1 files changed, 268 insertions, 0 deletions
diff --git a/src/sesh.c b/src/sesh.c
new file mode 100644
index 0000000..873748e
--- /dev/null
+++ b/src/sesh.c
@@ -0,0 +1,268 @@
+/*
+ * Copyright (c) 2008, 2010-2018 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 <sys/stat.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <signal.h>
+#include <time.h>
+#include <unistd.h>
+#ifdef HAVE_STDBOOL_H
+# include <stdbool.h>
+#else
+# include "compat/stdbool.h"
+#endif /* HAVE_STDBOOL_H */
+
+#include "sudo_gettext.h"	/* must be included before sudo_compat.h */
+
+#include "sudo_compat.h"
+#include "sudo_fatal.h"
+#include "sudo_conf.h"
+#include "sudo_debug.h"
+#include "sudo_exec.h"
+#include "sudo_plugin.h"
+#include "sudo_util.h"
+
+__dso_public int main(int argc, char *argv[], char *envp[]);
+
+static int sesh_sudoedit(int argc, char *argv[]);
+
+/*
+ * Exit codes defined in sudo_exec.h:
+ *  SESH_SUCCESS (0)         ... successful operation
+ *  SESH_ERR_FAILURE (1)     ... unspecified error
+ *  SESH_ERR_INVALID (30)    ... invalid -e arg value
+ *  SESH_ERR_BAD_PATHS (31)  ... odd number of paths
+ *  SESH_ERR_NO_FILES (32)   ... copy error, no files copied
+ *  SESH_ERR_SOME_FILES (33) ... copy error, no files copied
+ */
+int
+main(int argc, char *argv[], char *envp[])
+{
+    int ret;
+    debug_decl(main, SUDO_DEBUG_MAIN)
+
+    initprogname(argc > 0 ? argv[0] : "sesh");
+
+    setlocale(LC_ALL, "");
+    bindtextdomain(PACKAGE_NAME, LOCALEDIR);
+    textdomain(PACKAGE_NAME);
+
+    if (argc < 2)
+	sudo_fatalx(U_("requires at least one argument"));
+
+    /* Read sudo.conf and initialize the debug subsystem. */
+    if (sudo_conf_read(NULL, SUDO_CONF_DEBUG) == -1)
+	exit(EXIT_FAILURE);
+    sudo_debug_register(getprogname(), NULL, NULL,
+	sudo_conf_debug_files(getprogname()));
+
+    if (strcmp(argv[1], "-e") == 0) {
+	ret = sesh_sudoedit(argc, argv);
+    } else {
+	bool login_shell, noexec = false;
+	char *cp, *cmnd;
+	int fd = -1;
+
+	/* If the first char of argv[0] is '-', we are running a login shell. */
+	login_shell = argv[0][0] == '-';
+
+	/* If argv[0] ends in -noexec, pass the flag to sudo_execve() */
+	if ((cp = strrchr(argv[0], '-')) != NULL && cp != argv[0])
+	    noexec = strcmp(cp, "-noexec") == 0;
+
+	/* If argv[1] is --execfd=%d, extract the fd to exec with. */
+	if (strncmp(argv[1], "--execfd=", 9) == 0) {
+	    const char *errstr;
+
+	    cp = argv[1] + 9;
+	    fd = strtonum(cp, 0, INT_MAX, &errstr);
+	    if (errstr != NULL)
+		sudo_fatalx(U_("invalid file descriptor number: %s"), cp);
+	    argv++;
+	    argc--;
+	}
+
+	/* Shift argv and make a copy of the command to execute. */
+	argv++;
+	argc--;
+	if ((cmnd = strdup(argv[0])) == NULL)
+	    sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+
+	/* If invoked as a login shell, modify argv[0] accordingly. */
+	if (login_shell) {
+	    if ((cp = strrchr(argv[0], '/')) == NULL)
+		sudo_fatal(U_("unable to run %s as a login shell"), argv[0]);
+	    *cp = '-';
+	    argv[0] = cp;
+	}
+	sudo_execve(fd, cmnd, argv, envp, noexec);
+	sudo_warn(U_("unable to execute %s"), cmnd);
+	ret = SESH_ERR_FAILURE;
+    }
+    sudo_debug_exit_int(__func__, __FILE__, __LINE__, sudo_debug_subsys, ret);
+    _exit(ret);
+}
+
+static int
+sesh_sudoedit(int argc, char *argv[])
+{
+    int i, oflags_dst, post, ret = SESH_ERR_FAILURE;
+    int fd_src = -1, fd_dst = -1, follow = 0;
+    ssize_t nread, nwritten;
+    struct stat sb;
+    struct timespec times[2];
+    char buf[BUFSIZ];
+    debug_decl(sesh_sudoedit, SUDO_DEBUG_EDIT)
+
+    /* Check for -h flag (don't follow links). */
+    if (strcmp(argv[2], "-h") == 0) {
+	argv++;
+	argc--;
+	follow = O_NOFOLLOW;
+    }
+
+    if (argc < 3)
+	debug_return_int(SESH_ERR_FAILURE);
+
+    /*
+     * We need to know whether we are performing the copy operation
+     * before or after the editing. Without this we would not know
+     * which files are temporary and which are the originals.
+     *  post = 0 ... before
+     *  post = 1 ... after
+     */
+    if (strcmp(argv[2], "0") == 0)
+	post = 0;
+    else if (strcmp(argv[2], "1") == 0)
+	post = 1;
+    else /* invalid value */
+	debug_return_int(SESH_ERR_INVALID);
+
+    /* Align argv & argc to the beggining of the file list. */
+    argv += 3;
+    argc -= 3;
+
+    /* no files specified, nothing to do */
+    if (argc == 0)
+	debug_return_int(SESH_SUCCESS);
+    /* odd number of paths specified */
+    if (argc & 1)
+	debug_return_int(SESH_ERR_BAD_PATHS);
+
+    /*
+     * Use O_EXCL if we are not in the post editing stage
+     * so that it's ensured that the temporary files are
+     * created by us and that we are not opening any symlinks.
+     */
+    oflags_dst = O_WRONLY|O_TRUNC|O_CREAT|(post ? follow : O_EXCL);
+    for (i = 0; i < argc - 1; i += 2) {
+	const char *path_src = argv[i];
+	const char *path_dst = argv[i + 1];
+	/*
+	 * Try to open the source file for reading. If it
+	 * doesn't exist, that's OK, we'll create an empty
+	 * destination file.
+	 */
+	if ((fd_src = open(path_src, O_RDONLY|follow, S_IRUSR|S_IWUSR)) < 0) {
+	    if (errno != ENOENT) {
+		sudo_warn("%s", path_src);
+		if (post) {
+		    ret = SESH_ERR_SOME_FILES;
+		    goto nocleanup;
+		} else
+		    goto cleanup_0;
+	    }
+	}
+
+	if ((fd_dst = open(path_dst, oflags_dst, post ?
+	    (S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH) : (S_IRUSR|S_IWUSR))) < 0) {
+	    /* error - cleanup */
+	    sudo_warn("%s", path_dst);
+	    if (post) {
+		ret = SESH_ERR_SOME_FILES;
+		goto nocleanup;
+	    } else
+		goto cleanup_0;
+	}
+
+	if (fd_src != -1) {
+	    while ((nread = read(fd_src, buf, sizeof(buf))) > 0) {
+		if ((nwritten = write(fd_dst, buf, nread)) != nread) {
+		    sudo_warn("%s", path_src);
+		    if (post) {
+			ret = SESH_ERR_SOME_FILES;
+			goto nocleanup;
+		    } else
+			goto cleanup_0;
+		}
+	    }
+	}
+
+	if (!post) {
+	    if (fd_src == -1 || fstat(fd_src, &sb) != 0)
+		memset(&sb, 0, sizeof(sb));
+	    /* Make mtime on temp file match src. */
+	    mtim_get(&sb, times[0]);
+	    times[1].tv_sec = times[0].tv_sec;
+	    times[1].tv_nsec = times[0].tv_nsec;
+	    if (futimens(fd_dst, times) == -1) {
+		if (utimensat(AT_FDCWD, path_dst, times, 0) == -1)
+		    sudo_warn("%s", path_dst);
+	    }
+	}
+	close(fd_dst);
+	fd_dst = -1;
+	if (fd_src != -1) {
+	    close(fd_src);
+	    fd_src = -1;
+	}
+    }
+
+    ret = SESH_SUCCESS;
+    if (post) {
+	/* Remove temporary files (post=1) */
+	for (i = 0; i < argc - 1; i += 2)
+	    unlink(argv[i]);
+    }
+nocleanup:
+    if (fd_dst != -1)
+	close(fd_dst);
+    if (fd_src != -1)
+	close(fd_src);
+    return(ret);
+cleanup_0:
+    /* Remove temporary files (post=0) */
+    for (i = 0; i < argc - 1; i += 2)
+	unlink(argv[i + 1]);
+    if (fd_dst != -1)
+	close(fd_dst);
+    if (fd_src != -1)
+	close(fd_src);
+    return(SESH_ERR_NO_FILES);
+}