diff options
Diffstat (limited to 'apt-pkg/contrib/fileutl.cc')
| -rw-r--r-- | apt-pkg/contrib/fileutl.cc | 34 |
1 files changed, 33 insertions, 1 deletions
diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc index 6b8f04dea..de67a94b9 100644 --- a/apt-pkg/contrib/fileutl.cc +++ b/apt-pkg/contrib/fileutl.cc @@ -48,6 +48,7 @@ #include <errno.h> #include <glob.h> #include <pwd.h> +#include <grp.h> #include <set> #include <algorithm> @@ -64,6 +65,10 @@ #include <endian.h> #include <stdint.h> +#if __gnu_linux__ +#include <sys/prctl.h> +#endif + #include <apti18n.h> /*}}}*/ @@ -2173,14 +2178,41 @@ bool DropPrivs() if (getuid() != 0) return true; - const std::string nobody = _config->Find("APT::User::Nobody", "nobody"); + if(_config->FindB("Debug::NoDropPrivs", false) == true) + return true; + + const std::string nobody = _config->Find("APT::User::Nobody", "Debian-apt"); struct passwd *pw = getpwnam(nobody.c_str()); if (pw == NULL) return _error->Warning("No user %s, can not drop rights", nobody.c_str()); + +#if __gnu_linux__ + // see prctl(2), needs linux3.5 + int ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0,0, 0); + if(ret < 0) + _error->Warning("PR_SET_NO_NEW_PRIVS failed with %i", ret); +#endif + + if (setgroups(1, &pw->pw_gid) != 1) + return _error->Errno("setgroups", "Failed to setgroups"); + + if (setegid(pw->pw_gid) != 0) + return _error->Errno("setgid", "Failed to setgid"); if (setgid(pw->pw_gid) != 0) return _error->Errno("setgid", "Failed to setgid"); + if (setuid(pw->pw_uid) != 0) return _error->Errno("setuid", "Failed to setuid"); + // the seteuid() is probably uneeded (at least thats what the linux + // man-page says about setuid(2)) but we cargo culted it anyway + if (setuid(pw->pw_uid) != 0) + return _error->Errno("setuid", "Failed to setuid"); + + // be defensive + if(setgid(0) != -1 || setegid(0) != -1) + return _error->Error("Could restore gid to root, privilege dropping does not work"); + if(setuid(0) != -1 || seteuid(0) != -1) + return _error->Error("Could restore uid to root, privilege dropping does not work"); return true; } |