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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;
}
/**
* @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.
*
* @return The number of bytes read, 0 on end of file or SSH_ERROR
* on error.
* @return The number of bytes read, 0 on end of file, SSH_AGAIN on
* timeout and SSH_ERROR on error.
* @deprecated Please use ssh_channel_read instead
* @warning This function doesn't work in nonblocking/timeout mode
* @see ssh_channel_read
@@ -3032,8 +3031,6 @@ static int ssh_channel_read_termination(void *s)
return 0;
}
/* TODO: FIXME Fix the blocking behaviours */
/**
* @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.
*
* @return The number of bytes read, 0 on end of file or SSH_ERROR
* on error. In nonblocking mode it can return 0 if no data
* is available or SSH_AGAIN.
* @return The number of bytes read, 0 on end of file, SSH_AGAIN on
* timeout and SSH_ERROR on error.
*
* @warning This function may return less than count bytes of data, and won't
* 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
* infinite timeout.
*
* @return The number of bytes read, 0 on end of file or SSH_ERROR
* on error. In nonblocking mode it Can return 0 if no data
* is available or SSH_AGAIN.
* @return The number of bytes read, 0 on end of file, SSH_AGAIN on
* timeout, SSH_ERROR on error.
*
* @warning This function may return less than count bytes of data, and won't
* block until count bytes have been read.
@@ -3133,8 +3128,8 @@ int ssh_channel_read_timeout(ssh_channel channel,
timeout_ms,
ssh_channel_read_termination,
&ctx);
if (rc == SSH_ERROR){
return rc;
if (rc == SSH_ERROR || rc == SSH_AGAIN) {
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.
*
* @return The number of bytes read (0 if nothing is available),
* SSH_ERROR on error, and SSH_EOF if the channel is EOF.
* @return The number of bytes read, SSH_AGAIN if nothing is
* available, SSH_ERROR on error, and SSH_EOF if the 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)) {
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;
}
}
@@ -603,6 +603,12 @@ int ssh_scp_response(ssh_scp scp, char **response)
rc = ssh_channel_read(scp->channel, &code, 1, 0);
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;
}
@@ -760,6 +766,14 @@ int ssh_scp_read_string(ssh_scp scp, char *buffer, size_t len)
break;
}
if (err == SSH_AGAIN) {
ssh_set_error(scp->session,
SSH_FATAL,
"SCP: ssh_channel_read timeout");
err = SSH_ERROR;
break;
}
read++;
if (buffer[read - 1] == '\n') {
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);
if (rc != SSH_ERROR) {
scp->processed += rc;
} else {
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;
}
scp->processed += rc;
/* Check if we arrived at end of file */
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");
sftp_set_error(sftp, SSH_FX_EOF);
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 {
nread += s;
@@ -112,6 +118,12 @@ sftp_packet sftp_packet_read(sftp_session sftp)
"Received EOF while reading sftp packet type");
sftp_set_error(sftp, SSH_FX_EOF);
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);
@@ -147,6 +159,12 @@ sftp_packet sftp_packet_read(sftp_session sftp)
"Received EOF while reading sftp packet");
sftp_set_error(sftp, SSH_FX_EOF);
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);
}
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 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);
if(ssh_channel_request_exec(channel,cmd)==SSH_ERROR)
goto error;
if((err=ssh_channel_read(channel,buffer,sizeof(buffer)-1,0))==SSH_ERROR)
goto error;
err = ssh_channel_read(channel, buffer, sizeof(buffer) - 1, 0);
if (err == SSH_ERROR)
goto error;
if (err == SSH_AGAIN) {
fprintf(stderr, "ssh_channel_read timeout");
goto error;
}
buffer[err]=0;
if(!strstr(buffer,"go")){
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)
fprintf(stdout,"Finished upload, now waiting the ack\n");
if((err=ssh_channel_read(channel,buffer,5,0))==SSH_ERROR)
err = ssh_channel_read(channel, buffer, 5, 0);
if (err == SSH_ERROR)
goto error;
if (err == SSH_AGAIN) {
fprintf(stderr, "ssh_channel_read timeout");
goto error;
}
buffer[err]=0;
if(!strstr(buffer,"done")){
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)
toread = args->chunksize;
r=ssh_channel_read(channel,buffer,toread,0);
if(r == SSH_ERROR)
goto error;
if (r == SSH_ERROR)
goto error;
if (r == SSH_AGAIN) {
fprintf(stderr, "ssh_channel_read timeout");
goto error;
}
total += r;
}

50
tests/client/torture_sftp_packet_read.c
View File

@@ -7,31 +7,35 @@
#include "config.h"
#include "torture.h"
#include "sftp.c"
#include "torture.h"
#include <libssh/socket.h>
#include <sys/types.h>
#include <pwd.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);
return 0;
}
static int sshd_teardown(void **state) {
static int
sshd_teardown(void **state)
{
torture_teardown_sshd_server(state);
return 0;
}
static int session_setup(void **state)
static int
session_setup(void **state)
{
struct torture_state *s = *state;
struct passwd *pwd;
struct passwd *pwd = NULL;
int rc;
pwd = getpwnam("bob");
@@ -53,7 +57,8 @@ static int session_setup(void **state)
return 0;
}
static int session_teardown(void **state)
static int
session_teardown(void **state)
{
struct torture_state *s = *state;
@@ -65,31 +70,42 @@ static int session_teardown(void **state)
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_sftp *t = s->ssh.tsftp;
sftp_packet packet = NULL;
int fds[2];
int rc;
// creating blocking fd is the default pipe behaviour
/* creating blocking fd is the default pipe behaviour */
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]);
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[1]);
}
int torture_run_tests(void) {
int
torture_run_tests(void)
{
int rc;
struct CMUnitTest tests[] = {
cmocka_unit_test_setup_teardown(torture_sftp_packet_read, session_setup,
session_teardown),
cmocka_unit_test_setup_teardown(torture_sftp_packet_read,
session_setup,
session_teardown),
};
ssh_init();