From c2c0d5058203070033b2d2e84c8b168bd4060650 Mon Sep 17 00:00:00 2001
From: Giuseppe Scrivano <gscrivan@redhat.com>
Date: Wed, 5 May 2021 17:49:52 +0200
Subject: rootless: improve automatic range split

sort.Search returns the smallest index, so provide the available IDs
in decreasing order.

It fixes an issue when splitting the current mappings over multiple
available IDs.

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
---
 pkg/rootless/rootless.go      |  4 +--
 pkg/rootless/rootless_test.go | 57 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/pkg/rootless/rootless.go b/pkg/rootless/rootless.go
index 0b9d719a9..93b4e2e9f 100644
--- a/pkg/rootless/rootless.go
+++ b/pkg/rootless/rootless.go
@@ -137,7 +137,7 @@ func GetAvailableGids() (int64, error) {
 // It assumes availableMappings is sorted by ID.
 func findIDInMappings(id int64, availableMappings []user.IDMap) *user.IDMap {
 	i := sort.Search(len(availableMappings), func(i int) bool {
-		return availableMappings[i].ID >= id
+		return availableMappings[i].ID <= id
 	})
 	if i < 0 || i >= len(availableMappings) {
 		return nil
@@ -157,7 +157,7 @@ func MaybeSplitMappings(mappings []spec.LinuxIDMapping, availableMappings []user
 	overflow.Size = 0
 	consumed := 0
 	sort.Slice(availableMappings, func(i, j int) bool {
-		return availableMappings[i].ID < availableMappings[j].ID
+		return availableMappings[i].ID > availableMappings[j].ID
 	})
 	for {
 		cur := overflow
diff --git a/pkg/rootless/rootless_test.go b/pkg/rootless/rootless_test.go
index ef574099c..fe9b23cdf 100644
--- a/pkg/rootless/rootless_test.go
+++ b/pkg/rootless/rootless_test.go
@@ -98,4 +98,61 @@ func TestMaybeSplitMappings(t *testing.T) {
 	if !reflect.DeepEqual(newMappings, desiredMappings) {
 		t.Fatal("wrong mappings generated")
 	}
+
+	mappings = []spec.LinuxIDMapping{
+		{
+			ContainerID: 0,
+			HostID:      0,
+			Size:        4,
+		},
+	}
+	desiredMappings = []spec.LinuxIDMapping{
+		{
+			ContainerID: 0,
+			HostID:      0,
+			Size:        1,
+		},
+		{
+			ContainerID: 1,
+			HostID:      1,
+			Size:        1,
+		},
+		{
+			ContainerID: 2,
+			HostID:      2,
+			Size:        1,
+		},
+		{
+			ContainerID: 3,
+			HostID:      3,
+			Size:        1,
+		},
+	}
+	availableMappings = []user.IDMap{
+		{
+			ID:       0,
+			ParentID: 0,
+			Count:    1,
+		},
+		{
+			ID:       1,
+			ParentID: 1,
+			Count:    1,
+		},
+		{
+			ID:       2,
+			ParentID: 2,
+			Count:    1,
+		},
+		{
+			ID:       3,
+			ParentID: 3,
+			Count:    1,
+		},
+	}
+
+	newMappings = MaybeSplitMappings(mappings, availableMappings)
+	if !reflect.DeepEqual(newMappings, desiredMappings) {
+		t.Fatal("wrong mappings generated")
+	}
 }
-- 
cgit v1.2.3-54-g00ecf