Commit 8d1bca32 authored Jun 11, 2011 by Jeff Layton Committed by Steve French Jun 13, 2011

cifs: correctly handle NULL tcon pointer in CIFSTCon



Long ago (in commit 00e485b0), I added some code to handle share-level
passwords in CIFSTCon. That code ignored the fact that it's legit to
pass in a NULL tcon pointer when connecting to the IPC$ share on the
server.

This wasn't really a problem until recently as we only called CIFSTCon
this way when the server returned -EREMOTE. With the introduction of
commit c1508ca2 however, it gets called this way on every mount, causing
an oops when share-level security is in effect.

Fix this by simply treating a NULL tcon pointer as if user-level
security were in effect. I'm not aware of any servers that protect the
IPC$ share with a specific password anyway. Also, add a comment to the
top of CIFSTCon to ensure that we don't make the same mistake again.

Cc: <stable@kernel.org>
Reported-by: Martijn Uffing <mp3project@sarijopen.student.utwente.nl>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

parent 3e715513

fs/cifs/connect.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -3174,6 +3174,10 @@ out:
		return rc;
		}

		/*
		* Issue a TREE_CONNECT request. Note that for IPC$ shares, that the tcon
		* pointer may be NULL.
		*/
		int
		CIFSTCon(unsigned int xid, struct cifs_ses *ses,
		const char tree, struct cifs_tcon tcon,
		@@ -3208,7 +3212,7 @@ CIFSTCon(unsigned int xid, struct cifs_ses *ses,
		pSMB->AndXCommand = 0xFF;
		pSMB->Flags = cpu_to_le16(TCON_EXTENDED_SECINFO);
		bcc_ptr = &pSMB->Password[0];
		if ((ses->server->sec_mode) & SECMODE_USER) {
		if (!tcon \|\| (ses->server->sec_mode & SECMODE_USER)) {
		pSMB->PasswordLength = cpu_to_le16(1); /* minimum */
		bcc_ptr = 0; / password is null byte */
		bcc_ptr++; /* skip password */

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