First attempt at dropping privileges

4 files changed, 90 insertions, 0 deletions

diff --git a/vendor/github.com/sid77/drop/LICENSE b/vendor/github.com/sid77/drop/LICENSE
new file mode 100644
index 0000000..37004bf
--- /dev/null
+++ b/vendor/github.com/sid77/drop/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2016 Marco Bonetti
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/vendor/github.com/sid77/drop/drop.go b/vendor/github.com/sid77/drop/drop.go
new file mode 100644
index 0000000..0fb64a9
--- /dev/null
+++ b/vendor/github.com/sid77/drop/drop.go
@@ -0,0 +1,35 @@
+package drop
+
+import (
+	"os/user"
+	"strconv"
+
+	"github.com/sid77/drop/syscall"
+)
+
+func DropPrivileges(runAsUser string) (err error) {
+	usr, err := user.Lookup(runAsUser)
+	if err != nil {
+		return err
+	}
+
+	gid, err := strconv.Atoi(usr.Gid)
+	if err != nil {
+		return err
+	}
+
+	uid, err := strconv.Atoi(usr.Uid)
+	if err != nil {
+		return err
+	}
+
+	if err = syscall.Setgid(gid); err != nil {
+		return err
+	}
+
+	if err = syscall.Setuid(uid); err != nil {
+		return err
+	}
+
+	return nil
+}
diff --git a/vendor/github.com/sid77/drop/syscall/setre.go b/vendor/github.com/sid77/drop/syscall/setre.go
new file mode 100644
index 0000000..ecf5ea9
--- /dev/null
+++ b/vendor/github.com/sid77/drop/syscall/setre.go
@@ -0,0 +1,17 @@
+// +build !linux
+
+package syscall
+
+import (
+	"syscall"
+)
+
+func Setuid(uid int) error {
+	err := syscall.Setreuid(uid, uid)
+	return err
+}
+
+func Setgid(gid int) error {
+	err := syscall.Setregid(gid, gid)
+	return err
+}
diff --git a/vendor/github.com/sid77/drop/syscall/setres.go b/vendor/github.com/sid77/drop/syscall/setres.go
new file mode 100644
index 0000000..afe43b9
--- /dev/null
+++ b/vendor/github.com/sid77/drop/syscall/setres.go
@@ -0,0 +1,17 @@
+// +build linux
+
+package syscall
+
+import (
+	"syscall"
+)
+
+func Setuid(uid int) error {
+	err := syscall.Setresuid(uid, uid, uid)
+	return err
+}
+
+func Setgid(gid int) error {
+	err := syscall.Setresgid(gid, gid, gid)
+	return err
+}