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-rw-r--r--pkg/sentry/socket/netlink/BUILD1
-rw-r--r--pkg/sentry/socket/netlink/socket.go29
-rw-r--r--pkg/sentry/socket/unix/io.go13
-rw-r--r--pkg/sentry/socket/unix/unix.go23
-rw-r--r--test/syscalls/linux/BUILD1
-rw-r--r--test/syscalls/linux/socket_non_stream.cc113
-rw-r--r--test/syscalls/linux/socket_non_stream_blocking.cc37
-rw-r--r--test/syscalls/linux/socket_stream.cc55
8 files changed, 250 insertions, 22 deletions
diff --git a/pkg/sentry/socket/netlink/BUILD b/pkg/sentry/socket/netlink/BUILD
index 79589e3c8..136821963 100644
--- a/pkg/sentry/socket/netlink/BUILD
+++ b/pkg/sentry/socket/netlink/BUILD
@@ -22,7 +22,6 @@ go_library(
"//pkg/sentry/kernel",
"//pkg/sentry/kernel/auth",
"//pkg/sentry/kernel/time",
- "//pkg/sentry/safemem",
"//pkg/sentry/socket",
"//pkg/sentry/socket/netlink/port",
"//pkg/sentry/socket/unix",
diff --git a/pkg/sentry/socket/netlink/socket.go b/pkg/sentry/socket/netlink/socket.go
index 4a1b87a9a..d2e3644a6 100644
--- a/pkg/sentry/socket/netlink/socket.go
+++ b/pkg/sentry/socket/netlink/socket.go
@@ -29,7 +29,6 @@ import (
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
- "gvisor.dev/gvisor/pkg/sentry/safemem"
"gvisor.dev/gvisor/pkg/sentry/socket"
"gvisor.dev/gvisor/pkg/sentry/socket/netlink/port"
"gvisor.dev/gvisor/pkg/sentry/socket/unix"
@@ -500,29 +499,29 @@ func (s *Socket) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags int, have
trunc := flags&linux.MSG_TRUNC != 0
r := unix.EndpointReader{
+ Ctx: t,
Endpoint: s.ep,
Peek: flags&linux.MSG_PEEK != 0,
}
+ doRead := func() (int64, error) {
+ return dst.CopyOutFrom(t, &r)
+ }
+
// If MSG_TRUNC is set with a zero byte destination then we still need
// to read the message and discard it, or in the case where MSG_PEEK is
// set, leave it be. In both cases the full message length must be
- // returned. However, the memory manager for the destination will not read
- // the endpoint if the destination is zero length.
- //
- // In order for the endpoint to be read when the destination size is zero,
- // we must cause a read of the endpoint by using a separate fake zero
- // length block sequence and calling the EndpointReader directly.
+ // returned.
if trunc && dst.Addrs.NumBytes() == 0 {
- // Perform a read to a zero byte block sequence. We can ignore the
- // original destination since it was zero bytes. The length returned by
- // ReadToBlocks is ignored and we return the full message length to comply
- // with MSG_TRUNC.
- _, err := r.ReadToBlocks(safemem.BlockSeqOf(safemem.BlockFromSafeSlice(make([]byte, 0))))
- return int(r.MsgSize), linux.MSG_TRUNC, from, fromLen, socket.ControlMessages{}, syserr.FromError(err)
+ doRead = func() (int64, error) {
+ err := r.Truncate()
+ // Always return zero for bytes read since the destination size is
+ // zero.
+ return 0, err
+ }
}
- if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock || flags&linux.MSG_DONTWAIT != 0 {
+ if n, err := doRead(); err != syserror.ErrWouldBlock || flags&linux.MSG_DONTWAIT != 0 {
var mflags int
if n < int64(r.MsgSize) {
mflags |= linux.MSG_TRUNC
@@ -540,7 +539,7 @@ func (s *Socket) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags int, have
defer s.EventUnregister(&e)
for {
- if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock {
+ if n, err := doRead(); err != syserror.ErrWouldBlock {
var mflags int
if n < int64(r.MsgSize) {
mflags |= linux.MSG_TRUNC
diff --git a/pkg/sentry/socket/unix/io.go b/pkg/sentry/socket/unix/io.go
index 2ec1a662d..2447f24ef 100644
--- a/pkg/sentry/socket/unix/io.go
+++ b/pkg/sentry/socket/unix/io.go
@@ -83,6 +83,19 @@ type EndpointReader struct {
ControlTrunc bool
}
+// Truncate calls RecvMsg on the endpoint without writing to a destination.
+func (r *EndpointReader) Truncate() error {
+ // Ignore bytes read since it will always be zero.
+ _, ms, c, ct, err := r.Endpoint.RecvMsg(r.Ctx, [][]byte{}, r.Creds, r.NumRights, r.Peek, r.From)
+ r.Control = c
+ r.ControlTrunc = ct
+ r.MsgSize = ms
+ if err != nil {
+ return err.ToError()
+ }
+ return nil
+}
+
// ReadToBlocks implements safemem.Reader.ReadToBlocks.
func (r *EndpointReader) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error) {
return safemem.FromVecReaderFunc{func(bufs [][]byte) (int64, error) {
diff --git a/pkg/sentry/socket/unix/unix.go b/pkg/sentry/socket/unix/unix.go
index 885758054..91effe89a 100644
--- a/pkg/sentry/socket/unix/unix.go
+++ b/pkg/sentry/socket/unix/unix.go
@@ -544,8 +544,27 @@ func (s *SocketOperations) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags
if senderRequested {
r.From = &tcpip.FullAddress{}
}
+
+ doRead := func() (int64, error) {
+ return dst.CopyOutFrom(t, &r)
+ }
+
+ // If MSG_TRUNC is set with a zero byte destination then we still need
+ // to read the message and discard it, or in the case where MSG_PEEK is
+ // set, leave it be. In both cases the full message length must be
+ // returned.
+ if trunc && dst.Addrs.NumBytes() == 0 {
+ doRead = func() (int64, error) {
+ err := r.Truncate()
+ // Always return zero for bytes read since the destination size is
+ // zero.
+ return 0, err
+ }
+
+ }
+
var total int64
- if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock || dontWait {
+ if n, err := doRead(); err != syserror.ErrWouldBlock || dontWait {
var from linux.SockAddr
var fromLen uint32
if r.From != nil && len([]byte(r.From.Addr)) != 0 {
@@ -580,7 +599,7 @@ func (s *SocketOperations) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags
defer s.EventUnregister(&e)
for {
- if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock {
+ if n, err := doRead(); err != syserror.ErrWouldBlock {
var from linux.SockAddr
var fromLen uint32
if r.From != nil {
diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD
index 064ce8429..ce8abe217 100644
--- a/test/syscalls/linux/BUILD
+++ b/test/syscalls/linux/BUILD
@@ -2888,7 +2888,6 @@ cc_library(
":unix_domain_socket_test_util",
"//test/util:test_util",
"//test/util:thread_util",
- "//test/util:timer_util",
"@com_google_absl//absl/time",
"@com_google_googletest//:gtest",
],
diff --git a/test/syscalls/linux/socket_non_stream.cc b/test/syscalls/linux/socket_non_stream.cc
index d91c5ed39..c61817f14 100644
--- a/test/syscalls/linux/socket_non_stream.cc
+++ b/test/syscalls/linux/socket_non_stream.cc
@@ -113,7 +113,7 @@ TEST_P(NonStreamSocketPairTest, RecvmsgMsghdrFlagMsgTrunc) {
EXPECT_EQ(0, memcmp(received_data, sent_data, sizeof(received_data)));
// Check that msghdr flags were updated.
- EXPECT_EQ(msg.msg_flags, MSG_TRUNC);
+ EXPECT_EQ(msg.msg_flags & MSG_TRUNC, MSG_TRUNC);
}
// Stream sockets allow data sent with multiple sends to be peeked at in a
@@ -193,7 +193,7 @@ TEST_P(NonStreamSocketPairTest, MsgTruncTruncationRecvmsgMsghdrFlagMsgTrunc) {
EXPECT_EQ(0, memcmp(received_data, sent_data, sizeof(received_data)));
// Check that msghdr flags were updated.
- EXPECT_EQ(msg.msg_flags, MSG_TRUNC);
+ EXPECT_EQ(msg.msg_flags & MSG_TRUNC, MSG_TRUNC);
}
TEST_P(NonStreamSocketPairTest, MsgTruncSameSize) {
@@ -224,5 +224,114 @@ TEST_P(NonStreamSocketPairTest, MsgTruncNotFull) {
EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
}
+// This test tests reading from a socket with MSG_TRUNC and a zero length
+// receive buffer. The user should be able to get the message length.
+TEST_P(NonStreamSocketPairTest, RecvmsgMsgTruncZeroLen) {
+ auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+ char sent_data[10];
+ RandomizeBuffer(sent_data, sizeof(sent_data));
+ ASSERT_THAT(
+ RetryEINTR(send)(sockets->first_fd(), sent_data, sizeof(sent_data), 0),
+ SyscallSucceedsWithValue(sizeof(sent_data)));
+
+ // The receive buffer is of zero length.
+ char received_data[0] = {};
+
+ struct iovec iov;
+ iov.iov_base = received_data;
+ iov.iov_len = sizeof(received_data);
+ struct msghdr msg = {};
+ msg.msg_flags = -1;
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+
+ // The syscall succeeds returning the full size of the message on the socket.
+ ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &msg, MSG_TRUNC),
+ SyscallSucceedsWithValue(sizeof(sent_data)));
+
+ // Check that MSG_TRUNC is set on msghdr flags.
+ EXPECT_EQ(msg.msg_flags & MSG_TRUNC, MSG_TRUNC);
+}
+
+// This test tests reading from a socket with MSG_TRUNC | MSG_PEEK and a zero
+// length receive buffer. The user should be able to get the message length
+// without reading data off the socket.
+TEST_P(NonStreamSocketPairTest, RecvmsgMsgTruncMsgPeekZeroLen) {
+ auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+ char sent_data[10];
+ RandomizeBuffer(sent_data, sizeof(sent_data));
+ ASSERT_THAT(
+ RetryEINTR(send)(sockets->first_fd(), sent_data, sizeof(sent_data), 0),
+ SyscallSucceedsWithValue(sizeof(sent_data)));
+
+ // The receive buffer is of zero length.
+ char peek_data[0] = {};
+
+ struct iovec peek_iov;
+ peek_iov.iov_base = peek_data;
+ peek_iov.iov_len = sizeof(peek_data);
+ struct msghdr peek_msg = {};
+ peek_msg.msg_flags = -1;
+ peek_msg.msg_iov = &peek_iov;
+ peek_msg.msg_iovlen = 1;
+
+ // The syscall succeeds returning the full size of the message on the socket.
+ ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &peek_msg,
+ MSG_TRUNC | MSG_PEEK),
+ SyscallSucceedsWithValue(sizeof(sent_data)));
+
+ // Check that MSG_TRUNC is set on msghdr flags because the receive buffer is
+ // smaller than the message size.
+ EXPECT_EQ(peek_msg.msg_flags & MSG_TRUNC, MSG_TRUNC);
+
+ char received_data[sizeof(sent_data)] = {};
+
+ struct iovec received_iov;
+ received_iov.iov_base = received_data;
+ received_iov.iov_len = sizeof(received_data);
+ struct msghdr received_msg = {};
+ received_msg.msg_flags = -1;
+ received_msg.msg_iov = &received_iov;
+ received_msg.msg_iovlen = 1;
+
+ // Next we can read the actual data.
+ ASSERT_THAT(
+ RetryEINTR(recvmsg)(sockets->second_fd(), &received_msg, MSG_TRUNC),
+ SyscallSucceedsWithValue(sizeof(sent_data)));
+
+ EXPECT_EQ(0, memcmp(sent_data, received_data, sizeof(sent_data)));
+
+ // Check that MSG_TRUNC is not set on msghdr flags because we read the whole
+ // message.
+ EXPECT_EQ(received_msg.msg_flags & MSG_TRUNC, 0);
+}
+
+// This test tests reading from a socket with MSG_TRUNC | MSG_PEEK and a zero
+// length receive buffer and MSG_DONTWAIT. The user should be able to get an
+// EAGAIN or EWOULDBLOCK error response.
+TEST_P(NonStreamSocketPairTest, RecvmsgTruncPeekDontwaitZeroLen) {
+ auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+ // NOTE: We don't send any data on the socket.
+
+ // The receive buffer is of zero length.
+ char peek_data[0] = {};
+
+ struct iovec peek_iov;
+ peek_iov.iov_base = peek_data;
+ peek_iov.iov_len = sizeof(peek_data);
+ struct msghdr peek_msg = {};
+ peek_msg.msg_flags = -1;
+ peek_msg.msg_iov = &peek_iov;
+ peek_msg.msg_iovlen = 1;
+
+ // recvmsg fails with EAGAIN because no data is available on the socket.
+ ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &peek_msg,
+ MSG_TRUNC | MSG_PEEK | MSG_DONTWAIT),
+ SyscallFailsWithErrno(EAGAIN));
+}
+
} // namespace testing
} // namespace gvisor
diff --git a/test/syscalls/linux/socket_non_stream_blocking.cc b/test/syscalls/linux/socket_non_stream_blocking.cc
index 62d87c1af..b052f6e61 100644
--- a/test/syscalls/linux/socket_non_stream_blocking.cc
+++ b/test/syscalls/linux/socket_non_stream_blocking.cc
@@ -25,6 +25,7 @@
#include "test/syscalls/linux/socket_test_util.h"
#include "test/syscalls/linux/unix_domain_socket_test_util.h"
#include "test/util/test_util.h"
+#include "test/util/thread_util.h"
namespace gvisor {
namespace testing {
@@ -44,5 +45,41 @@ TEST_P(BlockingNonStreamSocketPairTest, RecvLessThanBufferWaitAll) {
SyscallSucceedsWithValue(sizeof(sent_data)));
}
+// This test tests reading from a socket with MSG_TRUNC | MSG_PEEK and a zero
+// length receive buffer and MSG_DONTWAIT. The recvmsg call should block on
+// reading the data.
+TEST_P(BlockingNonStreamSocketPairTest,
+ RecvmsgTruncPeekDontwaitZeroLenBlocking) {
+ auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+ // NOTE: We don't initially send any data on the socket.
+ const int data_size = 10;
+ char sent_data[data_size];
+ RandomizeBuffer(sent_data, data_size);
+
+ // The receive buffer is of zero length.
+ char peek_data[0] = {};
+
+ struct iovec peek_iov;
+ peek_iov.iov_base = peek_data;
+ peek_iov.iov_len = sizeof(peek_data);
+ struct msghdr peek_msg = {};
+ peek_msg.msg_flags = -1;
+ peek_msg.msg_iov = &peek_iov;
+ peek_msg.msg_iovlen = 1;
+
+ ScopedThread t([&]() {
+ // The syscall succeeds returning the full size of the message on the
+ // socket. This should block until there is data on the socket.
+ ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &peek_msg,
+ MSG_TRUNC | MSG_PEEK),
+ SyscallSucceedsWithValue(data_size));
+ });
+
+ absl::SleepFor(absl::Seconds(1));
+ ASSERT_THAT(RetryEINTR(send)(sockets->first_fd(), sent_data, data_size, 0),
+ SyscallSucceedsWithValue(data_size));
+}
+
} // namespace testing
} // namespace gvisor
diff --git a/test/syscalls/linux/socket_stream.cc b/test/syscalls/linux/socket_stream.cc
index 346443f96..6522b2e01 100644
--- a/test/syscalls/linux/socket_stream.cc
+++ b/test/syscalls/linux/socket_stream.cc
@@ -104,7 +104,60 @@ TEST_P(StreamSocketPairTest, RecvmsgMsghdrFlagsNoMsgTrunc) {
EXPECT_EQ(0, memcmp(received_data, sent_data, sizeof(received_data)));
// Check that msghdr flags were cleared (MSG_TRUNC was not set).
- EXPECT_EQ(msg.msg_flags, 0);
+ ASSERT_EQ(msg.msg_flags & MSG_TRUNC, 0);
+}
+
+TEST_P(StreamSocketPairTest, RecvmsgTruncZeroLen) {
+ auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+ char sent_data[10];
+ RandomizeBuffer(sent_data, sizeof(sent_data));
+ ASSERT_THAT(
+ RetryEINTR(send)(sockets->first_fd(), sent_data, sizeof(sent_data), 0),
+ SyscallSucceedsWithValue(sizeof(sent_data)));
+
+ char received_data[0] = {};
+
+ struct iovec iov;
+ iov.iov_base = received_data;
+ iov.iov_len = sizeof(received_data);
+ struct msghdr msg = {};
+ msg.msg_flags = -1;
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+
+ ASSERT_THAT(RetryEINTR(recvmsg)(sockets->second_fd(), &msg, MSG_TRUNC),
+ SyscallSucceedsWithValue(0));
+
+ // Check that msghdr flags were cleared (MSG_TRUNC was not set).
+ ASSERT_EQ(msg.msg_flags & MSG_TRUNC, 0);
+}
+
+TEST_P(StreamSocketPairTest, RecvmsgTruncPeekZeroLen) {
+ auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
+
+ char sent_data[10];
+ RandomizeBuffer(sent_data, sizeof(sent_data));
+ ASSERT_THAT(
+ RetryEINTR(send)(sockets->first_fd(), sent_data, sizeof(sent_data), 0),
+ SyscallSucceedsWithValue(sizeof(sent_data)));
+
+ char received_data[0] = {};
+
+ struct iovec iov;
+ iov.iov_base = received_data;
+ iov.iov_len = sizeof(received_data);
+ struct msghdr msg = {};
+ msg.msg_flags = -1;
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+
+ ASSERT_THAT(
+ RetryEINTR(recvmsg)(sockets->second_fd(), &msg, MSG_TRUNC | MSG_PEEK),
+ SyscallSucceedsWithValue(0));
+
+ // Check that msghdr flags were cleared (MSG_TRUNC was not set).
+ ASSERT_EQ(msg.msg_flags & MSG_TRUNC, 0);
}
TEST_P(StreamSocketPairTest, MsgTrunc) {
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 20:42:05 +0000