[3.13.y.z extended stable] Patch "x86/efi: Include a .bss section within the PE/COFF headers" has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Wed Aug 6 20:54:40 UTC 2014
This is a note to let you know that I have just added a patch titled
x86/efi: Include a .bss section within the PE/COFF headers
to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue
This patch is scheduled to be released in version 3.13.11.6.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
------
>From 6e737129fc1e4a92668ee01c22e13bb622ce77c2 Mon Sep 17 00:00:00 2001
From: Michael Brown <mbrown at fensystems.co.uk>
Date: Thu, 10 Jul 2014 12:26:20 +0100
Subject: x86/efi: Include a .bss section within the PE/COFF headers
MIME-Version: 1.0
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commit c7fb93ec51d462ec3540a729ba446663c26a0505 upstream.
The PE/COFF headers currently describe only the initialised-data
portions of the image, and result in no space being allocated for the
uninitialised-data portions. Consequently, the EFI boot stub will end
up overwriting unexpected areas of memory, with unpredictable results.
Fix by including a .bss section in the PE/COFF headers (functionally
equivalent to the init_size field in the bzImage header).
Signed-off-by: Michael Brown <mbrown at fensystems.co.uk>
Cc: Thomas Bächler <thomas at archlinux.org>
Cc: Josh Boyer <jwboyer at fedoraproject.org>
Signed-off-by: Matt Fleming <matt.fleming at intel.com>
[ luis: backported to 3.11: used Michael's backport ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
arch/x86/boot/header.S | 26 ++++++++++++++++++++++----
arch/x86/boot/tools/build.c | 37 ++++++++++++++++++++++++++++++-------
2 files changed, 52 insertions(+), 11 deletions(-)
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 9ec06a1..4257124 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -91,10 +91,9 @@ bs_die:
.section ".bsdata", "a"
bugger_off_msg:
- .ascii "Direct floppy boot is not supported. "
- .ascii "Use a boot loader program instead.\r\n"
+ .ascii "Use a boot loader.\r\n"
.ascii "\n"
- .ascii "Remove disk and press any key to reboot ...\r\n"
+ .ascii "Remove disk and press any key to reboot...\r\n"
.byte 0
#ifdef CONFIG_EFI_STUB
@@ -108,7 +107,7 @@ coff_header:
#else
.word 0x8664 # x86-64
#endif
- .word 3 # nr_sections
+ .word 4 # nr_sections
.long 0 # TimeDateStamp
.long 0 # PointerToSymbolTable
.long 1 # NumberOfSymbols
@@ -250,6 +249,25 @@ section_table:
.word 0 # NumberOfLineNumbers
.long 0x60500020 # Characteristics (section flags)
+ #
+ # The offset & size fields are filled in by build.c.
+ #
+ .ascii ".bss"
+ .byte 0
+ .byte 0
+ .byte 0
+ .byte 0
+ .long 0
+ .long 0x0
+ .long 0 # Size of initialized data
+ # on disk
+ .long 0x0
+ .long 0 # PointerToRelocations
+ .long 0 # PointerToLineNumbers
+ .word 0 # NumberOfRelocations
+ .word 0 # NumberOfLineNumbers
+ .long 0xc8000080 # Characteristics (section flags)
+
#endif /* CONFIG_EFI_STUB */
# Kernel attributes; used by setup. This is part 1 of the
diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c
index 8e15b22..3dafaeb 100644
--- a/arch/x86/boot/tools/build.c
+++ b/arch/x86/boot/tools/build.c
@@ -142,7 +142,7 @@ static void usage(void)
#ifdef CONFIG_EFI_STUB
-static void update_pecoff_section_header(char *section_name, u32 offset, u32 size)
+static void update_pecoff_section_header_fields(char *section_name, u32 vma, u32 size, u32 datasz, u32 offset)
{
unsigned int pe_header;
unsigned short num_sections;
@@ -163,10 +163,10 @@ static void update_pecoff_section_header(char *section_name, u32 offset, u32 siz
put_unaligned_le32(size, section + 0x8);
/* section header vma field */
- put_unaligned_le32(offset, section + 0xc);
+ put_unaligned_le32(vma, section + 0xc);
/* section header 'size of initialised data' field */
- put_unaligned_le32(size, section + 0x10);
+ put_unaligned_le32(datasz, section + 0x10);
/* section header 'file offset' field */
put_unaligned_le32(offset, section + 0x14);
@@ -178,6 +178,11 @@ static void update_pecoff_section_header(char *section_name, u32 offset, u32 siz
}
}
+static void update_pecoff_section_header(char *section_name, u32 offset, u32 size)
+{
+ update_pecoff_section_header_fields(section_name, offset, size, size, offset);
+}
+
static void update_pecoff_setup_and_reloc(unsigned int size)
{
u32 setup_offset = 0x200;
@@ -202,9 +207,6 @@ static void update_pecoff_text(unsigned int text_start, unsigned int file_sz)
pe_header = get_unaligned_le32(&buf[0x3c]);
- /* Size of image */
- put_unaligned_le32(file_sz, &buf[pe_header + 0x50]);
-
/*
* Size of code: Subtract the size of the first sector (512 bytes)
* which includes the header.
@@ -219,6 +221,22 @@ static void update_pecoff_text(unsigned int text_start, unsigned int file_sz)
update_pecoff_section_header(".text", text_start, text_sz);
}
+static void update_pecoff_bss(unsigned int file_sz, unsigned int init_sz)
+{
+ unsigned int pe_header;
+ unsigned int bss_sz = init_sz - file_sz;
+
+ pe_header = get_unaligned_le32(&buf[0x3c]);
+
+ /* Size of uninitialized data */
+ put_unaligned_le32(bss_sz, &buf[pe_header + 0x24]);
+
+ /* Size of image */
+ put_unaligned_le32(init_sz, &buf[pe_header + 0x50]);
+
+ update_pecoff_section_header_fields(".bss", file_sz, bss_sz, 0, 0);
+}
+
#endif /* CONFIG_EFI_STUB */
@@ -270,6 +288,9 @@ int main(int argc, char ** argv)
int fd;
void *kernel;
u32 crc = 0xffffffffUL;
+#ifdef CONFIG_EFI_STUB
+ unsigned int init_sz;
+#endif
/* Defaults for old kernel */
#ifdef CONFIG_X86_32
@@ -343,7 +364,9 @@ int main(int argc, char ** argv)
put_unaligned_le32(sys_size, &buf[0x1f4]);
#ifdef CONFIG_EFI_STUB
- update_pecoff_text(setup_sectors * 512, sz + i + ((sys_size * 16) - sz));
+ update_pecoff_text(setup_sectors * 512, i + (sys_size * 16));
+ init_sz = get_unaligned_le32(&buf[0x260]);
+ update_pecoff_bss(i + (sys_size * 16), init_sz);
#ifdef CONFIG_X86_64 /* Yes, this is really how we defined it :( */
efi_stub_entry -= 0x200;
--
1.9.1
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