linux-kernel - [PATCH 6/7] x86, kaslr: report kernel offset on panic

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1380656245-29975-7-git-send-email-keescook@chromium.org>
Date:	Tue,  1 Oct 2013 12:37:24 -0700
From:	Kees Cook <keescook@...omium.org>
To:	linux-kernel@...r.kernel.org
Cc:	x86@...nel.org, kernel-hardening@...ts.openwall.com,
	adurbin@...gle.com, Eric Northup <digitaleric@...gle.com>,
	jln@...gle.com, wad@...gle.com,
	Mathias Krause <minipli@...glemail.com>,
	Zhang Yanfei <zhangyanfei@...fujitsu.com>,
	"H. Peter Anvin" <hpa@...or.com>, keescook@...omium.org
Subject: [PATCH 6/7] x86, kaslr: report kernel offset on panic

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

Signed-off-by: Kees Cook <keescook@...omium.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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/