Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

unixcreds: use euid instead of uid #14

Merged
merged 1 commit into from
Dec 1, 2017
Merged

unixcreds: use euid instead of uid #14

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
14 changes: 11 additions & 3 deletions unixcreds_linux.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,14 @@ func (fn UnixCredentialsFunc) Handshake(ctx context.Context, conn net.Conn) (net
return uc, ucred, nil
}

// UnixSocketRequireUidGid requires specific *effective* UID/GID, rather than the real UID/GID.
//
// For example, if a daemon binary is owned by the root (UID 0) with SUID bit but running as an
// unprivileged user (UID 1001), the effective UID becomes 0, and the real UID becomes 1001.
// So calling this function with uid=0 allows a connection from effective UID 0 but rejects
// a connection from effective UID 1001.
//
// See socket(7), SO_PEERCRED: "The returned credentials are those that were in effect at the time of the call to connect(2) or socketpair(2)."
func UnixSocketRequireUidGid(uid, gid int) UnixCredentialsFunc {
return func(ucred *unix.Ucred) error {
return requireUidGid(ucred, uid, gid)
Expand All @@ -53,14 +61,14 @@ func UnixSocketRequireRoot() UnixCredentialsFunc {
return UnixSocketRequireUidGid(0, 0)
}

// UnixSocketRequireSameUser resolves the current unix user and returns a
// UnixSocketRequireSameUser resolves the current effective unix user and returns a
// UnixCredentialsFunc that will validate incoming unix connections against the
// current credentials.
//
// This is useful when using abstract sockets that are accessible by all users.
func UnixSocketRequireSameUser() UnixCredentialsFunc {
uid, gid := os.Getuid(), os.Getgid()
return UnixSocketRequireUidGid(uid, gid)
euid, egid := os.Geteuid(), os.Getegid()
return UnixSocketRequireUidGid(euid, egid)
}

func requireRoot(ucred *unix.Ucred) error {
Expand Down