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rootless: not close more FDs than needed #2967

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merged 1 commit into from
Apr 18, 2019
+34 −21
Merged

rootless: not close more FDs than needed #2967

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55 changes: 34 additions & 21 deletions pkg/rootless/rootless_linux.c
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Original file line number Diff line number Diff line change
Expand Up @@ -16,11 +16,13 @@
#include <sys/types.h>
#include <sys/prctl.h>
#include <dirent.h>
#include <sys/select.h>

static const char *_max_user_namespaces = "/proc/sys/user/max_user_namespaces";
static const char *_unprivileged_user_namespaces = "/proc/sys/kernel/unprivileged_userns_clone";

static int n_files;
static int open_files_max_fd;
fd_set open_files_set;

static void __attribute__((constructor)) init()
{
Expand All @@ -32,11 +34,16 @@ static void __attribute__((constructor)) init()
{
struct dirent *ent;

FD_ZERO (&open_files_set);
for (ent = readdir (d); ent; ent = readdir (d))
{
int fd = atoi (ent->d_name);
if (fd > n_files && fd != dirfd (d))
n_files = fd;
if (fd != dirfd (d))
{
if (fd > open_files_max_fd)
open_files_max_fd = fd;
FD_SET (fd, &open_files_set);
}
}
closedir (d);
}
Expand Down Expand Up @@ -164,8 +171,11 @@ reexec_userns_join (int userns, int mountns)
{
/* We passed down these fds, close them. */
int f;
for (f = 3; f < n_files; f++)
close (f);
for (f = 3; f < open_files_max_fd; f++)
{
if (FD_ISSET (f, &open_files_set))
close (f);
}
return pid;
}

Expand Down Expand Up @@ -274,22 +284,25 @@ reexec_in_user_namespace (int ready)
check_proc_sys_userns_file (_max_user_namespaces);
check_proc_sys_userns_file (_unprivileged_user_namespaces);
}
if (pid) {
if (do_socket_activation) {
long num_fds;
num_fds = strtol(listen_fds, NULL, 10);
if (num_fds != LONG_MIN && num_fds != LONG_MAX) {
long i;
for (i = 0; i < num_fds; i++) {
close(3+i);
if (pid)
{
if (do_socket_activation)
{
long num_fds;
num_fds = strtol (listen_fds, NULL, 10);
if (num_fds != LONG_MIN && num_fds != LONG_MAX)
{
long i;
for (i = 3; i < num_fds + 3; i++)
if (FD_ISSET (i, &open_files_set))
close (i);
}
unsetenv ("LISTEN_PID");
unsetenv ("LISTEN_FDS");
unsetenv ("LISTEN_FDNAMES");
}
}
unsetenv("LISTEN_PID");
unsetenv("LISTEN_FDS");
unsetenv("LISTEN_FDNAMES");
return pid;
}
return pid;
}

argv = get_cmd_line_args (ppid);
if (argv == NULL)
Expand All @@ -300,8 +313,8 @@ reexec_in_user_namespace (int ready)

if (do_socket_activation) {
char s[32];
sprintf(s, "%d", getpid());
setenv("LISTEN_PID", s, true);
sprintf (s, "%d", getpid());
setenv ("LISTEN_PID", s, true);
}

setenv ("_CONTAINERS_USERNS_CONFIGURED", "init", 1);
Expand Down