Adding upstream version 1.8.27.upstream/1.8.27upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 193 insertions, 0 deletions

diff --git a/src/signal.c b/src/signal.c
new file mode 100644
index 0000000..5c60225
--- /dev/null
+++ b/src/signal.c
@@ -0,0 +1,193 @@
+/*
+ * Copyright (c) 2009-2016 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+#include <config.h>
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef HAVE_STRING_H
+# include <string.h>
+#endif /* HAVE_STRING_H */
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif /* HAVE_STRINGS_H */
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+
+#include "sudo.h"
+#include "sudo_exec.h"
+
+static struct signal_state {
+    int signo;
+    int restore;
+    struct sigaction sa;
+} saved_signals[] = {
+    { SIGALRM },	/* SAVED_SIGALRM */
+    { SIGCHLD },	/* SAVED_SIGCHLD */
+    { SIGCONT },	/* SAVED_SIGCONT */
+    { SIGHUP },		/* SAVED_SIGHUP */
+    { SIGINT },		/* SAVED_SIGINT */
+    { SIGPIPE },	/* SAVED_SIGPIPE */
+    { SIGQUIT },	/* SAVED_SIGQUIT */
+    { SIGTERM },	/* SAVED_SIGTERM */
+    { SIGTSTP },	/* SAVED_SIGTSTP */
+    { SIGTTIN },	/* SAVED_SIGTTIN */
+    { SIGTTOU },	/* SAVED_SIGTTOU */
+    { SIGUSR1 },	/* SAVED_SIGUSR1 */
+    { SIGUSR2 },	/* SAVED_SIGUSR2 */
+    { -1 }
+};
+
+static sig_atomic_t pending_signals[NSIG];
+
+static void
+sudo_handler(int signo)
+{
+    /* Mark signal as pending. */
+    pending_signals[signo] = 1;
+}
+
+bool
+signal_pending(int signo)
+{
+    return pending_signals[signo] == 1;
+}
+
+/*
+ * Save signal handler state so it can be restored before exec.
+ */
+void
+save_signals(void)
+{
+    struct signal_state *ss;
+    debug_decl(save_signals, SUDO_DEBUG_MAIN)
+
+    for (ss = saved_signals; ss->signo != -1; ss++) {
+	if (sigaction(ss->signo, NULL, &ss->sa) != 0)
+	    sudo_warn(U_("unable to save handler for signal %d"), ss->signo);
+    }
+
+    debug_return;
+}
+
+/*
+ * Restore signal handlers to initial state for exec.
+ */
+void
+restore_signals(void)
+{
+    struct signal_state *ss;
+    debug_decl(restore_signals, SUDO_DEBUG_MAIN)
+
+    for (ss = saved_signals; ss->signo != -1; ss++) {
+	if (ss->restore) {
+	    sudo_debug_printf(SUDO_DEBUG_INFO,
+		"restoring handler for signal %d: %s", ss->signo,
+		ss->sa.sa_handler == SIG_IGN ? "SIG_IGN" :
+		ss->sa.sa_handler == SIG_DFL ? "SIG_DFL" : "???");
+	    if (sigaction(ss->signo, &ss->sa, NULL) != 0) {
+		sudo_warn(U_("unable to restore handler for signal %d"),
+		    ss->signo);
+	    }
+	}
+    }
+
+    debug_return;
+}
+
+/*
+ * Trap tty-generated (and other) signals so we can't be killed before
+ * calling the policy close function.  The signal pipe will be drained
+ * in sudo_execute() before running the command and new handlers will
+ * be installed in the parent.
+ */
+void
+init_signals(void)
+{
+    struct sigaction sa;
+    struct signal_state *ss;
+    debug_decl(init_signals, SUDO_DEBUG_MAIN)
+
+    memset(&sa, 0, sizeof(sa));
+    sigfillset(&sa.sa_mask);
+    sa.sa_flags = SA_RESTART;
+    sa.sa_handler = sudo_handler;
+
+    for (ss = saved_signals; ss->signo > 0; ss++) {
+	switch (ss->signo) {
+	    case SIGCONT:
+	    case SIGPIPE:
+	    case SIGTTIN:
+	    case SIGTTOU:
+		/* Don't install these until exec time. */
+		break;
+	    default:
+		if (ss->sa.sa_handler != SIG_IGN) {
+		    if (sigaction(ss->signo, &sa, NULL) != 0) {
+			sudo_warn(U_("unable to set handler for signal %d"),
+			    ss->signo);
+		    }
+		}
+		break;
+	}
+    }
+    /* Ignore SIGPIPE until exec. */
+    if (saved_signals[SAVED_SIGPIPE].sa.sa_handler != SIG_IGN) {
+	sudo_debug_printf(SUDO_DEBUG_INFO,
+	    "will restore signal %d on exec", SIGPIPE);
+	saved_signals[SAVED_SIGPIPE].restore = true;
+	sa.sa_handler = SIG_IGN;
+	if (sigaction(SIGPIPE, &sa, NULL) != 0)
+	    sudo_warn(U_("unable to set handler for signal %d"), SIGPIPE);
+    }
+
+    debug_return;
+}
+
+/*
+ * Like sigaction() but sets restore flag in saved_signals[]
+ * if needed.
+ */
+int
+sudo_sigaction(int signo, struct sigaction *sa, struct sigaction *osa)
+{
+    struct signal_state *ss;
+    int ret;
+    debug_decl(sudo_sigaction, SUDO_DEBUG_MAIN)
+
+    for (ss = saved_signals; ss->signo > 0; ss++) {
+	if (ss->signo == signo) {
+	    /* If signal was or now is ignored, restore old handler on exec. */
+	    if (ss->sa.sa_handler == SIG_IGN || sa->sa_handler == SIG_IGN) {
+		sudo_debug_printf(SUDO_DEBUG_INFO,
+		    "will restore signal %d on exec", signo);
+		ss->restore = true;
+	    }
+	    break;
+	}
+    }
+    ret = sigaction(signo, sa, osa);
+
+    debug_return_int(ret);
+}