podman-remote: prevent leaking secret into image

Prevents temp secrets leaking into image by moving it away from context
directory to parent builder directory. Builder directory automatically
gets cleaned up when we are done with the build.

Signed-off-by: Aditya Rajan <arajan@redhat.com>

3 files changed, 32 insertions, 1 deletions

diff --git a/pkg/api/handlers/compat/images_build.go b/pkg/api/handlers/compat/images_build.go
index 200d72192..3aa1af71a 100644
--- a/pkg/api/handlers/compat/images_build.go
+++ b/pkg/api/handlers/compat/images_build.go
@@ -259,7 +259,19 @@ func BuildImage(w http.ResponseWriter, r *http.Request) {
 					arr := strings.SplitN(token, "=", 2)
 					if len(arr) > 1 {
 						if arr[0] == "src" {
-							modifiedSrc := fmt.Sprintf("src=%s", filepath.Join(contextDirectory, arr[1]))
+							/* move secret away from contextDir */
+							/* to make sure we dont accidentally commit temporary secrets to image*/
+							builderDirectory, _ := filepath.Split(contextDirectory)
+							// following path is outside build context
+							newSecretPath := filepath.Join(builderDirectory, arr[1])
+							oldSecretPath := filepath.Join(contextDirectory, arr[1])
+							err := os.Rename(oldSecretPath, newSecretPath)
+							if err != nil {
+								utils.BadRequest(w, "secrets", query.Secrets, err)
+								return
+							}
+
+							modifiedSrc := fmt.Sprintf("src=%s", newSecretPath)
 							modifiedOpt = append(modifiedOpt, modifiedSrc)
 						} else {
 							modifiedOpt = append(modifiedOpt, token)
diff --git a/test/e2e/build/Dockerfile.with-secret-verify-leak b/test/e2e/build/Dockerfile.with-secret-verify-leak
new file mode 100644
index 000000000..0957ac6a6
--- /dev/null
+++ b/test/e2e/build/Dockerfile.with-secret-verify-leak
@@ -0,0 +1,3 @@
+FROM alpine
+COPY * /
+RUN --mount=type=secret,id=mysecret cat /run/secrets/mysecret
diff --git a/test/e2e/build_test.go b/test/e2e/build_test.go
index ad401ca83..c541f25ae 100644
--- a/test/e2e/build_test.go
+++ b/test/e2e/build_test.go
@@ -82,6 +82,22 @@ var _ = Describe("Podman build", func() {
 		Expect(session).Should(Exit(0))
 	})
 
+	It("podman build with a secret from file and verify if secret file is not leaked into image", func() {
+		session := podmanTest.Podman([]string{"build", "-f", "build/Dockerfile.with-secret-verify-leak", "-t", "secret-test-leak", "--secret", "id=mysecret,src=build/secret.txt", "build/"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		Expect(session.OutputToString()).To(ContainSubstring("somesecret"))
+
+		session = podmanTest.Podman([]string{"run", "--rm", "secret-test-leak", "ls"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		Expect(session.OutputToString()).To(Not(ContainSubstring("podman-build-secret")))
+
+		session = podmanTest.Podman([]string{"rmi", "secret-test-leak"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+	})
+
 	It("podman build with logfile", func() {
 		logfile := filepath.Join(podmanTest.TempDir, "logfile")
 		session := podmanTest.Podman([]string{"build", "--pull-never", "--tag", "test", "--logfile", logfile, "build/basicalpine"})