From mboxrd@z Thu Jan 1 00:00:00 1970 From: ronnie sahlberg Subject: Re: [PATCH] cifs: fix remaining rsp_iov issues Date: Thu, 12 Oct 2017 09:33:09 +1000 Message-ID: References: <20171011054140.26535-1-lsahlber@redhat.com> <20171011054140.26535-2-lsahlber@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Ronnie Sahlberg , linux-cifs , Steve French To: Pavel Shilovsky Return-path: In-Reply-To: Sender: linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: On Thu, Oct 12, 2017 at 4:33 AM, Pavel Shilovsky wrote: > 2017-10-10 22:41 GMT-07:00 Ronnie Sahlberg : >> This patch fixes the remaining issues with rsp_iov where >> we might dereference uninitialized pointers or pass them >> to free_rsp_buf(). >> There is also one memory leak that is fixed. >> >> Signed-off-by: Ronnie Sahlberg >> --- >> fs/cifs/smb2pdu.c | 43 +++++++++++++++++++++++++------------------ >> 1 file changed, 25 insertions(+), 18 deletions(-) >> >> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c >> index 6ff4c275ca9a..fd2b2b8e86b0 100644 >> --- a/fs/cifs/smb2pdu.c >> +++ b/fs/cifs/smb2pdu.c >> @@ -470,7 +470,7 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses) >> struct smb2_negotiate_req *req; >> struct smb2_negotiate_rsp *rsp; >> struct kvec iov[1]; >> - struct kvec rsp_iov; >> + struct kvec rsp_iov = { NULL, 0 }; >> int rc = 0; >> int resp_buftype; >> struct TCP_Server_Info *server = ses->server; >> @@ -1884,7 +1884,7 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid, >> struct smb2_sync_hdr *shdr; >> struct cifs_ses *ses; >> struct kvec iov[2]; >> - struct kvec rsp_iov; >> + struct kvec rsp_iov = { NULL, 0 }; >> int resp_buftype; >> int n_iov; >> int rc = 0; >> @@ -1981,6 +1981,8 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid, >> rc = SendReceive2(xid, ses, iov, n_iov, &resp_buftype, flags, &rsp_iov); >> cifs_small_buf_release(req); >> rsp = (struct smb2_ioctl_rsp *)rsp_iov.iov_base; >> + if (rsp == NULL) >> + goto ioctl_exit; > > Why do we need this? rsp pointer will be NULL if rc != 0 which is > covered by the code below. Note that resp_buftype will be set to > NO_BUFFER, so NULL/garbage pointer de-referencing shouldn't happen. Thanks. I missed resp_buftype. > >> >> if ((rc != 0) && (rc != -EINVAL)) { >> cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE); >> @@ -2064,7 +2066,7 @@ SMB2_close(const unsigned int xid, struct cifs_tcon *tcon, >> struct smb2_close_rsp *rsp; >> struct cifs_ses *ses = tcon->ses; >> struct kvec iov[1]; >> - struct kvec rsp_iov; >> + struct kvec rsp_iov = { NULL, 0 }; >> int resp_buftype; >> int rc = 0; >> int flags = 0; >> @@ -2168,9 +2170,9 @@ query_info(const unsigned int xid, struct cifs_tcon *tcon, >> u32 *dlen) >> { >> struct smb2_query_info_req *req; >> - struct smb2_query_info_rsp *rsp = NULL; >> + struct smb2_query_info_rsp *rsp; >> struct kvec iov[2]; >> - struct kvec rsp_iov; >> + struct kvec rsp_iov = { NULL, 0 }; >> int rc = 0; >> int resp_buftype; >> struct cifs_ses *ses = tcon->ses; >> @@ -2404,7 +2406,7 @@ SMB2_flush(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid, >> struct smb2_flush_req *req; >> struct cifs_ses *ses = tcon->ses; >> struct kvec iov[1]; >> - struct kvec rsp_iov; >> + struct kvec rsp_iov = { NULL, 0 }; >> int resp_buftype; >> int rc = 0; >> int flags = 0; >> @@ -2639,10 +2641,10 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms, >> { >> int resp_buftype, rc = -EACCES; >> struct smb2_read_plain_req *req = NULL; >> - struct smb2_read_rsp *rsp = NULL; >> + struct smb2_read_rsp *rsp; >> struct smb2_sync_hdr *shdr; >> struct kvec iov[2]; >> - struct kvec rsp_iov; >> + struct kvec rsp_iov = { NULL, 0 }; >> unsigned int total_len; >> __be32 req_len; >> struct smb_rqst rqst = { .rq_iov = iov, >> @@ -2669,6 +2671,10 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms, >> cifs_small_buf_release(req); >> >> rsp = (struct smb2_read_rsp *)rsp_iov.iov_base; >> + if (rsp == NULL) { >> + cifs_dbg(VFS, "rsp is NULL in read\n"); >> + return -EIO; >> + } >> shdr = get_sync_hdr(rsp); > > This is another long-term bug, thanks. We should probably refactor the > code a little bit here and move rc != 0 check before calling > get_sync_hdr(). I will do that. > >> >> if (shdr->Status == STATUS_END_OF_FILE) { >> @@ -2856,9 +2862,9 @@ SMB2_write(const unsigned int xid, struct cifs_io_parms *io_parms, >> { >> int rc = 0; >> struct smb2_write_req *req = NULL; >> - struct smb2_write_rsp *rsp = NULL; >> + struct smb2_write_rsp *rsp; >> int resp_buftype; >> - struct kvec rsp_iov; >> + struct kvec rsp_iov = { NULL, 0 }; >> int flags = 0; >> >> *nbytes = 0; >> @@ -2963,7 +2969,7 @@ SMB2_query_directory(const unsigned int xid, struct cifs_tcon *tcon, >> struct smb2_query_directory_req *req; >> struct smb2_query_directory_rsp *rsp = NULL; >> struct kvec iov[2]; >> - struct kvec rsp_iov; >> + struct kvec rsp_iov = { NULL, 0 }; >> int rc = 0; >> int len; >> int resp_buftype = CIFS_NO_BUFFER; >> @@ -3093,9 +3099,9 @@ send_set_info(const unsigned int xid, struct cifs_tcon *tcon, >> void **data, unsigned int *size) >> { >> struct smb2_set_info_req *req; >> - struct smb2_set_info_rsp *rsp = NULL; >> + struct smb2_set_info_rsp *rsp; >> struct kvec *iov; >> - struct kvec rsp_iov; >> + struct kvec rsp_iov = { NULL, 0 }; >> int rc = 0; >> int resp_buftype; >> unsigned int i; >> @@ -3376,9 +3382,9 @@ int >> SMB2_QFS_info(const unsigned int xid, struct cifs_tcon *tcon, >> u64 persistent_fid, u64 volatile_fid, struct kstatfs *fsdata) >> { >> - struct smb2_query_info_rsp *rsp = NULL; >> + struct smb2_query_info_rsp *rsp; >> struct kvec iov; >> - struct kvec rsp_iov; >> + struct kvec rsp_iov = { NULL, 0 }; >> int rc = 0; >> int resp_buftype; >> struct cifs_ses *ses = tcon->ses; >> @@ -3419,9 +3425,9 @@ int >> SMB2_QFS_attr(const unsigned int xid, struct cifs_tcon *tcon, >> u64 persistent_fid, u64 volatile_fid, int level) >> { >> - struct smb2_query_info_rsp *rsp = NULL; >> + struct smb2_query_info_rsp *rsp; >> struct kvec iov; >> - struct kvec rsp_iov; >> + struct kvec rsp_iov = { NULL, 0 }; >> int rc = 0; >> int resp_buftype, max_len, min_len; >> struct cifs_ses *ses = tcon->ses; >> @@ -3492,7 +3498,7 @@ smb2_lockv(const unsigned int xid, struct cifs_tcon *tcon, >> int rc = 0; >> struct smb2_lock_req *req = NULL; >> struct kvec iov[2]; >> - struct kvec rsp_iov; >> + struct kvec rsp_iov = { NULL, 0 }; >> int resp_buf_type; >> unsigned int count; >> int flags = CIFS_NO_RESP; >> @@ -3525,6 +3531,7 @@ smb2_lockv(const unsigned int xid, struct cifs_tcon *tcon, >> rc = SendReceive2(xid, tcon->ses, iov, 2, &resp_buf_type, flags, >> &rsp_iov); >> cifs_small_buf_release(req); >> + free_rsp_buf(resp_buf_type, rsp_iov.iov_base); > > flags == CIFS_NO_RESP above, so, no memory leak should happen and do > not need to call free_rsp_buf(). I see. thanks. > >> if (rc) { >> cifs_dbg(FYI, "Send error in smb2_lockv = %d\n", rc); >> cifs_stats_fail_inc(tcon, SMB2_LOCK_HE); >> -- >> 2.13.3 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-cifs" in >> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > That's being said I think we need to merge "[PATCH 06/12] cifs: > initialize rsp_iov in SMB2_read and add check for NULL" with a stable > tag because it fixes the real bug. > > I am not apposite of initializing struct kvec rsp_iov to { NULL, 0 } > but it doesn't seem suitable to stable kernels because like in > SMB2_ioctl() example we do not cause problems calling > free_rsp_buf(resp_buftype, rsp) with resp_buftype == CIFS_NO_BUFFER. > > -- > Best regards, > Pavel Shilovsky > -- > To unsubscribe from this list: send the line "unsubscribe linux-cifs" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html