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fix: sftp_packet_read stuck in an infinite loop in blocking mode

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Signed-off-by: Liu Husong <huliu@janestreet.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Eshan Kelkar <eshankelkar@galorithm.com>
This commit is contained in:
Liu Husong
2024-06-04 00:53:31 +08:00
committed by husong998
parent c662bcc466
commit 2d3b7e07af
5 changed files with 104 additions and 43 deletions
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25
src/channels.c
View File

@@ -2925,7 +2925,6 @@ error:
return rc; return rc;
} }
/** /**
* @brief Read data from a channel into a buffer. * @brief Read data from a channel into a buffer.
* *
@@ -2939,8 +2938,8 @@ error:
* *
* @param is_stderr A boolean value to mark reading from the stderr stream. * @param is_stderr A boolean value to mark reading from the stderr stream.
* *
* @return The number of bytes read, 0 on end of file or SSH_ERROR * @return The number of bytes read, 0 on end of file, SSH_AGAIN on
* on error. * timeout and SSH_ERROR on error.
* @deprecated Please use ssh_channel_read instead * @deprecated Please use ssh_channel_read instead
* @warning This function doesn't work in nonblocking/timeout mode * @warning This function doesn't work in nonblocking/timeout mode
* @see ssh_channel_read * @see ssh_channel_read
@@ -3032,8 +3031,6 @@ static int ssh_channel_read_termination(void *s)
return 0; return 0;
} }
/* TODO: FIXME Fix the blocking behaviours */
/** /**
* @brief Reads data from a channel. * @brief Reads data from a channel.
* *
@@ -3045,9 +3042,8 @@ static int ssh_channel_read_termination(void *s)
* *
* @param[in] is_stderr A boolean value to mark reading from the stderr flow. * @param[in] is_stderr A boolean value to mark reading from the stderr flow.
* *
* @return The number of bytes read, 0 on end of file or SSH_ERROR * @return The number of bytes read, 0 on end of file, SSH_AGAIN on
* on error. In nonblocking mode it can return 0 if no data * timeout and SSH_ERROR on error.
* is available or SSH_AGAIN.
* *
* @warning This function may return less than count bytes of data, and won't * @warning This function may return less than count bytes of data, and won't
* block until count bytes have been read. * block until count bytes have been read.
@@ -3075,9 +3071,8 @@ int ssh_channel_read(ssh_channel channel, void *dest, uint32_t count, int is_std
* @param[in] timeout_ms A timeout in milliseconds. A value of -1 means * @param[in] timeout_ms A timeout in milliseconds. A value of -1 means
* infinite timeout. * infinite timeout.
* *
* @return The number of bytes read, 0 on end of file or SSH_ERROR * @return The number of bytes read, 0 on end of file, SSH_AGAIN on
* on error. In nonblocking mode it Can return 0 if no data * timeout, SSH_ERROR on error.
* is available or SSH_AGAIN.
* *
* @warning This function may return less than count bytes of data, and won't * @warning This function may return less than count bytes of data, and won't
* block until count bytes have been read. * block until count bytes have been read.
@@ -3133,8 +3128,8 @@ int ssh_channel_read_timeout(ssh_channel channel,
timeout_ms, timeout_ms,
ssh_channel_read_termination, ssh_channel_read_termination,
&ctx); &ctx);
if (rc == SSH_ERROR){ if (rc == SSH_ERROR || rc == SSH_AGAIN) {
return rc; return rc;
} }
/* /*
@@ -3188,8 +3183,8 @@ int ssh_channel_read_timeout(ssh_channel channel,
* *
* @param[in] is_stderr A boolean to select the stderr stream. * @param[in] is_stderr A boolean to select the stderr stream.
* *
* @return The number of bytes read (0 if nothing is available), * @return The number of bytes read, SSH_AGAIN if nothing is
* SSH_ERROR on error, and SSH_EOF if the channel is EOF. * available, SSH_ERROR on error, and SSH_EOF if the channel is EOF.
* *
* @see ssh_channel_is_eof() * @see ssh_channel_is_eof()
*/ */

26
src/scp.c
View File

@@ -266,7 +266,7 @@ int ssh_scp_close(ssh_scp scp)
*/ */
while (!ssh_channel_is_eof(scp->channel)) { while (!ssh_channel_is_eof(scp->channel)) {
rc = ssh_channel_read(scp->channel, buffer, sizeof(buffer), 0); rc = ssh_channel_read(scp->channel, buffer, sizeof(buffer), 0);
if (rc == SSH_ERROR || rc == 0) { if (rc == SSH_ERROR || rc == SSH_AGAIN || rc == 0) {
break; break;
} }
} }
@@ -603,6 +603,12 @@ int ssh_scp_response(ssh_scp scp, char **response)
rc = ssh_channel_read(scp->channel, &code, 1, 0); rc = ssh_channel_read(scp->channel, &code, 1, 0);
if (rc == SSH_ERROR) { if (rc == SSH_ERROR) {
scp->state = SSH_SCP_ERROR;
return SSH_ERROR;
}
if (rc == SSH_AGAIN) {
ssh_set_error(scp->session, SSH_FATAL, "SCP: ssh_channel_read timeout");
scp->state = SSH_SCP_ERROR;
return SSH_ERROR; return SSH_ERROR;
} }
@@ -760,6 +766,14 @@ int ssh_scp_read_string(ssh_scp scp, char *buffer, size_t len)
break; break;
} }
if (err == SSH_AGAIN) {
ssh_set_error(scp->session,
SSH_FATAL,
"SCP: ssh_channel_read timeout");
err = SSH_ERROR;
break;
}
read++; read++;
if (buffer[read - 1] == '\n') { if (buffer[read - 1] == '\n') {
break; break;
@@ -1027,12 +1041,16 @@ int ssh_scp_read(ssh_scp scp, void *buffer, size_t size)
} }
rc = ssh_channel_read(scp->channel, buffer, size, 0); rc = ssh_channel_read(scp->channel, buffer, size, 0);
if (rc != SSH_ERROR) { if (rc == SSH_ERROR) {
scp->processed += rc;
} else {
scp->state = SSH_SCP_ERROR; scp->state = SSH_SCP_ERROR;
return SSH_ERROR; return SSH_ERROR;
} }
if (rc == SSH_AGAIN) {
ssh_set_error(scp->session, SSH_FATAL, "SCP: ssh_channel_read timeout");
scp->state = SSH_SCP_ERROR;
return SSH_ERROR;
}
scp->processed += rc;
/* Check if we arrived at end of file */ /* Check if we arrived at end of file */
if (scp->processed == scp->filelen) { if (scp->processed == scp->filelen) {

21
src/sftp_common.c
View File

@@ -87,6 +87,12 @@ sftp_packet sftp_packet_read(sftp_session sftp)
"Received EOF while reading sftp packet size"); "Received EOF while reading sftp packet size");
sftp_set_error(sftp, SSH_FX_EOF); sftp_set_error(sftp, SSH_FX_EOF);
goto error; goto error;
} else {
ssh_set_error(sftp->session,
SSH_FATAL,
"Timeout while reading sftp packet size");
sftp_set_error(sftp, SSH_FX_FAILURE);
goto error;
} }
} else { } else {
nread += s; nread += s;
@@ -112,6 +118,12 @@ sftp_packet sftp_packet_read(sftp_session sftp)
"Received EOF while reading sftp packet type"); "Received EOF while reading sftp packet type");
sftp_set_error(sftp, SSH_FX_EOF); sftp_set_error(sftp, SSH_FX_EOF);
goto error; goto error;
} else {
ssh_set_error(sftp->session,
SSH_FATAL,
"Timeout while reading sftp packet type");
sftp_set_error(sftp, SSH_FX_FAILURE);
goto error;
} }
} }
} while (nread < 1); } while (nread < 1);
@@ -147,6 +159,12 @@ sftp_packet sftp_packet_read(sftp_session sftp)
"Received EOF while reading sftp packet"); "Received EOF while reading sftp packet");
sftp_set_error(sftp, SSH_FX_EOF); sftp_set_error(sftp, SSH_FX_EOF);
goto error; goto error;
} else {
ssh_set_error(sftp->session,
SSH_FATAL,
"Timeout while reading sftp packet");
sftp_set_error(sftp, SSH_FX_FAILURE);
goto error;
} }
} }
} }
@@ -697,7 +715,8 @@ static void request_queue_free(sftp_request_queue queue)
SAFE_FREE(queue); SAFE_FREE(queue);
} }
static int sftp_enqueue(sftp_session sftp, sftp_message msg) static int
sftp_enqueue(sftp_session sftp, sftp_message msg)
{ {
sftp_request_queue queue = NULL; sftp_request_queue queue = NULL;
sftp_request_queue ptr; sftp_request_queue ptr;

25
tests/benchmarks/bench_raw.c
View File

@@ -135,8 +135,13 @@ int benchmarks_raw_up (ssh_session session, struct argument_s *args,
snprintf(cmd,sizeof(cmd),"%s /tmp/eater.py", PYTHON_PATH); snprintf(cmd,sizeof(cmd),"%s /tmp/eater.py", PYTHON_PATH);
if(ssh_channel_request_exec(channel,cmd)==SSH_ERROR) if(ssh_channel_request_exec(channel,cmd)==SSH_ERROR)
goto error; goto error;
if((err=ssh_channel_read(channel,buffer,sizeof(buffer)-1,0))==SSH_ERROR) err = ssh_channel_read(channel, buffer, sizeof(buffer) - 1, 0);
goto error; if (err == SSH_ERROR)
goto error;
if (err == SSH_AGAIN) {
fprintf(stderr, "ssh_channel_read timeout");
goto error;
}
buffer[err]=0; buffer[err]=0;
if(!strstr(buffer,"go")){ if(!strstr(buffer,"go")){
fprintf(stderr,"parse error : %s\n",buffer); fprintf(stderr,"parse error : %s\n",buffer);
@@ -160,9 +165,13 @@ int benchmarks_raw_up (ssh_session session, struct argument_s *args,
if(args->verbose>0) if(args->verbose>0)
fprintf(stdout,"Finished upload, now waiting the ack\n"); fprintf(stdout,"Finished upload, now waiting the ack\n");
err = ssh_channel_read(channel, buffer, 5, 0);
if((err=ssh_channel_read(channel,buffer,5,0))==SSH_ERROR) if (err == SSH_ERROR)
goto error; goto error;
if (err == SSH_AGAIN) {
fprintf(stderr, "ssh_channel_read timeout");
goto error;
}
buffer[err]=0; buffer[err]=0;
if(!strstr(buffer,"done")){ if(!strstr(buffer,"done")){
fprintf(stderr,"parse error : %s\n",buffer); fprintf(stderr,"parse error : %s\n",buffer);
@@ -272,8 +281,12 @@ int benchmarks_raw_down (ssh_session session, struct argument_s *args,
if(toread > args->chunksize) if(toread > args->chunksize)
toread = args->chunksize; toread = args->chunksize;
r=ssh_channel_read(channel,buffer,toread,0); r=ssh_channel_read(channel,buffer,toread,0);
if(r == SSH_ERROR) if (r == SSH_ERROR)
goto error; goto error;
if (r == SSH_AGAIN) {
fprintf(stderr, "ssh_channel_read timeout");
goto error;
}
total += r; total += r;
} }

50
tests/client/torture_sftp_packet_read.c
View File

@@ -7,31 +7,35 @@
#include "config.h" #include "config.h"
#include "torture.h"
#include "sftp.c" #include "sftp.c"
#include "torture.h"
#include <libssh/socket.h>
#include <sys/types.h>
#include <pwd.h>
#include <errno.h> #include <errno.h>
#include <libssh/socket.h>
#include <pwd.h>
#include <sys/types.h>
static int sshd_setup(void **state) static int
sshd_setup(void **state)
{ {
torture_setup_sshd_server(state, false); torture_setup_sshd_server(state, false);
return 0; return 0;
} }
static int sshd_teardown(void **state) { static int
sshd_teardown(void **state)
{
torture_teardown_sshd_server(state); torture_teardown_sshd_server(state);
return 0; return 0;
} }
static int session_setup(void **state) static int
session_setup(void **state)
{ {
struct torture_state *s = *state; struct torture_state *s = *state;
struct passwd *pwd; struct passwd *pwd = NULL;
int rc; int rc;
pwd = getpwnam("bob"); pwd = getpwnam("bob");
@@ -53,7 +57,8 @@ static int session_setup(void **state)
return 0; return 0;
} }
static int session_teardown(void **state) static int
session_teardown(void **state)
{ {
struct torture_state *s = *state; struct torture_state *s = *state;
@@ -65,31 +70,42 @@ static int session_teardown(void **state)
return 0; return 0;
} }
static void torture_sftp_packet_read(void **state) { static void
torture_sftp_packet_read(void **state)
{
struct torture_state *s = *state; struct torture_state *s = *state;
struct torture_sftp *t = s->ssh.tsftp; struct torture_sftp *t = s->ssh.tsftp;
sftp_packet packet = NULL;
int fds[2]; int fds[2];
int rc; int rc;
// creating blocking fd is the default pipe behaviour /* creating blocking fd is the default pipe behaviour */
rc = pipe(fds); rc = pipe(fds);
assert_true(rc == 0); assert_return_code(rc, errno);
t->ssh->opts.timeout = 1;
ssh_socket_set_fd(t->ssh->socket, fds[0]); ssh_socket_set_fd(t->ssh->socket, fds[0]);
rc = sftp_packet_read(t->sftp); /*
assert_true(rc == SSH_AGAIN); * Making sure that the sftp_packet_read function times out and returns
* NULL.
*/
packet = sftp_packet_read(t->sftp);
assert_null(packet);
close(fds[0]); close(fds[0]);
close(fds[1]); close(fds[1]);
} }
int torture_run_tests(void) { int
torture_run_tests(void)
{
int rc; int rc;
struct CMUnitTest tests[] = { struct CMUnitTest tests[] = {
cmocka_unit_test_setup_teardown(torture_sftp_packet_read, session_setup, cmocka_unit_test_setup_teardown(torture_sftp_packet_read,
session_teardown), session_setup,
session_teardown),
}; };
ssh_init(); ssh_init();