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From: Thomas Garnier <thgarnie@chromium.org>
To: kernel-hardening@lists.openwall.com
Cc: kristen@linux.intel.com, Thomas Garnier <thgarnie@chromium.org>,
	Arnd Bergmann <arnd@arndb.de>,
	linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v6 24/27] x86/mm: Make the x86 GOT read-only
Date: Thu, 31 Jan 2019 11:24:31 -0800	[thread overview]
Message-ID: <20190131192533.34130-25-thgarnie@chromium.org> (raw)
In-Reply-To: <20190131192533.34130-1-thgarnie@chromium.org>

The GOT is changed during early boot when relocations are applied. Make
it read-only directly. This table exists only for PIE binary.

Position Independent Executable (PIE) support will allow to extend the
KASLR randomization range below 0xffffffff80000000.

Signed-off-by: Thomas Garnier <thgarnie@chromium.org>
---
 include/asm-generic/vmlinux.lds.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 3d7a6a9c2370..0a038594c878 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -323,6 +323,17 @@
 	__end_ro_after_init = .;
 #endif
 
+#ifdef CONFIG_X86_PIE
+#define RO_GOT_X86							\
+	.got        : AT(ADDR(.got) - LOAD_OFFSET) {			\
+		__start_got = .;					\
+		*(.got);						\
+		__end_got = .;						\
+	}
+#else
+#define RO_GOT_X86
+#endif
+
 /*
  * Read only Data
  */
@@ -379,6 +390,7 @@
 		__end_builtin_fw = .;					\
 	}								\
 									\
+	RO_GOT_X86							\
 	TRACEDATA							\
 									\
 	/* Kernel symbol table: Normal symbols */			\
-- 
2.20.1.495.gaa96b0ce6b-goog

  parent reply	other threads:[~2019-01-31 19:24 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-31 19:24 [PATCH v6 00/27] x86: PIE support and option to extend KASLR randomization Thomas Garnier
2019-01-31 19:24 ` [PATCH v6 15/27] compiler: Option to default to hidden symbols Thomas Garnier
2019-01-31 19:24   ` Thomas Garnier
2019-02-01  7:12   ` Dan Carpenter
2019-02-01  7:12     ` Dan Carpenter
2019-02-01 17:00     ` Thomas Garnier
2019-02-01 17:00       ` Thomas Garnier
2019-02-01  8:22   ` Adrian Hunter
2019-02-01  8:22     ` Adrian Hunter
2019-02-01 17:35     ` Thomas Garnier
2019-02-01 17:35       ` Thomas Garnier
2019-01-31 19:24 ` Thomas Garnier [this message]
2019-01-31 19:24   ` [PATCH v6 24/27] x86/mm: Make the x86 GOT read-only Thomas Garnier
2019-01-31 19:59 ` [PATCH v6 00/27] x86: PIE support and option to extend KASLR randomization Kees Cook
2019-01-31 21:40 ` Konrad Rzeszutek Wilk
2019-01-31 22:42   ` Thomas Garnier

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