podman/0003-Properly-validate-cache-IDs-and-sources.patch

From daca228525b387598a36d7de15a816ee8146b98d Mon Sep 17 00:00:00 2001
From: Danish Prakash <contact@danishpraka.sh>
Date: Tue, 15 Oct 2024 22:39:03 +0530
Subject: [PATCH 3/4] Properly validate cache IDs and sources

The `--mount type=cache` argument to the `RUN` instruction in
Dockerfiles was using `filepath.Join` on user input, allowing
crafted paths to be used to gain access to paths on the host,
when the command should normally be limited only to Buildah;s own
cache and context directories. Switch to `filepath.SecureJoin` to
resolve the issue.

Fixes CVE-2024-9675

Signed-off-by: Matt Heon <mheon@redhat.com>
Signed-off-by: Danish Prakash <contact@danishpraka.sh>
---
 .../buildah/internal/volumes/volumes.go       | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/vendor/github.com/containers/buildah/internal/volumes/volumes.go b/vendor/github.com/containers/buildah/internal/volumes/volumes.go
index da6b768fdc21..610e9fcf11b2 100644
--- a/vendor/github.com/containers/buildah/internal/volumes/volumes.go
+++ b/vendor/github.com/containers/buildah/internal/volumes/volumes.go
@@ -23,6 +23,7 @@ import (
 	"github.com/containers/storage/pkg/idtools"
 	"github.com/containers/storage/pkg/lockfile"
 	"github.com/containers/storage/pkg/unshare"
+	digest "github.com/opencontainers/go-digest"
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 	selinux "github.com/opencontainers/selinux/go-selinux"
 )
@@ -374,7 +375,11 @@ func GetCacheMount(args []string, store storage.Store, imageMountLabel string, a
 			return newMount, nil, fmt.Errorf("no stage found with name %s", fromStage)
 		}
 		// path should be /contextDir/specified path
-		newMount.Source = filepath.Join(mountPoint, filepath.Clean(string(filepath.Separator)+newMount.Source))
+		evaluated, err := copier.Eval(mountPoint, string(filepath.Separator)+newMount.Source, copier.EvalOptions{})
+		if err != nil {
+			return newMount, nil, err
+		}
+		newMount.Source = evaluated
 	} else {
 		// we need to create cache on host if no image is being used
 
@@ -391,11 +396,15 @@ func GetCacheMount(args []string, store storage.Store, imageMountLabel string, a
 		}
 
 		if id != "" {
-			newMount.Source = filepath.Join(cacheParent, filepath.Clean(id))
-			buildahLockFilesDir = filepath.Join(BuildahCacheLockfileDir, filepath.Clean(id))
+			// Don't let the user control where we place the directory.
+			dirID := digest.FromString(id).Encoded()[:16]
+			newMount.Source = filepath.Join(cacheParent, dirID)
+			buildahLockFilesDir = filepath.Join(BuildahCacheLockfileDir, dirID)
 		} else {
-			newMount.Source = filepath.Join(cacheParent, filepath.Clean(newMount.Destination))
-			buildahLockFilesDir = filepath.Join(BuildahCacheLockfileDir, filepath.Clean(newMount.Destination))
+			// Don't let the user control where we place the directory.
+			dirID := digest.FromString(newMount.Destination).Encoded()[:16]
+			newMount.Source = filepath.Join(cacheParent, dirID)
+			buildahLockFilesDir = filepath.Join(BuildahCacheLockfileDir, dirID)
 		}
 		idPair := idtools.IDPair{
 			UID: uid,
-- 
2.46.0