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f1f047bd7c
pSMB->hdr.Protocol is an array of size 4 bytes, hence when the compiler
analyzes this line of code
parm_data = ((char *) &pSMB->hdr.Protocol) + offset;
it legitimately complains about the fact that offset points outside the
bounds of the array. Notice that the compiler gives priority to the object
as an array, rather than merely the address of one more byte in a structure
to wich offset should be added (which seems to be the actual intention of
the original implementation).
Fix this by explicitly instructing the compiler to treat the code as a
sequence of bytes in struct smb_com_transaction2_spi_req, and not as an
array accessed through pointer notation.
Notice that ((char *)pSMB) + sizeof(pSMB->hdr.smb_buf_length) points to
the same address as ((char *) &pSMB->hdr.Protocol), therefore this results
in no differences in binary output.
Fixes the following -Wstringop-overflow warnings when built s390
architecture with defconfig (GCC 13):
CC [M] fs/smb/client/cifssmb.o
In function 'cifs_init_ace',
inlined from 'posix_acl_to_cifs' at fs/smb/client/cifssmb.c:3046:3,
inlined from 'cifs_do_set_acl' at fs/smb/client/cifssmb.c:3191:15:
fs/smb/client/cifssmb.c:2987:31: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
2987 | cifs_ace->cifs_e_perm = local_ace->e_perm;
| ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~
In file included from fs/smb/client/cifssmb.c:27:
fs/smb/client/cifspdu.h: In function 'cifs_do_set_acl':
fs/smb/client/cifspdu.h:384:14: note: at offset [7, 11] into destination object 'Protocol' of size 4
384 | __u8 Protocol[4];
| ^~~~~~~~
In function 'cifs_init_ace',
inlined from 'posix_acl_to_cifs' at fs/smb/client/cifssmb.c:3046:3,
inlined from 'cifs_do_set_acl' at fs/smb/client/cifssmb.c:3191:15:
fs/smb/client/cifssmb.c:2988:30: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
2988 | cifs_ace->cifs_e_tag = local_ace->e_tag;
| ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~
fs/smb/client/cifspdu.h: In function 'cifs_do_set_acl':
fs/smb/client/cifspdu.h:384:14: note: at offset [6, 10] into destination object 'Protocol' of size 4
384 | __u8 Protocol[4];
| ^~~~~~~~
This helps with the ongoing efforts to globally enable
-Wstringop-overflow.
Link: https://github.com/KSPP/linux/issues/310
Fixes: dc1af4c4b4 ("cifs: implement set acl method")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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.