diff options
author | Daichi Hirono <hirono@google.com> | 2017-06-15 15:48:07 +0900 |
---|---|---|
committer | Daichi Hirono <hirono@google.com> | 2017-06-20 00:25:28 +0000 |
commit | afa345325647e66dc7add78f7100dc81bd066dbb (patch) | |
tree | 0ce95a8d9d3a94cf48b2ff1d231fd76b01a5bc93 /libappfuse/FuseBridgeLoop.cc | |
parent | 7b1d736dac3eb1b3b75cfd1904a29cc9ec09c75d (diff) | |
download | system_core-afa345325647e66dc7add78f7100dc81bd066dbb.tar.gz system_core-afa345325647e66dc7add78f7100dc81bd066dbb.tar.bz2 system_core-afa345325647e66dc7add78f7100dc81bd066dbb.zip |
Skip FUSE request from /dev/fuse if unique=0
APCT log shows that we got FUSE request unique=0 and replying to such
request causes a EINVAL.
The possible reasons of getting unique=0 here are:
* /dev/fuse actually submits such requests. In this case, not replying
to such request probabbly safe as the kernel cannot wait corresponding
response without a unique number. We can observing the kernel code to
find out what unique=0 actually means.
* Memory corruption happens and unique number are cleared with zero.
In this case, if we skip unique=0 request, libappfuse does not reply
to the kernel request and APCT result will become timeout .
To see which case happens, the CL ScopedLogSeverity to output
verbose logs and lets FuseBridgeLoop skip a request from /dev/fuse if unique=0.
Bug: 62429763
Test: libappfuse_tests
Change-Id: I8c4d532564b690d55573b92260170b0cd68150ab
Diffstat (limited to 'libappfuse/FuseBridgeLoop.cc')
-rw-r--r-- | libappfuse/FuseBridgeLoop.cc | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/libappfuse/FuseBridgeLoop.cc b/libappfuse/FuseBridgeLoop.cc index 07923071b..5a897a472 100644 --- a/libappfuse/FuseBridgeLoop.cc +++ b/libappfuse/FuseBridgeLoop.cc @@ -173,13 +173,20 @@ class FuseBridgeEntry { } FuseBridgeState ReadFromDevice(FuseBridgeLoopCallback* callback) { + // To observe APCT failures. + base::ScopedLogSeverity log_severity(base::VERBOSE); + LOG(VERBOSE) << "ReadFromDevice"; if (!buffer_.request.Read(device_fd_)) { return FuseBridgeState::kClosing; } const uint32_t opcode = buffer_.request.header.opcode; - LOG(VERBOSE) << "Read a fuse packet, opcode=" << opcode; + const uint64_t unique = buffer_.request.header.unique; + LOG(VERBOSE) << "Read a fuse packet, opcode=" << opcode << " unique=" << unique; + if (unique == 0) { + return FuseBridgeState::kWaitToReadEither; + } switch (opcode) { case FUSE_FORGET: // Do not reply to FUSE_FORGET. |