Replace GetNode with ResolvePath in Mounts

Now unwinding will properly handle binaries inside bind-mounted directories.

Drive-by:
 - Get rid of n^2 path handling
 - Get rid of namespace alias
PiperOrigin-RevId: 358353666
Change-Id: Ieec7690ec6a1ae6d358de375220566b69e8cb094
This commit is contained in:
Wiktor Garbacz 2021-02-19 00:43:06 -08:00 committed by Copybara-Service
parent ec64f47bba
commit 3d0fa1f891
7 changed files with 58 additions and 56 deletions

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@ -16,7 +16,7 @@ set(workdir "${CMAKE_BINARY_DIR}/_deps/absl-populate")
set(SAPI_ABSL_GIT_REPOSITORY https://github.com/abseil/abseil-cpp.git
CACHE STRING "")
set(SAPI_ABSL_GIT_TAG 4fd9a1ec5077daac14eeee05df931d658ec0b7b8
set(SAPI_ABSL_GIT_TAG b315753c0b8b4aa4e3e1479375eddb518393bab6
CACHE STRING "") # 2020-11-19
set(SAPI_ABSL_SOURCE_DIR "${CMAKE_BINARY_DIR}/_deps/absl-src" CACHE STRING "")
set(SAPI_ABSL_BINARY_DIR "${CMAKE_BINARY_DIR}/_deps/absl-build" CACHE STRING "")

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@ -17,7 +17,7 @@ set(workdir "${CMAKE_BINARY_DIR}/_deps/protobuf-populate")
set(SAPI_PROTOBUF_GIT_REPOSITORY
https://github.com/protocolbuffers/protobuf.git
CACHE STRING "")
set(SAPI_PROTOBUF_GIT_TAG v3.11.4 CACHE STRING "") # 2020-02-14
set(SAPI_PROTOBUF_GIT_TAG v3.14.0 CACHE STRING "") # 2020-11-14
set(SAPI_PROTOBUF_SOURCE_DIR "${CMAKE_BINARY_DIR}/_deps/protobuf-src"
CACHE STRING "")
set(SAPI_PROTOBUF_BINARY_DIR "${CMAKE_BINARY_DIR}/_deps/protobuf-build"

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@ -34,9 +34,9 @@ def sapi_deps():
maybe(
http_archive,
name = "com_google_absl",
sha256 = "59d1ada90ee43dd514c659246d24f7edc003eede0f3243f030f0daa03371e458", # 2020-11-19
strip_prefix = "abseil-cpp-4fd9a1ec5077daac14eeee05df931d658ec0b7b8",
urls = ["https://github.com/abseil/abseil-cpp/archive/4fd9a1ec5077daac14eeee05df931d658ec0b7b8.zip"],
sha256 = "e140988c4d3c22f829a3095f0d34a0783aa2f8829556283f10b8eb63a9428b19", # 2021-02-19
strip_prefix = "abseil-cpp-b315753c0b8b4aa4e3e1479375eddb518393bab6",
urls = ["https://github.com/abseil/abseil-cpp/archive/b315753c0b8b4aa4e3e1479375eddb518393bab6.zip"],
)
maybe(
http_archive,
@ -83,9 +83,9 @@ def sapi_deps():
maybe(
http_archive,
name = "com_google_protobuf",
sha256 = "9748c0d90e54ea09e5e75fb7fac16edce15d2028d4356f32211cfa3c0e956564", # 2020-02-14
strip_prefix = "protobuf-3.11.4",
urls = ["https://github.com/protocolbuffers/protobuf/archive/v3.11.4.zip"],
sha256 = "bf0e5070b4b99240183b29df78155eee335885e53a8af8683964579c214ad301", # 2020-11-14
strip_prefix = "protobuf-3.14.0",
urls = ["https://github.com/protocolbuffers/protobuf/archive/v3.14.0.zip"],
)
# libcap

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@ -423,12 +423,8 @@ add_library(sandbox2_mounts ${SAPI_LIB_TYPE}
)
add_library(sandbox2::mounts ALIAS sandbox2_mounts)
target_link_libraries(sandbox2_mounts
PRIVATE absl::core_headers
absl::flat_hash_set
absl::status
absl::statusor
PRIVATE absl::flat_hash_set
absl::str_format
absl::strings
protobuf::libprotobuf
sapi::config
sapi::file_base
@ -438,7 +434,11 @@ target_link_libraries(sandbox2_mounts
sapi::base
sapi::raw_logging
sapi::status
PUBLIC sandbox2::mounttree_proto
PUBLIC absl::core_headers
absl::status
absl::statusor
absl::strings
sandbox2::mounttree_proto
)
# sandboxed_api/sandbox2:namespace

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@ -34,6 +34,7 @@
#include "absl/strings/str_join.h"
#include "absl/strings/str_split.h"
#include "absl/strings/string_view.h"
#include "absl/strings/strip.h"
#include "sandboxed_api/config.h"
#include "sandboxed_api/sandbox2/util/minielf.h"
#include "sandboxed_api/util/fileops.h"
@ -46,12 +47,11 @@ namespace sandbox2 {
namespace {
namespace cpu = ::sapi::cpu;
namespace file = ::sapi::file;
namespace file_util = ::sapi::file_util;
namespace host_cpu = ::sapi::host_cpu;
bool PathContainsNullByte(absl::string_view path) {
return path.find('\x00') != absl::string_view::npos;
return absl::StrContains(path, '\x00');
}
bool IsSameFile(const std::string& path1, const std::string& path2) {
@ -105,7 +105,8 @@ absl::string_view GetOutsidePath(const MountTree::Node& node) {
absl::StatusOr<std::string> ExistingPathInsideDir(
absl::string_view dir_path, absl::string_view relative_path) {
auto path = file::CleanPath(file::JoinPath(dir_path, relative_path));
auto path =
sapi::file::CleanPath(sapi::file::JoinPath(dir_path, relative_path));
if (file_util::fileops::StripBasename(path) != dir_path) {
return absl::InvalidArgumentError("Relative path goes above the base dir");
}
@ -192,9 +193,9 @@ absl::Status Mounts::Insert(absl::string_view path,
break;
}
std::string fixed_path = file::CleanPath(path);
std::string fixed_path = sapi::file::CleanPath(path);
if (!file::IsAbsolutePath(fixed_path)) {
if (!sapi::file::IsAbsolutePath(fixed_path)) {
return absl::InvalidArgumentError("Only absolute paths are supported");
}
@ -202,22 +203,15 @@ absl::Status Mounts::Insert(absl::string_view path,
return absl::InvalidArgumentError("The root already exists");
}
std::vector<absl::string_view> parts;
auto split = file::SplitPath(fixed_path);
absl::string_view cur = split.first;
auto final_part = std::string(split.second);
while (cur != "/") {
auto split = file::SplitPath(cur);
cur = split.first;
parts.push_back(split.second);
}
std::vector<absl::string_view> parts =
absl::StrSplit(absl::StripPrefix(fixed_path, "/"), '/');
std::string final_part(parts.back());
parts.pop_back();
MountTree* curtree = &mount_tree_;
for (auto part = parts.rbegin(); part != parts.rend(); ++part) {
for (absl::string_view part : parts) {
curtree = &(curtree->mutable_entries()
->insert({std::string(*part), MountTree()})
->insert({std::string(part), MountTree()})
.first->second);
if (curtree->has_node() && curtree->node().has_file_node()) {
return absl::FailedPreconditionError(
@ -272,26 +266,38 @@ absl::Status Mounts::AddDirectoryAt(absl::string_view outside,
return Insert(inside, node);
}
const MountTree::Node* Mounts::GetNode(const std::string& path) const {
std::string fixed_path = file::CleanPath(path);
absl::string_view cur = fixed_path;
std::vector<std::string> parts;
while (cur != "/") {
auto split = file::SplitPath(cur);
cur = split.first;
parts.push_back(std::string(split.second));
absl::StatusOr<std::string> Mounts::ResolvePath(absl::string_view path) const {
if (!sapi::file::IsAbsolutePath(path)) {
return absl::InvalidArgumentError("Path has to be absolute");
}
std::string fixed_path = sapi::file::CleanPath(path);
absl::string_view tail = absl::StripPrefix(fixed_path, "/");
const MountTree* curtree = &mount_tree_;
for (auto part = parts.rbegin(); part != parts.rend(); ++part) {
const auto& p = curtree->entries().find(*part);
if (p == curtree->entries().end()) {
return nullptr;
while (!tail.empty()) {
std::pair<absl::string_view, absl::string_view> parts =
absl::StrSplit(tail, absl::MaxSplits('/', 1));
absl::string_view cur = parts.first;
tail = parts.second;
const auto it = curtree->entries().find(cur);
if (it == curtree->entries().end()) {
if (curtree->node().has_dir_node()) {
return sapi::file::JoinPath(curtree->node().dir_node().outside(), tail);
}
return absl::NotFoundError("Path could not be resolved in the mounts");
}
curtree = &p->second;
curtree = &it->second;
}
return &curtree->node();
switch (curtree->node().node_case()) {
case MountTree::Node::kFileNode:
case MountTree::Node::kDirNode:
return std::string(GetOutsidePath(curtree->node()));
case MountTree::Node::kRootNode:
case MountTree::Node::kTmpfsNode:
case MountTree::Node::NODE_NOT_SET:
break;
}
return absl::NotFoundError("Path could not be resolved in the mounts");
}
namespace {
@ -347,7 +353,7 @@ absl::Status Mounts::AddMappingsForBinary(const std::string& path,
std::string path = search_path;
for (int hw_cap = 0; hw_cap < hw_cap_paths.size(); ++hw_cap) {
if ((hw_caps_set & (1 << hw_cap)) != 0) {
path = file::JoinPath(path, hw_cap_paths[hw_cap]);
path = sapi::file::JoinPath(path, hw_cap_paths[hw_cap]);
}
}
if (file_util::fileops::Exists(path, /*fully_resolve=*/false)) {
@ -647,7 +653,7 @@ void CreateMounts(const MountTree& tree, const std::string& path,
// Traverse the subtrees.
for (const auto& kv : tree.entries()) {
std::string new_path = file::JoinPath(path, kv.first);
std::string new_path = sapi::file::JoinPath(path, kv.first);
CreateMounts(kv.second, new_path, create_backing_files);
}
}

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@ -20,6 +20,7 @@
#include "absl/base/attributes.h"
#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "absl/strings/string_view.h"
#include "sandboxed_api/sandbox2/mounttree.pb.h"
@ -76,7 +77,7 @@ class Mounts {
void RecursivelyListMounts(std::vector<std::string>* outside_entries,
std::vector<std::string>* inside_entries);
const MountTree::Node* GetNode(const std::string& path) const;
absl::StatusOr<std::string> ResolvePath(absl::string_view path) const;
private:
friend class MountTreeTest;

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@ -217,13 +217,8 @@ bool StackTracePeer::LaunchLibunwindSandbox(const Regs* regs,
// The exe_path will have a mountable path of the application, even if it was
// removed.
std::string exe_path;
// Resolve app_path backing file.
const auto* app_node = mounts.GetNode(app_path);
if (app_node) {
exe_path = app_node->file_node().outside();
}
std::string exe_path = mounts.ResolvePath(app_path).value_or("");
if (exe_path.empty()) {
// File was probably removed.