f9fc1ec28b
Some configurations with gcc-12 or gcc-13 produce a warning for the source
and destination of a memcpy() in atmel_sha_hmac_compute_ipad_hash() potentially
overlapping:
In file included from include/linux/string.h:254,
from drivers/crypto/atmel-sha.c:15:
drivers/crypto/atmel-sha.c: In function 'atmel_sha_hmac_compute_ipad_hash':
include/linux/fortify-string.h:57:33: error: '__builtin_memcpy' accessing 129 or more bytes at offsets 408 and 280 overlaps 1 or more bytes at offset 408 [-Werror=restrict]
57 | #define __underlying_memcpy __builtin_memcpy
| ^
include/linux/fortify-string.h:648:9: note: in expansion of macro '__underlying_memcpy'
648 | __underlying_##op(p, q, __fortify_size); \
| ^~~~~~~~~~~~~
include/linux/fortify-string.h:693:26: note: in expansion of macro '__fortify_memcpy_chk'
693 | #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \
| ^~~~~~~~~~~~~~~~~~~~
drivers/crypto/atmel-sha.c:1773:9: note: in expansion of macro 'memcpy'
1773 | memcpy(hmac->opad, hmac->ipad, bs);
| ^~~~~~
The same thing happens in two more drivers that have the same logic:
drivers/crypto/chelsio/chcr_algo.c: In function 'chcr_ahash_setkey':
include/linux/fortify-string.h:57:33: error: '__builtin_memcpy' accessing 129 or more bytes at offsets 260 and 132 overlaps 1 or more bytes at offset 260 [-Werror=restrict]
drivers/crypto/bcm/cipher.c: In function 'ahash_hmac_setkey':
include/linux/fortify-string.h:57:33: error: '__builtin_memcpy' accessing between 129 and 4294967295 bytes at offsets 840 and 712 overlaps between 1 and 4294967167 bytes at offset 840 [-Werror=restrict]
I don't think it can actually happen because the size is strictly bounded
to the available block sizes, at most 128 bytes, though inlining decisions
could lead gcc to not see that.
Use the unsafe_memcpy() helper instead of memcpy(), with the only difference
being that this skips the hardening checks that produce the warning.
Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.