Kristen Carlson Accardi
2020-02-06 12:41 ` Kees Cook
2020-02-11 12:39 ` Jessica Yu
2020-02-05 22:39 ` [RFC PATCH 11/11] x86/boot: Move "boot heap" out of .bss Kristen Carlson Accardi
2020-02-06 0:11 ` Arvind Sankar
2020-02-06 0:33 ` Kristen Carlson Accardi
2020-02-06 11:13 ` Kees Cook
2020-02-06 14:25 ` Arvind Sankar
2020-02-06 21:32 ` Kees Cook
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