This is a note to let you know that I've just added the patch titled
x86, efi: Fix endian issues and unaligned accesses
to the 3.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-efi-fix-endian-issues-and-unaligned-accesses.patch
and it can be found in the queue-3.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 92f42c50f227ad228f815a8f4eec872524dae3a5 Mon Sep 17 00:00:00 2001
From: Matt Fleming <[email protected]>
Date: Tue, 28 Feb 2012 13:37:24 +0000
Subject: x86, efi: Fix endian issues and unaligned accesses
From: Matt Fleming <[email protected]>
commit 92f42c50f227ad228f815a8f4eec872524dae3a5 upstream.
We may need to convert the endianness of the data we read from/write
to 'buf', so let's use {get,put}_unaligned_le32() to do that. Failure
to do so can result in accessing invalid memory, leading to a
segfault. Stephen Rothwell noticed this bug while cross-building an
x86_64 allmodconfig kernel on PowerPC.
We need to read from and write to 'buf' a byte at a time otherwise
it's possible we'll perform an unaligned access, which can lead to bus
errors when cross-building an x86 kernel on risc architectures.
Cc: H. Peter Anvin <[email protected]>
Cc: Nick Bowler <[email protected]>
Tested-by: Stephen Rothwell <[email protected]>
Reported-by: Stephen Rothwell <[email protected]>
Signed-off-by: Matt Fleming <[email protected]>
Link:
http://lkml.kernel.org/r/[email protected]
Signed-off-by: H. Peter Anvin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/boot/tools/build.c | 31 +++++++++++++++----------------
1 file changed, 15 insertions(+), 16 deletions(-)
--- a/arch/x86/boot/tools/build.c
+++ b/arch/x86/boot/tools/build.c
@@ -34,6 +34,7 @@
#include <fcntl.h>
#include <sys/mman.h>
#include <asm/boot.h>
+#include <tools/le_byteshift.h>
typedef unsigned char u8;
typedef unsigned short u16;
@@ -41,6 +42,7 @@ typedef unsigned long u32;
#define DEFAULT_MAJOR_ROOT 0
#define DEFAULT_MINOR_ROOT 0
+#define DEFAULT_ROOT_DEV (DEFAULT_MAJOR_ROOT << 8 | DEFAULT_MINOR_ROOT)
/* Minimal number of setup sectors */
#define SETUP_SECT_MIN 5
@@ -159,7 +161,7 @@ int main(int argc, char ** argv)
die("read-error on `setup'");
if (c < 1024)
die("The setup must be at least 1024 bytes");
- if (buf[510] != 0x55 || buf[511] != 0xaa)
+ if (get_unaligned_le16(&buf[510]) != 0xAA55)
die("Boot block hasn't got boot flag (0xAA55)");
fclose(file);
@@ -171,8 +173,7 @@ int main(int argc, char ** argv)
memset(buf+c, 0, i-c);
/* Set the default root device */
- buf[508] = DEFAULT_MINOR_ROOT;
- buf[509] = DEFAULT_MAJOR_ROOT;
+ put_unaligned_le16(DEFAULT_ROOT_DEV, &buf[508]);
fprintf(stderr, "Setup is %d bytes (padded to %d bytes).\n", c, i);
@@ -192,44 +193,42 @@ int main(int argc, char ** argv)
/* Patch the setup code with the appropriate size parameters */
buf[0x1f1] = setup_sectors-1;
- buf[0x1f4] = sys_size;
- buf[0x1f5] = sys_size >> 8;
- buf[0x1f6] = sys_size >> 16;
- buf[0x1f7] = sys_size >> 24;
+ put_unaligned_le32(sys_size, &buf[0x1f4]);
#ifdef CONFIG_EFI_STUB
file_sz = sz + i + ((sys_size * 16) - sz);
- pe_header = *(unsigned int *)&buf[0x3c];
+ pe_header = get_unaligned_le32(&buf[0x3c]);
/* Size of code */
- *(unsigned int *)&buf[pe_header + 0x1c] = file_sz;
+ put_unaligned_le32(file_sz, &buf[pe_header + 0x1c]);
/* Size of image */
- *(unsigned int *)&buf[pe_header + 0x50] = file_sz;
+ put_unaligned_le32(file_sz, &buf[pe_header + 0x50]);
#ifdef CONFIG_X86_32
/* Address of entry point */
- *(unsigned int *)&buf[pe_header + 0x28] = i;
+ put_unaligned_le32(i, &buf[pe_header + 0x28]);
/* .text size */
- *(unsigned int *)&buf[pe_header + 0xb0] = file_sz;
+ put_unaligned_le32(file_sz, &buf[pe_header + 0xb0]);
/* .text size of initialised data */
- *(unsigned int *)&buf[pe_header + 0xb8] = file_sz;
+ put_unaligned_le32(file_sz, &buf[pe_header + 0xb8]);
#else
/*
* Address of entry point. startup_32 is at the beginning and
* the 64-bit entry point (startup_64) is always 512 bytes
* after.
*/
- *(unsigned int *)&buf[pe_header + 0x28] = i + 512;
+ put_unaligned_le32(i + 512, &buf[pe_header + 0x28]);
/* .text size */
- *(unsigned int *)&buf[pe_header + 0xc0] = file_sz;
+ put_unaligned_le32(file_sz, &buf[pe_header + 0xc0]);
/* .text size of initialised data */
- *(unsigned int *)&buf[pe_header + 0xc8] = file_sz;
+ put_unaligned_le32(file_sz, &buf[pe_header + 0xc8]);
+
#endif /* CONFIG_X86_32 */
#endif /* CONFIG_EFI_STUB */
Patches currently in stable-queue which might be from [email protected] are
queue-3.3/x86-boot-restrict-cflags-for-hostprogs.patch
queue-3.3/x86-efi-fix-endian-issues-and-unaligned-accesses.patch
queue-3.3/x86-efi-fix-pointer-math-issue-in-handle_ramdisks.patch
queue-3.3/tools-include-add-byteshift-headers-for-endian-access.patch
queue-3.3/x86-mkpiggy-don-t-open-code-put_unaligned_le32.patch
queue-3.3/x86-boot-correct-cflags-for-hostprogs.patch
queue-3.3/x86-efi-add-dedicated-efi-stub-entry-point.patch
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