Attachment 3947 Details for Bug 6004 – patch to alter how cifs sends the vcnumber now also handles reconnect

[patch] patch to alter how cifs sends the vcnumber now also handles reconnect

vc-number-fix.patch (text/plain), 7.64 KB, created by Steve French on 2009-02-19 23:41:11 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Steve French

Created: 2009-02-19 23:41:11 UTC

Size: 7.64 KB

patch

obsolete

>diff --git a/fs/cifs/CHANGES b/fs/cifs/CHANGES
>index 72063f5..851388f 100644
>--- a/fs/cifs/CHANGES
>+++ b/fs/cifs/CHANGES
>@@ -1,3 +1,13 @@
>+Version 1.57
>+------------
>+Improve support for multiple security contexts to the same server. We
>+used to use the same "vcnumber" for all connections which could cause
>+the server to treat subsequent connections, especially those that
>+are authenticated as guest, as reconnections, invalidating the earlier
>+user's smb session.  This fix allows cifs to mount multiple times to the
>+same server with different userids without risking invalidating earlier
>+established security contexts.
>+
> Version 1.56
> ------------
> Add "forcemandatorylock" mount option to allow user to use mandatory
>diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
>index 7ac4818..2b1d28a 100644
>--- a/fs/cifs/cifsfs.h
>+++ b/fs/cifs/cifsfs.h
>@@ -100,5 +100,5 @@ extern long cifs_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
> extern const struct export_operations cifs_export_ops;
> #endif /* EXPERIMENTAL */
> 
>-#define CIFS_VERSION   "1.56"
>+#define CIFS_VERSION   "1.57"
> #endif				/* _CIFSFS_H */
>diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
>index 94c1ca0..e004f6d 100644
>--- a/fs/cifs/cifsglob.h
>+++ b/fs/cifs/cifsglob.h
>@@ -164,9 +164,12 @@ struct TCP_Server_Info {
> 	/* multiplexed reads or writes */
> 	unsigned int maxBuf;	/* maxBuf specifies the maximum */
> 	/* message size the server can send or receive for non-raw SMBs */
>-	unsigned int maxRw;	/* maxRw specifies the maximum */
>+	unsigned int max_rw;	/* maxRw specifies the maximum */
> 	/* message size the server can send or receive for */
> 	/* SMB_COM_WRITE_RAW or SMB_COM_READ_RAW. */
>+	unsigned int max_vcs;	/* maximum number of smb sessions, at least
>+				   those that can be specified uniquely with
>+				   vcnumbers */
> 	char sessid[4];		/* unique token id for this session */
> 	/* (returned on Negotiate */
> 	int capabilities; /* allow selective disabling of caps by smb sess */
>@@ -210,6 +213,7 @@ struct cifsSesInfo {
> 	unsigned overrideSecFlg;  /* if non-zero override global sec flags */
> 	__u16 ipc_tid;		/* special tid for connection to IPC share */
> 	__u16 flags;
>+	__u16 vcnum;
> 	char *serverOS;		/* name of operating system underlying server */
> 	char *serverNOS;	/* name of network operating system of server */
> 	char *serverDomain;	/* security realm of server */
>diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
>index 552642a..939e2f7 100644
>--- a/fs/cifs/cifssmb.c
>+++ b/fs/cifs/cifssmb.c
>@@ -528,14 +528,15 @@ CIFSSMBNegotiate(unsigned int xid, struct cifsSesInfo *ses)
> 		server->maxReq = le16_to_cpu(rsp->MaxMpxCount);
> 		server->maxBuf = min((__u32)le16_to_cpu(rsp->MaxBufSize),
> 				(__u32)CIFSMaxBufSize + MAX_CIFS_HDR_SIZE);
>+		server->max_vcs = le16_to_cpu(rsp->MaxNumberVcs);
> 		GETU32(server->sessid) = le32_to_cpu(rsp->SessionKey);
> 		/* even though we do not use raw we might as well set this
> 		accurately, in case we ever find a need for it */
> 		if ((le16_to_cpu(rsp->RawMode) & RAW_ENABLE) == RAW_ENABLE) {
>-			server->maxRw = 0xFF00;
>+			server->max_rw = 0xFF00;
> 			server->capabilities = CAP_MPX_MODE | CAP_RAW_MODE;
> 		} else {
>-			server->maxRw = 0;/* we do not need to use raw anyway */
>+			server->max_rw = 0;/* do not need to use raw anyway */
> 			server->capabilities = CAP_MPX_MODE;
> 		}
> 		tmp = (__s16)le16_to_cpu(rsp->ServerTimeZone);
>@@ -638,7 +639,7 @@ CIFSSMBNegotiate(unsigned int xid, struct cifsSesInfo *ses)
> 	/* probably no need to store and check maxvcs */
> 	server->maxBuf = min(le32_to_cpu(pSMBr->MaxBufferSize),
> 			(__u32) CIFSMaxBufSize + MAX_CIFS_HDR_SIZE);
>-	server->maxRw = le32_to_cpu(pSMBr->MaxRawSize);
>+	server->max_rw = le32_to_cpu(pSMBr->MaxRawSize);
> 	cFYI(DBG2, ("Max buf = %d", ses->server->maxBuf));
> 	GETU32(ses->server->sessid) = le32_to_cpu(pSMBr->SessionKey);
> 	server->capabilities = le32_to_cpu(pSMBr->Capabilities);
>diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
>index b234407..5c68b42 100644
>--- a/fs/cifs/sess.c
>+++ b/fs/cifs/sess.c
>@@ -34,15 +34,99 @@
> extern void SMBNTencrypt(unsigned char *passwd, unsigned char *c8,
> 			 unsigned char *p24);
> 
>+/* Checks if this is the first smb session to be reconnected after
>+   the socket has been reestablished (so we know whether to use vc 0).
>+   Called while holding the cifs_tcp_ses_lock, so do not block */
>+static bool is_first_ses_reconnect(struct cifsSesInfo *ses)
>+{
>+	struct list_head *tmp;
>+	struct cifsSesInfo *tmp_ses;
>+
>+	list_for_each(tmp, &ses->server->smb_ses_list) {
>+		tmp_ses = list_entry(tmp, struct cifsSesInfo,
>+				     smb_ses_list);
>+		if (tmp_ses->need_reconnect == false)
>+			return false;
>+	}
>+	/* could not find a session that was already connected,
>+	   this must be the first one we are reconnecting */
>+	return true;
>+}
>+
>+/*
>+ *	vc number 0 is treated specially by some servers, and should be the
>+ *      first one we request.  After that we can use vcnumbers up to maxvcs,
>+ *	one for each smb session (some Windows versions set maxvcs incorrectly
>+ *	so maxvc=1 can be ignored).  If we have too many vcs, we can reuse
>+ *	any vc but zero (some servers reset the connection on vcnum zero)
>+ *
>+ */
>+static __le16 get_next_vcnum(struct cifsSesInfo *ses)
>+{
>+	__u16 vcnum = 0;
>+	struct list_head *tmp;
>+	struct cifsSesInfo *tmp_ses;
>+	__u16 max_vcs = ses->server->max_vcs;
>+	__u16 i;
>+	int free_vc_found = 0;
>+
>+	/* Quoting the MS-SMB specification: "Windows-based SMB servers set this
>+	field to one but do not enforce this limit, which allows an SMB client
>+	to establish more virtual circuits than allowed by this value ... but
>+	other server implementations can enforce this limit." */
>+	if (max_vcs < 2)
>+		max_vcs = 0xFFFF;
>+
>+	write_lock(&cifs_tcp_ses_lock);
>+	if ((ses->need_reconnect) && is_first_ses_reconnect(ses))
>+			goto get_vc_num_exit;  /* vcnum will be zero */
>+	for (i = ses->server->srv_count - 1; i < max_vcs; i++) {
>+		if (i == 0) /* this is the only connection, use vc 0 */
>+			break;
>+
>+		free_vc_found = 1;
>+
>+		list_for_each(tmp, &ses->server->smb_ses_list) {
>+			tmp_ses = list_entry(tmp, struct cifsSesInfo,
>+					     smb_ses_list);
>+			if (tmp_ses->vcnum == i) {
>+				free_vc_found = 0;
>+				break; /* found duplicate, try next vcnum */
>+			}
>+		}
>+		if (free_vc_found)
>+			break; /* we found a vcnumber that will work - use it */
>+	}
>+
>+	if (i == 0)
>+		vcnum = 0; /* for most common case, ie if one smb session, use
>+			      vc zero.  Also for case when no free vcnum, zero
>+			      is safest to send (some clients only send zero) */
>+	else if (free_vc_found == 0)
>+		vcnum = 1;  /* we can not reuse vc=0 safely, since some servers
>+				reset all uids on that, but 1 is ok. */
>+	else
>+		vcnum = i;
>+	ses->vcnum = vcnum;
>+get_vc_num_exit:
>+	write_unlock(&cifs_tcp_ses_lock);
>+
>+	return le16_to_cpu(vcnum);
>+}
>+
> static __u32 cifs_ssetup_hdr(struct cifsSesInfo *ses, SESSION_SETUP_ANDX *pSMB)
> {
> 	__u32 capabilities = 0;
> 
> 	/* init fields common to all four types of SessSetup */
>-	/* note that header is initialized to zero in header_assemble */
>+	/* Note that offsets for first seven fields in req struct are same  */
>+	/*	in CIFS Specs so does not matter which of 3 forms of struct */
>+	/*	that we use in next few lines                               */
>+	/* Note that header is initialized to zero in header_assemble */
> 	pSMB->req.AndXCommand = 0xFF;
> 	pSMB->req.MaxBufferSize = cpu_to_le16(ses->server->maxBuf);
> 	pSMB->req.MaxMpxCount = cpu_to_le16(ses->server->maxReq);
>+	pSMB->req.VcNumber = get_next_vcnum(ses);
> 
> 	/* Now no need to set SMBFLG_CASELESS or obsolete CANONICAL PATH */
> 
>@@ -71,7 +155,6 @@ static __u32 cifs_ssetup_hdr(struct cifsSesInfo *ses, SESSION_SETUP_ANDX *pSMB)
> 	if (ses->capabilities & CAP_UNIX)
> 		capabilities |= CAP_UNIX;
> 
>-	/* BB check whether to init vcnum BB */
> 	return capabilities;
> }
>

Actions: View

Attachments on bug 6004: 3838 | 3839 | 3840 | 3841 | 3895 | 3899 | 3947