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cifs: correctly handle NULL tcon pointer in CIFSTCon

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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>
This commit is contained in:
Jeff Layton 2011-06-11 21:17:10 -04:00 committed by Steve French
parent 3e71551364
commit 8d1bca328b
1 changed files with 5 additions and 1 deletions
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6
fs/cifs/connect.c
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@ -3174,6 +3174,10 @@ out:
return rc; return rc;
} }
/*
* Issue a TREE_CONNECT request. Note that for IPC$ shares, that the tcon
* pointer may be NULL.
*/
int int
CIFSTCon(unsigned int xid, struct cifs_ses *ses, CIFSTCon(unsigned int xid, struct cifs_ses *ses,
const char *tree, struct cifs_tcon *tcon, const char *tree, struct cifs_tcon *tcon,
@ -3208,7 +3212,7 @@ CIFSTCon(unsigned int xid, struct cifs_ses *ses,
pSMB->AndXCommand = 0xFF; pSMB->AndXCommand = 0xFF;
pSMB->Flags = cpu_to_le16(TCON_EXTENDED_SECINFO); pSMB->Flags = cpu_to_le16(TCON_EXTENDED_SECINFO);
bcc_ptr = &pSMB->Password[0]; 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 */ pSMB->PasswordLength = cpu_to_le16(1); /* minimum */
*bcc_ptr = 0; /* password is null byte */ *bcc_ptr = 0; /* password is null byte */
bcc_ptr++; /* skip password */ bcc_ptr++; /* skip password */