[PATCH] Fix segfault in smbXsrv_session_create()
Jeremy Allison
jra at samba.org
Thu Mar 1 19:00:31 UTC 2018
On Thu, Mar 01, 2018 at 03:04:21PM +0100, Andreas Schneider via samba-technical wrote:
> Hi,
>
> the attached patch fixes a segfault in smbXsrv_session_create()
>
> https://bugzilla.samba.org/show_bug.cgi?id=13315
>
> The core dump I analyzed is from 4.6.2.
>
> Review is very welcome!
Good catch Andreas - I wonder how that failure
actually happened - a memory contrained system ?
RB+.
Jeremy.
>
> Andreas
>
> --
> Andreas Schneider GPG-ID: CC014E3D
> Samba Team asn at samba.org
> www.samba.org
> From 9e869efa0073cf5be214d2d5e8bf9c37e5a80162 Mon Sep 17 00:00:00 2001
> From: Andreas Schneider <asn at samba.org>
> Date: Mon, 19 Feb 2018 18:07:50 +0100
> Subject: [PATCH] s3:smbd: Do not crash if we fail to init the session table
>
> This should the following segfault with SMB1:
>
> #6 sig_fault (sig=<optimized out>) at ../lib/util/fault.c:94
> #7 <signal handler called>
> #8 smbXsrv_session_create (conn=conn at entry=0x5654d3512af0, now=now at entry=131594481900356690, _session=_session at entry=0x7ffc93a778e8)
> at ../source3/smbd/smbXsrv_session.c:1212
> #9 0x00007f7618aa21ef in reply_sesssetup_and_X (req=req at entry=0x5654d35174b0) at ../source3/smbd/sesssetup.c:961
> #10 0x00007f7618ae17b0 in switch_message (type=<optimized out>, req=req at entry=0x5654d35174b0) at ../source3/smbd/process.c:1726
> #11 0x00007f7618ae3550 in construct_reply (deferred_pcd=0x0, encrypted=false, seqnum=0, unread_bytes=0, size=140, inbuf=0x0, xconn=0x5654d35146d0)
> at ../source3/smbd/process.c:1762
> #12 process_smb (xconn=xconn at entry=0x5654d3512af0, inbuf=<optimized out>, nread=140, unread_bytes=0, seqnum=0, encrypted=<optimized out>,
> deferred_pcd=deferred_pcd at entry=0x0) at ../source3/smbd/process.c:2008
> #13 0x00007f7618ae4c41 in smbd_server_connection_read_handler (xconn=0x5654d3512af0, fd=40) at ../source3/smbd/process.c:2608
> #14 0x00007f761587eedb in epoll_event_loop_once () from /lib64/libtevent.so.0
>
> Inspection the core shows that:
> conn->client-session_table is NULL
> conn->protocol is PROTOCOL_NONE
>
> BUG: https://bugzilla.samba.org/show_bug.cgi?id=13315
>
> Signed-off-by: Andreas Schneider <asn at samba.org>
> ---
> source3/smbd/negprot.c | 23 ++++++++++++++++++++---
> 1 file changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/source3/smbd/negprot.c b/source3/smbd/negprot.c
> index 3a9363d528b..a36822e1907 100644
> --- a/source3/smbd/negprot.c
> +++ b/source3/smbd/negprot.c
> @@ -65,6 +65,8 @@ static void reply_lanman1(struct smb_request *req, uint16_t choice)
> time_t t = time(NULL);
> struct smbXsrv_connection *xconn = req->xconn;
> uint16_t raw;
> + NTSTATUS status;
> +
> if (lp_async_smb_echo_handler()) {
> raw = 0;
> } else {
> @@ -88,7 +90,11 @@ static void reply_lanman1(struct smb_request *req, uint16_t choice)
> SSVAL(req->outbuf,smb_vwv11, 8);
> }
>
> - smbXsrv_connection_init_tables(xconn, PROTOCOL_LANMAN1);
> + status = smbXsrv_connection_init_tables(xconn, PROTOCOL_LANMAN1);
> + if (!NT_STATUS_IS_OK(status)) {
> + reply_nterror(req, status);
> + return;
> + }
>
> /* Reply, SMBlockread, SMBwritelock supported. */
> SCVAL(req->outbuf,smb_flg, FLAG_REPLY|FLAG_SUPPORT_LOCKREAD);
> @@ -115,6 +121,8 @@ static void reply_lanman2(struct smb_request *req, uint16_t choice)
> time_t t = time(NULL);
> struct smbXsrv_connection *xconn = req->xconn;
> uint16_t raw;
> + NTSTATUS status;
> +
> if (lp_async_smb_echo_handler()) {
> raw = 0;
> } else {
> @@ -140,7 +148,11 @@ static void reply_lanman2(struct smb_request *req, uint16_t choice)
> SSVAL(req->outbuf,smb_vwv11, 8);
> }
>
> - smbXsrv_connection_init_tables(xconn, PROTOCOL_LANMAN2);
> + status = smbXsrv_connection_init_tables(xconn, PROTOCOL_LANMAN2);
> + if (!NT_STATUS_IS_OK(status)) {
> + reply_nterror(req, status);
> + return;
> + }
>
> /* Reply, SMBlockread, SMBwritelock supported. */
> SCVAL(req->outbuf,smb_flg,FLAG_REPLY|FLAG_SUPPORT_LOCKREAD);
> @@ -260,6 +272,7 @@ static void reply_nt1(struct smb_request *req, uint16_t choice)
> struct smbXsrv_connection *xconn = req->xconn;
> bool signing_desired = false;
> bool signing_required = false;
> + NTSTATUS status;
>
> xconn->smb1.negprot.encrypted_passwords = lp_encrypt_passwords();
>
> @@ -336,7 +349,11 @@ static void reply_nt1(struct smb_request *req, uint16_t choice)
> SSVAL(req->outbuf,smb_vwv0,choice);
> SCVAL(req->outbuf,smb_vwv1,secword);
>
> - smbXsrv_connection_init_tables(xconn, PROTOCOL_NT1);
> + status = smbXsrv_connection_init_tables(xconn, PROTOCOL_NT1);
> + if (!NT_STATUS_IS_OK(status)) {
> + reply_nterror(req, status);
> + return;
> + }
>
> SSVAL(req->outbuf,smb_vwv1+1, lp_max_mux()); /* maxmpx */
> SSVAL(req->outbuf,smb_vwv2+1, 1); /* num vcs */
> --
> 2.16.2
>
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