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Re: FW: scp upload failure memory leak

From: Jeff Weber <jweber_at_amsc.com>
Date: Mon, 9 Jun 2008 12:20:26 -0500

Daniel:

On Mon, May 26, 2008 at 11:39:26PM +0200, Daniel Stenberg wrote:
> On Mon, 26 May 2008, Daniel Stenberg wrote:
>
>> Argh, it killed test case 612. I'll have to do some more work and get
>> back.
>
> Okay, it was test 621 it broke (me and my lousy typing!), but here's my
> updated attempt and this one doesn't break anything for me and yet it fixes
> the two memory leak cases. See the attachement. I'll commit this within a
> day or two unless someone finds problems with it.

I got this memory leak from libssh2-0.18 + libcurl 7.18.1 + ssh.c patch below,
when uploading via sftp and authenticating via user, password. I do not get a
leak when authenticating via public key.

This command line shows the leak:
# curl --netrc-optional -v -T "{/etc/termcap,/etc/passwd}" sftp://myurl/

Valgrind output:
==00:00:00:23.447 914== 170 bytes in 5 blocks are definitely lost in loss
record
 1 of 3
 ==00:00:00:23.447 914== at 0x401B504: malloc (vg_replace_malloc.c:149)
 ==00:00:00:23.447 914== by 0x404E2A3: curl_domalloc (memdebug.c:136)
 ==00:00:00:23.448 914== by 0x405B1C8: libssh2_malloc (ssh.c:281)
 ==00:00:00:23.448 914== by 0x41F607E: libssh2_packet_read (transport.c:426)
 ==00:00:00:23.448 914== by 0x41E79D8: libssh2_packet_requirev_ex
 (packet.c:12
 15)
 ==00:00:00:23.448 914== by 0x41F4E30:
 libssh2_userauth_keyboard_interactive_e
 x (userauth.c:1234)
 ==00:00:00:23.448 914== by 0x405BD15: ssh_statemach_act (ssh.c:694)
 ==00:00:00:23.448 914== by 0x405EDD3: ssh_easy_statemach (ssh.c:1987)
 ==00:00:00:23.448 914== by 0x405EF68: ssh_connect (ssh.c:2073)
 ==00:00:00:23.448 914== by 0x404077D: Curl_protocol_connect (url.c:2795)
 ==00:00:00:23.448 914== by 0x4042AE8: SetupConnection (url.c:4281)
 ==00:00:00:23.448 914== by 0x4042C2A: Curl_connect (url.c:4355)
 ==00:00:00:23.448 914== by 0x404CD0A: connect_host (transfer.c:2275)
 ==00:00:00:23.449 914== by 0x404CEAD: Curl_perform (transfer.c:2354)
 ==00:00:00:23.449 914== by 0x404D884: curl_easy_perform (easy.c:509)
 ==00:00:00:23.449 914== by 0x805156D: operate (main.c:4684)
 ==00:00:00:23.449 914== by 0x8051DA8: main (main.c:4992)

curl debug output:
* About to connect() to myhost port 22 (#0)
* Trying xxx.xxx.xxx.xxx... connected
* Connected to myhost (xxx.xxx.xxx.xxx) port 22 (#0)
* SFTP 0x4368f88 state change from SSH_STOP to SSH_S_STARTUP
* SFTP 0x4368f88 state change from SSH_S_STARTUP to SSH_AUTHLIST
* SSH authentication methods available: publickey,keyboard-interactive
* SFTP 0x4368f88 state change from SSH_AUTHLIST to SSH_AUTH_PKEY_INIT
* Using ssh public key file /root/.ssh/id_dsa.pub
* Using ssh private key file /root/.ssh/id_dsa
* SFTP 0x4368f88 state change from SSH_AUTH_PKEY_INIT to SSH_AUTH_PKEY
* SSH public key authentication failed: Unable to open public key file
* SFTP 0x4368f88 state change from SSH_AUTH_PKEY to SSH_AUTH_PASS_INIT
* SFTP 0x4368f88 state change from SSH_AUTH_PASS_INIT to SSH_AUTH_HOST_INIT
* SFTP 0x4368f88 state change from SSH_AUTH_HOST_INIT to SSH_AUTH_KEY_INIT
* SFTP 0x4368f88 state change from SSH_AUTH_KEY_INIT to SSH_AUTH_KEY
* Initialized keyboard interactive authentication
* SFTP 0x4368f88 state change from SSH_AUTH_KEY to SSH_AUTH_DONE
* Authentication complete
* SFTP 0x4368f88 state change from SSH_AUTH_DONE to SSH_SFTP_INIT
* SFTP 0x4368f88 state change from SSH_SFTP_INIT to SSH_SFTP_REALPATH
* SSH CONNECT phase done
* SFTP 0x4368f88 state change from SSH_SFTP_REALPATH to SSH_STOP
* DO phase starts
* SFTP 0x4368f88 state change from SSH_STOP to SSH_SFTP_QUOTE_INIT
* SFTP 0x4368f88 state change from SSH_SFTP_QUOTE_INIT to SSH_SFTP_TRANS_INIT
* SFTP 0x4368f88 state change from SSH_SFTP_TRANS_INIT to SSH_SFTP_UPLOAD_INIT
* SFTP 0x4368f88 state change from SSH_SFTP_UPLOAD_INIT to SSH_STOP
* DO phase is complete
} [data not shown]
  % Total % Received % Xferd Average Speed Time Time Time Current
                                 Dload Upload Total Spent Left Speed
  0 8969 0 0 0 0 0 0 --:--:-- 0:00:13 --:--:-- 0*
SFTP 0x4368f88 state change from SSH_STOP to SSH_SFTP_CLOSE
* SFTP DONE done
* SFTP 0x4368f88 state change from SSH_SFTP_CLOSE to SSH_STOP
100 8969 0 0 100 8969 0 617 0:00:14 0:00:14 --:--:-- 617*
Connection #0 to host myhost left intact

* Re-using existing connection! (#0) with host myhost
* Connected to myhost (xxx.xxx.xxx.xxx) port 22 (#0)
* DO phase starts
* SFTP 0x4368f88 state change from SSH_STOP to SSH_SFTP_QUOTE_INIT
* SFTP 0x4368f88 state change from SSH_SFTP_QUOTE_INIT to SSH_SFTP_TRANS_INIT
* SFTP 0x4368f88 state change from SSH_SFTP_TRANS_INIT to SSH_SFTP_UPLOAD_INIT
* SFTP 0x4368f88 state change from SSH_SFTP_UPLOAD_INIT to SSH_STOP
* DO phase is complete
} [data not shown]
  0 696 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0*
SFTP 0x4368f88 state change from SSH_STOP to SSH_SFTP_CLOSE
* SFTP DONE done
* SFTP 0x4368f88 state change from SSH_SFTP_CLOSE to SSH_STOP
100 696 0 0 100 696 0 1482 --:--:-- --:--:-- --:--:-- 1482*
Connection #0 to host myhost left intact

* SSH DISCONNECT starts now
* SFTP 0x4368f88 state change from SSH_STOP to SSH_SFTP_SHUTDOWN
* SFTP 0x4368f88 state change from SSH_SFTP_SHUTDOWN to SSH_SESSION_DISCONNECT
* SFTP 0x4368f88 state change from SSH_SESSION_DISCONNECT to SSH_SESSION_FREE
* SFTP 0x4368f88 state change from SSH_SESSION_FREE to SSH_STOP
* SSH DISCONNECT is done
* Closing connection #0

    Jeff
>
> --
>
> / daniel.haxx.se

> Index: lib/ssh.c
> ===================================================================
> RCS file: /cvsroot/curl/curl/lib/ssh.c,v
> retrieving revision 1.101
> diff -u -r1.101 ssh.c
> --- lib/ssh.c 21 May 2008 21:08:31 -0000 1.101
> +++ lib/ssh.c 26 May 2008 21:37:11 -0000
> @@ -1698,6 +1698,20 @@
> break;
>
> case SSH_SFTP_SHUTDOWN:
> + /* during times we get here due to a broken transfer and then the
> + sftp_handle might not have been taken down so make sure that is done
> + before we proceed */
> +
> + if(sshc->sftp_handle) {
> + rc = libssh2_sftp_close(sshc->sftp_handle);
> + if(rc == LIBSSH2_ERROR_EAGAIN) {
> + break;
> + }
> + else if(rc < 0) {
> + infof(data, "Failed to close libssh2 file\n");
> + }
> + sshc->sftp_handle = NULL;
> + }
> if(sshc->sftp_session) {
> rc = libssh2_sftp_shutdown(sshc->sftp_session);
> if(rc == LIBSSH2_ERROR_EAGAIN) {
> @@ -1893,6 +1907,20 @@
> break;
>
> case SSH_SESSION_DISCONNECT:
> + /* during weird times when we've been prematurely aborted, the channel
> + is still alive when we reach this state and we MUST kill the channel
> + properly first */
> + if(sshc->ssh_channel) {
> + rc = libssh2_channel_free(sshc->ssh_channel);
> + if(rc == LIBSSH2_ERROR_EAGAIN) {
> + break;
> + }
> + else if(rc < 0) {
> + infof(data, "Failed to free libssh2 scp subsystem\n");
> + }
> + sshc->ssh_channel = NULL;
> + }
> +
> if(sshc->ssh_session) {
> rc = libssh2_session_disconnect(sshc->ssh_session, "Shutdown");
> if(rc == LIBSSH2_ERROR_EAGAIN) {
> @@ -2152,23 +2180,25 @@
> Curl_safefree(conn->data->state.proto.ssh);
> conn->data->state.proto.ssh = NULL;
>
> - state(conn, SSH_SESSION_DISCONNECT);
> + if(conn->proto.sshc.ssh_session) {
> + /* only if there's a session still around to use! */
> +
> + state(conn, SSH_SESSION_DISCONNECT);
>
> - result = ssh_easy_statemach(conn);
> + result = ssh_easy_statemach(conn);
> + }
>
> return result;
> }
>
> -static CURLcode scp_done(struct connectdata *conn, CURLcode status,
> - bool premature)
> +/* generic done function for both SCP and SFTP called from their specific
> + done functions */
> +static CURLcode ssh_done(struct connectdata *conn, CURLcode status)
> {
> CURLcode result = CURLE_OK;
> bool done = FALSE;
> - (void)premature; /* not used */
> - (void)status; /* unused */
>
> if(status == CURLE_OK) {
> - state(conn, SSH_SCP_DONE);
> /* run the state-machine */
> if(conn->data->state.used_interface == Curl_if_multi) {
> result = ssh_multi_statemach(conn, &done);
> @@ -2185,12 +2215,25 @@
>
> if(done) {
> struct SSHPROTO *sftp_scp = conn->data->state.proto.ssh;
> +
> Curl_safefree(sftp_scp->path);
> sftp_scp->path = NULL;
> Curl_pgrsDone(conn);
> }
>
> return result;
> +}
> +
> +
> +static CURLcode scp_done(struct connectdata *conn, CURLcode status,
> + bool premature)
> +{
> + (void)premature; /* not used */
> +
> + if(status == CURLE_OK)
> + state(conn, SSH_SCP_DONE);
> +
> + return ssh_done(conn, status);
>
> }
>
> @@ -2295,8 +2338,11 @@
> Curl_safefree(conn->data->state.proto.ssh);
> conn->data->state.proto.ssh = NULL;
>
> - state(conn, SSH_SFTP_SHUTDOWN);
> - result = ssh_easy_statemach(conn);
> + if(conn->proto.sshc.ssh_session) {
> + /* only if there's a session still around to use! */
> + state(conn, SSH_SFTP_SHUTDOWN);
> + result = ssh_easy_statemach(conn);
> + }
>
> DEBUGF(infof(conn->data, "SSH DISCONNECT is done\n"));
>
> @@ -2307,12 +2353,8 @@
> static CURLcode sftp_done(struct connectdata *conn, CURLcode status,
> bool premature)
> {
> - CURLcode result = CURLE_OK;
> - bool done = FALSE;
> struct ssh_conn *sshc = &conn->proto.sshc;
>
> - (void)status; /* unused */
> -
> if(status == CURLE_OK) {
> /* Before we shut down, see if there are any post-quote commands to send: */
> if(!status && !premature && conn->data->set.postquote) {
> @@ -2321,25 +2363,8 @@
> }
> else
> state(conn, SSH_SFTP_CLOSE);
> -
> - /* run the state-machine */
> - if(conn->data->state.used_interface == Curl_if_multi)
> - result = ssh_multi_statemach(conn, &done);
> - else {
> - result = ssh_easy_statemach(conn);
> - done = TRUE;
> - }
> - }
> - else {
> - result = status;
> - done = TRUE;
> }
> -
> - if(done) {
> - Curl_pgrsDone(conn);
> - }
> -
> - return result;
> + return ssh_done(conn, status);
> }
>
> /* return number of sent bytes */

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Received on 2008-06-09

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