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* executor: add runner modeDmitry Vyukov2024-06-241-12/+5
| | | | | | | Move all syz-fuzzer logic into syz-executor and remove syz-fuzzer. Also restore syz-runtest functionality in the manager. Update #4917 (sets most signal handlers to SIG_IGN)
* executor: fix is_kernel_data/pc for gVisorDmitry Vyukov2024-06-211-0/+4
| | | | The address ranges in is_kernel_data/pc are only true for normal Linux.
* executor: factor out is_kernel_pc helperDmitry Vyukov2024-06-111-7/+11
| | | | Factor out is_kernel_pc helper and add kernel pc range for test OS for testing.
* executor: add end-to-end coverage/signal/comparisons testDmitry Vyukov2024-06-111-0/+11
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* executor: optimize waiting for child processes exitDmitry Vyukov2024-06-101-0/+5
| | | | | | | Currently we sleep only for 1 ms, which may produce some excessive CPU load (we usually have 6/8 such processes waiting). Make it sleep for 10 ms, but also make the sleep return immediately on child exit. This shuold both improve latency and reduce CPU load.
* executor: remove noshmem modeDmitry Vyukov2024-06-041-4/+0
| | | | | | | | | All OSes we have now support shmem. Support for Fuchia/Starnix/Windows wasn't implemented, but generally they support shared memory. Remove all of the complexity and code associated with noshmem mode. If/when we revive these OSes, it's easier to properly implement shmem mode for them.
* executor: fix gvisor signalDmitry Vyukov2024-06-031-1/+3
| | | | | | | | | Fix 2 bugs: 1. We remove low 12 bits of every PC on amd64 b/c use_cover_edges return true. This results in extremly low signal (gvisor PC are dense integers). 2. We hash prev/next PC on arm64 which does not make sense since gvisor coverage is not a trace. This results in falsely large signal.
* executor: rework feature setupDmitry Vyukov2024-06-031-9/+51
| | | | | | | | | | | | | Return failure reason from setup functions rather than crash. This will provide better error messages, but also allow setup w/o creating subprocesses which will be needed when we combine fuzzer and executor. Also close all resources created during setup. This is also useful for in-process setup, but also should improve chances of reproducing a bug with C reproducer. Currently leaked file descriptors may disturb repro execution (e.g. it may act on a wrong fd).
* pkg/vminfo: move feature checking to hostDmitry Vyukov2024-05-151-7/+45
| | | | | | | | | | | | | | | | | Feature checking procedure is split into 2 phases: 1. syz-fuzzer invokes "syz-executor setup feature" for each feature one-by-one, and checks if executor does not fail. Executor can also return a special "this feature does not need custom setup", this allows to not call setup of these features in each new VM. 2. pkg/vminfo runs a simple program with ipc.ExecOpts specific for a concrete feature, e.g. for wifi injection it will try to run a program with wifi feature enabled, if setup of the feature fails, executor should also exit with an error. For coverage features we also additionally check that we actually got coverage. Then pkg/vminfo combines results of these 2 checks into final result. syz-execprog now also uses vminfo package and mimics the same checking procedure. Update #1541
* executor: add guard pages around the kcov mappingAlexander Potapenko2024-04-041-2/+16
| | | | | | | | | | | Because the executor may place other mappings next to the buffer used by kcov, occasional out-of-bound writes to them may corrupt the coverage, creating garbage PCs (see https://github.com/google/syzkaller/issues/4531). To prevent those, map two extra pages for the kcov buffer, and protect them, so that OOB writes cause a segfault. Fixes https://github.com/google/syzkaller/issues/4532
* all: support swap feature on LinuxAleksandr Nogikh2023-06-151-0/+1
| | | | | If the feature is supported on the device, allocate a 128MB swap file after VM boot and activate it.
* vm/starnix: add support for fuzzing starnix (#3624)juanPabloMiceli2023-01-191-0/+4
| | | | | | | This commit adds a new VM for fuzzing starnix. The VM will boot a fuchsia image using the `ffx` tool and will connect to an adb server inside it. Fuzzing will be done using HostFuzzer mode due to some features not being implemented yet in starnix. Once this is possible, fuzzing will be performed without HostFuzzer mode. Co-authored-by: Juampi Miceli <jpmiceli@google.com>
* executor: better errors for failed mmapsDmitry Vyukov2022-10-211-6/+9
| | | | | | A fixed-address mmap can fail completely or return a different address. Log what it was. Based on: https://groups.google.com/g/syzkaller/c/lto00RwlDIQ
* executor: fail on SEGV during clone()Aleksandr Nogikh2022-01-211-0/+11
| | | | | | | | | | | | | | | As was found out in #2921, fork bombs are still possible in Linux-based instances. One of the possible reasons is described below. An invalid stack can be passed to the clone() call, thus causing it to stumble on an invalid memory access right during returning from the clone() call. This is in turn catched by the NONFAILING() macro and the control actually jumps over it and eventually both the child and the parent continue executing the same code. Prevent it by handling SIGSEGV and SIGBUS differently during the clone process. Co-authored-by: Andrei Vagin <avagin@google.com>
* executor: delay kcov mmap until it is neededAleksandr Nogikh2021-12-031-16/+16
| | | | | | | | | The previous strategy (delay kcov instance creation) seems not to work very well in carefully sandboxed environments. Let's see if the new approach is more versatile. Open a kcov handle for each thread at syz-executor's initialization, but don't mmap it right away.
* executor: reserve fds that will belong to kcovAleksandr Nogikh2021-12-031-0/+8
| | | | | | | | | As now kcov instances may get set up during fuzzing, performing dup2 in cover_open is no longer safe as it may close some important resource. Prevent that by reserving most of fds that belong to the kcov fds range. Unfortunately we must duplicate the code because of the way kcov implementations are organized.
* executor: remove unused sysctl setupDmitry Vyukov2021-10-121-1/+0
| | | | | | | pkg/host.Setup never asks to setup "sysctl" feature explicitly, sysctl's are assumed to be setup whenever "syz-executor setup" is executed. Thus "sysctl" does not need to be present in the list of available things to setup.
* executor: fix remote coverage collectionAleksandr Nogikh2021-08-261-0/+2
| | | | | | | | | Currently the data_offset field of cover_t is only initialized for per-syscall coverage collection. As a result, remote coverage is read from an invalid location, fails to pass sanity checks and is not returned to syzkaller. Fix the initialization of cover_t fields.
* pkg/report: detect executor failuresDmitry Vyukov2021-02-211-1/+1
| | | | | | | | | | | | Currently all executor fail errors go into "lost connection" bucket. This is not very useful. First, there are different executor failures. Second, it's not possible to understand what failures happen how frequently. Third, there are not authentic lost connection. Create separate SYZFAIL: bugs for them. Update #573 Update #502 Update #318
* sys/linux: add ieee802154 descriptionsDmitry Vyukov2021-02-121-0/+1
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* executor: fix kcov_remote_arg declarationDmitry Vyukov2020-12-301-41/+18
| | | | | kcov_remote_arg was changed to a portable format so we don't need to handle differences between 64/32-bits anymore.
* executor: don't use coverage edges for gvisorDmitry Vyukov2020-12-161-5/+9
| | | | gvisor coverage is not a trace, so producing edges won't work.
* sys/linux, sys/freebsd: apply more ignore_return attributesDmitry Vyukov2020-12-051-7/+1
| | | | | | | | | | | | | | 1. Apply ignore_return to semctl$GETVAL which produces random errno values on linux and freebsd. 2. Apply ignore_return to prctl and remove the custom code in executor. 3. Remove the custom errno ignoring code in fuchsia executor. The calls are already marked as ignore_return, so this is just a leftover. 4. Only reset errno for ignore_return. The syscall can still return a resource (maybe). We only need to reset errno for fallback coverage.
* pkg/csource: setup sysctl's in C reproducersDmitry Vyukov2020-10-281-39/+1
| | | | | | Sysctl's are not captured as part of reproducers. This can result in failure to reproduce a bug on developer machine. Include sysctl setup as part of C reproducers.
* executor: setup sysctl's in setup_machineDmitry Vyukov2020-10-281-8/+35
| | | | | | | | | | | Currently we assume that sysctl's are setup as part of machine boot. This introduces a non-trivial dependency on image creation and sysctl's are not captured by as part of C reproducers and are not captured by syzbot dashboard. This can make some reproducers fail on developer machines or on syzbot later when sysctl's change. Setup sysctl's in executor as part of machine setup. It makes it much more controllable and hermetic.
* executor/linux: stop dumping mount information when failed to open kcov fileTetsuo Handa2020-09-281-40/+1
| | | | | Since ENOENT problem was solved by commit 318430cbb3b2ceef ("executor/linux: change mount propagation type to private"), remove the debug code for this problem.
* executor: make exit code during fail() depend on fault injectionAleksandr Nogikh2020-09-221-6/+3
| | | | | | | | | | | | | | | | | | | | | | fail()'s are often used during the validation of kernel reactions to queries that were issued by pseudo syscalls implementations. As fault injection may cause the kernel not to succeed in handling these queries (e.g. socket writes or reads may fail), this could ultimately lead to unwanted "lost connection to test machine" crashes. In order to avoid this and, on the other hand, to still have the ability to signal a disastrous situation, the exit code of this function now depends on the current context. All fail() invocations during system call execution with enabled fault injection lead to termination with zero exit code. In all other cases, the exit code is kFailStatus. This is achieved by introduction of a special thread-specific variable `current_thread` that allows to access information about the thread in which the current code is executing. Also, this commit eliminates current_cover as it is no longer needed.
* executor: detect gvisorDmitry Vyukov2020-09-121-1/+14
| | | | | | gvisor coverage is not in the range of linux kernel coverage. So the coverage filter does not work. Detect if running under gvisor and skip the coverage filter.
* executor/linux: dump more information when failed to open kcov fileTetsuo Handa2020-08-131-0/+17
| | | | | | | | | | | | With commit 50e21c6be6188f42 ("executor/linux: dump mount information when failed to open kcov file"), we got an unexpected result. /sys/kernel/ does not exist despite /sys/ exists. /proc/mounts cannot be opened despite /proc/ exists. If sysfs is not mounted on /sys/ and proc is not mounted on /proc/ , maybe other filesystems (e.g. devtmpfs, cgroup) are not mounted as well. Let's dump "/", "/proc/" and "/sys/", and then mount /proc/ and dump /proc/mounts .
* executor/linux: dump mount information when failed to open kcov fileTetsuo Handa2020-08-121-1/+23
| | | | | | | | | There are many "lost connection to test machine (5)" reports where the testing terminated due to ENOENT upon open("/sys/kernel/debug/kcov"). Since some testcase might be unintendedly modifying mount information, let's start from checking whether/how mount is broken. This commit might be reverted after the cause is identified and fixed.
* ipc: fix endianness issuesAlexander Egorenkov2020-06-231-2/+4
| | | | | | | | Use native byte-order for IPC and program serialization. This way we will be able to support both little- and big-endian architectures. Signed-off-by: Alexander Egorenkov <Alexander.Egorenkov@ibm.com>
* executor: surround the data mapping with PROT_NONE pagesDmitry Vyukov2020-04-181-1/+10
| | | | | | | | | | | Surround the main data mapping with PROT_NONE pages to make virtual address layout more consistent across different configurations (static/non-static build) and C repros. One observed case before: executor had a mapping above the data mapping (output region), while C repros did not have that mapping above, as the result in one case VMA had next link, while in the other it didn't and it caused a bug to not reproduce with the C repro. The bug that reproduces only with the mapping above: https://lkml.org/lkml/2020/4/17/819
* csource, executor: add usb emulation featureAndrey Konovalov2020-04-031-0/+1
| | | | | | | | | The feature gets enabled when /dev/raw-gadget is present and accessible. With this feature enabled, executor will do chmod 0666 /dev/raw-gadget on startup, which makes it possible to do USB fuzzing in setuid and namespace sandboxes. There should be no backwards compatibility issues with syz reproducers that don't explicitly enable this feature, as they currently only work in none sandbox.
* executor: prevent "NMI handler took too long" messagesDmitry Vyukov2020-03-061-0/+12
| | | | | | | | nmi_check_duration() prints "INFO: NMI handler took too long" on slow debug kernels. It happens a lot in qemu, and the messages are frequently corrupted (intermixed with other kernel output as they are printed from NMI) and are not matched against the suppression in pkg/report. This write prevents these messages from being printed.
* executor: ignore prctl in fallback coverageDmitry Vyukov2020-01-151-1/+7
| | | | | | Some prctl commands don't respect the normal convention for return values (e.g. PR_GET_TIMERSLACK, but there are more) and may produce all possible errno values. This conflicts with fallback coverage.
* executor: fix syz_mount_imageDmitry Vyukov2019-12-101-1/+7
| | | | | | | 1. It always crashed in cover_reset when coverage is disabled. 2. Use NONFAILING when accessing image segments. 3. Give it additional 100 ms as it may be slow. 4. Add a test for syz_mount_image.
* executor: don't use static_assertDmitry Vyukov2019-12-061-2/+2
| | | | | Not all gcc's everywhere support C++11 by default. We have some old on Travis.
* executor: fix remote coverage setupDmitry Vyukov2019-12-061-15/+39
| | | | | | | | | Layout of kcov_remote_arg is ABI-dependent, as the result when 32-bit userspace talks to 64-bit kernel it does not work out of the box. We need both statically different structs for kernels of different bitnesses, but also dynamic dispatch because a 32-bit userspace can talk to both 64-bit and 32-bit kernels.
* executor: update kcov remote coverage interfaceAndrey Konovalov2019-10-281-6/+12
| | | | The kcov extension is being upstreamed and the interfaces has been changed.
* executor, host, csource: Add support to enable KCSANMarco Elver2019-10-041-0/+1
| | | | | | | | | By default, the current KCSAN .config does not enable KCSAN during boot, since we encounter races during boot which would prevent syzkaller from ever executing. This adds support to detect if KCSAN is available, and enables it on the fuzzer host.
* executor: Protect the coverage bufferAndrew Turner2019-06-041-0/+8
| | | | | | | | | Add functions to protect and unprotect the coverage buffer. The buffer is protected from being written to while tracing. When the trace data is sorted we need to make it read/write, but can return it to read only after this has completed. Leave the first page as read/write as we need to clear the length field.
* executor: implement support for leak checkingDmitry Vyukov2019-05-201-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | Leak checking support was half done and did not really work. This is heavy-lifting to make it work. 1. Move leak/fault setup into executor. pkg/host was a wrong place for them because we need then in C repros too. The pkg/host periodic callback functionality did not work too, we need it in executor so that we can reuse it in C repros too. Remove setup/callback functions in pkg/host entirely. 2. Do leak setup/checking in C repros. The way leak checking is invoked is slightly different from fuzzer, but much better then no support at all. At least the checking code is shared. 3. Add Leak option to pkg/csource and -leak flag to syz-prog2c. 4. Don't enalbe leak checking in fuzzer while we are triaging initial corpus. It's toooo slow. 5. Fix pkg/repro to do something more sane for leak bugs. Few other minor fixes here and there.
* executor: change syscall argument type to intptr_tmunjinoo2019-05-071-1/+1
| | | | | The type size of long depends on compiler. Therefore, changing to intptr_t makes it depends on architecture.
* executor: fix remote coverage area sizeAndrey Konovalov2019-01-281-1/+1
| | | | It should be in number of words not in bytes.
* kcov: some fixes for extra coverageAndrey Konovalov2019-01-171-1/+1
| | | | | | Use PC tracing mode when detecting KCOV_REMOTE_ENABLE support in the kernel. Also fix kcov_remote_handle_usb argument.
* all: support extra coverageAndrey Konovalov2019-01-161-10/+41
| | | | | | | | | | | | | | | Right now syzkaller only supports coverage collected from the threads that execute syscalls. However some useful things happen in background threads, and it would be nice to collect coverage from those threads as well. This change adds extra coverage support to syzkaller. This coverage is not associated with a particular syscall, but rather with the whole program. Executor passes extra coverage over the same ipc mechanism to syz-fuzzer with syscall number set to -1. syz-fuzzer then passes this coverage to syz-manager with the call name "extra". This change requires the following kcov patch: https://github.com/xairy/linux/pull/2
* sys/linux: add syz_execute_funcDmitry Vyukov2018-08-301-1/+1
| | | | | | The function executes random code. Update #310
* executor: remap cover fd's to higher valuesDmitry Vyukov2018-08-081-2/+5
| | | | | | Remap cover fd's to 24x range to prevent interference with fd's used during fuzzing and also to make fd number consistent with/without cover enabled.
* executor: overhaulDmitry Vyukov2018-07-241-40/+109
| | | | | | | | | | | | | | | | | Make as much code as possible shared between all OSes. In particular main is now common across all OSes. Make more code shared between executor and csource (in particular, loop function and threaded execution logic). Also make loop and threaded logic shared across all OSes. Make more posix/unix code shared across OSes (e.g. signal handling, pthread creation, etc). Plus other changes along similar lines. Also support test OS in executor (based on portable posix) and add 4 arches that cover all execution modes (fork server/no fork server, shmem/no shmem). This change paves way for testing of executor code and allows to preserve consistency across OSes and executor/csource.
* executor: introduce uint64/32/16/8 typesDmitry Vyukov2017-12-271-3/+3
| | | | | | | | | | | | | | | The "define uint64_t unsigned long long" were too good to work. With a different toolchain I am getting: cstdint:69:11: error: expected unqualified-id using ::uint64_t; ^ executor/common.h:34:18: note: expanded from macro 'uint64_t' Do it the proper way: introduce uint64/32/16/8 types and use them. pkg/csource then does s/uint64/uint64_t/ to not clutter code with additional typedefs.
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