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MIPS: boot/compressed: Use array reference for image bounds

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As done with other image addresses in other architectures, use an
explicit flexible array instead of "address of char", which can trip
bounds checking done by the compiler. Found when building with
-Warray-bounds:

In file included from ./include/linux/byteorder/little_endian.h:5,
                 from ./arch/mips/include/uapi/asm/byteorder.h:15,
                 from ./arch/mips/include/asm/bitops.h:21,
                 from ./include/linux/bitops.h:33,
                 from ./include/linux/kernel.h:22,
                 from arch/mips/boot/compressed/decompress.c:13:
arch/mips/boot/compressed/decompress.c: In function 'decompress_kernel':
./include/asm-generic/unaligned.h:14:8: warning: array subscript -1 is outside array bounds of 'unsigned char[1]' [-Warray-bounds]
   14 |  __pptr->x;        \
      |  ~~~~~~^~~
./include/uapi/linux/byteorder/little_endian.h:35:51: note: in definition of macro '__le32_to_cpu'
   35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
      |                                                   ^
./include/asm-generic/unaligned.h:32:21: note: in expansion of macro '__get_unaligned_t'
   32 |  return le32_to_cpu(__get_unaligned_t(__le32, p));
      |                     ^~~~~~~~~~~~~~~~~
arch/mips/boot/compressed/decompress.c:29:37: note: while referencing '__image_end'
   29 | extern unsigned char __image_begin, __image_end;
      |                                     ^~~~~~~~~~~

Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-mips@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This commit is contained in:
Kees Cook 2022-03-09 10:50:32 -08:00 committed by Thomas Bogendoerfer
parent 4528668ca3
commit 4d409ca3e5
1 changed files with 5 additions and 5 deletions
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10
arch/mips/boot/compressed/decompress.c
View file

@ -26,7 +26,7 @@ unsigned long free_mem_ptr;
unsigned long free_mem_end_ptr;
/* The linker tells us where the image is. */
extern unsigned char __image_begin, __image_end;
extern unsigned char __image_begin[], __image_end[];
/* debug interfaces */
#ifdef CONFIG_DEBUG_ZBOOT
@ -91,9 +91,9 @@ void decompress_kernel(unsigned long boot_heap_start)
{
unsigned long zimage_start, zimage_size;
zimage_start = (unsigned long)(&__image_begin);
zimage_size = (unsigned long)(&__image_end) -
(unsigned long)(&__image_begin);
zimage_start = (unsigned long)(__image_begin);
zimage_size = (unsigned long)(__image_end) -
(unsigned long)(__image_begin);
puts("zimage at: ");
puthex(zimage_start);
@ -121,7 +121,7 @@ void decompress_kernel(unsigned long boot_heap_start)
dtb_size = fdt_totalsize((void *)&__appended_dtb);
/* last four bytes is always image size in little endian */
image_size = get_unaligned_le32((void *)&__image_end - 4);
image_size = get_unaligned_le32((void *)__image_end - 4);
/* The device tree's address must be properly aligned */
image_size = ALIGN(image_size, STRUCT_ALIGNMENT);