journal-file: protect against alloca(0)

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

diff --git a/src/shared/util.c b/src/shared/util.c
index 66276aa54e3925aa6c21225bd39f71a6616de4ec..c396fc7c6d4ccdbee1ea35f2239f059053034130 100644 (file)
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -4936,15 +4936,15 @@ int fd_inc_sndbuf(int fd, size_t n) {
         socklen_t l = sizeof(value);
 
         r = getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &value, &l);
-        if (r >= 0 &&
-            l == sizeof(value) &&
-            (size_t) value >= n*2)
+        if (r >= 0 && l == sizeof(value) && (size_t) value >= n*2)
                 return 0;
 
+        /* If we have the privileges we will ignore the kernel limit. */
+
         value = (int) n;
-        r = setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &value, sizeof(value));
-        if (r < 0)
-                return -errno;
+        if (setsockopt(fd, SOL_SOCKET, SO_SNDBUFFORCE, &value, sizeof(value)) < 0)
+                if (setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &value, sizeof(value)) < 0)
+                        return -errno;
 
         return 1;
 }
@@ -4954,16 +4954,15 @@ int fd_inc_rcvbuf(int fd, size_t n) {
         socklen_t l = sizeof(value);
 
         r = getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &value, &l);
-        if (r >= 0 &&
-            l == sizeof(value) &&
-            (size_t) value >= n*2)
+        if (r >= 0 && l == sizeof(value) && (size_t) value >= n*2)
                 return 0;
 
-        value = (int) n;
-        r = setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &value, sizeof(value));
-        if (r < 0)
-                return -errno;
+        /* If we have the privileges we will ignore the kernel limit. */
 
+        value = (int) n;
+        if (setsockopt(fd, SOL_SOCKET, SO_RCVBUFFORCE, &value, sizeof(value)) < 0)
+                if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &value, sizeof(value)) < 0)
+                        return -errno;
         return 1;
 }
 
@@ -5220,10 +5219,10 @@ 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);
 
@@ -5266,6 +5265,53 @@ 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))
@@ -6022,5 +6068,11 @@ int namespace_enter(int namespace_fd, int root_fd) {
         if (chroot(".") < 0)
                 return -errno;
 
+        if (setresgid(0, 0, 0) < 0)
+                return -errno;
+
+        if (setresuid(0, 0, 0) < 0)
+                return -errno;
+
         return 0;
 }