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-rw-r--r--include/libbb.h2
-rw-r--r--libbb/login.c26
-rw-r--r--loginutils/login.c14
-rw-r--r--loginutils/sulogin.c25
4 files changed, 42 insertions, 25 deletions
diff --git a/include/libbb.h b/include/libbb.h
index 77c678c..f79d80d 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -623,6 +623,8 @@ enum {
#endif
void bb_daemonize_or_rexec(int flags, char **argv);
void bb_sanitize_stdio(void);
+/* Clear dangerous stuff, set PATH */
+void sanitize_env_for_suid(void);
extern const char *opt_complementary;
diff --git a/libbb/login.c b/libbb/login.c
index 308e1bf..1af3165 100644
--- a/libbb/login.c
+++ b/libbb/login.c
@@ -99,3 +99,29 @@ void print_login_prompt(void)
fputs(LOGIN, stdout);
fflush(stdout);
}
+
+/* Clear dangerous stuff, set PATH */
+static const char forbid[] ALIGN1 =
+ "ENV" "\0"
+ "BASH_ENV" "\0"
+ "HOME" "\0"
+ "IFS" "\0"
+ "SHELL" "\0"
+ "LD_LIBRARY_PATH" "\0"
+ "LD_PRELOAD" "\0"
+ "LD_TRACE_LOADED_OBJECTS" "\0"
+ "LD_BIND_NOW" "\0"
+ "LD_AOUT_LIBRARY_PATH" "\0"
+ "LD_AOUT_PRELOAD" "\0"
+ "LD_NOWARN" "\0"
+ "LD_KEEPDIR" "\0";
+
+void sanitize_env_for_suid(void)
+{
+ const char *p = forbid;
+ do {
+ unsetenv(p);
+ p += strlen(p) + 1;
+ } while (*p);
+ putenv((char*)bb_PATH_root_path);
+}
diff --git a/loginutils/login.c b/loginutils/login.c
index bddc0f5..c05edde 100644
--- a/loginutils/login.c
+++ b/loginutils/login.c
@@ -201,7 +201,7 @@ static void motd(void)
int fd;
fd = open(bb_path_motd_file, O_RDONLY);
- if (fd) {
+ if (fd >= 0) {
fflush(stdout);
bb_copyfd_eof(fd, STDOUT_FILENO);
close(fd);
@@ -216,6 +216,10 @@ static void alarm_handler(int sig ATTRIBUTE_UNUSED)
ndelay_on(1);
ndelay_on(2);
printf("\r\nLogin timed out after %d seconds\r\n", TIMEOUT);
+ /* unix API is brain damaged regarding O_NONBLOCK,
+ * we should undo it, or else we can affect other processes */
+ ndelay_off(1);
+ ndelay_off(2);
exit(EXIT_SUCCESS);
}
@@ -254,6 +258,11 @@ int login_main(int argc, char **argv)
* and any extra open fd's are closed.
* (The name of the function is misleading. Not daemonizing here.) */
bb_daemonize_or_rexec(DAEMON_ONLY_SANITIZE | DAEMON_CLOSE_EXTRA_FDS, NULL);
+ /* More of suid paranoia if called by non-root */
+ if (!amroot) {
+ /* Clear dangerous stuff, set PATH */
+ sanitize_env_for_suid();
+ }
opt = getopt32(argv, "f:h:p", &opt_user, &opt_host);
if (opt & LOGIN_OPT_f) {
@@ -411,7 +420,8 @@ int login_main(int argc, char **argv)
fchown(0, pw->pw_uid, pw->pw_gid);
fchmod(0, 0600);
- if (ENABLE_LOGIN_SCRIPTS) {
+ /* We trust environment only if we run by root */
+ if (ENABLE_LOGIN_SCRIPTS && amroot) {
char *t_argv[2];
t_argv[0] = getenv("LOGIN_PRE_SUID_SCRIPT");
diff --git a/loginutils/sulogin.c b/loginutils/sulogin.c
index f1545b7..af457ef 100644
--- a/loginutils/sulogin.c
+++ b/loginutils/sulogin.c
@@ -9,22 +9,6 @@
#include "libbb.h"
-static const char forbid[] ALIGN1 =
- "ENV" "\0"
- "BASH_ENV" "\0"
- "HOME" "\0"
- "IFS" "\0"
- "PATH" "\0"
- "SHELL" "\0"
- "LD_LIBRARY_PATH" "\0"
- "LD_PRELOAD" "\0"
- "LD_TRACE_LOADED_OBJECTS" "\0"
- "LD_BIND_NOW" "\0"
- "LD_AOUT_LIBRARY_PATH" "\0"
- "LD_AOUT_PRELOAD" "\0"
- "LD_NOWARN" "\0"
- "LD_KEEPDIR" "\0";
-
//static void catchalarm(int ATTRIBUTE_UNUSED junk)
//{
// exit(EXIT_FAILURE);
@@ -37,7 +21,6 @@ int sulogin_main(int argc, char **argv)
char *cp;
int timeout = 0;
char *timeout_arg;
- const char *p;
struct passwd *pwd;
const char *shell;
#if ENABLE_FEATURE_SHADOWPASSWDS
@@ -66,12 +49,8 @@ int sulogin_main(int argc, char **argv)
bb_error_msg_and_die("not a tty");
}
- /* Clear out anything dangerous from the environment */
- p = forbid;
- do {
- unsetenv(p);
- p += strlen(p) + 1;
- } while (*p);
+ /* Clear dangerous stuff, set PATH */
+ sanitize_env_for_suid();
// bb_askpass() already handles this
// signal(SIGALRM, catchalarm);