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wolfssh
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wolfSSHd Connection Closure 

1. Initialize all the fds to -1.
2. Add flags for peerConnected and stdoutEmpty.
3. Remove the idle counter.
4. When the socket would block on write, set a flag to check the socket for
   writing later to call the worker which will send pending data.
5. When reading the pipes, a 0 returns means the pipe is closed. Deal
   with that.
6. If the ssh write fails, interrupt the subordinate process.
7. When waiting for the peer to close its channel and shutdown, sleep
   for 100ms, rather than 1us. It takes a little while to tear down.
8. Shutdown the peer socket. Spin on receiving the peer socket until it
   closes or has an error.
9. Fixed a few function wrappers; was using Xname instead of Wname.
pull/718/head
John Safranek 2024-06-03 14:43:57 -07:00
parent 4dabe1cb94
commit 6c69c12bf7
1 changed files with 67 additions and 27 deletions
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94
apps/wolfsshd/wolfsshd.c
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@ -247,7 +247,7 @@ static byte* getBufferFromFile(const char* fileName, word32* bufSz, void* heap)
if (WFOPEN(NULL, &file, fileName, "rb") != 0)
return NULL;
WFSEEK(NULL, file, 0, XSEEK_END);
WFSEEK(NULL, file, 0, WSEEK_END);
fileSz = (word32)WFTELL(NULL, file);
WREWIND(NULL, file);
@ -1158,7 +1158,14 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
byte channelBuffer[EXAMPLE_BUFFER_SZ];
char* forcedCmd;
int windowFull = 0;
int idle = 0;
int peerConnected = 1;
int stdoutEmpty = 0;
childFd = -1;
stdoutPipe[0] = -1;
stdoutPipe[1] = -1;
stderrPipe[0] = -1;
stderrPipe[1] = -1;
forcedCmd = wolfSSHD_ConfigGetForcedCmd(usrConf);
@ -1168,7 +1175,7 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
forcedCmd = (char*)subCmd;
}
if (forcedCmd != NULL && XSTRCMP(forcedCmd, "internal-sftp") == 0) {
if (forcedCmd != NULL && WSTRCMP(forcedCmd, "internal-sftp") == 0) {
wolfSSH_Log(WS_LOG_ERROR,
"[SSHD] Only SFTP connections allowed for user "
"%s", wolfSSH_GetUsername(ssh));
@ -1216,6 +1223,8 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
if (forcedCmd) {
close(stdoutPipe[0]);
close(stderrPipe[0]);
stdoutPipe[0] = -1;
stderrPipe[0] = -1;
if (dup2(stdoutPipe[1], STDOUT_FILENO) == -1) {
wolfSSH_Log(WS_LOG_ERROR,
"[SSHD] Error redirecting stdout pipe");
@ -1288,9 +1297,7 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
setenv("SHELL", pPasswd->pw_shell, 1);
if (pPasswd->pw_shell) {
word32 shellSz = (word32)WSTRLEN(pPasswd->pw_shell);
if (shellSz < sizeof(shell)) {
if (WSTRLEN(pPasswd->pw_shell) < sizeof(shell)) {
char* cursor;
char* start;
@ -1313,12 +1320,11 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
}
/* default to /bin/sh if user shell is not set */
WMEMSET(cmd, 0, sizeof(cmd));
if (XSTRLEN(pPasswd->pw_shell) == 0) {
XSNPRINTF(cmd, sizeof(cmd), "%s", "/bin/sh");
if (pPasswd->pw_shell && WSTRLEN(pPasswd->pw_shell)) {
WSNPRINTF(cmd, sizeof(cmd), "%s", pPasswd->pw_shell);
}
else {
XSNPRINTF(cmd, sizeof(cmd),"%s", pPasswd->pw_shell);
WSNPRINTF(cmd, sizeof(cmd), "%s", "/bin/sh");
}
errno = 0;
@ -1387,20 +1393,24 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
close(stderrPipe[1]);
}
while (idle < MAX_IDLE_COUNT) {
while (ChildRunning || windowFull || !stdoutEmpty || peerConnected) {
byte tmp[2];
fd_set readFds;
fd_set writeFds;
WS_SOCKET_T maxFd;
int cnt_r;
int cnt_w;
int pending = 0;
idle++; /* increment idle count, gets reset if not idle */
FD_ZERO(&readFds);
FD_SET(sshFd, &readFds);
maxFd = sshFd;
FD_ZERO(&writeFds);
if (windowFull) {
FD_SET(sshFd, &writeFds);
}
/* select on stdout/stderr pipes with forced commands */
if (forcedCmd) {
FD_SET(stdoutPipe[0], &readFds);
@ -1418,18 +1428,18 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
}
if (wolfSSH_stream_peek(ssh, tmp, 1) <= 0) {
rc = select((int)maxFd + 1, &readFds, NULL, NULL, NULL);
rc = select((int)maxFd + 1, &readFds, &writeFds, NULL, NULL);
if (rc == -1)
break;
}
else {
pending = 1; /* found some pending SSH data */
idle = 0;
}
if (windowFull || pending || FD_ISSET(sshFd, &readFds)) {
word32 lastChannel = 0;
windowFull = 0;
/* The following tries to read from the first channel inside
the stream. If the pending data in the socket is for
another channel, this will return an error with id
@ -1440,7 +1450,6 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
if (cnt_r < 0) {
rc = wolfSSH_get_error(ssh);
if (rc == WS_CHAN_RXD) {
idle = 0;
if (lastChannel == shellChannelId) {
cnt_r = wolfSSH_ChannelIdRead(ssh, shellChannelId,
channelBuffer,
@ -1454,6 +1463,11 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
}
}
else if (rc == WS_CHANNEL_CLOSED) {
peerConnected = 0;
continue;
}
else if (rc == WS_WANT_WRITE) {
windowFull = 1;
continue;
}
else if (rc != WS_WANT_READ) {
@ -1468,7 +1482,10 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
shellBuffer, cnt_r);
if (cnt_w == WS_WINDOW_FULL) {
windowFull = 1;
idle = 0;
continue;
}
else if (cnt_w == WS_WANT_WRITE) {
windowFull = 1;
continue;
}
else {
@ -1489,13 +1506,16 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
}
else {
if (cnt_r > 0) {
idle = 0;
cnt_w = wolfSSH_extended_data_send(ssh, shellBuffer,
cnt_r);
if (cnt_w == WS_WINDOW_FULL) {
windowFull = 1;
continue;
}
else if (cnt_w == WS_WANT_WRITE) {
windowFull = 1;
continue;
}
else if (cnt_w < 0)
break;
}
@ -1507,23 +1527,31 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
cnt_r = (int)read(stdoutPipe[0], shellBuffer,
sizeof shellBuffer);
/* This read will return 0 on EOF */
if (cnt_r <= 0) {
if (cnt_r < 0) {
int err = errno;
if (err != EAGAIN && err != 0) {
break;
}
}
else if (cnt_r == 0) {
stdoutEmpty = 1;
}
else {
if (cnt_r > 0) {
idle = 0;
cnt_w = wolfSSH_ChannelIdSend(ssh, shellChannelId,
shellBuffer, cnt_r);
if (cnt_w == WS_WINDOW_FULL) {
windowFull = 1;
continue;
}
else if (cnt_w < 0)
else if (cnt_w == WS_WANT_WRITE) {
windowFull = 1;
continue;
}
else if (cnt_w < 0) {
kill(childPid, SIGINT);
break;
}
}
}
}
@ -1540,22 +1568,27 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
}
else {
if (cnt_r > 0) {
idle = 0;
cnt_w = wolfSSH_ChannelIdSend(ssh, shellChannelId,
shellBuffer, cnt_r);
if (cnt_w == WS_WINDOW_FULL) {
windowFull = 1;
continue;
}
else if (cnt_w < 0)
else if (cnt_w == WS_WANT_WRITE) {
windowFull = 1;
continue;
}
else if (cnt_w < 0) {
kill(childPid, SIGINT);
break;
}
}
}
}
}
if (ChildRunning && idle) {
idle = 0; /* waiting on child process */
if (!ChildRunning && peerConnected && stdoutEmpty && !windowFull) {
peerConnected = 0;
}
}
@ -1868,7 +1901,7 @@ static void* HandleConnection(void* arg)
#ifdef _WIN32
Sleep(1);
#else
usleep(1);
usleep(100000);
#endif
}
@ -1882,6 +1915,13 @@ static void* HandleConnection(void* arg)
/* check if there is a response to the shutdown */
wolfSSH_free(ssh);
if (conn != NULL) {
byte sc[1024];
shutdown(conn->fd, 1);
/* Spin until socket closes. */
do {
ret = (int)recv(conn->fd, sc, 1024, 0);
} while (ret > 0);
WCLOSESOCKET(conn->fd);
}
wolfSSH_Log(WS_LOG_INFO, "[SSHD] Return from closing connection = %d", ret);
@ -2037,7 +2077,7 @@ static char* _convertHelper(WCHAR* in, void* heap) {
if (ret != NULL) {
size_t numConv = 0;
if (wcstombs_s(&numConv, ret, retSz, in, retSz) != 0) {
XFREE(ret, heap, DYNTYPE_SSHD);
WFREE(ret, heap, DYNTYPE_SSHD);
ret = NULL;
}
}