4.19-stable review patch. If anyone has any objections, please let me know.
------------------ From: Ronnie Sahlberg <[email protected]> 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: 1eb9fb52040f ("cifs: create SMB2_open_init()/SMB2_open_free() helpers") Signed-off-by: Ronnie Sahlberg <[email protected]> Signed-off-by: Steve French <[email protected]> Reviewed-by: Aurelien Aptel <[email protected]> CC: Stable <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/cifs/smb2pdu.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) --- 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 @@ -2535,7 +2537,8 @@ SMB2_close_init(struct cifs_tcon *tcon, 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 @@ -2685,7 +2688,8 @@ SMB2_query_info_init(struct cifs_tcon *t 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
