isa/sudo
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Use pipes to the sudo process if stdout or stderr is not a tty.

Browse Source 
Still needs some polishing and a decision as to whether it is
desirable to add additonal entry points for logging stdout/stderr/stdin
when they are not ttys.  That would allow a replay program to keep
things separate and to know whether the terminal needs to be in raw
mode at replay time.
This commit is contained in:
Todd C. Miller
2010-05-03 10:12:54 -04:00
parent 5475020561
commit dd256f25ca
1 changed files with 172 additions and 142 deletions
Download Patch File Download Diff File Expand all files Collapse all files

314
src/script.c
View File

@@ -79,9 +79,12 @@
#include "sudo_plugin.h" #include "sudo_plugin.h"
#include "sudo_plugin_int.h" #include "sudo_plugin_int.h"
#define SFD_MASTER 0 #define SFD_STDIN 0
#define SFD_SLAVE 1 #define SFD_STDOUT 1
#define SFD_USERTTY 2 #define SFD_STDERR 2
#define SFD_MASTER 3
#define SFD_SLAVE 4
#define SFD_USERTTY 5
#define TERM_COOKED 0 #define TERM_COOKED 0
#define TERM_CBREAK 1 #define TERM_CBREAK 1
@@ -94,14 +97,18 @@
# define ts_cols ws_col # define ts_cols ws_col
#endif #endif
struct script_buf { struct io_buffer {
int len; /* buffer length (how much read in) */ struct io_buffer *next;
int len; /* buffer length (how much produced) */
int off; /* write position (how much already consumed) */ int off; /* write position (how much already consumed) */
int rfd; /* reader (producer) */
int wfd; /* writer (consumer) */
int (*action)(char *buf, unsigned int len);
char buf[16 * 1024]; char buf[16 * 1024];
}; };
static int script_fds[3] = { -1, -1, -1 }; static int script_fds[6] = { -1, -1, -1, -1, -1, -1};
static int ttyout; static int ttyout = TRUE;
static sig_atomic_t recvsig[NSIG]; static sig_atomic_t recvsig[NSIG];
static sig_atomic_t ttymode = TERM_COOKED; static sig_atomic_t ttymode = TERM_COOKED;
@@ -115,8 +122,8 @@ static int foreground;
static char slavename[PATH_MAX]; static char slavename[PATH_MAX];
static int suspend_parent(int signo, struct script_buf *output); static int suspend_parent(int signo, int fd, struct io_buffer *output);
static void flush_output(struct script_buf *output); static void flush_output(struct io_buffer *iobufs);
static void handler(int s); static void handler(int s);
static int script_child(const char *path, char *argv[], char *envp[], int, int); static int script_child(const char *path, char *argv[], char *envp[], int, int);
static void script_run(const char *path, char *argv[], char *envp[], int); static void script_run(const char *path, char *argv[], char *envp[], int);
@@ -202,7 +209,7 @@ check_foreground(void)
* Returns SIGUSR1 if the child should be resume in foreground else SIGUSR2. * Returns SIGUSR1 if the child should be resume in foreground else SIGUSR2.
*/ */
static int static int
suspend_parent(int signo, struct script_buf *output) suspend_parent(int signo, int fd, struct io_buffer *iobufs)
{ {
sigaction_t sa, osa; sigaction_t sa, osa;
int n, oldmode = ttymode, rval = 0; int n, oldmode = ttymode, rval = 0;
@@ -230,8 +237,8 @@ suspend_parent(int signo, struct script_buf *output)
/* FALLTHROUGH */ /* FALLTHROUGH */
case SIGSTOP: case SIGSTOP:
case SIGTSTP: case SIGTSTP:
/* Flush any remaining output to master tty. */ /* Flush any remaining output before suspending. */
flush_output(output); flush_output(iobufs);
/* Restore original tty mode before suspending. */ /* Restore original tty mode before suspending. */
if (oldmode != TERM_COOKED) { if (oldmode != TERM_COOKED) {
@@ -264,7 +271,7 @@ suspend_parent(int signo, struct script_buf *output)
ttymode == TERM_CBREAK); ttymode == TERM_CBREAK);
} while (!n && errno == EINTR); } while (!n && errno == EINTR);
} else { } else {
/* background process, no access to tty. */ /* Background process, no access to tty. */
ttymode = TERM_COOKED; ttymode = TERM_COOKED;
} }
} }
@@ -320,6 +327,21 @@ terminate_child(pid_t pid, int use_pgrp)
} }
} }
static struct io_buffer *
io_buf_new(int rfd, int wfd, int (*action)(char *, unsigned int),
struct io_buffer *head)
{
struct io_buffer *iob;
iob = emalloc(sizeof(*iob));
zero_bytes(iob, sizeof(*iob));
iob->rfd = rfd;
iob->wfd = wfd;
iob->action = action;
iob->next = head;
return iob;
}
/* /*
* This is a little bit tricky due to how POSIX job control works and * This is a little bit tricky due to how POSIX job control works and
* we fact that we have two different controlling terminals to deal with. * we fact that we have two different controlling terminals to deal with.
@@ -339,9 +361,9 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
struct command_status *cstat) struct command_status *cstat)
{ {
sigaction_t sa; sigaction_t sa;
struct script_buf input, output; struct io_buffer *iob, *iobufs = NULL;
int n, nready; int n, nready;
int sv[2]; int pv[2], sv[2];
fd_set *fdsr, *fdsw; fd_set *fdsr, *fdsw;
int rbac_enabled = 0; int rbac_enabled = 0;
int log_io, maxfd; int log_io, maxfd;
@@ -376,7 +398,7 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
zero_bytes(&sa, sizeof(sa)); zero_bytes(&sa, sizeof(sa));
sigemptyset(&sa.sa_mask); sigemptyset(&sa.sa_mask);
/* Ignore SIGPIPE from other end of socketpair. */ /* Ignore SIGPIPE, check errno instead... */
sa.sa_flags = SA_RESTART; sa.sa_flags = SA_RESTART;
sa.sa_handler = SIG_IGN; sa.sa_handler = SIG_IGN;
sigaction(SIGPIPE, &sa, NULL); sigaction(SIGPIPE, &sa, NULL);
@@ -407,8 +429,41 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
/* Are we the foreground process? */ /* Are we the foreground process? */
foreground = tcgetpgrp(script_fds[SFD_USERTTY]) == ppgrp; foreground = tcgetpgrp(script_fds[SFD_USERTTY]) == ppgrp;
/* If stdout is not a tty we handle post-processing differently. */ /*
ttyout = isatty(STDOUT_FILENO); * Setup stdin/stdout/stderr for child, to be duped after forking.
*/
/* XXX - use a pipe for stdin if not a tty? */
script_fds[SFD_STDIN] = isatty(STDIN_FILENO) ?
script_fds[SFD_SLAVE] : STDIN_FILENO;
script_fds[SFD_STDOUT] = script_fds[SFD_SLAVE];
script_fds[SFD_STDERR] = script_fds[SFD_SLAVE];
/* Copy /dev/tty -> pty master */
iobufs = io_buf_new(script_fds[SFD_USERTTY], script_fds[SFD_MASTER],
log_input, iobufs);
/* Copy pty master -> /dev/tty */
iobufs = io_buf_new(script_fds[SFD_MASTER], script_fds[SFD_USERTTY],
log_output, iobufs);
/*
* If either stdout or stderr is not a tty we use a pipe
* to interpose ourselves instead of duping the pty fd.
* NOTE: we don't currently log tty/stdout/stderr separately.
*/
if (!isatty(STDOUT_FILENO)) {
ttyout = FALSE;
if (pipe(pv) != 0)
error(1, "unable to create pipe");
iobufs = io_buf_new(pv[0], STDOUT_FILENO, log_output, iobufs);
script_fds[SFD_STDOUT] = pv[1];
}
if (!isatty(STDERR_FILENO)) {
if (pipe(pv) != 0)
error(1, "unable to create pipe");
iobufs = io_buf_new(pv[0], STDERR_FILENO, log_output, iobufs);
script_fds[SFD_STDERR] = pv[1];
}
/* Job control signals to relay from parent to child. */ /* Job control signals to relay from parent to child. */
sa.sa_flags = 0; /* do not restart syscalls */ sa.sa_flags = 0; /* do not restart syscalls */
@@ -478,25 +533,26 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
maxfd = sv[0]; maxfd = sv[0];
if (log_io) { if (log_io) {
if (maxfd < script_fds[SFD_MASTER]) /* Close the writer end of the stdout/stderr pipes. */
maxfd = script_fds[SFD_MASTER]; if (script_fds[SFD_STDOUT] != script_fds[SFD_SLAVE])
if (maxfd < script_fds[SFD_USERTTY]) close(script_fds[SFD_STDOUT]);
maxfd = script_fds[SFD_USERTTY]; if (script_fds[SFD_STDERR] != script_fds[SFD_SLAVE])
close(script_fds[SFD_STDERR]);
n = fcntl(script_fds[SFD_MASTER], F_GETFL, 0); for (iob = iobufs; iob; iob = iob->next) {
if (n != -1) { /* Determine maxfd */
n |= O_NONBLOCK; if (iob->rfd > maxfd)
(void) fcntl(script_fds[SFD_MASTER], F_SETFL, n); maxfd = iob->rfd;
} if (iob->wfd > maxfd)
n = fcntl(script_fds[SFD_USERTTY], F_GETFL, 0); maxfd = iob->wfd;
if (n != -1) {
n |= O_NONBLOCK; /* Set non-blocking mode. */
(void) fcntl(script_fds[SFD_USERTTY], F_SETFL, n); n = fcntl(iob->rfd, F_GETFL, 0);
} if (n != -1 && !ISSET(n, O_NONBLOCK))
n = fcntl(STDOUT_FILENO, F_GETFL, 0); (void) fcntl(iob->rfd, F_SETFL, n | O_NONBLOCK);
if (n != -1) { n = fcntl(iob->wfd, F_GETFL, 0);
n |= O_NONBLOCK; if (n != -1 && !ISSET(n, O_NONBLOCK))
(void) fcntl(STDOUT_FILENO, F_SETFL, n); (void) fcntl(iob->wfd, F_SETFL, n | O_NONBLOCK);
} }
} }
@@ -506,8 +562,6 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
*/ */
fdsr = (fd_set *)emalloc2(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask)); fdsr = (fd_set *)emalloc2(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask));
fdsw = (fd_set *)emalloc2(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask)); fdsw = (fd_set *)emalloc2(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask));
zero_bytes(&input, sizeof(input));
zero_bytes(&output, sizeof(output));
for (;;) { for (;;) {
if (recvsig[SIGCHLD]) { if (recvsig[SIGCHLD]) {
pid_t pid; pid_t pid;
@@ -533,22 +587,20 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
zero_bytes(fdsw, howmany(maxfd + 1, NFDBITS) * sizeof(fd_mask)); zero_bytes(fdsw, howmany(maxfd + 1, NFDBITS) * sizeof(fd_mask));
zero_bytes(fdsr, howmany(maxfd + 1, NFDBITS) * sizeof(fd_mask)); zero_bytes(fdsr, howmany(maxfd + 1, NFDBITS) * sizeof(fd_mask));
if (log_io) {
if (input.off == input.len)
input.off = input.len = 0;
if (output.off == output.len)
output.off = output.len = 0;
if (ttymode == TERM_RAW && input.len != sizeof(input.buf))
FD_SET(script_fds[SFD_USERTTY], fdsr);
if (output.len != sizeof(output.buf))
FD_SET(script_fds[SFD_MASTER], fdsr);
if (output.len > output.off)
FD_SET(STDOUT_FILENO, fdsw);
if (input.len > input.off)
FD_SET(script_fds[SFD_MASTER], fdsw);
}
FD_SET(sv[0], fdsr); FD_SET(sv[0], fdsr);
for (iob = iobufs; iob; iob = iob->next) {
if (iob->off == iob->len)
iob->off = iob->len = 0;
/* Don't read/write /dev/tty if we are not in the foreground. */
if (ttymode == TERM_RAW || iob->rfd != script_fds[SFD_USERTTY]) {
if (iob->len != sizeof(iob->buf))
FD_SET(iob->rfd, fdsr);
}
if (ttymode == TERM_RAW || iob->wfd != script_fds[SFD_USERTTY]) {
if (iob->len > iob->off)
FD_SET(iob->wfd, fdsw);
}
}
for (n = 0; n < NSIG; n++) { for (n = 0; n < NSIG; n++) {
if (recvsig[n] && n != SIGCHLD) { if (recvsig[n] && n != SIGCHLD) {
if (log_io) { if (log_io) {
@@ -587,7 +639,7 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
if (WIFSTOPPED(cstat->val)) { if (WIFSTOPPED(cstat->val)) {
/* Suspend parent and tell child how to resume on return. */ /* Suspend parent and tell child how to resume on return. */
sudo_debug(8, "child stopped, suspending parent"); sudo_debug(8, "child stopped, suspending parent");
n = suspend_parent(WSTOPSIG(cstat->val), &output); n = suspend_parent(WSTOPSIG(cstat->val), script_fds[SFD_USERTTY], iobufs);
recvsig[n] = TRUE; recvsig[n] = TRUE;
continue; continue;
} else { } else {
@@ -599,8 +651,6 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
break; break;
} }
} }
if (!log_io)
continue;
if (FD_ISSET(sv[0], fdsw)) { if (FD_ISSET(sv[0], fdsw)) {
for (n = 0; n < NSIG; n++) { for (n = 0; n < NSIG; n++) {
@@ -619,72 +669,49 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
} }
} }
} }
if (FD_ISSET(script_fds[SFD_USERTTY], fdsr)) {
n = read(script_fds[SFD_USERTTY], input.buf + input.len, for (iob = iobufs; iob; iob = iob->next) {
sizeof(input.buf) - input.len); if (FD_ISSET(iob->rfd, fdsr)) {
if (n == -1) { n = read(iob->rfd, iob->buf + iob->len,
if (errno == EINTR) sizeof(iob->buf) - iob->len);
continue; if (n == -1) {
if (errno != EAGAIN) if (errno == EINTR)
break; continue;
} else { if (errno != EAGAIN)
if (n == 0) break;
break; /* got EOF */ } else {
if (!log_input(input.buf + input.len, n)) if (n == 0)
terminate_child(child, TRUE); break; /* got EOF */
input.len += n; if (!iob->action(iob->buf + iob->len, n))
terminate_child(child, TRUE);
iob->len += n;
}
} }
} if (FD_ISSET(iob->wfd, fdsw)) {
if (FD_ISSET(script_fds[SFD_MASTER], fdsw)) { n = write(iob->wfd, iob->buf + iob->off,
n = write(script_fds[SFD_MASTER], input.buf + input.off, iob->len - iob->off);
input.len - input.off); if (n == -1) {
if (n == -1) { if (errno == EINTR)
if (errno == EINTR) continue;
continue; if (errno != EAGAIN)
if (errno != EAGAIN) break;
break; } else {
} else { iob->off += n;
input.off += n; }
}
}
if (FD_ISSET(script_fds[SFD_MASTER], fdsr)) {
n = read(script_fds[SFD_MASTER], output.buf + output.len,
sizeof(output.buf) - output.len);
if (n == -1) {
if (errno == EINTR)
continue;
if (errno != EAGAIN)
break;
} else {
if (n == 0)
break; /* got EOF */
if (!log_output(output.buf + output.len, n))
terminate_child(child, TRUE);
output.len += n;
}
}
if (FD_ISSET(STDOUT_FILENO, fdsw)) {
n = write(STDOUT_FILENO, output.buf + output.off,
output.len - output.off);
if (n == -1) {
if (errno == EINTR)
continue;
if (errno != EAGAIN)
break;
} else {
output.off += n;
} }
} }
} }
if (log_io) { if (log_io) {
/* Flush any remaining output to stdout (plugin already got it) */ /* Flush any remaining output (the plugin already got it) */
n = fcntl(STDOUT_FILENO, F_GETFL, 0); for (iob = iobufs; iob; iob = iob->next) {
if (n != -1) { n = fcntl(iob->wfd, F_GETFL, 0);
n &= ~O_NONBLOCK; if (n != -1 && ISSET(n, O_NONBLOCK)) {
(void) fcntl(STDOUT_FILENO, F_SETFL, n); CLR(n, O_NONBLOCK);
(void) fcntl(iob->wfd, F_SETFL, n);
}
} }
flush_output(&output); flush_output(iobufs);
do { do {
n = term_restore(script_fds[SFD_USERTTY], 0); n = term_restore(script_fds[SFD_USERTTY], 0);
@@ -694,10 +721,10 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
int signo = WTERMSIG(cstat->val); int signo = WTERMSIG(cstat->val);
if (signo && signo != SIGINT && signo != SIGPIPE) { if (signo && signo != SIGINT && signo != SIGPIPE) {
char *reason = strsignal(signo); char *reason = strsignal(signo);
write(STDOUT_FILENO, reason, strlen(reason)); write(script_fds[SFD_USERTTY], reason, strlen(reason));
if (WCOREDUMP(cstat->val)) if (WCOREDUMP(cstat->val))
write(STDOUT_FILENO, " (core dumped)", 14); write(script_fds[SFD_USERTTY], " (core dumped)", 14);
write(STDOUT_FILENO, "\n", 1); write(script_fds[SFD_USERTTY], "\n", 1);
} }
} }
} }
@@ -979,34 +1006,38 @@ bad:
} }
static void static void
flush_output(struct script_buf *output) flush_output(struct io_buffer *iobufs)
{ {
struct io_buffer *iob, output;
int n; int n;
while (output->len > output->off) { /* XXX - really only want to flush output buffers, does it matter? */
n = write(STDOUT_FILENO, output->buf + output->off, for (iob = iobufs; iob; iob = iob->next) {
output->len - output->off); while (iob->len > iob->off) {
if (n <= 0) n = write(iob->wfd, iob->buf + iob->off, iob->len - iob->off);
break; if (n <= 0)
output->off += n; break;
iob->off += n;
}
} }
/* Make sure there is no output remaining on the master pty. */ /* Make sure there is no output remaining on the master pty. */
/* XXX - pipes too? */
for (;;) { for (;;) {
n = read(script_fds[SFD_MASTER], output->buf, sizeof(output->buf)); n = read(script_fds[SFD_MASTER], output.buf, sizeof(output.buf));
if (n <= 0) if (n <= 0)
break; break;
/* XXX */ /* XXX */
log_output(output->buf, n); log_output(output.buf, n);
output->off = 0; output.off = 0;
output->len = n; output.len = n;
do { do {
n = write(STDOUT_FILENO, output->buf + output->off, n = write(script_fds[SFD_USERTTY], output.buf + output.off,
output->len - output->off); output.len - output.off);
if (n <= 0) if (n <= 0)
break; break;
output->off += n; output.off += n;
} while (output->len > output->off); } while (output.len > output.off);
} }
} }
@@ -1018,21 +1049,20 @@ script_run(const char *path, char *argv[], char *envp[], int rbac_enabled)
/* Set child process group here too to avoid a race. */ /* Set child process group here too to avoid a race. */
setpgid(0, self); setpgid(0, self);
/* /* Wire up standard fds, note that stdout/stderr may be pipes. */
* We have guaranteed that the slave fd > 3 dup2(script_fds[SFD_STDIN], STDIN_FILENO);
*/ dup2(script_fds[SFD_STDOUT], STDOUT_FILENO);
if (isatty(STDIN_FILENO)) dup2(script_fds[SFD_STDERR], STDERR_FILENO);
dup2(script_fds[SFD_SLAVE], STDIN_FILENO);
dup2(script_fds[SFD_SLAVE], STDOUT_FILENO);
dup2(script_fds[SFD_SLAVE], STDERR_FILENO);
close(script_fds[SFD_SLAVE]);
/* Wait for parent to grant us the tty if we are foreground. */ /* Wait for parent to grant us the tty if we are foreground. */
if (foreground) { if (foreground) {
while (tcgetpgrp(STDOUT_FILENO) != self) while (tcgetpgrp(script_fds[SFD_SLAVE]) != self)
; /* spin */ ; /* spin */
} }
/* We have guaranteed that the slave fd > 3 */
close(script_fds[SFD_SLAVE]);
#ifdef HAVE_SELINUX #ifdef HAVE_SELINUX
if (rbac_enabled) if (rbac_enabled)
selinux_execve(path, argv, envp); selinux_execve(path, argv, envp);