Support running with child namespaces

By default killall should not kill processes in a namespace it is not
part of. If this is allowed, it allows callers to break namespaces they
did not expect to affect, requiring rewrite of all callers to fix.

So by default, we should work in the current namespace. If -N 0 is
specified, then we look at all namespaces, and if any other pid is
specified we look in only that namespace.

Signed-off-by: Debabrata Banerjee <dbanerje@akamai.com>

diff --git a/src/killall.c b/src/killall.c
index bd882f0c8123f75c83fc0e997c85bd2183a6bbab..518bd4a071519c8680b558fad8d263889e7972f2 100644 (file)
--- a/src/killall.c
+++ b/src/killall.c
@@ -80,6 +80,8 @@
 #define ER_UNKWN   -3
 #define ER_OOFRA   -4
 
+static pid_t opt_ns_pid = 0;
+
 static int verbose = 0, exact = 0, interactive = 0, reg = 0,
            quiet = 0, wait_until_dead = 0, process_group = 0,
            ignore_case = 0;
@@ -190,6 +192,42 @@ parse_time_units(const char* age)
    return -1;
 }
 
+enum ns_type {
+    IPCNS = 0,
+    MNTNS,
+    NETNS,
+    PIDNS,
+    USERNS,
+    UTSNS
+};
+
+static const char *ns_names[] = {
+    [IPCNS] = "ipc",
+    [MNTNS] = "mnt",
+    [NETNS] = "net",
+    [PIDNS] = "pid",
+    [USERNS] = "user",
+    [UTSNS] = "uts",
+};
+
+#define NUM_NS 6
+
+const char *get_ns_name(int id) {
+    if (id >= NUM_NS)
+        return NULL;
+    return ns_names[id];
+}
+
+static int get_ns(pid_t pid, int id) {
+       struct stat st;
+       char buff[50];
+       snprintf(buff, sizeof(buff), "/proc/%i/ns/%s", pid, get_ns_name(id));
+       if (stat(buff, &st))
+               return 0;
+       else
+               return st.st_ino;
+}
+
 static int
 match_process_uid(pid_t pid, uid_t uid)
 {
@@ -197,7 +235,7 @@ match_process_uid(pid_t pid, uid_t uid)
        uid_t puid;
        FILE *f;
        int re = -1;
-       
+
        snprintf (buf, sizeof buf, PROC_BASE "/%d/status", pid);
        if (!(f = fopen (buf, "r")))
                return 0;
@@ -317,7 +355,7 @@ load_proc_cmdline(const pid_t pid, const char *comm, char **command, int *got_lo
     char *path, *p, *command_buf;
     int cmd_size = 128;
     int okay;
-    
+
     if (asprintf (&path, PROC_BASE "/%d/cmdline", pid) < 0)
        return -1;
     if (!(file = fopen (path, "r")))
@@ -444,11 +482,15 @@ kill_all (int signal, int name_count, char **namelist, struct passwd *pwent)
     int i, j, length, got_long, error;
     int pids, max_pids, pids_killed;
     unsigned long found;
-    regex_t *reglist = NULL;;
+    regex_t *reglist = NULL;
+    long ns_ino = 0;
 #ifdef WITH_SELINUX
     security_context_t lcontext=NULL;
 #endif /*WITH_SELINUX*/
 
+    if (opt_ns_pid)
+       ns_ino = get_ns(opt_ns_pid, PIDNS);
+
     if (name_count && reg)
        reglist = build_regexp_list(name_count, namelist);
     else
@@ -482,6 +524,8 @@ kill_all (int signal, int name_count, char **namelist, struct passwd *pwent)
        /* match by UID */
         if (pwent && match_process_uid(pid_table[i], pwent->pw_uid)==0)
            continue;
+       if (opt_ns_pid && ns_ino && ns_ino != get_ns(pid_table[i], PIDNS))
+           continue;
 
 #ifdef WITH_SELINUX
         /* match by SELinux context */
@@ -688,7 +732,10 @@ usage (const char *msg)
     "  -u,--user USER      kill only process(es) running as USER\n"
     "  -v,--verbose        report if the signal was successfully sent\n"
     "  -V,--version        display version information\n"
-    "  -w,--wait           wait for processes to die\n"));
+    "  -w,--wait           wait for processes to die\n"
+    "  -n,--ns PID         match processes that belong to the same namespaces\n"
+    "                      as PID or 0 for all namespaces\n"));
+
 #ifdef WITH_SELINUX
   fprintf(stderr, _(
     "  -Z,--context REGEXP kill only process(es) having context\n"
@@ -749,12 +796,15 @@ main (int argc, char **argv)
     {"user", 1, NULL, 'u'},
     {"verbose", 0, NULL, 'v'},
     {"wait", 0, NULL, 'w'},
+    {"ns", 1, NULL, 'n' },
 #ifdef WITH_SELINUX
     {"context", 1, NULL, 'Z'},
 #endif /*WITH_SELINUX*/
     {"version", 0, NULL, 'V'},
     {0,0,0,0 }};
 
+  opt_ns_pid = getpid();
+
   /* Setup the i18n */
 #ifdef ENABLE_NLS
   setlocale(LC_ALL, "");
@@ -778,9 +828,9 @@ main (int argc, char **argv)
 
   opterr = 0;
 #ifdef WITH_SELINUX
-  while ( (optc = getopt_long_only(argc,argv,"egy:o:ilqrs:u:vwZ:VI",options,NULL)) != -1) {
+  while ( (optc = getopt_long_only(argc,argv,"egy:o:ilqrs:u:vwZ:VIn:",options,NULL)) != -1) {
 #else
-  while ( (optc = getopt_long_only(argc,argv,"egy:o:ilqrs:u:vwVI",options,NULL)) != -1) {
+  while ( (optc = getopt_long_only(argc,argv,"egy:o:ilqrs:u:vwVIn:",options,NULL)) != -1) {
 #endif
     switch (optc) {
     case 'e':
@@ -845,6 +895,9 @@ main (int argc, char **argv)
       }
            sig_num = get_signal (argv[optind]+1, "killall");
       break;
+    case 'n':
+      opt_ns_pid = atoi(optarg);
+      break;
 #ifdef WITH_SELINUX
     case 'Z': 
       if (is_selinux_enabled()>0) {