From d45cb127aac2929184dce83f03627dc44e3f5b16 Mon Sep 17 00:00:00 2001
From: Michael Tremer <michael.tremer@ipfire.org>
Date: Tue, 19 Dec 2023 12:52:13 +0000
Subject: [PATCH] jail: Only connect the current terminal if requested

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---
 src/libpakfire/jail.c | 88 +++++++++++++++++++++++++------------------
 1 file changed, 51 insertions(+), 37 deletions(-)

diff --git a/src/libpakfire/jail.c b/src/libpakfire/jail.c
index a14899584..83e7af91b 100644
--- a/src/libpakfire/jail.c
+++ b/src/libpakfire/jail.c
@@ -676,6 +676,10 @@ static int pakfire_jail_drain_buffer(struct pakfire_jail* jail, int fd, struct p
 	if (!buffer->used)
 		return 0;
 
+	// Do not try to write to an invalid file descriptor
+	if (fd < 0)
+		return 0;
+
 	// Drain the buffer
 	r = write(fd, buffer->data, buffer->used);
 
@@ -926,6 +930,10 @@ static int pakfire_jail_enable_raw_mode(struct pakfire_jail* jail,
 	struct termios raw_attrs;
 	int r;
 
+	// Skip if we don't know the file descriptor
+	if (stdio->fd < 0)
+		return 0;
+
 	// Skip everything if fd is not a TTY
 	if (!isatty(stdio->fd))
 		return 0;
@@ -978,6 +986,10 @@ static int pakfire_jail_restore_attrs(struct pakfire_jail* jail,
 		const struct pakfire_jail_pty_stdio* stdio) {
 	int r;
 
+	// Skip if we don't know the file descriptor
+	if (stdio->fd < 0)
+		return 0;
+
 	// Skip everything if fd is not a TTY
 	if (!isatty(stdio->fd))
 		return 0;
@@ -1011,50 +1023,52 @@ static int pakfire_jail_setup_pty_forwarding(struct pakfire_jail* jail,
 	// Store the file descriptor
 	ctx->pty.master.fd = fd;
 
-	// Configure stdin/stdout
-	ctx->pty.stdin.fd  = STDIN_FILENO;
-	ctx->pty.stdout.fd = STDOUT_FILENO;
+	// Add the master to the event loop
+	r = pakfire_jail_epoll_add_fd(jail, epollfd, ctx->pty.master.fd, EPOLLIN|EPOLLOUT|EPOLLET);
+	if (r)
+		return r;
 
-	// Fetch dimensions
-	if (isatty(ctx->pty.stdout.fd)) {
-		r = ioctl(ctx->pty.stdout.fd, TIOCGWINSZ, &size);
-		if (r) {
-			CTX_ERROR(jail->ctx, "Failed to determine terminal dimensions: %s\n", strerror(errno));
-			return -errno;
-		}
+	if (ctx->flags & PAKFIRE_JAIL_PTY_FORWARDING) {
+		// Configure stdin/stdout
+		ctx->pty.stdin.fd  = STDIN_FILENO;
+		ctx->pty.stdout.fd = STDOUT_FILENO;
 
-		// Set dimensions
-		r = ioctl(ctx->pty.master.fd, TIOCSWINSZ, &size);
-		if (r) {
-			CTX_ERROR(jail->ctx, "Failed setting dimensions: %s\n", strerror(errno));
-			return -errno;
-		}
-	}
+		// Fetch dimensions
+		if (isatty(ctx->pty.stdout.fd)) {
+			r = ioctl(ctx->pty.stdout.fd, TIOCGWINSZ, &size);
+			if (r) {
+				CTX_ERROR(jail->ctx, "Failed to determine terminal dimensions: %s\n", strerror(errno));
+				return -errno;
+			}
 
-	// Enable RAW mode on standard input
-	r = pakfire_jail_enable_raw_mode(jail, &ctx->pty.stdin);
-	if (r)
-		return r;
+			// Set dimensions
+			r = ioctl(ctx->pty.master.fd, TIOCSWINSZ, &size);
+			if (r) {
+				CTX_ERROR(jail->ctx, "Failed setting dimensions: %s\n", strerror(errno));
+				return -errno;
+			}
+		}
 
-	// Enable RAW mode on standard output
-	r = pakfire_jail_enable_raw_mode(jail, &ctx->pty.stdout);
-	if (r)
-		return r;
+		// Enable RAW mode on standard input
+		r = pakfire_jail_enable_raw_mode(jail, &ctx->pty.stdin);
+		if (r)
+			return r;
 
-	// Add the master to the event loop
-	r = pakfire_jail_epoll_add_fd(jail, epollfd, ctx->pty.master.fd, EPOLLIN|EPOLLOUT|EPOLLET);
-	if (r)
-		return r;
+		// Enable RAW mode on standard output
+		r = pakfire_jail_enable_raw_mode(jail, &ctx->pty.stdout);
+		if (r)
+			return r;
 
-	// Add standard input to the event loop
-	r = pakfire_jail_epoll_add_fd(jail, epollfd, ctx->pty.stdin.fd, EPOLLIN|EPOLLET);
-	if (r)
-		return r;
+		// Add standard input to the event loop
+		r = pakfire_jail_epoll_add_fd(jail, epollfd, ctx->pty.stdin.fd, EPOLLIN|EPOLLET);
+		if (r)
+			return r;
 
-	// Add standard output to the event loop
-	r = pakfire_jail_epoll_add_fd(jail, epollfd, ctx->pty.stdout.fd, EPOLLOUT|EPOLLET);
-	if (r)
-		return r;
+		// Add standard output to the event loop
+		r = pakfire_jail_epoll_add_fd(jail, epollfd, ctx->pty.stdout.fd, EPOLLOUT|EPOLLET);
+		if (r)
+			return r;
+	}
 
 	return 0;
 }
-- 
2.47.2