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USB: ene_usb6250: Allocate enough memory for full object

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[ Upstream commit ce33e64c17 ]

The allocation of PageBuffer is 512 bytes in size, but the dereferencing
of struct ms_bootblock_idi (also size 512) happens at a calculated offset
within the allocation, which means the object could potentially extend
beyond the end of the allocation. Avoid this case by just allocating
enough space to catch any accesses beyond the end. Seen with GCC 13:

../drivers/usb/storage/ene_ub6250.c: In function 'ms_lib_process_bootblock':
../drivers/usb/storage/ene_ub6250.c:1050:44: warning: array subscript 'struct ms_bootblock_idi[0]' is partly outside array bounds of 'unsigned char[512]' [-Warray-bounds=]
 1050 |                         if (le16_to_cpu(idi->wIDIgeneralConfiguration) != MS_IDI_GENERAL_CONF)
      |                                            ^~
../include/uapi/linux/byteorder/little_endian.h:37:51: note: in definition of macro '__le16_to_cpu'
   37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
      |                                                   ^
../drivers/usb/storage/ene_ub6250.c:1050:29: note: in expansion of macro 'le16_to_cpu'
 1050 |                         if (le16_to_cpu(idi->wIDIgeneralConfiguration) != MS_IDI_GENERAL_CONF)
      |                             ^~~~~~~~~~~
In file included from ../drivers/usb/storage/ene_ub6250.c:5:
In function 'kmalloc',
    inlined from 'ms_lib_process_bootblock' at ../drivers/usb/storage/ene_ub6250.c:942:15:
../include/linux/slab.h:580:24: note: at offset [256, 512] into object of size 512 allocated by 'kmalloc_trace'
  580 |                 return kmalloc_trace(
      |                        ^~~~~~~~~~~~~~
  581 |                                 kmalloc_caches[kmalloc_type(flags)][index],
      |                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  582 |                                 flags, size);
      |                                 ~~~~~~~~~~~~

Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230204183546.never.849-kees@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Kees Cook 2023-02-04 10:35:46 -08:00 committed by Greg Kroah-Hartman
parent cc5472b517
commit 5ee39d2216
1 changed files with 1 additions and 1 deletions
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2
drivers/usb/storage/ene_ub6250.c
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@ -939,7 +939,7 @@ static int ms_lib_process_bootblock(struct us_data *us, u16 PhyBlock, u8 *PageDa
struct ms_lib_type_extdat ExtraData;
struct ene_ub6250_info *info = (struct ene_ub6250_info *) us->extra;
PageBuffer = kmalloc(MS_BYTES_PER_PAGE, GFP_KERNEL);
PageBuffer = kzalloc(MS_BYTES_PER_PAGE * 2, GFP_KERNEL);
if (PageBuffer == NULL)
return (u32)-1;