- Use the correct instruction in safecopy.checkXstate(). Before this CL:
```
TEXT pkg/sentry/arch/fpu/fpu.initX86FPState.abi0(SB)
...
fpu_amd64.s:78 0x7661b2 480fae2f XRSTOR64 0(DI)
TEXT pkg/safecopy/safecopy.checkXstate.abi0(SB)
...
xrstor_amd64.s:54 0x7648a0 0fae2f XRSTOR 0(DI)
```
I'm not sure what the actual difference between XRSTOR and XRSTOR64 is, but
Linux is careful to use XRSTOR64 (arch/x86/kernel/fpu/xstate.h:XRSTOR,
REX_PREFIX) so it probably matters.
- When an AfterLoad callback fails, log the error message before the failing
object, since the latter can be huge and prevent the error message from being
logged.
- Include additional information in the error message emitted by
fpu.State.AfterLoad().
PiperOrigin-RevId: 605534648
For all trivial and zero frame-sized functions, we now require an explicit
NOFRAME annotation as the heuristic has changed. See go.dev/cl/466316.
Most of these functions do not *require* NOFRAME, but this change encodes
the existing behavior in order to avoid accidental bugs or regressions.
PiperOrigin-RevId: 513946210
Removes package syserror and moves still relevant code to either linuxerr
or to syserr (to be later removed).
Internal errors are converted from random types to *errors.Error types used
in linuxerr. Internal errors are in linuxerr/internal.go.
PiperOrigin-RevId: 390724202
Both marshal and usermem are depended on by many packages and a dependency on
marshal can often create circular dependencies. marshal should consider adding
internal dependencies carefully moving forward.
Fixes#6160
PiperOrigin-RevId: 379199882
Go 1.17 is adding a new register-based calling convention [1] ("ABIInternal"),
which used is when calling between Go functions. Assembly functions are still
written using the old ABI ("ABI0"). That is, they still accept arguments on the
stack, and pass arguments to other functions on the stack. The call rules look
approximately like this:
1. Direct call from Go function to Go function: compiler emits direct
ABIInternal call.
2. Indirect call from Go function to Go function: compiler emits indirect
ABIInternal call.
3. Direct call from Go function to assembly function: compiler emits direct
ABI0 call.
4. Indirect call from Go function to assembly function: compiler emits indirect
ABIInternal call to ABI conversion wrapper function.
5. Direct or indirect call from assembly function to assembly function:
assembly/linker emits call to original ABI0 function.
6. Direct or indirect call from assembly function to Go function:
assembly/linker emits ABI0 call to ABI conversion wrapper function.
Case 4 is the interesting one here. Since the compiler can't know the ABI of an
indirect call, all indirect calls are made with ABIInternal. In order to
support indirect ABI0 assembly function calls, a wrapper is generated that
translates ABIInternal arguments to ABI0 arguments, calls the target function,
and then converts results back.
When the address of an ABI0 function is taken from Go code, it evaluates to the
address of this wrapper function rather than the target function so that later
indirect calls will work as expected.
This is normally fine, but gVisor does more than just call some of the assembly
functions we take the address of: either noting the start and end address for
future reference from a signal handler (safecopy), or copying the function text
to a new mapping (platforms).
Both of these fail with wrappers enabled (currently, this is Go tip with
GOEXPERIMENT=regabiwrappers) because these operations end up operating on the
wrapper instead of the target function.
We work around this issue by taking advantage of case 5: references to assembly
symbols from other assembly functions resolve directly to the desired target
symbol. Thus, rather than using reflect to get the address of a Go reference to
the functions, we create assembly stubs that return the address of the
function. This approach works just as well on current versions of Go, so the
change can be made immediately and doesn't require any build tags.
[1] https://go.googlesource.com/go/+/refs/heads/master/src/cmd/compile/abi-internal.md
PiperOrigin-RevId: 368505655
Split usermem package to help remove syserror dependency in go_marshal.
New hostarch package contains code not dependent on syserror.
PiperOrigin-RevId: 365651233
The syscall package has been deprecated in favor of golang.org/x/sys.
Note that syscall is still used in the following places:
- pkg/sentry/socket/hostinet/stack.go: some netlink related functionalities
are not yet available in golang.org/x/sys.
- syscall.Stat_t is still used in some places because os.FileInfo.Sys() still
returns it and not unix.Stat_t.
Updates #214
PiperOrigin-RevId: 360701387
In the case of other signals (preemption), inject a normal bounce and
defer the signal until the vCPU has been returned from guest mode.
PiperOrigin-RevId: 303799678
This is failing in Go1.14 due to new checkptr constraints. This version
should avoid hitting this constraints by doing "dangerous" pointer math
less dangerously?
PiperOrigin-RevId: 293205764
Because the abi will depend on the core types for marshalling (usermem,
context, safemem, safecopy), these need to be flattened from the sentry
directory. These packages contain no sentry-specific details.
PiperOrigin-RevId: 291811289
Koichi Shiraishi
Jamie LiuandgVisor bot
Andrei VaginandgVisor bot
Adin ScannellandgVisor bot
Etienne PerotandgVisor bot
Zach KoopmansandgVisor bot
Ian LewisandgVisor bot
Ayush RanjanandgVisor bot
Michael PrattandgVisor bot