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 <[email protected]> --- fs/cifs/connect.c | 2 +- fs/cifs/misc.c | 51 +++++++++++++++++++++++++-------------------------- 2 files changed, 26 insertions(+), 27 deletions(-) diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 5adbeec..28007fd 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -422,7 +422,7 @@ readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig, /* * FIXME: allocation here may cause deadlocks under memory pressure. - * Switch this to use a fixed, per-socket buffer? + * Switch this to use a fixed, per-socket buffer. */ iov = kmalloc(sizeof(*iov_orig) * nr_segs, GFP_KERNEL); if (!iov) 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 @@ check_smb_hdr(struct smb_hdr *smb, __u16 mid) } 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 @@ checkSMB(struct smb_hdr *smb, __u16 mid, unsigned int length) } 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 @@ checkSMB(struct smb_hdr *smb, __u16 mid, unsigned int length) * 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; -- 1.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
