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From: Kees Cook <keescook@chromium.org>
To: linux-kernel@vger.kernel.org
Cc: x86@kernel.org, kernel-hardening@lists.openwall.com,
	adurbin@google.com, Eric Northup <digitaleric@google.com>,
	jln@google.com, wad@google.com,
	Mathias Krause <minipli@googlemail.com>,
	Zhang Yanfei <zhangyanfei@cn.fujitsu.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	keescook@chromium.org
Subject: [PATCH v8 5/6] x86, kaslr: report kernel offset on panic
Date: Thu, 10 Oct 2013 17:18:17 -0700	[thread overview]
Message-ID: <1381450698-28710-6-git-send-email-keescook@chromium.org> (raw)
In-Reply-To: <1381450698-28710-1-git-send-email-keescook@chromium.org>

When the system panics, include the kernel offset in the report to assist
in debugging.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/x86/kernel/setup.c |   26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index f0de629..1708862 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -824,6 +824,20 @@ static void __init trim_low_memory_range(void)
 }
 	
 /*
+ * Dump out kernel offset information on panic.
+ */
+static int
+dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
+{
+	pr_emerg("Kernel Offset: 0x%lx from 0x%lx "
+		 "(relocation range: 0x%lx-0x%lx)\n",
+		 (unsigned long)&_text - __START_KERNEL, __START_KERNEL,
+		 __START_KERNEL_map, MODULES_VADDR-1);
+
+	return 0;
+}
+
+/*
  * Determine if we were loaded by an EFI loader.  If so, then we have also been
  * passed the efi memmap, systab, etc., so we should use these data structures
  * for initialization.  Note, the efi init code path is determined by the
@@ -1242,3 +1256,15 @@ void __init i386_reserve_resources(void)
 }
 
 #endif /* CONFIG_X86_32 */
+
+static struct notifier_block kernel_offset_notifier = {
+	.notifier_call = dump_kernel_offset
+};
+
+static int __init register_kernel_offset_dumper(void)
+{
+	atomic_notifier_chain_register(&panic_notifier_list,
+					&kernel_offset_notifier);
+	return 0;
+}
+__initcall(register_kernel_offset_dumper);
-- 
1.7.9.5


WARNING: multiple messages have this Message-ID (diff)
From: Kees Cook <keescook@chromium.org>
To: linux-kernel@vger.kernel.org
Cc: x86@kernel.org, kernel-hardening@lists.openwall.com,
	adurbin@google.com, Eric Northup <digitaleric@google.com>,
	jln@google.com, wad@google.com,
	Mathias Krause <minipli@googlemail.com>,
	Zhang Yanfei <zhangyanfei@cn.fujitsu.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	keescook@chromium.org
Subject: [kernel-hardening] [PATCH v8 5/6] x86, kaslr: report kernel offset on panic
Date: Thu, 10 Oct 2013 17:18:17 -0700	[thread overview]
Message-ID: <1381450698-28710-6-git-send-email-keescook@chromium.org> (raw)
In-Reply-To: <1381450698-28710-1-git-send-email-keescook@chromium.org>

When the system panics, include the kernel offset in the report to assist
in debugging.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/x86/kernel/setup.c |   26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index f0de629..1708862 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -824,6 +824,20 @@ static void __init trim_low_memory_range(void)
 }
 	
 /*
+ * Dump out kernel offset information on panic.
+ */
+static int
+dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
+{
+	pr_emerg("Kernel Offset: 0x%lx from 0x%lx "
+		 "(relocation range: 0x%lx-0x%lx)\n",
+		 (unsigned long)&_text - __START_KERNEL, __START_KERNEL,
+		 __START_KERNEL_map, MODULES_VADDR-1);
+
+	return 0;
+}
+
+/*
  * Determine if we were loaded by an EFI loader.  If so, then we have also been
  * passed the efi memmap, systab, etc., so we should use these data structures
  * for initialization.  Note, the efi init code path is determined by the
@@ -1242,3 +1256,15 @@ void __init i386_reserve_resources(void)
 }
 
 #endif /* CONFIG_X86_32 */
+
+static struct notifier_block kernel_offset_notifier = {
+	.notifier_call = dump_kernel_offset
+};
+
+static int __init register_kernel_offset_dumper(void)
+{
+	atomic_notifier_chain_register(&panic_notifier_list,
+					&kernel_offset_notifier);
+	return 0;
+}
+__initcall(register_kernel_offset_dumper);
-- 
1.7.9.5

  parent reply	other threads:[~2013-10-11  0:18 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-11  0:18 [PATCH v8 0/6] Kernel base address randomization Kees Cook
2013-10-11  0:18 ` [kernel-hardening] " Kees Cook
2013-10-11  0:18 ` [PATCH v8 1/6] x86, boot: move CPU flags out of cpucheck Kees Cook
2013-10-11  0:18   ` [kernel-hardening] " Kees Cook
2013-10-13 12:01   ` [tip:x86/kaslr] x86, boot: Move " tip-bot for Kees Cook
2013-10-13 12:02   ` [tip:x86/kaslr] x86, boot: Rename get_flags() and check_flags() to *_cpuflags() tip-bot for H. Peter Anvin
2013-10-11  0:18 ` [PATCH v8 2/6] x86, kaslr: return location from decompress_kernel Kees Cook
2013-10-11  0:18   ` [kernel-hardening] " Kees Cook
2013-10-13 12:01   ` [tip:x86/kaslr] x86, kaslr: Return " tip-bot for Kees Cook
2013-10-11  0:18 ` [PATCH v8 3/6] x86, kaslr: provide randomness functions Kees Cook
2013-10-11  0:18   ` [kernel-hardening] " Kees Cook
2013-10-13 12:01   ` [tip:x86/kaslr] x86, kaslr: Provide " tip-bot for Kees Cook
2013-11-11 18:20     ` Ingo Molnar
2013-11-11 18:31       ` Ingo Molnar
2013-11-11 19:32         ` Kees Cook
2013-11-11 19:37           ` H. Peter Anvin
2013-11-11 20:07             ` Ingo Molnar
2013-11-11 20:11               ` Kees Cook
2013-11-11 20:16                 ` H. Peter Anvin
2013-11-11 19:27       ` H. Peter Anvin
2013-11-11 19:37         ` Kees Cook
2013-11-11 19:42           ` H. Peter Anvin
2013-11-11 19:58             ` Ingo Molnar
2013-11-11 20:04               ` H. Peter Anvin
2013-11-11 20:09                 ` Ingo Molnar
2013-11-13 18:16       ` Pavel Machek
2013-11-13 18:40         ` H. Peter Anvin
2013-11-13 23:23           ` Pavel Machek
2013-11-13 23:25             ` H. Peter Anvin
2013-10-11  0:18 ` [PATCH v8 4/6] x86, kaslr: select random position from e820 maps Kees Cook
2013-10-11  0:18   ` [kernel-hardening] " Kees Cook
2013-10-13 12:01   ` [tip:x86/kaslr] x86, kaslr: Select " tip-bot for Kees Cook
2013-10-11  0:18 ` Kees Cook [this message]
2013-10-11  0:18   ` [kernel-hardening] [PATCH v8 5/6] x86, kaslr: report kernel offset on panic Kees Cook
2013-10-13 12:01   ` [tip:x86/kaslr] x86, kaslr: Report " tip-bot for Kees Cook
2013-10-11  0:18 ` [PATCH v8 6/6] x86, kaslr: raise max positions to 1GiB on x86_64 Kees Cook
2013-10-11  0:18   ` [kernel-hardening] " Kees Cook
2013-10-13 12:02   ` [tip:x86/kaslr] x86, kaslr: Raise the maximum virtual address to -1 GiB " tip-bot for Kees Cook

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