ping: fix breakage from -I fix

passwd: SELinux support by KaiGai Kohei <kaigai@ak.jp.nec.com>

2 files changed, 43 insertions, 0 deletions

diff --git a/libbb/selinux_common.c b/libbb/selinux_common.c
index ff076f6f0..7478cc7b5 100644
--- a/libbb/selinux_common.c
+++ b/libbb/selinux_common.c
@@ -38,3 +38,17 @@ void setfscreatecon_or_die(security_context_t scontext)
                                 "file creation context to %s", scontext);
         }
 }
+
+void selinux_preserve_fcontext(int fdesc)
+{
+        security_context_t context;
+
+        if (fgetfilecon(fdesc, &context) < 0) {
+                if (errno == ENODATA || errno == ENOTSUP)
+                        return;
+                bb_perror_msg_and_die("fgetfilecon failed");
+        }
+        setfscreatecon_or_die(context);
+        freecon(context);
+}
+
diff --git a/libbb/update_passwd.c b/libbb/update_passwd.c
index 8914b8b45..388adf81f 100644
--- a/libbb/update_passwd.c
+++ b/libbb/update_passwd.c
@@ -11,6 +11,31 @@
 
 #include "libbb.h"
 
+#if ENABLE_SELINUX
+static void check_selinux_update_passwd(const char *username)
+{
+        security_context_t context;
+        char *seuser;
+
+        if (getuid() != (uid_t)0 || is_selinux_enabled() == 0)
+                return;         /* No need to check */
+
+        if (getprevcon_raw(&context) < 0)
+                bb_perror_msg_and_die("getprevcon failed");
+        seuser = strtok(context, ":");
+        if (!seuser)
+                bb_error_msg_and_die("invalid context '%s'", context);
+        if (strcmp(seuser, username) != 0) {
+                if (checkPasswdAccess(PASSWD__PASSWD) != 0)
+                        bb_error_msg_and_die("SELinux: access denied");
+        }
+        if (ENABLE_FEATURE_CLEAN_UP)
+                freecon(context);
+}
+#else
+#define check_selinux_update_passwd(username) ((void)0)
+#endif
+
 int update_passwd(const char *filename, const char *username,
                         const char *new_pw)
 {
@@ -27,6 +52,8 @@ int update_passwd(const char *filename, const char *username,
         int cnt = 0;
         int ret = -1; /* failure */
 
+        check_selinux_update_passwd(username);
+
         /* New passwd file, "/etc/passwd+" for now */
         fnamesfx = xasprintf("%s+", filename);
         sfx_char = &fnamesfx[strlen(fnamesfx)-1];
@@ -38,6 +65,8 @@ int update_passwd(const char *filename, const char *username,
                 goto free_mem;
         old_fd = fileno(old_fp);
 
+        selinux_preserve_fcontext(old_fd);
+
         /* Try to create "/etc/passwd+". Wait if it exists. */
         i = 30;
         do {