diff options
| author | Nicholas Roth <nicholas@rothemail.net> | 2022-10-30 18:04:58 -0500 |
|---|---|---|
| committer | Jacopo Mondi <jacopo@jmondi.org> | 2022-12-01 11:32:13 +0100 |
| commit | 69050ca70469c40b90fad8bc2b3182ebe1ea4f5a (patch) | |
| tree | 5cfc6f7a9aed031e6eb8e7c3e2d448718c66356c | |
| parent | ac58d82c55806dea35275344f0fd12a4cf2c8904 (diff) | |
ipa: add a flag to disable isolation for Android
Currently, libcamera isolates any IPAs whose signatures cannot be
verified. Shared objects are created at build-time, and then signed. The
public signing key is embedded in a .cpp file, and libcamera verifies
IPA signatures at runtime. When libcamera cannot authenticate an IPA, it
runs it out-of-process.
This is problematic on three levels:
* IPA signing fundamentally does not work on Android for vendor modules
like HALs (discussed below)
* Executables built to run out-of-process are not ABI-compatible with
Android, making isolation infeasible [1]
* Linux phone hardware tends to be low-end because of the FOSS
requirement, so the performance hit from out-of-process IPA isolation
is significant
IPA signing fundamentally does not work for Android vendor modules:
After we "meson install" built .so files to a known location, Android
explicitly access them in PREBUILT_SHARED_LIBRARY or BUILD_PREBUILIT
to transform the .so files by stripping symbols among other things [2].
By modifying prebuilt libraries after we have already signed them, the
build system renders our signatures useless on Android.
Android distribution maintainers can use this flag to disable signature
verification, which will allow them to use libcamera.
[1] https://github.com/waydroid/waydroid/issues/519
[2] https://cs.android.com/android/platform/superproject/+/master:build/make/core/cc_prebuilt_internal.mk?q=cc_prebuilt_internal
Signed-off-by: Nicholas Roth <nicholas@rothemail.net>
| -rw-r--r-- | meson.build | 4 | ||||
| -rw-r--r-- | meson_options.txt | 5 | ||||
| -rw-r--r-- | src/libcamera/ipa_manager.cpp | 11 |
3 files changed, 20 insertions, 0 deletions
diff --git a/meson.build b/meson.build index e4c0be16..2529444d 100644 --- a/meson.build +++ b/meson.build @@ -76,6 +76,10 @@ if cc.has_header_symbol('stdlib.h', 'secure_getenv', prefix : '#define _GNU_SOUR config_h.set('HAVE_SECURE_GETENV', 1) endif +if get_option('allow_unsigned_ipas_in_process') + config_h.set('ALLOW_UNSIGNED_IPAS_IN_PROCESS', 1) +endif + common_arguments = [ '-Wshadow', '-include', meson.current_build_dir() / 'config.h', diff --git a/meson_options.txt b/meson_options.txt index 1ba6778c..3f9fe245 100644 --- a/meson_options.txt +++ b/meson_options.txt @@ -64,3 +64,8 @@ option('pycamera', type : 'feature', value : 'disabled', description : 'Enable libcamera Python bindings (experimental)') + +option('allow_unsigned_ipas_in_process', + type : 'boolean', + value : false, + description : 'Allow unsigned IPAs to run in libcamera\'s address space') diff --git a/src/libcamera/ipa_manager.cpp b/src/libcamera/ipa_manager.cpp index 030ef43f..403cc42a 100644 --- a/src/libcamera/ipa_manager.cpp +++ b/src/libcamera/ipa_manager.cpp @@ -114,6 +114,14 @@ IPAManager::IPAManager() LOG(IPAManager, Warning) << "Public key not valid"; #endif +#if ALLOW_UNSIGNED_IPAS_IN_PROCESS + LOG(IPAManager, Warning) + << "All IPAs running in-process without signature verification." + << " This is recommended only for tightly-managed installs" + << " in contexts where both signature verification and out-of-process" + << " execution are infeasible, such as Android HALs."; +#endif + unsigned int ipaCount = 0; /* User-specified paths take precedence. */ @@ -281,6 +289,9 @@ IPAModule *IPAManager::module(PipelineHandler *pipe, uint32_t minVersion, bool IPAManager::isSignatureValid([[maybe_unused]] IPAModule *ipa) const { +#if ALLOW_UNSIGNED_IPAS_IN_PROCESS + return true; +#endif #if HAVE_IPA_PUBKEY char *force = utils::secure_getenv("LIBCAMERA_IPA_FORCE_ISOLATION"); if (force && force[0] != '\0') { |