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Modified sandbox to limit ioctl. Use .value() instead of manually checking .ok().

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This commit is contained in:
Andrei Medar 2020-10-02 15:52:29 +00:00
parent 7e1d9179e5
commit 589776b6f9
6 changed files with 105 additions and 153 deletions
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3
oss-internship-2020/libarchive/.clang-format
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@ -1,3 +0,0 @@
BasedOnStyle: Google
DerivePointerAlignment: false
PointerAlignment: Left

1
oss-internship-2020/libarchive/.gitignore vendored
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@ -1,4 +1,3 @@
build/
.clang-format
.cache
.vscode

4
oss-internship-2020/libarchive/README.md
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@ -13,8 +13,7 @@ After this, run the following commands: -->
`cmake --build .`
The example binary file can be found at `build/examples/sapi_minitar` and the unit tests at `build/test/sapi_minitar_test`.
The example binary file can be found at **build/examples/sapi_minitar** and the unit tests at **build/test/sapi_minitar_test**.
## Patches
@ -28,7 +27,6 @@ The code is found in the **examples** directory and is structured as follows:
- **sapi_minitar.h** and **sapi_minitar.cc** - The two main functions (***create*** and ***extract***) and also other helper functions.
- **sandbox.h** - Custom security policies, depending on the whether the user creates or extracts an archive.
On top of that, unit tests can be found in the **test/minitar_test.cc** file.
## Usage

8
oss-internship-2020/libarchive/examples/sandbox.h
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@ -16,8 +16,10 @@
#define SAPI_LIBARCHIVE_EXAMPLES_SANDBOX_H
#include <asm/unistd_64.h>
#include <linux/fs.h>
#include "libarchive_sapi.sapi.h"
#include "sandboxed_api/sandbox2/util/bpf_helper.h"
#include "sandboxed_api/sandbox2/util/fileops.h"
// When creating an archive, we need read permissions on each of the
@ -56,11 +58,13 @@ class SapiLibarchiveSandboxCreate : public LibarchiveSandbox {
__NR_fstatfs,
__NR_socket,
__NR_connect,
__NR_ioctl,
__NR_flistxattr,
__NR_recvmsg,
__NR_getdents64,
});
})
// Allow ioctl only for FS_IOC_GETFLAGS.
.AddPolicyOnSyscall(__NR_ioctl,
{ARG(1), JEQ(FS_IOC_GETFLAGS, ALLOW)});
// We check whether the entry is a file or a directory.
for (const auto& i : files_) {

236
oss-internship-2020/libarchive/examples/sapi_minitar.cc
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@ -13,6 +13,7 @@
// limitations under the License.
#include "sapi_minitar.h"
#include "sandboxed_api/sandbox2/util/path.h"
void create(const char* initial_filename, int compress, const char** argv,
@ -36,7 +37,6 @@ void create(const char* initial_filename, int compress, const char** argv,
std::transform(relative_paths.begin(), relative_paths.end(),
relative_paths.begin(), sandbox2::file::CleanPath);
// At this point, we have the relative and absolute paths (cleaned) saved
// in vectors.
@ -45,47 +45,36 @@ void create(const char* initial_filename, int compress, const char** argv,
CHECK(sandbox.Init().ok()) << "Error during sandbox initialization";
LibarchiveApi api(&sandbox);
absl::StatusOr<archive*> ret = api.archive_write_new();
CHECK(ret.ok()) << "write_new call failed";
CHECK(ret.value() != NULL) << "Failed to create write archive";
archive* ret = api.archive_write_new().value();
CHECK(ret != NULL) << "Failed to create write archive";
// Treat the pointer as remote. There is no need to copy the data
// to the client process.
sapi::v::RemotePtr a(ret.value());
sapi::v::RemotePtr a(ret);
absl::StatusOr<int> ret2;
int ret2;
switch (compress) {
case 'j':
case 'y':
ret2 = api.archive_write_add_filter_bzip2(&a);
CHECK(ret2.ok()) << "write_add_filter_bzip2 call failed";
CHECK(ret2.value() != ARCHIVE_FATAL)
CHECK(api.archive_write_add_filter_bzip2(&a).value() == ARCHIVE_OK)
<< "Unexpected result from write_add_filter_bzip2 call";
break;
case 'Z':
ret2 = api.archive_write_add_filter_compress(&a);
CHECK(ret2.ok()) << "write_add_filter_compress call failed";
CHECK(ret2.value() != ARCHIVE_FATAL)
CHECK(api.archive_write_add_filter_compress(&a).value() == ARCHIVE_OK)
<< "Unexpected result from write_add_filter_compress call";
break;
case 'z':
ret2 = api.archive_write_add_filter_gzip(&a);
CHECK(ret2.ok()) << "write_add_filter_gzip call failed";
CHECK(ret2.value() != ARCHIVE_FATAL)
CHECK(api.archive_write_add_filter_gzip(&a).value() == ARCHIVE_OK)
<< "Unexpected result from write_add_filter_gzip call";
break;
default:
ret2 = api.archive_write_add_filter_none(&a);
CHECK(ret2.ok()) << "write_add_filter_none call failed";
CHECK(ret2.value() != ARCHIVE_FATAL)
CHECK(api.archive_write_add_filter_none(&a).value() == ARCHIVE_OK)
<< "Unexpected result from write_add_filter_none call";
break;
}
ret2 = api.archive_write_set_format_ustar(&a);
CHECK(ret2.ok()) << "write_set_format_ustar call failed";
CHECK(ret2.value() != ARCHIVE_FATAL)
CHECK(api.archive_write_set_format_ustar(&a).value() == ARCHIVE_OK)
<< "Unexpected result from write_set_format_ustar call";
const char* filename_ptr = filename.data();
@ -93,56 +82,51 @@ void create(const char* initial_filename, int compress, const char** argv,
filename_ptr = NULL;
}
ret2 = api.archive_write_open_filename(
&a, sapi::v::ConstCStr(filename_ptr).PtrBefore());
CHECK(ret2.ok()) << "write_open_filename call failed";
CHECK(ret2.value() != ARCHIVE_FATAL)
CHECK(api.archive_write_open_filename(
&a, sapi::v::ConstCStr(filename_ptr).PtrBefore())
.value() == ARCHIVE_OK)
<< "Unexpected result from write_open_filename call";
int file_idx = 0;
// We can directly use the vectors defined before.
for (int file_idx = 0; file_idx < absolute_paths.size(); ++file_idx) {
ret = api.archive_read_disk_new();
CHECK(ret.ok()) << "read_disk_new call failed";
CHECK(ret.value() != NULL) << "Failed to create read_disk archive";
ret = api.archive_read_disk_new().value();
CHECK(ret != NULL) << "Failed to create read_disk archive";
sapi::v::RemotePtr disk(ret.value());
sapi::v::RemotePtr disk(ret);
ret2 = api.archive_read_disk_set_standard_lookup(&disk);
CHECK(ret2.ok()) << "read_disk_set_standard_lookup call failed";
CHECK(ret2.value() != ARCHIVE_FATAL)
CHECK(api.archive_read_disk_set_standard_lookup(&disk).value() ==
ARCHIVE_OK)
<< "Unexpected result from read_disk_set_standard_lookup call";
// We use the absolute path first.
ret2 = api.archive_read_disk_open(
&disk,
sapi::v::ConstCStr(absolute_paths[file_idx].c_str()).PtrBefore());
CHECK(ret2.ok()) << "read_disk_open call failed";
CHECK(ret2.value() == ARCHIVE_OK)
CHECK(
api.archive_read_disk_open(
&disk,
sapi::v::ConstCStr(absolute_paths[file_idx].c_str()).PtrBefore())
.value() == ARCHIVE_OK)
<< CheckStatusAndGetString(api.archive_error_string(&disk), sandbox);
for (;;) {
absl::StatusOr<archive_entry*> ret3;
ret3 = api.archive_entry_new();
archive_entry* ret3;
ret3 = api.archive_entry_new().value();
CHECK(ret3.ok()) << "entry_new call failed";
CHECK(ret3.value() != NULL) << "Failed to create archive_entry";
CHECK(ret3 != NULL) << "Failed to create archive_entry";
sapi::v::RemotePtr entry(ret3.value());
sapi::v::RemotePtr entry(ret3);
ret2 = api.archive_read_next_header2(&disk, &entry);
CHECK(ret2.ok()) << "read_next_header2 call failed";
ret2 = api.archive_read_next_header2(&disk, &entry).value();
if (ret2.value() == ARCHIVE_EOF) {
if (ret2 == ARCHIVE_EOF) {
break;
}
CHECK(ret2.value() == ARCHIVE_OK)
CHECK(ret2 == ARCHIVE_OK)
<< CheckStatusAndGetString(api.archive_error_string(&disk), sandbox);
ret2 = api.archive_read_disk_descend(&disk);
CHECK(ret2.ok()) << "read_disk_descend call failed";
CHECK(api.archive_read_disk_descend(&disk).ok())
<< "read_disk_descend call failed";
// After using the absolute path before, we now need to add the pathname
// to the archive entry. This would help store the files by their relative
@ -185,21 +169,20 @@ void create(const char* initial_filename, int compress, const char** argv,
<< std::endl;
}
ret2 = api.archive_write_header(&a, &entry);
CHECK(ret2.ok()) << "write_header call failed";
ret2 = api.archive_write_header(&a, &entry).value();
if (ret2.value() < ARCHIVE_OK) {
if (ret2 < ARCHIVE_OK) {
std::cout << CheckStatusAndGetString(api.archive_error_string(&a),
sandbox)
<< std::endl;
}
CHECK(ret2.value() != ARCHIVE_FATAL)
CHECK(ret2 != ARCHIVE_FATAL)
<< "Unexpected result from write_header call";
// In the following section, the calls (read, archive_write_data) are done
// on the sandboxed process since we do not need to transfer the data in
// the client process.
if (ret2.value() > ARCHIVE_FAILED) {
if (ret2 > ARCHIVE_FAILED) {
int fd = open(CheckStatusAndGetString(
api.archive_entry_sourcepath(&entry), sandbox)
.c_str(),
@ -240,26 +223,21 @@ void create(const char* initial_filename, int compress, const char** argv,
CHECK(api.archive_entry_free(&entry).ok()) << "entry_free call failed";
}
ret2 = api.archive_read_close(&disk);
CHECK(ret2.ok()) << "read_close call failed";
CHECK(!ret2.value()) << "Unexpected result from read_close call";
CHECK(api.archive_read_close(&disk).value() == ARCHIVE_OK)
<< "Unexpected result from read_close call";
ret2 = api.archive_read_free(&disk);
CHECK(ret2.ok()) << "read_free call failed";
CHECK(!ret2.value()) << "Unexpected result from read_free call";
CHECK(api.archive_read_free(&disk).value() == ARCHIVE_OK)
<< "Unexpected result from read_free call";
}
ret2 = api.archive_write_close(&a);
CHECK(ret2.ok()) << "write_close call failed";
CHECK(!ret2.value()) << "Unexpected result from write_close call";
CHECK(api.archive_write_close(&a).value() == ARCHIVE_OK)
<< "Unexpected result from write_close call";
ret2 = api.archive_write_free(&a);
CHECK(ret2.ok()) << "write_free call failed";
CHECK(!ret2.value()) << "Unexpected result from write_free call";
CHECK(api.archive_write_free(&a).value() == ARCHIVE_OK)
<< "Unexpected result from write_free call";
}
void extract(const char* filename, int do_extract, int flags,
bool verbose) {
void extract(const char* filename, int do_extract, int flags, bool verbose) {
std::string tmp_dir;
if (do_extract) {
tmp_dir = CreateTempDirAtCWD();
@ -268,10 +246,11 @@ void extract(const char* filename, int do_extract, int flags,
// We can use a struct like this in order to delete the temporary
// directory that was created earlier whenever the function ends.
struct ExtractTempDirectoryCleanup {
ExtractTempDirectoryCleanup(const std::string& dir): dir_(dir) {}
ExtractTempDirectoryCleanup(const std::string& dir) : dir_(dir) {}
~ExtractTempDirectoryCleanup() {
sandbox2::file_util::fileops::DeleteRecursively(dir_);
}
private:
std::string dir_;
};
@ -290,52 +269,36 @@ void extract(const char* filename, int do_extract, int flags,
CHECK(sandbox.Init().ok()) << "Error during sandbox initialization";
LibarchiveApi api(&sandbox);
absl::StatusOr<archive*> ret = api.archive_read_new();
CHECK(ret.ok()) << "archive_read_new call failed";
CHECK(ret.value() != NULL) << "Failed to create read archive";
archive* ret = api.archive_read_new().value();
CHECK(ret != NULL) << "Failed to create read archive";
sapi::v::RemotePtr a(ret.value());
sapi::v::RemotePtr a(ret);
ret = api.archive_write_disk_new();
CHECK(ret.ok()) << "write_disk_new call failed";
CHECK(ret.value() != NULL) << "Failed to create write disk archive";
ret = api.archive_write_disk_new().value();
CHECK(ret != NULL) << "Failed to create write disk archive";
sapi::v::RemotePtr ext(ret.value());
sapi::v::RemotePtr ext(ret);
absl::StatusOr<int> ret2;
ret2 = api.archive_write_disk_set_options(&ext, flags);
CHECK(ret2.ok()) << "write_disk_set_options call failed";
CHECK(ret2.value() != ARCHIVE_FATAL)
int ret2;
CHECK(api.archive_write_disk_set_options(&ext, flags).value() == ARCHIVE_OK)
<< "Unexpected result from write_disk_set_options call";
ret2 = api.archive_read_support_filter_bzip2(&a);
CHECK(ret2.ok()) << "read_support_filter_bzip2 call failed";
CHECK(ret2.value() != ARCHIVE_FATAL)
CHECK(api.archive_read_support_filter_bzip2(&a).value() == ARCHIVE_OK)
<< "Unexpected result from read_support_filter_bzip2 call";
ret2 = api.archive_read_support_filter_gzip(&a);
CHECK(ret2.ok()) << "read_suppport_filter_gzip call failed";
CHECK(ret2.value() != ARCHIVE_FATAL)
CHECK(api.archive_read_support_filter_gzip(&a).value() == ARCHIVE_OK)
<< "Unexpected result from read_suppport_filter_gzip call";
ret2 = api.archive_read_support_filter_compress(&a);
CHECK(ret2.ok()) << "read_support_filter_compress call failed";
CHECK(ret2.value() != ARCHIVE_FATAL)
CHECK(api.archive_read_support_filter_compress(&a).value() == ARCHIVE_OK)
<< "Unexpected result from read_support_filter_compress call";
ret2 = api.archive_read_support_format_tar(&a);
CHECK(ret2.ok()) << "read_support_format_tar call failed";
CHECK(ret2.value() != ARCHIVE_FATAL)
CHECK(api.archive_read_support_format_tar(&a).value() == ARCHIVE_OK)
<< "Unexpected result fromread_support_format_tar call";
ret2 = api.archive_read_support_format_cpio(&a);
CHECK(ret2.ok()) << "read_support_format_cpio call failed";
CHECK(ret2.value() != ARCHIVE_FATAL)
CHECK(api.archive_read_support_format_cpio(&a).value() == ARCHIVE_OK)
<< "Unexpected result from read_support_format_tar call";
ret2 = api.archive_write_disk_set_standard_lookup(&ext);
CHECK(ret2.ok()) << "write_disk_set_standard_lookup call failed";
CHECK(ret2.value() != ARCHIVE_FATAL)
CHECK(api.archive_write_disk_set_standard_lookup(&ext).value() == ARCHIVE_OK)
<< "Unexpected result from write_disk_set_standard_lookup call";
const char* filename_ptr = filename_absolute.c_str();
@ -345,23 +308,21 @@ void extract(const char* filename, int do_extract, int flags,
// The entries are saved with a relative path so they are all created
// relative to the current working directory.
ret2 = api.archive_read_open_filename(
&a, sapi::v::ConstCStr(filename_ptr).PtrBefore(), kBlockSize);
CHECK(ret2.ok()) << "read_open_filename call failed";
CHECK(!ret2.value()) << CheckStatusAndGetString(api.archive_error_string(&a),
sandbox);
CHECK(api.archive_read_open_filename(
&a, sapi::v::ConstCStr(filename_ptr).PtrBefore(), kBlockSize)
.value() == ARCHIVE_OK)
<< CheckStatusAndGetString(api.archive_error_string(&a), sandbox);
for (;;) {
sapi::v::IntBase<struct archive_entry*> entry_ptr_tmp(0);
sapi::v::IntBase<archive_entry*> entry_ptr_tmp(0);
ret2 = api.archive_read_next_header(&a, entry_ptr_tmp.PtrAfter());
CHECK(ret2.ok()) << "read_next_header call failed";
ret2 = api.archive_read_next_header(&a, entry_ptr_tmp.PtrAfter()).value();
if (ret2.value() == ARCHIVE_EOF) {
if (ret2 == ARCHIVE_EOF) {
break;
}
CHECK(ret2.value() == ARCHIVE_OK)
CHECK(ret2 == ARCHIVE_OK)
<< CheckStatusAndGetString(api.archive_error_string(&a), sandbox);
sapi::v::RemotePtr entry(entry_ptr_tmp.GetValue());
@ -377,10 +338,9 @@ void extract(const char* filename, int do_extract, int flags,
}
if (do_extract) {
ret2 = api.archive_write_header(&ext, &entry);
CHECK(ret2.ok()) << "write_header call failed";
ret2 = api.archive_write_header(&ext, &entry).value();
if (ret2.value() != ARCHIVE_OK) {
if (ret2 != ARCHIVE_OK) {
std::cout << CheckStatusAndGetString(api.archive_error_string(&a),
sandbox);
} else {
@ -389,56 +349,51 @@ void extract(const char* filename, int do_extract, int flags,
}
}
ret2 = api.archive_read_close(&a);
CHECK(ret2.ok()) << "read_close call failed";
CHECK(!ret2.value()) << "Unexpected value from read_close call";
CHECK(api.archive_read_close(&a).value() == ARCHIVE_OK)
<< "Unexpected value from read_close call";
ret2 = api.archive_read_free(&a);
CHECK(ret2.ok()) << "read_free call failed";
CHECK(!ret2.value()) << "Unexpected result from read_free call";
CHECK(api.archive_read_free(&a).value() == ARCHIVE_OK)
<< "Unexpected result from read_free call";
ret2 = api.archive_write_close(&ext);
CHECK(ret2.ok()) << "write_close call failed";
CHECK(!ret2.value()) << "Unexpected result from write_close call";
CHECK(api.archive_write_close(&ext).value() == ARCHIVE_OK)
<< "Unexpected result from write_close call";
ret2 = api.archive_write_free(&ext);
CHECK(ret2.ok()) << "write_free call failed";
CHECK(!ret2.value()) << "Unexpected result from write_free call";
CHECK(api.archive_write_free(&ext).value() == ARCHIVE_OK)
<< "Unexpected result from write_free call";
}
int copy_data(sapi::v::RemotePtr* ar, sapi::v::RemotePtr* aw,
LibarchiveApi& api, SapiLibarchiveSandboxExtract& sandbox) {
absl::StatusOr<int> ret;
int ret;
sapi::v::IntBase<struct archive_entry*> buff_ptr_tmp(0);
sapi::v::IntBase<archive_entry*> buff_ptr_tmp(0);
sapi::v::ULLong size;
sapi::v::SLLong offset;
for (;;) {
ret = api.archive_read_data_block(ar, buff_ptr_tmp.PtrAfter(),
size.PtrAfter(), offset.PtrAfter());
CHECK(ret.ok()) << "read_data_block call failed";
size.PtrAfter(), offset.PtrAfter())
.value();
if (ret.value() == ARCHIVE_EOF) {
if (ret == ARCHIVE_EOF) {
return ARCHIVE_OK;
}
if (ret.value() != ARCHIVE_OK) {
if (ret != ARCHIVE_OK) {
std::cout << CheckStatusAndGetString(api.archive_error_string(ar),
sandbox);
return ret.value();
return ret;
}
sapi::v::RemotePtr buff(buff_ptr_tmp.GetValue());
ret = api.archive_write_data_block(aw, &buff, size.GetValue(),
offset.GetValue());
offset.GetValue())
.value();
CHECK(ret.ok()) << "write_data_block call failed";
if (ret.value() != ARCHIVE_OK) {
if (ret != ARCHIVE_OK) {
std::cout << CheckStatusAndGetString(api.archive_error_string(ar),
sandbox);
return ret.value();
return ret;
}
}
}
@ -452,12 +407,9 @@ std::string MakeAbsolutePathAtCWD(const std::string& path) {
std::string CheckStatusAndGetString(const absl::StatusOr<char*>& status,
LibarchiveSandbox& sandbox) {
CHECK(status.ok() && status.value() != NULL) << "Could not get error message";
absl::StatusOr<std::string> ret =
sandbox.GetCString(sapi::v::RemotePtr(status.value()));
CHECK(ret.ok()) << "Could not transfer error message";
return ret.value();
char* str = status.value();
CHECK(str != NULL) << "Could not get error message";
return sandbox.GetCString(sapi::v::RemotePtr(str)).value();
}
std::string CreateTempDirAtCWD() {
@ -465,6 +417,8 @@ std::string CreateTempDirAtCWD() {
CHECK(!cwd.empty()) << "Could not get current working directory";
cwd.append("/");
// We can manually check for .ok() result in this case because it offers
// important debugging information.
absl::StatusOr<std::string> result = sandbox2::CreateTempDir(cwd);
CHECK(result.ok()) << "Could not create temporary directory at " << cwd;
return result.value();

6
oss-internship-2020/libarchive/examples/sapi_minitar.h
View File

@ -12,8 +12,8 @@
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef SAPI_LIBARCHIVE_MINITAR_H
#define SAPI_LIBARCHIVE_MINITAR_H
#ifndef SAPI_LIBARCHIVE_EXAMPLES_MINITAR_H
#define SAPI_LIBARCHIVE_EXAMPLES_MINITAR_H
#include <archive.h>
#include <archive_entry.h>
@ -59,4 +59,4 @@ std::string CheckStatusAndGetString(const absl::StatusOr<char*>& status,
// process changes the current working directory to this temporary directory.
std::string CreateTempDirAtCWD();
#endif // SAPI_LIBARCHIVE_MINITAR_H
#endif // SAPI_LIBARCHIVE_EXAMPLES_MINITAR_H