core: refuse doing %h, %s, %U specifier resolving in PID 1

[elogind.git] / src / shared / util.c

diff --git a/src/shared/util.c b/src/shared/util.c
index d31bd529498365b56e07c7a95be82ab986154d61..20aec2a5c9cafa236b76806dd21b84b934a11ee6 100644 (file)
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -59,6 +59,7 @@
 #include <langinfo.h>
 #include <locale.h>
 #include <libgen.h>
+#undef basename
 
 #include "macro.h"
 #include "util.h"
@@ -373,17 +374,21 @@ char *split(const char *c, size_t *l, const char *separator, char **state) {
 /* Split a string into words, but consider strings enclosed in '' and
  * "" as words even if they include spaces. */
 char *split_quoted(const char *c, size_t *l, char **state) {
-        char *current, *e;
+        const char *current, *e;
         bool escaped = false;
 
-        current = *state ? *state : (char*) c;
+        assert(c);
+        assert(l);
+        assert(state);
 
-        if (!*current || *c == 0)
-                return NULL;
+        current = *state ? *state : c;
 
         current += strspn(current, WHITESPACE);
 
-        if (*current == '\'') {
+        if (*current == 0)
+                return NULL;
+
+        else if (*current == '\'') {
                 current ++;
 
                 for (e = current; *e; e++) {
@@ -396,7 +401,8 @@ char *split_quoted(const char *c, size_t *l, char **state) {
                 }
 
                 *l = e-current;
-                *state = *e == 0 ? e : e+1;
+                *state = (char*) (*e == 0 ? e : e+1);
+
         } else if (*current == '\"') {
                 current ++;
 
@@ -410,7 +416,8 @@ char *split_quoted(const char *c, size_t *l, char **state) {
                 }
 
                 *l = e-current;
-                *state = *e == 0 ? e : e+1;
+                *state = (char*) (*e == 0 ? e : e+1);
+
         } else {
                 for (e = current; *e; e++) {
                         if (escaped)
@@ -421,7 +428,7 @@ char *split_quoted(const char *c, size_t *l, char **state) {
                                 break;
                 }
                 *l = e-current;
-                *state = e;
+                *state = (char*) e;
         }
 
         return (char*) current;
@@ -491,7 +498,7 @@ int get_starttime_of_pid(pid_t pid, unsigned long long *st) {
 
         f = fopen(p, "re");
         if (!f)
-                return -errno;
+                return errno == ENOENT ? -ESRCH : -errno;
 
         if (!fgets(line, sizeof(line), f)) {
                 if (ferror(f))
@@ -557,6 +564,7 @@ char *truncate_nl(char *s) {
 
 int get_process_comm(pid_t pid, char **name) {
         const char *p;
+        int r;
 
         assert(name);
         assert(pid >= 0);
@@ -566,7 +574,11 @@ int get_process_comm(pid_t pid, char **name) {
         else
                 p = procfs_file_alloca(pid, "comm");
 
-        return read_one_line_file(p, name);
+        r = read_one_line_file(p, name);
+        if (r == -ENOENT)
+                return -ESRCH;
+
+        return r;
 }
 
 int get_process_cmdline(pid_t pid, size_t max_length, bool comm_fallback, char **line) {
@@ -723,7 +735,7 @@ int get_process_exe(pid_t pid, char **name) {
 
         r = readlink_malloc(p, name);
         if (r < 0)
-                return r;
+                return r == -ENOENT ? -ESRCH : r;
 
         d = endswith(*name, " (deleted)");
         if (d)
@@ -2490,7 +2502,7 @@ int getttyname_malloc(int fd, char **r) {
         assert(r);
 
         k = ttyname_r(fd, path, sizeof(path));
-        if (k != 0)
+        if (k > 0)
                 return -k;
 
         char_array_0(path);
@@ -3950,8 +3962,8 @@ int fopen_temporary(const char *path, FILE **_f, char **_temp_path) {
         if (!t)
                 return -ENOMEM;
 
-        fn = path_get_file_name(path);
-        k = fn-path;
+        fn = basename(path);
+        k = fn - path;
         memcpy(t, path, k);
         t[k] = '.';
         stpcpy(stpcpy(t+k+1, fn), "XXXXXX");
@@ -4136,7 +4148,7 @@ int symlink_atomic(const char *from, const char *to) {
         if (!t)
                 return -ENOMEM;
 
-        fn = path_get_file_name(to);
+        fn = basename(to);
         k = fn-to;
         memcpy(t, to, k);
         t[k] = '.';
@@ -5208,10 +5220,10 @@ int make_console_stdio(void) {
 }
 
 int get_home_dir(char **_h) {
-        char *h;
+        struct passwd *p;
         const char *e;
+        char *h;
         uid_t u;
-        struct passwd *p;
 
         assert(_h);
 
@@ -5254,6 +5266,53 @@ int get_home_dir(char **_h) {
         return 0;
 }
 
+int get_shell(char **_s) {
+        struct passwd *p;
+        const char *e;
+        char *s;
+        uid_t u;
+
+        assert(_s);
+
+        /* Take the user specified one */
+        e = getenv("SHELL");
+        if (e) {
+                s = strdup(e);
+                if (!s)
+                        return -ENOMEM;
+
+                *_s = s;
+                return 0;
+        }
+
+        /* Hardcode home directory for root to avoid NSS */
+        u = getuid();
+        if (u == 0) {
+                s = strdup("/bin/sh");
+                if (!s)
+                        return -ENOMEM;
+
+                *_s = s;
+                return 0;
+        }
+
+        /* Check the database... */
+        errno = 0;
+        p = getpwuid(u);
+        if (!p)
+                return errno > 0 ? -errno : -ESRCH;
+
+        if (!path_is_absolute(p->pw_shell))
+                return -EINVAL;
+
+        s = strdup(p->pw_shell);
+        if (!s)
+                return -ENOMEM;
+
+        *_s = s;
+        return 0;
+}
+
 bool filename_is_safe(const char *p) {
 
         if (isempty(p))
@@ -5368,7 +5427,7 @@ bool is_locale_utf8(void) {
                 goto out;
         }
 
-        if(streq(set, "UTF-8")) {
+        if (streq(set, "UTF-8")) {
                 cached_answer = true;
                 goto out;
         }
@@ -5780,10 +5839,18 @@ void* greedy_realloc(void **p, size_t *allocated, size_t need) {
         size_t a;
         void *q;
 
+        assert(p);
+        assert(allocated);
+
         if (*allocated >= need)
                 return *p;
 
         a = MAX(64u, need * 2);
+
+        /* check for overflows */
+        if (a < need)
+                return NULL;
+
         q = realloc(*p, a);
         if (!q)
                 return NULL;
@@ -5793,6 +5860,25 @@ void* greedy_realloc(void **p, size_t *allocated, size_t need) {
         return q;
 }
 
+void* greedy_realloc0(void **p, size_t *allocated, size_t need) {
+        size_t prev;
+        uint8_t *q;
+
+        assert(p);
+        assert(allocated);
+
+        prev = *allocated;
+
+        q = greedy_realloc(p, allocated, need);
+        if (!q)
+                return NULL;
+
+        if (*allocated > prev)
+                memset(&q[prev], 0, *allocated - prev);
+
+        return q;
+}
+
 bool id128_is_valid(const char *s) {
         size_t i, l;
 
@@ -5892,7 +5978,7 @@ int shall_restore_state(void) {
                 return 1;
 
         FOREACH_WORD_QUOTED(w, l, line, state)
-                if (l == 23 && memcmp(w, "systemd.restore_state=0", 23))
+                if (l == 23 && strneq(w, "systemd.restore_state=0", 23))
                         return 0;
 
         return 1;
@@ -5912,3 +5998,82 @@ int proc_cmdline(char **ret) {
 
         return 1;
 }
+
+int container_get_leader(const char *machine, pid_t *pid) {
+        _cleanup_free_ char *s = NULL, *class = NULL;
+        const char *p;
+        pid_t leader;
+        int r;
+
+        assert(machine);
+        assert(pid);
+
+        p = strappenda("/run/systemd/machines/", machine);
+        r = parse_env_file(p, NEWLINE, "LEADER", &s, "CLASS", &class, NULL);
+        if (r == -ENOENT)
+                return -EHOSTDOWN;
+        if (r < 0)
+                return r;
+        if (!s)
+                return -EIO;
+
+        if (!streq_ptr(class, "container"))
+                return -EIO;
+
+        r = parse_pid(s, &leader);
+        if (r < 0)
+                return r;
+        if (leader <= 1)
+                return -EIO;
+
+        *pid = leader;
+        return 0;
+}
+
+int namespace_open(pid_t pid, int *namespace_fd, int *root_fd) {
+        _cleanup_close_ int nsfd = -1;
+        const char *ns, *root;
+        int rfd;
+
+        assert(pid >= 0);
+        assert(namespace_fd);
+        assert(root_fd);
+
+        ns = procfs_file_alloca(pid, "ns/mnt");
+        nsfd = open(ns, O_RDONLY|O_NOCTTY|O_CLOEXEC);
+        if (nsfd < 0)
+                return -errno;
+
+        root = procfs_file_alloca(pid, "root");
+        rfd = open(root, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
+        if (rfd < 0)
+                return -errno;
+
+        *namespace_fd = nsfd;
+        *root_fd = rfd;
+        nsfd = -1;
+
+        return 0;
+}
+
+int namespace_enter(int namespace_fd, int root_fd) {
+        assert(namespace_fd >= 0);
+        assert(root_fd >= 0);
+
+        if (setns(namespace_fd, CLONE_NEWNS) < 0)
+                return -errno;
+
+        if (fchdir(root_fd) < 0)
+                return -errno;
+
+        if (chroot(".") < 0)
+                return -errno;
+
+        if (setresgid(0, 0, 0) < 0)
+                return -errno;
+
+        if (setresuid(0, 0, 0) < 0)
+                return -errno;
+
+        return 0;
+}