Commit b4d965a3 authored Oct 24, 2018 by Ronnie Sahlberg Committed by Greg Kroah-Hartman Mar 13, 2019

cifs: allow calling SMB2_xxx_free(NULL)



commit 32a1fb36f6e50183871c2c1fcf5493c633e84732 upstream.

Change these free functions to allow passing NULL as the argument and
treat it as a no-op just like free(NULL) would.
Or, if rqst->rq_iov is NULL.

The second scenario could happen for smb2_queryfs() if the call
to SMB2_query_info_init() fails and we go to qfs_exit to clean up
and free all resources.
In that case we have not yet assigned rqst[2].rq_iov and thus
the rq_iov dereference in SMB2_close_free() will cause a NULL pointer
dereference.

[ bp: upstream patch also fixes SMB2_set_info_free which was introduced in 4.20 ]

Fixes:  1eb9fb52 ("cifs: create SMB2_open_init()/SMB2_open_free() helpers")

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent e5d7b94c

fs/cifs/smb2pdu.c

+10 −6

Original line number	Diff line number	Diff line
		@@ -2243,11 +2243,13 @@ SMB2_open_free(struct smb_rqst *rqst)
		{
		int i;

		if (rqst && rqst->rq_iov) {
		cifs_small_buf_release(rqst->rq_iov[0].iov_base);
		for (i = 1; i < rqst->rq_nvec; i++)
		if (rqst->rq_iov[i].iov_base != smb2_padding)
		kfree(rqst->rq_iov[i].iov_base);
		}
		}

		int
		SMB2_open(const unsigned int xid, struct cifs_open_parms oparms, __le16 path,
		@@ -2535,6 +2537,7 @@ SMB2_close_init(struct cifs_tcon tcon, struct smb_rqst rqst,
		void
		SMB2_close_free(struct smb_rqst *rqst)
		{
		if (rqst && rqst->rq_iov)
		cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
		}

		@@ -2685,6 +2688,7 @@ SMB2_query_info_init(struct cifs_tcon tcon, struct smb_rqst rqst,
		void
		SMB2_query_info_free(struct smb_rqst *rqst)
		{
		if (rqst && rqst->rq_iov)
		cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
		}