diff options
| -rw-r--r-- | pkg/sentry/syscalls/linux/sys_splice.go | 8 | ||||
| -rw-r--r-- | test/syscalls/linux/splice.cc | 75 |
2 files changed, 83 insertions, 0 deletions
diff --git a/pkg/sentry/syscalls/linux/sys_splice.go b/pkg/sentry/syscalls/linux/sys_splice.go index a7c98efcb..17e3dde1f 100644 --- a/pkg/sentry/syscalls/linux/sys_splice.go +++ b/pkg/sentry/syscalls/linux/sys_splice.go @@ -207,6 +207,10 @@ func Splice(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal return 0, nil, syserror.ESPIPE } if outOffset != 0 { + if !outFile.Flags().Pwrite { + return 0, nil, syserror.EINVAL + } + var offset int64 if _, err := t.CopyIn(outOffset, &offset); err != nil { return 0, nil, err @@ -220,6 +224,10 @@ func Splice(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal return 0, nil, syserror.ESPIPE } if inOffset != 0 { + if !inFile.Flags().Pread { + return 0, nil, syserror.EINVAL + } + var offset int64 if _, err := t.CopyIn(inOffset, &offset); err != nil { return 0, nil, err diff --git a/test/syscalls/linux/splice.cc b/test/syscalls/linux/splice.cc index 1875f4533..e25f264f6 100644 --- a/test/syscalls/linux/splice.cc +++ b/test/syscalls/linux/splice.cc @@ -13,6 +13,7 @@ // limitations under the License. #include <fcntl.h> +#include <sys/eventfd.h> #include <sys/sendfile.h> #include <unistd.h> @@ -135,6 +136,80 @@ TEST(SpliceTest, PipeOffsets) { SyscallFailsWithErrno(ESPIPE)); } +// Event FDs may be used with splice without an offset. +TEST(SpliceTest, FromEventFD) { + // Open the input eventfd with an initial value so that it is readable. + constexpr uint64_t kEventFDValue = 1; + int efd; + ASSERT_THAT(efd = eventfd(kEventFDValue, 0), SyscallSucceeds()); + const FileDescriptor inf(efd); + + // Create a new pipe. + int fds[2]; + ASSERT_THAT(pipe(fds), SyscallSucceeds()); + const FileDescriptor rfd(fds[0]); + const FileDescriptor wfd(fds[1]); + + // Splice 8-byte eventfd value to pipe. + constexpr int kEventFDSize = 8; + EXPECT_THAT(splice(inf.get(), nullptr, wfd.get(), nullptr, kEventFDSize, 0), + SyscallSucceedsWithValue(kEventFDSize)); + + // Contents should be equal. + std::vector<char> rbuf(kEventFDSize); + ASSERT_THAT(read(rfd.get(), rbuf.data(), rbuf.size()), + SyscallSucceedsWithValue(kEventFDSize)); + EXPECT_EQ(memcmp(rbuf.data(), &kEventFDValue, rbuf.size()), 0); +} + +// Event FDs may not be used with splice with an offset. +TEST(SpliceTest, FromEventFDOffset) { + int efd; + ASSERT_THAT(efd = eventfd(0, 0), SyscallSucceeds()); + const FileDescriptor inf(efd); + + // Create a new pipe. + int fds[2]; + ASSERT_THAT(pipe(fds), SyscallSucceeds()); + const FileDescriptor rfd(fds[0]); + const FileDescriptor wfd(fds[1]); + + // Attempt to splice 8-byte eventfd value to pipe with offset. + // + // This is not allowed because eventfd doesn't support pread. + constexpr int kEventFDSize = 8; + loff_t in_off = 0; + EXPECT_THAT(splice(inf.get(), &in_off, wfd.get(), nullptr, kEventFDSize, 0), + SyscallFailsWithErrno(EINVAL)); +} + +// Event FDs may not be used with splice with an offset. +TEST(SpliceTest, ToEventFDOffset) { + // Create a new pipe. + int fds[2]; + ASSERT_THAT(pipe(fds), SyscallSucceeds()); + const FileDescriptor rfd(fds[0]); + const FileDescriptor wfd(fds[1]); + + // Fill with a value. + constexpr int kEventFDSize = 8; + std::vector<char> buf(kEventFDSize); + buf[0] = 1; + ASSERT_THAT(write(wfd.get(), buf.data(), buf.size()), + SyscallSucceedsWithValue(kEventFDSize)); + + int efd; + ASSERT_THAT(efd = eventfd(0, 0), SyscallSucceeds()); + const FileDescriptor outf(efd); + + // Attempt to splice 8-byte eventfd value to pipe with offset. + // + // This is not allowed because eventfd doesn't support pwrite. + loff_t out_off = 0; + EXPECT_THAT(splice(rfd.get(), nullptr, outf.get(), &out_off, kEventFDSize, 0), + SyscallFailsWithErrno(EINVAL)); +} + TEST(SpliceTest, ToPipe) { // Open the input file. const TempPath in_file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); |