From f1e3c8f002be54617656fc4ca525c3f1e57323f3 Mon Sep 17 00:00:00 2001 From: Julian Andres Klode Date: Wed, 24 Sep 2014 20:59:53 +0200 Subject: [PATCH] DropPrivs: Improve comments Git-Dch: ignore --- apt-pkg/contrib/fileutl.cc | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc index 05c2f2e00..7ccaaa03f 100644 --- a/apt-pkg/contrib/fileutl.cc +++ b/apt-pkg/contrib/fileutl.cc @@ -2175,7 +2175,7 @@ bool Popen(const char* Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode) bool DropPrivs() { - /* uid will be 0 in the end, but gid might be different anyway */ + // uid will be 0 in the end, but gid might be different anyway uid_t old_uid = getuid(); gid_t old_gid = getgid(); @@ -2195,7 +2195,7 @@ bool DropPrivs() if(ret < 0) _error->Warning("PR_SET_NO_NEW_PRIVS failed with %i", ret); #endif - + // Do not change the order here, it might break things if (setgroups(1, &pw->pw_gid)) return _error->Errno("setgroups", "Failed to setgroups"); @@ -2207,27 +2207,27 @@ bool DropPrivs() 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 (seteuid(pw->pw_uid) != 0) return _error->Errno("seteuid", "Failed to seteuid"); - /* Try changing GID/EGID */ + // Check that uid and gid changes do not work anymore if (pw->pw_gid != old_gid && (setgid(old_gid) != -1 || setegid(old_gid) != -1)) return _error->Error("Could restore a gid to root, privilege dropping did not work"); if (pw->pw_uid != old_uid && (setuid(old_uid) != -1 || seteuid(old_uid) != -1)) return _error->Error("Could restore a uid to root, privilege dropping did not work"); - /* Verify the list of supplementary groups is what we expected */ + // Verify that the user has only a single group, and the correct one gid_t groups[1]; if (getgroups(1, groups) != 1) return _error->Errno("getgroups", "Could not get new groups"); if (groups[0] != pw->pw_gid) return _error->Error("Could not switch group"); - /* Verify gid, egid, uid, and euid */ + + // Verify that gid, egid, uid, and euid changed if (getgid() != pw->pw_gid) return _error->Error("Could not switch group"); if (getegid() != pw->pw_gid) @@ -2257,6 +2257,5 @@ bool DropPrivs() return _error->Error("Could not switch saved set-group-ID"); #endif - /* TODO: Check saved uid/saved gid as well */ return true; } -- 2.45.2