From f5fffcee27c09143ba80e5257dbd1f381d86342f Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 17 Jan 2012 13:49:17 -0500 Subject: [PATCH] cifs: better instrumentation for coalesce_t2 When coalesce_t2 returns an error, have it throw a cFYI message that explains the reason. Also rename some variables to clarify what they represent. Reported-and-Tested-by: Konstantinos Skarlatos Signed-off-by: Jeff Layton Signed-off-by: Steve French --- fs/cifs/connect.c | 84 ++++++++++++++++++++++++++++------------------- 1 file changed, 50 insertions(+), 34 deletions(-) diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 4666780f315d..5cc15856e4ad 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -225,74 +225,90 @@ static int check2ndT2(struct smb_hdr *pSMB) static int coalesce_t2(struct smb_hdr *psecond, struct smb_hdr *pTargetSMB) { - struct smb_t2_rsp *pSMB2 = (struct smb_t2_rsp *)psecond; + struct smb_t2_rsp *pSMBs = (struct smb_t2_rsp *)psecond; struct smb_t2_rsp *pSMBt = (struct smb_t2_rsp *)pTargetSMB; - char *data_area_of_target; - char *data_area_of_buf2; + char *data_area_of_tgt; + char *data_area_of_src; int remaining; - unsigned int byte_count, total_in_buf; - __u16 total_data_size, total_in_buf2; + unsigned int byte_count, total_in_tgt; + __u16 tgt_total_cnt, src_total_cnt, total_in_src; - total_data_size = get_unaligned_le16(&pSMBt->t2_rsp.TotalDataCount); + src_total_cnt = get_unaligned_le16(&pSMBs->t2_rsp.TotalDataCount); + tgt_total_cnt = get_unaligned_le16(&pSMBt->t2_rsp.TotalDataCount); - if (total_data_size != - get_unaligned_le16(&pSMB2->t2_rsp.TotalDataCount)) - cFYI(1, "total data size of primary and secondary t2 differ"); + if (tgt_total_cnt != src_total_cnt) + cFYI(1, "total data count of primary and secondary t2 differ " + "source=%hu target=%hu", src_total_cnt, tgt_total_cnt); - total_in_buf = get_unaligned_le16(&pSMBt->t2_rsp.DataCount); + total_in_tgt = get_unaligned_le16(&pSMBt->t2_rsp.DataCount); - remaining = total_data_size - total_in_buf; + remaining = tgt_total_cnt - total_in_tgt; - if (remaining < 0) + if (remaining < 0) { + cFYI(1, "Server sent too much data. tgt_total_cnt=%hu " + "total_in_tgt=%hu", tgt_total_cnt, total_in_tgt); return -EPROTO; + } - if (remaining == 0) /* nothing to do, ignore */ + if (remaining == 0) { + /* nothing to do, ignore */ + cFYI(1, "no more data remains"); return 0; + } - total_in_buf2 = get_unaligned_le16(&pSMB2->t2_rsp.DataCount); - if (remaining < total_in_buf2) { + total_in_src = get_unaligned_le16(&pSMBs->t2_rsp.DataCount); + if (remaining < total_in_src) cFYI(1, "transact2 2nd response contains too much data"); - } /* find end of first SMB data area */ - data_area_of_target = (char *)&pSMBt->hdr.Protocol + + data_area_of_tgt = (char *)&pSMBt->hdr.Protocol + get_unaligned_le16(&pSMBt->t2_rsp.DataOffset); - /* validate target area */ - data_area_of_buf2 = (char *)&pSMB2->hdr.Protocol + - get_unaligned_le16(&pSMB2->t2_rsp.DataOffset); + /* validate target area */ + data_area_of_src = (char *)&pSMBs->hdr.Protocol + + get_unaligned_le16(&pSMBs->t2_rsp.DataOffset); - data_area_of_target += total_in_buf; + data_area_of_tgt += total_in_tgt; - /* copy second buffer into end of first buffer */ - total_in_buf += total_in_buf2; + total_in_tgt += total_in_src; /* is the result too big for the field? */ - if (total_in_buf > USHRT_MAX) + if (total_in_tgt > USHRT_MAX) { + cFYI(1, "coalesced DataCount too large (%u)", total_in_tgt); return -EPROTO; - put_unaligned_le16(total_in_buf, &pSMBt->t2_rsp.DataCount); + } + put_unaligned_le16(total_in_tgt, &pSMBt->t2_rsp.DataCount); /* fix up the BCC */ byte_count = get_bcc(pTargetSMB); - byte_count += total_in_buf2; + byte_count += total_in_src; /* is the result too big for the field? */ - if (byte_count > USHRT_MAX) + if (byte_count > USHRT_MAX) { + cFYI(1, "coalesced BCC too large (%u)", byte_count); return -EPROTO; + } put_bcc(byte_count, pTargetSMB); byte_count = be32_to_cpu(pTargetSMB->smb_buf_length); - byte_count += total_in_buf2; + byte_count += total_in_src; /* don't allow buffer to overflow */ - if (byte_count > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) + if (byte_count > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) { + cFYI(1, "coalesced BCC exceeds buffer size (%u)", byte_count); return -ENOBUFS; + } pTargetSMB->smb_buf_length = cpu_to_be32(byte_count); - memcpy(data_area_of_target, data_area_of_buf2, total_in_buf2); + /* copy second buffer into end of first buffer */ + memcpy(data_area_of_tgt, data_area_of_src, total_in_src); - if (remaining == total_in_buf2) { - cFYI(1, "found the last secondary response"); - return 0; /* we are done */ - } else /* more responses to go */ + if (remaining != total_in_src) { + /* more responses to go */ + cFYI(1, "waiting for more secondary responses"); return 1; + } + + /* we are done */ + cFYI(1, "found the last secondary response"); + return 0; } static void -- GitLab