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From: Baoquan He <bhe@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com,
	x86@kernel.org, keescook@chromium.org, vgoyal@redhat.com,
	whissi@whissi.de, Baoquan He <bhe@redhat.com>
Subject: [PATCH 2/6] a bug that relocation can not be handled when kernel is loaded above 2G
Date: Wed, 21 Jan 2015 11:37:13 +0800	[thread overview]
Message-ID: <1421811437-2787-3-git-send-email-bhe@redhat.com> (raw)
In-Reply-To: <1421811437-2787-1-git-send-email-bhe@redhat.com>

When process 32 bit relocation a local variable extended is defined
to calculate the physical address of relocs entry. However its data
type is int which is enough for i386, but not for x86_64. That's why
relocation can only be handled when kernel is loaded below 2G,
otherwise a overflow will happen and cause system hang.

Here change it to long as 32 bit inverse relocation processing does,
and this change is safe for i386 relocation handling.

Signed-off-by: Baoquan He <bhe@redhat.com>
---
 arch/x86/boot/compressed/misc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index dcc1c53..324ccb5 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -278,7 +278,7 @@ static void handle_relocations(void *output, unsigned long output_len)
 	 * So we work backwards from the end of the decompressed image.
 	 */
 	for (reloc = output + output_len - sizeof(*reloc); *reloc; reloc--) {
-		int extended = *reloc;
+		long extended = *reloc;
 		extended += map;
 
 		ptr = (unsigned long)extended;
-- 
1.9.3


  parent reply	other threads:[~2015-01-21  3:37 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-21  3:37 [PATCH 0/6] randomize kernel physical address and virtual address separately Baoquan He
2015-01-21  3:37 ` [PATCH 1/6] remove a unused function parameter Baoquan He
2015-01-21  3:37 ` Baoquan He [this message]
2015-01-21  3:37 ` [PATCH 3/6] Introduce a function to randomize the kernel text mapping address Baoquan He
2015-01-21  3:37 ` [PATCH 4/6] adapt choose_kernel_location to add the kernel virtual address randomzation Baoquan He
2015-01-21  3:37 ` [PATCH 5/6] change the relocations behavior for kaslr on x86_64 Baoquan He
2015-01-21  3:37 ` [PATCH 6/6] extend the upper limit of kernel physical address randomization to 4G Baoquan He
2015-01-21  4:19 ` [PATCH 0/6] randomize kernel physical address and virtual address separately Andy Lutomirski
2015-01-21  4:46   ` Baoquan He
2015-02-01  8:10   ` Baoquan He
2015-02-01 13:13     ` Andy Lutomirski
2015-02-02  9:34       ` Baoquan He
2015-02-02 12:10       ` Baoquan He
2015-01-21  6:18 ` Kees Cook
2015-02-02 16:42 ` H. Peter Anvin
2015-02-03 15:30   ` Baoquan He

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