* wireguard: setup some initial devices in a triangle
The fuzzer will wind up undoing some of this, which is fine, but at
least it now has the chance of hitting some other paths it wasn't
before.
Closes: #1599
* wireguard: make code ugly after `make generate` pass
* wireguard: get rid of unused structs that are still interesting
* wireguard: compile in C++ mode with gcc 7
Complex designated initializers are only supported in C++ mode from gcc
8, and for whatever reason syzkaller wants to be compiled in C++ mode.
* wireguard: add braces around debug statements for checker
* wireguard: regenerate go source
We print whole reproducer programs on failure,
if lots of programs fail, this results in thousands
of lines of output, which is esp bad on travis.
Limit amount of output.
The stringnozescapes does not make sense with filename,
also we may need similar escaping for string flags.
Handle escaped strings on ast level instead.
This avoids introducing new type and works seamleassly with flags.
As alternative I've also tried using strconv.Quote/Unquote
but it leads to ugly half-escaped strings:
"\xb0\x80s\xe8\xd4N\x91\xe3ڒ,\"C\x82D\xbb\x88\\i\xe2i\xc8\xe9\xd85\xb1\x14):M\xdcn"
Make hex-encoded strings a separate string format instead.
0. Remove aetest build tag. We don't need it anymore, go test should work.
1. IsDevAppServer does not return true in tests anymore, so don't use it
2. Use a different mechanism to register test/prod config.
We don't have aetest tag anymore, so we need something even more dynamic.
3. Fix new golangci-lint warnings: all test files are checked now.
Update #1461
If we are going to write all values, don't write field names.
This only increases size of generated files.
The change reduces size of generated files by 5.8%
(62870496-59410354=3460142 bytes saved).
SHA-1 is insecure. See a representative summary of known attacks here:
https://en.wikipedia.org/wiki/Hash_function_security_summary
Some external build systems warn about sha1 uses and reject to build.
Whitelisting is pain. Switch to sha256.
Overall idea of netlink checking.
Currnetly we check netlink policies for common detectable mistakes.
First, we detect what looks like a netlink policy in our descriptions
(these are structs/unions only with nlattr/nlnext/nlnetw fields).
Then we find corresponding symbols (offset/size) in vmlinux using nm.
Then we read elf headers and locate where these symbols are in the rodata section.
Then read in the symbol data, which is an array of nla_policy structs.
These structs allow to easily figure out type/size of attributes.
Finally we compare our descriptions with the kernel policy description.
Update #590
They can't be a bitmask. This fixes important cases
of "0, 1" and "0, 1, 2" flags. Fix some descriptions
that added 0 to bitmasks explicitly (we should do it
automatically instead).
Will simplify runtime analysis of flags.
Also just no reason to make it more deterministic
and avoid unnecessary diffs in future if values are reordered.
Generate const[0] for flags without values and for flags
with a single value which is 0.
This is the intention in all existing cases (e.g. an enum with types
of something, but there is really only 1 type exists).
We disabled it in configs, now also disable during bisection.
This config only adds debug output. It should not be enabled at all,
but it was accidentially enabled on some instances for some periods of time,
and kernel is boot-broken for prolonged ranges of commits with deadlock
which makes bisections take weeks.
On X86-64, dereferencing a non-canonical address normally causes a #GP, for
which syzkaller already has a pattern. However, if the base register of the
non-canonical address is RBP (which can happen in builds that use RBP as a
general-purpose register because they don't use frame pointer unwinding),
#SS is thrown instead, for which syzkaller did not yet have a pattern.
To see this kind of fault, you can insert the following code in
kernel_init() after the call to rcu_end_inkernel_boot():
asm volatile(
"movabs $0x8000000000000000, %rbp\n\t"
"movq (%rbp), %rax\n\t"
"ud2\n\t"
);
Linux prints a different error message for #SS, so add that error message
to syzkaller's list of patterns.
BTF fails lots of builds with:
pahole version v1.9 is too old, need at least v1.13
Failed to generate BTF for vmlinux. Try to disable CONFIG_DEBUG_INFO_BTF.
Now other machines failed with redefinition IPVLAN_F_VEPA.
The #ifndef does not really work the way it should due
to the way pkg/csource preprocesses sources.
IPVLAN_F_VEPA is never defined during preprocessing.
Let's try this.
virt_wifi docs say that the enslaved device won't be usable
on itself. It's probably not a good idea to make lo unusable.
Enslave a dedicated veth instead.
Looks for source files in object dir.
This is required for out-of-tree linux builds.
E.g. security/selinux/flask.h contains some sources
with coverage callbacks, but it's auto-generated
and located in the build dir.
Use a random subset of syscalls/corpus/coverage for each individual VM run.
Hypothesis is that this should allow fuzzer to get more coverage
find more bugs in saturated state (stuck in local optimum).
See the issue and comments for details.
Update #1348
