The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 32a1fb36f6e50183871c2c1fcf5493c633e84732 Mon Sep 17 00:00:00 2001

From: Ronnie Sahlberg lsahlber@redhat.com Date: Wed, 24 Oct 2018 11:50:33 +1000 Subject: [PATCH] cifs: allow calling SMB2_xxx_free(NULL)

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.

Fixes: 1eb9fb52040f ("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

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 5a08c8f6a322..7d7b016fe8bb 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -2243,10 +2243,12 @@ SMB2_open_free(struct smb_rqst *rqst) { int i;

- 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); + 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 @@ -2536,7 +2538,8 @@ SMB2_close_init(struct cifs_tcon *tcon, struct smb_rqst *rqst, void SMB2_close_free(struct smb_rqst *rqst) { - cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */ + if (rqst && rqst->rq_iov) + cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */ }

int @@ -2689,7 +2692,8 @@ SMB2_query_info_init(struct cifs_tcon *tcon, struct smb_rqst *rqst, void SMB2_query_info_free(struct smb_rqst *rqst) { - cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */ + if (rqst && rqst->rq_iov) + cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */ }

static int @@ -3803,7 +3807,8 @@ SMB2_set_info_init(struct cifs_tcon *tcon, struct smb_rqst *rqst, void SMB2_set_info_free(struct smb_rqst *rqst) { - cifs_buf_release(rqst->rq_iov[0].iov_base); /* request */ + if (rqst && rqst->rq_iov) + cifs_buf_release(rqst->rq_iov[0].iov_base); /* request */ }

static int