cifs: clean up checkSMB
The variable names in this function are so ambiguous that it's very
difficult to know what it's doing. Rename them to make it a bit more
clear.
Also, remove a redundant length check. cifsd checks to make sure that
the rfclen isn't larger than the maximum frame size when it does the
receive.
Finally, change checkSMB to return a real error code (-EIO) when
it finds an error. That will help simplify some coming changes in the
callers.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 7c16933..4a1801b 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -420,19 +420,22 @@
}
int
-checkSMB(struct smb_hdr *smb, __u16 mid, unsigned int length)
+checkSMB(struct smb_hdr *smb, __u16 mid, unsigned int total_read)
{
- __u32 len = be32_to_cpu(smb->smb_buf_length);
+ __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
__u32 clc_len; /* calculated length */
- cFYI(0, "checkSMB Length: 0x%x, smb_buf_length: 0x%x", length, len);
+ cFYI(0, "checkSMB Length: 0x%x, smb_buf_length: 0x%x",
+ total_read, rfclen);
- if (length < 2 + sizeof(struct smb_hdr)) {
- if ((length >= sizeof(struct smb_hdr) - 1)
+ /* is this frame too small to even get to a BCC? */
+ if (total_read < 2 + sizeof(struct smb_hdr)) {
+ if ((total_read >= sizeof(struct smb_hdr) - 1)
&& (smb->Status.CifsError != 0)) {
+ /* it's an error return */
smb->WordCount = 0;
/* some error cases do not return wct and bcc */
return 0;
- } else if ((length == sizeof(struct smb_hdr) + 1) &&
+ } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
(smb->WordCount == 0)) {
char *tmp = (char *)smb;
/* Need to work around a bug in two servers here */
@@ -452,39 +455,35 @@
} else {
cERROR(1, "Length less than smb header size");
}
- return 1;
- }
- if (len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
- cERROR(1, "smb length greater than MaxBufSize, mid=%d",
- smb->Mid);
- return 1;
+ return -EIO;
}
+ /* otherwise, there is enough to get to the BCC */
if (check_smb_hdr(smb, mid))
- return 1;
+ return -EIO;
clc_len = smbCalcSize(smb);
- if (4 + len != length) {
+ if (4 + rfclen != total_read) {
cERROR(1, "Length read does not match RFC1001 length %d",
- len);
- return 1;
+ rfclen);
+ return -EIO;
}
- if (4 + len != clc_len) {
+ if (4 + rfclen != clc_len) {
/* check if bcc wrapped around for large read responses */
- if ((len > 64 * 1024) && (len > clc_len)) {
+ if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
/* check if lengths match mod 64K */
- if (((4 + len) & 0xFFFF) == (clc_len & 0xFFFF))
+ if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
return 0; /* bcc wrapped */
}
cFYI(1, "Calculated size %u vs length %u mismatch for mid=%u",
- clc_len, 4 + len, smb->Mid);
+ clc_len, 4 + rfclen, smb->Mid);
- if (4 + len < clc_len) {
+ if (4 + rfclen < clc_len) {
cERROR(1, "RFC1001 size %u smaller than SMB for mid=%u",
- len, smb->Mid);
- return 1;
- } else if (len > clc_len + 512) {
+ rfclen, smb->Mid);
+ return -EIO;
+ } else if (rfclen > clc_len + 512) {
/*
* Some servers (Windows XP in particular) send more
* data than the lengths in the SMB packet would
@@ -495,8 +494,8 @@
* data to 512 bytes.
*/
cERROR(1, "RFC1001 size %u more than 512 bytes larger "
- "than SMB for mid=%u", len, smb->Mid);
- return 1;
+ "than SMB for mid=%u", rfclen, smb->Mid);
+ return -EIO;
}
}
return 0;