From 6af8b8859fde3a2b63afee20f004e184896cec3a Mon Sep 17 00:00:00 2001 From: Ophestra Date: Thu, 13 Mar 2025 00:41:37 +0900 Subject: [PATCH] sandbox: read overflow ids Signed-off-by: Ophestra --- internal/sandbox/overflow.go | 37 ++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 internal/sandbox/overflow.go diff --git a/internal/sandbox/overflow.go b/internal/sandbox/overflow.go new file mode 100644 index 0000000..ebaad70 --- /dev/null +++ b/internal/sandbox/overflow.go @@ -0,0 +1,37 @@ +package sandbox + +import ( + "bytes" + "log" + "os" + "strconv" + "sync" +) + +var ( + ofUid int + ofGid int + ofOnce sync.Once +) + +const ( + ofUidPath = "/proc/sys/kernel/overflowuid" + ofGidPath = "/proc/sys/kernel/overflowgid" +) + +func mustReadOverflow() { + if v, err := os.ReadFile(ofUidPath); err != nil { + log.Fatalf("cannot read %q: %v", ofUidPath, err) + } else if ofUid, err = strconv.Atoi(string(bytes.TrimSpace(v))); err != nil { + log.Fatalf("cannot interpret %q: %v", ofUidPath, err) + } + + if v, err := os.ReadFile(ofGidPath); err != nil { + log.Fatalf("cannot read %q: %v", ofGidPath, err) + } else if ofGid, err = strconv.Atoi(string(bytes.TrimSpace(v))); err != nil { + log.Fatalf("cannot interpret %q: %v", ofGidPath, err) + } +} + +func OverflowUid() int { ofOnce.Do(mustReadOverflow); return ofUid } +func OverflowGid() int { ofOnce.Do(mustReadOverflow); return ofGid }