From 685d807958e952e8d34d1678cbd0cef545afe2d7 Mon Sep 17 00:00:00 2001
From: Sebastiaan van Stijn <github@gone.nl>
Date: Tue, 23 Apr 2019 12:56:51 +0200
Subject: [PATCH] Fix handling of unlimited (-1) ulimit values

Addresses https://github.com/moby/moby/issues/39125

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
---
 ulimit.go      |  9 +++++++--
 ulimit_test.go | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 2 deletions(-)

diff --git a/ulimit.go b/ulimit.go
index 5ac7fd8..fca0400 100644
--- a/ulimit.go
+++ b/ulimit.go
@@ -96,8 +96,13 @@ func ParseUlimit(val string) (*Ulimit, error) {
 		return nil, fmt.Errorf("too many limit value arguments - %s, can only have up to two, `soft[:hard]`", parts[1])
 	}
 
-	if soft > *hard {
-		return nil, fmt.Errorf("ulimit soft limit must be less than or equal to hard limit: %d > %d", soft, *hard)
+	if *hard != -1 {
+		if soft == -1 {
+			return nil, fmt.Errorf("ulimit soft limit must be less than or equal to hard limit: soft: -1 (unlimited), hard: %d", *hard)
+		}
+		if soft > *hard {
+			return nil, fmt.Errorf("ulimit soft limit must be less than or equal to hard limit: %d > %d", soft, *hard)
+		}
 	}
 
 	return &Ulimit{Name: parts[0], Soft: soft, Hard: *hard}, nil
diff --git a/ulimit_test.go b/ulimit_test.go
index 902e023..0095855 100644
--- a/ulimit_test.go
+++ b/ulimit_test.go
@@ -2,6 +2,7 @@ package units
 
 import (
 	"fmt"
+	"math"
 	"strconv"
 	"testing"
 )
@@ -50,6 +51,52 @@ func TestParseUlimitHardLessThanSoft(t *testing.T) {
 	if _, err := ParseUlimit("nofile=1024:1"); err == nil {
 		t.Fatal("expected error on hard limit less than soft limit")
 	}
+	if _, err := ParseUlimit("nofile=-1:1024"); err == nil {
+		t.Fatal("expected error on hard limit less than soft limit")
+	}
+}
+
+func TestParseUlimitUnlimited(t *testing.T) {
+	tt := []struct {
+		in       string
+		expected Ulimit
+	}{
+		{
+			in:       "nofile=-1",
+			expected: Ulimit{Name: "nofile", Soft: -1, Hard: -1},
+		},
+		{
+			in:       "nofile=1024",
+			expected: Ulimit{Name: "nofile", Soft: 1024, Hard: 1024},
+		},
+		{
+			in:       "nofile=1024:-1",
+			expected: Ulimit{Name: "nofile", Soft: 1024, Hard: -1},
+		},
+		{
+			in:       "nofile=-1:-1",
+			expected: Ulimit{Name: "nofile", Soft: -1, Hard: -1},
+		},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.in, func(t *testing.T) {
+			u, err := ParseUlimit(tc.in)
+			if err != nil {
+				t.Fatalf("unexpected error when setting unlimited hard limit: %v", err)
+			}
+			if u.Name != tc.expected.Name {
+				t.Fatalf("unexpected name. expected %s, got %s", tc.expected.Name, u.Name)
+			}
+			if u.Soft != tc.expected.Soft {
+				t.Fatalf("unexpected soft limit. expected %d, got %d", tc.expected.Soft, u.Soft)
+			}
+			if u.Hard != tc.expected.Hard {
+				t.Fatalf("unexpected hard limit. expected %d, got %d", tc.expected.Hard, u.Hard)
+			}
+
+		})
+	}
 }
 
 func TestParseUlimitInvalidValueType(t *testing.T) {
@@ -99,6 +146,7 @@ func TestGetRlimit(t *testing.T) {
 		{Ulimit{"rttime", 55, 102}, Rlimit{rlimitRttime, 55, 102}},
 		{Ulimit{"sigpending", 14, 20}, Rlimit{rlimitSigpending, 14, 20}},
 		{Ulimit{"stack", 1, 1}, Rlimit{rlimitStack, 1, 1}},
+		{Ulimit{"stack", -1, -1}, Rlimit{rlimitStack, math.MaxUint64, math.MaxUint64}},
 	}
 
 	for _, te := range tt {