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* executor: skips declaration of unused function 'doexit_thread' for fuchsiaKouame Behouba Manassé2022-06-221-0/+2
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* executor: write magic in write_extra_outputAndrei Vagin2022-05-241-0/+1
| | | | Fixes: fcfad4ffcf3a ("ipc: add magic in a call reply")
* ipc: add magic in a call replyAndrei Vagin2022-05-241-0/+3
| | | | | | | | | | When a shared memory is used, the executor can corrupt reply messages, so let's add magic to detect such cases. It is an attempt to debug issues like this one: https://syzkaller.appspot.com/bug?id=faca64c3182e9f130ca94b7931dd771be390ef67 Signed-off-by: Andrei Vagin <avagin@google.com>
* executor: allow external extensions of the setup phaseDmitry Vyukov2022-04-271-0/+4
| | | | Allow common_ext.h to provide setup_ext() function that is called during VM setup.
* executor: fail on SEGV during clone()Aleksandr Nogikh2022-01-211-0/+1
| | | | | | | | | | | | | | | 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: don't print errno for successful callsDmitry Vyukov2022-01-111-5/+7
| | | | Don't print the confuing errno 14 for successful calls.
* executor: ignore async flag in the non-threaded modeAleksandr Nogikh2021-12-131-3/+3
| | | | | | | | pkg/repro tries to clear the Threaded flag during repro simplification, so it's easier just to ignore the remaining async flags in that case - they won't be in the C repro either. Add a test to pkg/ipc to verify the new behavior.
* executor: do exitf instead of fail on kcov shortageAleksandr Nogikh2021-12-101-2/+2
| | | | | | | | | Set new kcov count limits: 6 for the default mode and 16 for the optimized mode (when the instances are mmapped a needed). Don't generate SYZFAIL when these limits are exhausted. Just increasing those limits won't help as syzkaller will anyway come up with programs that overcome them.
* all: add the `rerun` call propertyAleksandr Nogikh2021-12-101-0/+9
| | | | | | | | | | | | | | To be able to collide specific syscalls more precisely, we need to repeat the process many times. Introduce the `rerun` call property, which instructs `syz-executor` to repeat the call the specified number of times. The intended use is: call1() (rerun: 100, async) call2() (rerun: 100) For now, assign rerun values randomly to consecutive pairs of calls, where the first one is async.
* all: replace collide mode by `async` call propertyAleksandr Nogikh2021-12-101-98/+84
| | | | | | | | | | | | | Replace the currently existing straightforward approach to race triggering (that was almost entirely implemented inside syz-executor) with a more flexible one. The `async` call property instructs syz-executor not to block until the call has completed execution and proceed immediately to the next call. The decision on what calls to mark with `async` is made by syz-fuzzer. Ultimately this should let us implement more intelligent race provoking strategies as well as make more fine-grained reproducers.
* executor: fix kcov mmaping in the non-optimized modeAleksandr Nogikh2021-12-091-2/+0
| | | | | As all opened kcov instances are mmapped, we don't need to check it one more time at all.
* all: adapt to how mmapping a kcov instance works in LinuxAleksandr Nogikh2021-12-091-4/+22
| | | | | | | | | | | | | | | | | | | | It turns out that the current Linux implementation of KCOV does not properly handle multiple mmap invocations on the same instance. The first one succeedes, but the subsequent ones do not actually mmap anything, yet returning no error at all. The ability to mmap that memory multiple times allows us to increase syz-executor performance and it would be a pity to completely lose it (especially given that mmapping kcov works fine on *BSD). In some time a patch will be prepared, but still we will have to support both versions at the same time - the buggy one and the correct one. Detect whether the bug is present by writing a value at the pointer returned by mmap. If it is present, disable dynamic kcov mmapping and pre-mmap 5 instances in the main() function - it should be enough for all reasonable uses. Otherwise, pre-mmap 3 and let syz-executor mmap them as needed.
* executor: set fixed fd for the extra coverage kcov instanceAleksandr Nogikh2021-12-061-0/+2
| | | | | Currently it is dup2'd to 0, which is quite likely to be closed by the fuzzer. Dup2 it to a safer fd instead.
* executor: delay kcov mmap until it is neededAleksandr Nogikh2021-12-031-15/+12
| | | | | | | | | 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 Nogikh2021-12-031-3/+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: allocate output region for individual programsAleksandr Nogikh2021-12-031-18/+79
| | | | | | | | | | | | | | | | | | | | The amount of virtual memory affects the speed of forking/exiting. As in most cases we do it for each executed program, the difference may be substantial. We don't need 16MB of output data for each execution (in fact, experiments have shown that we never cross even 8MB on Linux). But reducing that cap in more than 2 times is a pretty bold decision, and perhaps it's better to just make the allocation process smarter. Mmap the output region depending on the exact amount of memory needed for a specific program. E.g. if comparisons are collected, the expected amount of output is maximal. If we only collect signals, the output is minimal. Mmap the minimally required region in the parent and then re-mmap it in the forked child if it turns out that a higher amount of memory is needed.
* executor: introduce threads without coverageAleksandr Nogikh2021-12-031-6/+24
| | | | | | | | | | | | | | | | Experiments have shown that the amount of allocated memory has a very big impact on the syz-executor's performance (at least under Linux) - much bigger than was expected. One source of that extra virtual memory is kcov and, in fact, usually we don't need all 16 kcov handles we create. E.g. only 4 are enough for 99.5% progs that syzkaller executes. The biggest consumer of threads - the collide mode doesn't need kcov at all. Let kcov handle be an optional property of a thread, not a mandatory one. Allocate only 3 kcov instances initially (they'll be preserved over forks) and let the forked processes create other kcov instances if they happen to be needed.
* executor: setup cgroups onceDmitry Vyukov2021-10-121-0/+1
| | | | | | | Currently we setup cgroups on every test process start (along with sandbox creation). That's unnecessary because that's global per-machine setup. Move cgroup setup into setup section that's executed once per machine from pkg/host.Setup.
* executor: check for single-line compound statementsDmitry Vyukov2021-10-011-2/+1
| | | | | | Historically the code base does not use single-line compound statements ({} around single-line blocks). But there are few precedents creeped into already. Add a check to keep the code base consistent.
* executor: fail if the first argument isn't a known commandAndrei Vagin2021-09-301-0/+5
| | | | | | | | | | | | | | | | | | We have seen cases when a test program re-execed the current binary: 11:53:29 executing program 0: openat$zero(0xffffffffffffff9c, &(0x7f0000000040), 0x0, 0x0) r0 = openat(0xffffffffffffff9c, &(0x7f0000000080)='/proc/self/exe\x00', 0x0, 0x0) lseek(r0, 0x4000000000000000, 0x4) execveat(r0, &(0x7f0000000080)='\x00', 0x0, 0x0, 0x1000) In such cases, we have to be sure that executor will not print SYZFAIL log messages and will not exit with kFailStatus. Since a659b3f1, syzkaller reports bugs in all these cases. Fixes: a659b3f1dc88 ("pkg/report: detect executor failures") Signed-off-by: Andrei Vagin <avagin@google.com>
* all: refactor fault injection into call propsAleksandr Nogikh2021-09-221-24/+21
| | | | | | | | | | | | Now that call properties mechanism is implemented, we can refactor fault injection. Unfortunately, it is impossible to remove all traces of the previous apprach. In reprolist and while performing syz-ci jobs, syzkaller still needs to parse the old format. Remove the old prog options-based approach whenever possible and replace it with the use of call properties.
* all: introduce call propertiesAleksandr Nogikh2021-09-221-3/+8
| | | | | | | | | Call properties let us specify how each individual call within a program must be executed. So far the only way to enforce extra rules was to pass extra program-level properties (e.g. that is how fault injection was done). However, it entangles the logic and not flexible enough. Implement an ability to pass properties along with each individual call.
* executor: fix remote coverage collectionAleksandr Nogikh2021-08-261-2/+0
| | | | | | | | | 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.
* executor: initial darwin supportPatrick Meyer2021-05-201-3/+20
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* executor, syz-fuzzer: fix readonly rootJoey Jiao2021-03-181-1/+11
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* executor: don't fail on "negative running"Dmitry Vyukov2021-03-041-1/+1
| | | | | See #502 This still happens periodically.
* prog: detect copyout overflowDmitry Vyukov2021-03-041-1/+1
| | | | | | Detect the case when a program requires more copyout than executor can handle. Curretnly these result in: "SYZFAIL: command refers to bad result" failures. Now syz-fuzzer should ignore them.
* executor: improve SYZFAIL messageDmitry Vyukov2021-02-261-1/+1
| | | | | | | Print details and errno after SYZFAIL line. pkg/report captures output after SYZFAIL line, so it's better to have details after that line so that they are captured in report.
* pkg/report: detect executor failuresDmitry Vyukov2021-02-211-53/+66
| | | | | | | | | | | | 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
* executor: don't fail in syz_genetlink_get_family_idDmitry Vyukov2021-02-191-0/+2
| | | | | | | | | | We used to use our own netlink socket and then fail on any errors. But commit "sys/linux: add ieee802154 descriptions" made it possible to use fuzzer-provided socket, and fuzzer can pass any invalid fd. So don't fail on errors now. Fixes #2444
* sys/linux: add ieee802154 descriptionsDmitry Vyukov2021-02-121-0/+1
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* all: make timeouts configurableDmitry Vyukov2020-12-281-4/+6
| | | | | | Add sys/targets.Timeouts struct that parametrizes timeouts throughout the system. The struct allows to control syscall/program/no output timeouts for OS/arch/VM/etc. See comment on the struct for more details.
* executor: remove hardcoded timeoutsDmitry Vyukov2020-12-251-10/+21
| | | | | In preparation for making timeouts tunable based on OS/arch/VM/etc de-hardcode all (almost) timeouts in executor.
* executor: don't use coverage edges for gvisorDmitry Vyukov2020-12-161-5/+3
| | | | gvisor coverage is not a trace, so producing edges won't work.
* executor: use coverage filter for comparisonsDmitry Vyukov2020-12-091-1/+1
| | | | | | Filter out all comparisons in non-interesting code. Comparisons are expensive, so it makes lots of sense, these filtered out can't give us any new interesting signal.
* executor: capture outgoing edges from interesting codeDmitry Vyukov2020-12-091-6/+10
| | | | | | | | | | Currently we capture only incoming edges into the interesting code when code coverage filter is used. Also capture outgoing edges. For code without indirect calls this does not matter as we always get the same edge. But for code with indirect edges we can capture more interesting coverage, and presumably different indirect calls are quite important.
* executor: minor coverage filter cleanupDmitry Vyukov2020-12-091-1/+1
| | | | | Slightly reduce number of ifdef's, define coverage_filter only in shmem mode and remove unnecessary cast.
* syz-manager/manager.go, executor/executor.cc: support coverage filterKaipeng Zeng2020-12-061-2/+9
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* sys/linux, sys/freebsd: apply more ignore_return attributesDmitry Vyukov2020-12-051-6/+3
| | | | | | | | | | | | | | 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 Vyukov2020-10-281-2/+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: increase prog_extra_cover_timeout for progs that inject 802.11 framesAleksandr Nogikh2020-10-051-1/+3
| | | | | This is required because we can only collect remote kcov coverage for these injected frames.
* executor: msvc support syz-executorSuraj K Suresh2020-10-031-6/+10
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* executor: check for \n in fail/exitf messagesDmitry Vyukov2020-09-281-1/+1
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* executor: make exit code during fail() depend on fault injectionAleksandr Nogikh2020-09-221-1/+24
| | | | | | | | | | | | | | | | | | | | | | 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.
* all: integrate with mac80211_hwsimAleksandr Nogikh2020-09-221-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Two virtual wireless devices are instantiated during network devices initialization. A new flag (-wifi) is added that controls whether these virtual wifi devices are instantiated and configured during proc initialization. Also, two new pseudo syscalls are added: 1. syz_80211_inject_frame(mac_addr, packet, packet_len) -- injects an arbitrary packet into the wireless stack. It is injected as if it originated from the device identitied by mac_addr. 2. syz_80211_join_ibss(interface_name, ssid, ssid_len, mode) -- puts a specific network interface into IBSS state and joins an IBSS network. Arguments of syz_80211_join_ibss: 1) interface_name -- null-terminated string that identifies a wireless interface 2) ssid, ssid_len -- SSID of an IBSS network to join to 3) mode -- mode of syz_80211_join_ibss operation (see below) Modes of operation: JOIN_IBSS_NO_SCAN (0x0) -- channel scan is not performed and syz_80211_join_ibss waits until the interface reaches IF_OPER_UP. JOIN_IBSS_BG_SCAN (0x1) -- channel scan is performed (takes ~ 9 seconds), syz_80211_join_ibss does not await IF_OPER_UP. JOIN_IBSS_BG_NO_SCAN (0x2) -- channel scan is not performed, syz_80211_join_ibss does not await IF_OPER_UP. Local testing ensured that these syscalls are indeed able to set up an operating network and inject packets into mac80211.
* sys/test/test: add a hanging testDmitry Vyukov2020-09-121-1/+1
| | | | Ensure that we can handle hanging syscalls in all modes.
* executor: warn about C89-style var declarationsDmitry Vyukov2020-08-141-4/+4
| | | | | | | | | | | | | | | | | We generally use the newer C99 var declarations combined with initialization because: - declarations are more local, reduced scope - fewer lines of code - less potential for using uninit vars and other bugs However, we have some relic code from times when we did not understand if we need to stick with C89 or not. Also some external contributions that don't follow style around. Add a static check for C89-style declarations and fix existing precedents. Akaros toolchain uses -std=gnu89 (or something) and does not allow variable declarations inside of for init statement. And we can't switch it to -std=c99 because Akaros headers are C89 themselves. So in common.h we need to declare loop counters outside of for.
* executor: add some code style checksDmitry Vyukov2020-08-061-1/+1
| | | | | | | Move the test from pkg/csource to executor/ in order to be able to (1) run it on *.cc files, (2) run on unprocessed *.h files, (3) produce line numbers. Add a check for missed space after //.
* all: initialize vhci in linuxTheOfficialFloW2020-07-301-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * all: initialize vhci in linux * executor/common_linux.h: improve vhci initialization * pkg/repro/repro.go: add missing vhci options * executor/common_linux.h: fix type and add missing header * executor, pkg: do it like NetInjection * pkg/csource/csource.go: do not emit syz_emit_vhci if vhci is not enabled * executor/common_linux.h: fix format string * executor/common_linux.h: initialize with memset For som reason {0} gets complains about missing braces... * executor/common_linux.h: simplify vhci init * executor/common_linux.h: try to bring all available hci devices up * executor/common_linux.h: find which hci device has been registered * executor/common_linux.h: use HCI_VENDOR_PKT response to retrieve device id * sys/linux/dev_vhci.txt: fix structs of inquiry and report packets * executor/common_linux.h: remove unnecessary return statement and check vendor_pkt read size * executor/common_linux.h: remove unnecessary return statement and check vendor_pkt read size * sys/linux/dev_vhci.txt: pack extended_inquiry_info_t * sys/linux/l2cap.txt: add l2cap_conf_opt struct * executor/common_linux.h: just fill bd addr will 0xaa * executor/common_linux.h: just fill bd addr will 0xaa
* executor: wrap all syscalls into NONFAILINGDmitry Vyukov2020-07-151-2/+5
| | | | | | | | | | | | | | | Currently we sprinkle NONFAILING all over pseudo-syscall code, around all individual accesses to fuzzer-generated pointers. This is tedious manual work and subject to errors. Wrap execute_syscall invocation with NONFAILING in execute_call once instead. Then we can remove NONFAILING from all pseudo-syscalls and never get back to this. Potential downsides: (1) this is coarser-grained and we will skip whole syscall on invalid pointer, but this is how normal syscalls work as well, so should not be a problem; (2) we will skip any clean up (closing of files, etc) as well; but this may be fine as well (programs can perfectly leave open file descriptors as well). Update #1918
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