From: Kees Cook keescook@chromium.org
[ Upstream commit ce33e64c1788912976b61314b56935abd4bc97ef ]
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 --- drivers/usb/storage/ene_ub6250.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/usb/storage/ene_ub6250.c b/drivers/usb/storage/ene_ub6250.c index 54679679c825d..16b63f2cd661e 100644 --- a/drivers/usb/storage/ene_ub6250.c +++ b/drivers/usb/storage/ene_ub6250.c @@ -937,7 +937,7 @@ 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;