tentatively merged into cifs-2.6.git for-next pending testing On Tue, Jul 11, 2023 at 6:20 PM Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> wrote: > > 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: dc1af4c4b472 ("cifs: implement set acl method") > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> > --- > fs/smb/client/cifssmb.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/smb/client/cifssmb.c b/fs/smb/client/cifssmb.c > index 19f7385abeec..9dee267f1893 100644 > --- a/fs/smb/client/cifssmb.c > +++ b/fs/smb/client/cifssmb.c > @@ -3184,7 +3184,7 @@ int cifs_do_set_acl(const unsigned int xid, struct cifs_tcon *tcon, > param_offset = offsetof(struct smb_com_transaction2_spi_req, > InformationLevel) - 4; > offset = param_offset + params; > - parm_data = ((char *) &pSMB->hdr.Protocol) + offset; > + parm_data = ((char *)pSMB) + sizeof(pSMB->hdr.smb_buf_length) + offset; > pSMB->ParameterOffset = cpu_to_le16(param_offset); > > /* convert to on the wire format for POSIX ACL */ > -- > 2.34.1 > -- Thanks, Steve
