From bc6bb0c7e5efb93f3bab3bde14954875474d14e8 Mon Sep 17 00:00:00 2001
From: Wiktor Garbacz <wiktorg@google.com>
Date: Wed, 14 Apr 2021 02:45:15 -0700
Subject: [PATCH] Fix `Mounts::ResolvePath` for dir nodes.

PiperOrigin-RevId: 368390904
Change-Id: I4f59e8d74b0d81497255cb0838d6d3132cae160b
---
 sandboxed_api/sandbox2/mounts.cc      |  2 +-
 sandboxed_api/sandbox2/mounts_test.cc | 53 +++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/sandboxed_api/sandbox2/mounts.cc b/sandboxed_api/sandbox2/mounts.cc
index d9de087..6585737 100644
--- a/sandboxed_api/sandbox2/mounts.cc
+++ b/sandboxed_api/sandbox2/mounts.cc
@@ -278,7 +278,6 @@ absl::StatusOr<std::string> Mounts::ResolvePath(absl::string_view path) const {
     std::pair<absl::string_view, absl::string_view> parts =
         absl::StrSplit(tail, absl::MaxSplits('/', 1));
     const std::string cur(parts.first);
-    tail = parts.second;
     const auto it = curtree->entries().find(cur);
     if (it == curtree->entries().end()) {
       if (curtree->node().has_dir_node()) {
@@ -287,6 +286,7 @@ absl::StatusOr<std::string> Mounts::ResolvePath(absl::string_view path) const {
       return absl::NotFoundError("Path could not be resolved in the mounts");
     }
     curtree = &it->second;
+    tail = parts.second;
   }
   switch (curtree->node().node_case()) {
     case MountTree::Node::kFileNode:
diff --git a/sandboxed_api/sandbox2/mounts_test.cc b/sandboxed_api/sandbox2/mounts_test.cc
index f701a23..b2da5cd 100644
--- a/sandboxed_api/sandbox2/mounts_test.cc
+++ b/sandboxed_api/sandbox2/mounts_test.cc
@@ -39,6 +39,7 @@ using ::sapi::GetTestTempPath;
 using ::sapi::IsOk;
 using ::sapi::StatusIs;
 using ::testing::Eq;
+using ::testing::StrEq;
 using ::testing::UnorderedElementsAreArray;
 
 constexpr size_t kTmpfsSize = 1024;
@@ -243,5 +244,57 @@ TEST(MountTreeTest, TestList) {
   // clang-format on
 }
 
+TEST(MountsResolvePathTest, Files) {
+  Mounts mounts;
+  ASSERT_THAT(mounts.AddFileAt("/A", "/a"), IsOk());
+  ASSERT_THAT(mounts.AddFileAt("/B", "/d/b"), IsOk());
+  ASSERT_THAT(mounts.AddFileAt("/C/D/E", "/d/c/e/f/h"), IsOk());
+  std::string resolved;
+  SAPI_ASSERT_OK_AND_ASSIGN(resolved, mounts.ResolvePath("/a"));
+  EXPECT_THAT(resolved, StrEq("/A"));
+  SAPI_ASSERT_OK_AND_ASSIGN(resolved, mounts.ResolvePath("/d/b"));
+  EXPECT_THAT(resolved, StrEq("/B"));
+  SAPI_ASSERT_OK_AND_ASSIGN(resolved, mounts.ResolvePath("/d/c/e/f/h"));
+  EXPECT_THAT(resolved, StrEq("/C/D/E"));
+  ASSERT_THAT(mounts.ResolvePath("/f"), StatusIs(absl::StatusCode::kNotFound));
+  ASSERT_THAT(mounts.ResolvePath("/d"), StatusIs(absl::StatusCode::kNotFound));
+  ASSERT_THAT(mounts.ResolvePath("/d/c/e/f"),
+              StatusIs(absl::StatusCode::kNotFound));
+  ASSERT_THAT(mounts.ResolvePath("/d/d"),
+              StatusIs(absl::StatusCode::kNotFound));
+}
+
+TEST(MountsResolvePathTest, Dirs) {
+  Mounts mounts;
+  ASSERT_THAT(mounts.AddDirectoryAt("/A", "/a"), IsOk());
+  ASSERT_THAT(mounts.AddDirectoryAt("/B", "/d/b"), IsOk());
+  ASSERT_THAT(mounts.AddDirectoryAt("/C/D/E", "/d/c/e/f/h"), IsOk());
+  ASSERT_THAT(mounts.AddFileAt("/J/G/H", "/d/c/e/f/h/j"), IsOk());
+  ASSERT_THAT(mounts.AddDirectoryAt("/K/L/M", "/d/c/e/f/h/k"), IsOk());
+  std::string resolved;
+  SAPI_ASSERT_OK_AND_ASSIGN(resolved, mounts.ResolvePath("/a"));
+  EXPECT_THAT(resolved, StrEq("/A"));
+  SAPI_ASSERT_OK_AND_ASSIGN(resolved, mounts.ResolvePath("/a/b/c/d/e"));
+  EXPECT_THAT(resolved, StrEq("/A/b/c/d/e"));
+  SAPI_ASSERT_OK_AND_ASSIGN(resolved, mounts.ResolvePath("/d/b"));
+  EXPECT_THAT(resolved, StrEq("/B"));
+  SAPI_ASSERT_OK_AND_ASSIGN(resolved, mounts.ResolvePath("/d/c/e/f/h"));
+  EXPECT_THAT(resolved, StrEq("/C/D/E"));
+  SAPI_ASSERT_OK_AND_ASSIGN(resolved, mounts.ResolvePath("/d/c/e/f/h/i"));
+  EXPECT_THAT(resolved, StrEq("/C/D/E/i"));
+  SAPI_ASSERT_OK_AND_ASSIGN(resolved, mounts.ResolvePath("/d/c/e/f/h/j"));
+  EXPECT_THAT(resolved, StrEq("/J/G/H"));
+  SAPI_ASSERT_OK_AND_ASSIGN(resolved, mounts.ResolvePath("/d/c/e/f/h/k"));
+  EXPECT_THAT(resolved, StrEq("/K/L/M"));
+  SAPI_ASSERT_OK_AND_ASSIGN(resolved, mounts.ResolvePath("/d/c/e/f/h/k/a"));
+  EXPECT_THAT(resolved, StrEq("/K/L/M/a"));
+  ASSERT_THAT(mounts.ResolvePath("/f"), StatusIs(absl::StatusCode::kNotFound));
+  ASSERT_THAT(mounts.ResolvePath("/d"), StatusIs(absl::StatusCode::kNotFound));
+  ASSERT_THAT(mounts.ResolvePath("/d/c/e/f"),
+              StatusIs(absl::StatusCode::kNotFound));
+  ASSERT_THAT(mounts.ResolvePath("/d/d"),
+              StatusIs(absl::StatusCode::kNotFound));
+}
+
 }  // namespace
 }  // namespace sandbox2