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io_ring: Handle EOF on IORING_OP_READV

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EOFs shouldn't be raised as an errno as error translation will
fail. Short reads aren't failures on a readv syscall.

Reported-by: syzbot+37fc0fc0df42740a5cea@syzkaller.appspotmail.com
PiperOrigin-RevId: 489242631
This commit is contained in:
Rahat Mahmood
2022-11-17 10:17:39 -08:00
committed by gVisor bot
parent dec1aed143
commit f3aaf43266
2 changed files with 58 additions and 0 deletions
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pkg/sentry/fsimpl/iouringfs/iouringfs.go
+6
View File
@@ -24,6 +24,7 @@ package iouringfs
import (
"fmt"
"io"
"sync"
"gvisor.dev/gvisor/pkg/abi/linux"
@@ -382,6 +383,11 @@ func (fd *FileDescription) ProcessSubmission(t *kernel.Task, sqe *linux.IOUringS
// For the NOP operation, we don't do anything special.
case linux.IORING_OP_READV:
retValue, cqeErr = fd.handleReadv(t, sqe, flags)
if cqeErr == io.EOF {
// Don't raise EOF as errno, error translation will fail. Short
// reads aren't failures.
cqeErr = nil
}
default: // Unsupported operation
retValue = -int32(linuxerr.EINVAL.Errno())
}
test/syscalls/linux/io_uring.cc
+52
View File
@@ -692,6 +692,58 @@ TEST(IOUringTest, SingleREADVTest) {
io_uring->store_cq_head(cq_head + 1);
}
// Tests that IORING_OP_READV handles EOF on an empty file correctly.
TEST(IOUringTest, ReadvEmptyFile) {
struct io_uring_params params;
std::unique_ptr<IOUring> io_uring =
ASSERT_NO_ERRNO_AND_VALUE(IOUring::InitIOUring(1, params));
uint32_t sq_head = io_uring->load_sq_head();
std::string file_name = NewTempAbsPath();
ASSERT_NO_ERRNO(CreateWithContents(file_name, "", 0666));
FileDescriptor filefd = ASSERT_NO_ERRNO_AND_VALUE(Open(file_name, O_RDONLY));
ASSERT_GE(filefd.get(), 0);
unsigned *sq_array = io_uring->get_sq_array();
struct io_uring_sqe *sqe = io_uring->get_sqes();
struct iovec iov;
iov.iov_len = 0;
void *buf;
ASSERT_THAT(posix_memalign(&buf, BLOCK_SZ, BLOCK_SZ), SyscallSucceeds());
iov.iov_base = buf;
sqe->flags = 0;
sqe->fd = filefd.get();
sqe->opcode = IORING_OP_READV;
sqe->addr = reinterpret_cast<uint64_t>(&iov);
sqe->len = 1;
sqe->off = 0;
sqe->user_data = reinterpret_cast<uint64_t>(&iov);
sq_array[0] = 0;
uint32_t sq_tail = io_uring->load_sq_tail();
io_uring->store_sq_tail(sq_tail + 1);
int ret = io_uring->Enter(1, 1, 0, nullptr);
ASSERT_EQ(ret, 1);
struct io_uring_cqe *cqe = io_uring->get_cqes();
sq_head = io_uring->load_sq_head();
ASSERT_EQ(sq_head, 1);
uint32_t cq_tail = io_uring->load_cq_tail();
ASSERT_EQ(cq_tail, 1);
ASSERT_EQ(cqe->res, 0); // 0 length read, EOF.
uint32_t cq_head = io_uring->load_cq_head();
io_uring->store_cq_head(cq_head + 1);
}
// Testing that io_uring_enter(2) successfully handles three READV operations
// from three different files submitted through a single invocation.
TEST(IOUringTest, ThreeREADVSingleEnterTest) {