Adding upstream version 1.8.27.upstream/1.8.27upstream

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

1 files changed, 219 insertions, 0 deletions

diff --git a/src/exec_common.c b/src/exec_common.c
new file mode 100644
index 0000000..53abdbf
--- /dev/null
+++ b/src/exec_common.c
@@ -0,0 +1,219 @@
+/*
+ * 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>
+#ifdef HAVE_PRIV_SET
+# include <priv.h>
+#endif
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+
+#include "sudo.h"
+#include "sudo_exec.h"
+
+#ifdef RTLD_PRELOAD_VAR
+/*
+ * Add a DSO file to LD_PRELOAD or the system equivalent.
+ */
+static char **
+preload_dso(char *envp[], const char *dso_file)
+{
+    char *preload = NULL;
+    int env_len;
+    int preload_idx = -1;
+    bool present = false;
+# ifdef RTLD_PRELOAD_ENABLE_VAR
+    bool enabled = false;
+# else
+    const bool enabled = true;
+# endif
+    debug_decl(preload_dso, SUDO_DEBUG_UTIL)
+
+    /*
+     * Preload a DSO file.  For a list of LD_PRELOAD-alikes, see
+     * http://www.fortran-2000.com/ArnaudRecipes/sharedlib.html
+     * XXX - need to support 32-bit and 64-bit variants
+     */
+
+    /* Count entries in envp, looking for LD_PRELOAD as we go. */
+    for (env_len = 0; envp[env_len] != NULL; env_len++) {
+	if (preload_idx == -1 && strncmp(envp[env_len], RTLD_PRELOAD_VAR "=",
+	    sizeof(RTLD_PRELOAD_VAR)) == 0) {
+	    const char *cp = envp[env_len] + sizeof(RTLD_PRELOAD_VAR);
+	    const char *end = cp + strlen(cp);
+	    const char *ep;
+	    const size_t dso_len = strlen(dso_file);
+
+	    /* Check to see if dso_file is already present. */
+	    for (cp = sudo_strsplit(cp, end, RTLD_PRELOAD_DELIM, &ep);
+		cp != NULL; cp = sudo_strsplit(NULL, end, RTLD_PRELOAD_DELIM,
+		&ep)) {
+		if ((size_t)(ep - cp) == dso_len) {
+		    if (memcmp(cp, dso_file, dso_len) == 0) {
+			/* already present */
+			present = true;
+			break;
+		    }
+		}
+	    }
+
+	    /* Save index of existing LD_PRELOAD variable. */
+	    preload_idx = env_len;
+	    continue;
+	}
+# ifdef RTLD_PRELOAD_ENABLE_VAR
+	if (strncmp(envp[env_len], RTLD_PRELOAD_ENABLE_VAR "=", sizeof(RTLD_PRELOAD_ENABLE_VAR)) == 0) {
+	    enabled = true;
+	    continue;
+	}
+# endif
+    }
+
+    /*
+     * Make a new copy of envp as needed.
+     * It would be nice to realloc the old envp[] but we don't know
+     * whether it was dynamically allocated. [TODO: plugin API]
+     */
+    if (preload_idx == -1 || !enabled) {
+	const int env_size = env_len + 1 + (preload_idx == -1) + enabled;
+
+	char **nenvp = reallocarray(NULL, env_size, sizeof(*envp));
+	if (nenvp == NULL)
+	    sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+	memcpy(nenvp, envp, env_len * sizeof(*envp));
+	nenvp[env_len] = NULL;
+	envp = nenvp;
+    }
+
+    /* Prepend our LD_PRELOAD to existing value or add new entry at the end. */
+    if (!present) {
+	if (preload_idx == -1) {
+# ifdef RTLD_PRELOAD_DEFAULT
+	    asprintf(&preload, "%s=%s%s%s", RTLD_PRELOAD_VAR, dso_file,
+		RTLD_PRELOAD_DELIM, RTLD_PRELOAD_DEFAULT);
+# else
+	    preload = sudo_new_key_val(RTLD_PRELOAD_VAR, dso_file);
+# endif
+	    if (preload == NULL) {
+		sudo_fatalx(U_("%s: %s"), __func__,
+		    U_("unable to allocate memory"));
+	    }
+	    envp[env_len++] = preload;
+	    envp[env_len] = NULL;
+	} else {
+	    int len = asprintf(&preload, "%s=%s%s%s", RTLD_PRELOAD_VAR,
+		dso_file, RTLD_PRELOAD_DELIM, envp[preload_idx]);
+	    if (len == -1) {
+		sudo_fatalx(U_("%s: %s"), __func__,
+		    U_("unable to allocate memory"));
+	    }
+	    envp[preload_idx] = preload;
+	}
+    }
+# ifdef RTLD_PRELOAD_ENABLE_VAR
+    if (!enabled) {
+	envp[env_len++] = RTLD_PRELOAD_ENABLE_VAR "=";
+	envp[env_len] = NULL;
+    }
+# endif
+
+    debug_return_ptr(envp);
+}
+#endif /* RTLD_PRELOAD_VAR */
+
+/*
+ * Disable execution of child processes in the command we are about
+ * to run.  On systems with privilege sets, we can remove the exec
+ * privilege.  On other systems we use LD_PRELOAD and the like.
+ */
+char **
+disable_execute(char *envp[], const char *dso)
+{
+    debug_decl(disable_execute, SUDO_DEBUG_UTIL)
+
+#ifdef HAVE_PRIV_SET
+    /* Solaris privileges, remove PRIV_PROC_EXEC post-execve. */
+    (void)priv_set(PRIV_ON, PRIV_INHERITABLE, "PRIV_FILE_DAC_READ", NULL);
+    (void)priv_set(PRIV_ON, PRIV_INHERITABLE, "PRIV_FILE_DAC_WRITE", NULL);
+    (void)priv_set(PRIV_ON, PRIV_INHERITABLE, "PRIV_FILE_DAC_SEARCH", NULL);
+    if (priv_set(PRIV_OFF, PRIV_LIMIT, "PRIV_PROC_EXEC", NULL) == 0)
+	debug_return_ptr(envp);
+    sudo_warn(U_("unable to remove PRIV_PROC_EXEC from PRIV_LIMIT"));
+#endif /* HAVE_PRIV_SET */
+
+#ifdef RTLD_PRELOAD_VAR
+    if (dso != NULL)
+	envp = preload_dso(envp, dso);
+#endif /* RTLD_PRELOAD_VAR */
+
+    debug_return_ptr(envp);
+}
+
+/*
+ * Like execve(2) but falls back to running through /bin/sh
+ * ala execvp(3) if we get ENOEXEC.
+ */
+int
+sudo_execve(int fd, const char *path, char *const argv[], char *envp[], bool noexec)
+{
+    debug_decl(sudo_execve, SUDO_DEBUG_UTIL)
+
+    sudo_debug_execve(SUDO_DEBUG_INFO, path, argv, envp);
+
+    /* Modify the environment as needed to disable further execve(). */
+    if (noexec)
+	envp = disable_execute(envp, sudo_conf_noexec_path());
+
+#ifdef HAVE_FEXECVE
+    if (fd != -1)
+	    fexecve(fd, argv, envp);
+    else
+#endif
+	    execve(path, argv, envp);
+    if (fd == -1 && errno == ENOEXEC) {
+	int argc;
+	char **nargv;
+
+	for (argc = 0; argv[argc] != NULL; argc++)
+	    continue;
+	nargv = reallocarray(NULL, argc + 2, sizeof(char *));
+	if (nargv != NULL) {
+	    nargv[0] = "sh";
+	    nargv[1] = (char *)path;
+	    memcpy(nargv + 2, argv + 1, argc * sizeof(char *));
+	    execve(_PATH_SUDO_BSHELL, nargv, envp);
+	    free(nargv);
+	}
+    }
+    debug_return_int(-1);
+}