Commit 2b7a8dc0 authored by Kees Cook's avatar Kees Cook Committed by Jens Axboe
Browse files

s390/dasd: Avoid field over-reading memcpy() 



In preparation for FORTIFY_SOURCE performing compile-time and run-time
field array bounds checking for memcpy(), memmove(), and memset(),
avoid intentionally reading across neighboring array fields.

Add a wrapping structure to serve as the memcpy() source, so the compiler
can do appropriate bounds checking, avoiding this future warning:

In function '__fortify_memcpy',
    inlined from 'create_uid' at drivers/s390/block/dasd_eckd.c:749:2:
./include/linux/fortify-string.h:246:4: error: call to '__read_overflow2_field' declared with attribute error: detected read beyond size of field (2nd parameter)

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarStefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20210701142221.3408680-3-sth@linux.ibm.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 299f2b5f

drivers/s390/block/dasd_eckd.c

+1 −1
Original line number Diff line number Diff line
@@ -746,7 +746,7 @@ static void create_uid(struct dasd_eckd_private *private) 
	memcpy(uid->vendor, private->ned->HDA_manufacturer,

	       sizeof(uid->vendor) - 1);

	EBCASC(uid->vendor, sizeof(uid->vendor) - 1);

	memcpy(uid->serial, private->ned->HDA_location,

	memcpy(uid->serial, &private->ned->serial,

	       sizeof(uid->serial) - 1);

	EBCASC(uid->serial, sizeof(uid->serial) - 1);

	uid->ssid = private->gneq->subsystemID;

drivers/s390/block/dasd_eckd.h

+4 −2
Original line number Diff line number Diff line
@@ -332,8 +332,10 @@ struct dasd_ned { 
	__u8 dev_type[6];

	__u8 dev_model[3];

	__u8 HDA_manufacturer[3];

	struct {

		__u8 HDA_location[2];

		__u8 HDA_seqno[12];

	} serial;

	__u8 ID;

	__u8 unit_addr;

} __attribute__ ((packed));