Messages in this thread |  | | From | Rosen Penev <> | | Date | Thu, 30 Apr 2026 17:47:41 -0700 | | Subject | Re: [PATCH] cifssmb: use struct_offset in memcpy calculations |
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On Thu, Apr 30, 2026 at 3:06 PM Rosen Penev <rosenp@gmail.com> wrote: > > It seems W=1/FORTIFY_SOURCE is getting confused about the math here. > > Use struct_offset to point FORTIFY_SOURCE to the correct place. > > Remove response_data variables and directly apply to memcpy. Simpler > and avoids excess casting. > > Signed-off-by: Rosen Penev <rosenp@gmail.com> > --- > fs/smb/client/cifssmb.c | 40 +++++++++++++--------------------------- > 1 file changed, 13 insertions(+), 27 deletions(-) > > diff --git a/fs/smb/client/cifssmb.c b/fs/smb/client/cifssmb.c > index 3990a9012264..8598cec5ebbd 100644 > --- a/fs/smb/client/cifssmb.c > +++ b/fs/smb/client/cifssmb.c > @@ -4090,9 +4090,9 @@ CIFSSMBQFileInfo(const unsigned int xid, struct cifs_tcon *tcon, > get_bcc(&pSMBr->hdr), 40); > else if (pFindData) { > __u16 data_offset = le16_to_cpu(pSMBr->t2.DataOffset); > - memcpy((char *) pFindData, > - (char *) &pSMBr->hdr.Protocol + > - data_offset, sizeof(FILE_ALL_INFO)); > + memcpy(pFindData, > + (char *)pSMBr + struct_offset(pSMBr, hdr.Protocol) + data_offset, > + sizeof(FILE_ALL_INFO)); > } else > rc = -ENOMEM; > } > @@ -4264,9 +4264,8 @@ CIFSSMBUnixQFileInfo(const unsigned int xid, struct cifs_tcon *tcon, > get_bcc(&pSMBr->hdr), sizeof(FILE_UNIX_BASIC_INFO)); > } else { > __u16 data_offset = le16_to_cpu(pSMBr->t2.DataOffset); > - memcpy((char *) pFindData, > - (char *) &pSMBr->hdr.Protocol + > - data_offset, > + memcpy(pFindData, > + (char *)pSMBr + struct_offset(pSMBr, hdr.Protocol) + data_offset, On further review, struct_offset might not be needed.
I believe
struct_offset(pSMBr, hdr.Protocol) == 0
since Protocol is the first member of hdr and hdr is the first member of pSMBr.
Not sure if removal is desired. > sizeof(FILE_UNIX_BASIC_INFO)); > } > } > @@ -4349,9 +4348,8 @@ CIFSSMBUnixQPathInfo(const unsigned int xid, struct cifs_tcon *tcon, > get_bcc(&pSMBr->hdr), sizeof(FILE_UNIX_BASIC_INFO)); > } else { > __u16 data_offset = le16_to_cpu(pSMBr->t2.DataOffset); > - memcpy((char *) pFindData, > - (char *) &pSMBr->hdr.Protocol + > - data_offset, > + memcpy(pFindData, > + (char *)pSMBr + struct_offset(pSMBr, hdr.Protocol) + data_offset, > sizeof(FILE_UNIX_BASIC_INFO)); > } > } > @@ -5079,7 +5077,6 @@ CIFSSMBQFSAttributeInfo(const unsigned int xid, struct cifs_tcon *tcon) > /* level 0x105 SMB_QUERY_FILE_SYSTEM_INFO */ > TRANSACTION2_QFSI_REQ *pSMB = NULL; > TRANSACTION2_QFSI_RSP *pSMBr = NULL; > - FILE_SYSTEM_ATTRIBUTE_INFO *response_data; > unsigned int in_len; > int rc = 0; > int bytes_returned = 0; > @@ -5130,11 +5127,8 @@ CIFSSMBQFSAttributeInfo(const unsigned int xid, struct cifs_tcon *tcon) > get_bcc(&pSMBr->hdr), 13); > } else { > __u16 data_offset = le16_to_cpu(pSMBr->t2.DataOffset); > - response_data = > - (FILE_SYSTEM_ATTRIBUTE_INFO > - *) (((char *) &pSMBr->hdr.Protocol) + > - data_offset); > - memcpy(&tcon->fsAttrInfo, response_data, > + memcpy(&tcon->fsAttrInfo, > + (char *)pSMBr + struct_offset(pSMBr, hdr.Protocol) + data_offset, > sizeof(FILE_SYSTEM_ATTRIBUTE_INFO)); > } > } > @@ -5152,7 +5146,6 @@ CIFSSMBQFSDeviceInfo(const unsigned int xid, struct cifs_tcon *tcon) > /* level 0x104 SMB_QUERY_FILE_SYSTEM_INFO */ > TRANSACTION2_QFSI_REQ *pSMB = NULL; > TRANSACTION2_QFSI_RSP *pSMBr = NULL; > - FILE_SYSTEM_DEVICE_INFO *response_data; > unsigned int in_len; > int rc = 0; > int bytes_returned = 0; > @@ -5205,11 +5198,8 @@ CIFSSMBQFSDeviceInfo(const unsigned int xid, struct cifs_tcon *tcon) > sizeof(FILE_SYSTEM_DEVICE_INFO)); > else { > __u16 data_offset = le16_to_cpu(pSMBr->t2.DataOffset); > - response_data = > - (FILE_SYSTEM_DEVICE_INFO *) > - (((char *) &pSMBr->hdr.Protocol) + > - data_offset); > - memcpy(&tcon->fsDevInfo, response_data, > + memcpy(&tcon->fsDevInfo, > + (char *)pSMBr + struct_offset(pSMBr, hdr.Protocol) + data_offset, > sizeof(FILE_SYSTEM_DEVICE_INFO)); > } > } > @@ -5227,7 +5217,6 @@ CIFSSMBQFSUnixInfo(const unsigned int xid, struct cifs_tcon *tcon) > /* level 0x200 SMB_QUERY_CIFS_UNIX_INFO */ > TRANSACTION2_QFSI_REQ *pSMB = NULL; > TRANSACTION2_QFSI_RSP *pSMBr = NULL; > - FILE_SYSTEM_UNIX_INFO *response_data; > unsigned int in_len; > int rc = 0; > int bytes_returned = 0; > @@ -5277,11 +5266,8 @@ CIFSSMBQFSUnixInfo(const unsigned int xid, struct cifs_tcon *tcon) > get_bcc(&pSMBr->hdr), 13); > } else { > __u16 data_offset = le16_to_cpu(pSMBr->t2.DataOffset); > - response_data = > - (FILE_SYSTEM_UNIX_INFO > - *) (((char *) &pSMBr->hdr.Protocol) + > - data_offset); > - memcpy(&tcon->fsUnixInfo, response_data, > + memcpy(&tcon->fsUnixInfo, > + (char *)pSMBr + struct_offset(pSMBr, hdr.Protocol) + data_offset, > sizeof(FILE_SYSTEM_UNIX_INFO)); > } > } > -- > 2.54.0 >
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