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cifs: Fix potential OOB access of lock element array

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If maxBuf is small but non-zero, it could result in a zero sized lock
element array which we would then try and access OOB.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
This commit is contained in:
Ross Lagerwall 2019-01-08 18:30:57 +00:00 committed by Steve French
parent 92a8109e4d
commit b9a74cde94
2 changed files with 6 additions and 6 deletions
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8
fs/cifs/file.c
View File

@ -1132,10 +1132,10 @@ cifs_push_mandatory_locks(struct cifsFileInfo *cfile)
/* /*
* Accessing maxBuf is racy with cifs_reconnect - need to store value * Accessing maxBuf is racy with cifs_reconnect - need to store value
* and check it for zero before using. * and check it before using.
*/ */
max_buf = tcon->ses->server->maxBuf; max_buf = tcon->ses->server->maxBuf;
if (!max_buf) { if (max_buf < (sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE))) {
free_xid(xid); free_xid(xid);
return -EINVAL; return -EINVAL;
} }
@ -1476,10 +1476,10 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
/* /*
* Accessing maxBuf is racy with cifs_reconnect - need to store value * Accessing maxBuf is racy with cifs_reconnect - need to store value
* and check it for zero before using. * and check it before using.
*/ */
max_buf = tcon->ses->server->maxBuf; max_buf = tcon->ses->server->maxBuf;
if (!max_buf) if (max_buf < (sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE)))
return -EINVAL; return -EINVAL;
BUILD_BUG_ON(sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE) > BUILD_BUG_ON(sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE) >

4
fs/cifs/smb2file.c
View File

@ -122,10 +122,10 @@ smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
/* /*
* Accessing maxBuf is racy with cifs_reconnect - need to store value * Accessing maxBuf is racy with cifs_reconnect - need to store value
* and check it for zero before using. * and check it before using.
*/ */
max_buf = tcon->ses->server->maxBuf; max_buf = tcon->ses->server->maxBuf;
if (!max_buf) if (max_buf < sizeof(struct smb2_lock_element))
return -EINVAL; return -EINVAL;
BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE); BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);