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-rw-r--r--pkg/abi/linux/fuse.go11
-rw-r--r--pkg/sentry/fsimpl/fuse/fusefs.go30
-rw-r--r--pkg/sentry/fsimpl/kernfs/filesystem.go2
-rw-r--r--pkg/sentry/fsimpl/kernfs/inode_impl_util.go2
-rw-r--r--pkg/sentry/fsimpl/kernfs/kernfs.go2
-rw-r--r--pkg/sentry/fsimpl/kernfs/symlink.go2
-rw-r--r--pkg/sentry/fsimpl/proc/task_fds.go2
-rw-r--r--pkg/sentry/fsimpl/proc/task_files.go6
-rw-r--r--pkg/sentry/fsimpl/proc/tasks_files.go12
-rw-r--r--test/fuse/BUILD5
-rw-r--r--test/fuse/linux/BUILD13
-rw-r--r--test/fuse/linux/readlink_test.cc85
12 files changed, 158 insertions, 14 deletions
diff --git a/pkg/abi/linux/fuse.go b/pkg/abi/linux/fuse.go
index ea5a7fd43..5de1433d7 100644
--- a/pkg/abi/linux/fuse.go
+++ b/pkg/abi/linux/fuse.go
@@ -483,3 +483,14 @@ func (r *FUSESymLinkIn) MarshalUnsafe(buf []byte) {
func (r *FUSESymLinkIn) SizeBytes() int {
return len(r.Name) + len(r.Target) + 2
}
+
+// FUSEEmptyIn is used by operations without request body.
+type FUSEEmptyIn struct{ marshal.StubMarshallable }
+
+// MarshalUnsafe do nothing for marshal.
+func (r *FUSEEmptyIn) MarshalUnsafe(buf []byte) {}
+
+// SizeBytes is 0 for empty request.
+func (r *FUSEEmptyIn) SizeBytes() int {
+ return 0
+}
diff --git a/pkg/sentry/fsimpl/fuse/fusefs.go b/pkg/sentry/fsimpl/fuse/fusefs.go
index 0021e2933..8db337a2e 100644
--- a/pkg/sentry/fsimpl/fuse/fusefs.go
+++ b/pkg/sentry/fsimpl/fuse/fusefs.go
@@ -225,6 +225,9 @@ type inode struct {
// version of the inode.
version uint64
+
+ // link is result of following a symbolic link.
+ link string
}
func (fs *filesystem) newRootInode(creds *auth.Credentials, mode linux.FileMode) *kernfs.Dentry {
@@ -406,6 +409,33 @@ func (i *inode) newEntry(ctx context.Context, name string, fileType linux.FileMo
return child.VFSDentry(), nil
}
+// Readlink implements kernfs.Inode.Readlink.
+func (i *inode) Readlink(ctx context.Context, mnt *vfs.Mount) (string, error) {
+ if i.Mode().FileType()&linux.S_IFLNK == 0 {
+ return "", syserror.EINVAL
+ }
+ if i.link == "" {
+ kernelTask := kernel.TaskFromContext(ctx)
+ if kernelTask == nil {
+ log.Warningf("fusefs.Inode.Readlink: couldn't get kernel task from context")
+ return "", syserror.EINVAL
+ }
+ req, err := i.fs.conn.NewRequest(auth.CredentialsFromContext(ctx), uint32(kernelTask.ThreadID()), i.NodeID, linux.FUSE_READLINK, &linux.FUSEEmptyIn{})
+ if err != nil {
+ return "", err
+ }
+ res, err := i.fs.conn.Call(kernelTask, req)
+ if err != nil {
+ return "", err
+ }
+ i.link = string(res.data[res.hdr.SizeBytes():])
+ if !mnt.Options().ReadOnly {
+ i.attributeTime = 0
+ }
+ }
+ return i.link, nil
+}
+
// statFromFUSEAttr makes attributes from linux.FUSEAttr to linux.Statx. The
// opts.Sync attribute is ignored since the synchronization is handled by the
// FUSE server.
diff --git a/pkg/sentry/fsimpl/kernfs/filesystem.go b/pkg/sentry/fsimpl/kernfs/filesystem.go
index 904203070..7aaf1146d 100644
--- a/pkg/sentry/fsimpl/kernfs/filesystem.go
+++ b/pkg/sentry/fsimpl/kernfs/filesystem.go
@@ -548,7 +548,7 @@ func (fs *Filesystem) ReadlinkAt(ctx context.Context, rp *vfs.ResolvingPath) (st
if !d.Impl().(*Dentry).isSymlink() {
return "", syserror.EINVAL
}
- return inode.Readlink(ctx)
+ return inode.Readlink(ctx, rp.Mount())
}
// RenameAt implements vfs.FilesystemImpl.RenameAt.
diff --git a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
index 74408e322..53758a4b8 100644
--- a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
+++ b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
@@ -172,7 +172,7 @@ func (InodeNoDynamicLookup) Valid(ctx context.Context) bool {
type InodeNotSymlink struct{}
// Readlink implements Inode.Readlink.
-func (InodeNotSymlink) Readlink(context.Context) (string, error) {
+func (InodeNotSymlink) Readlink(context.Context, *vfs.Mount) (string, error) {
return "", syserror.EINVAL
}
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs.go b/pkg/sentry/fsimpl/kernfs/kernfs.go
index 67a0347fe..f656e2a8b 100644
--- a/pkg/sentry/fsimpl/kernfs/kernfs.go
+++ b/pkg/sentry/fsimpl/kernfs/kernfs.go
@@ -437,7 +437,7 @@ type inodeDynamicLookup interface {
type inodeSymlink interface {
// Readlink returns the target of a symbolic link. If an inode is not a
// symlink, the implementation should return EINVAL.
- Readlink(ctx context.Context) (string, error)
+ Readlink(ctx context.Context, mnt *vfs.Mount) (string, error)
// Getlink returns the target of a symbolic link, as used by path
// resolution:
diff --git a/pkg/sentry/fsimpl/kernfs/symlink.go b/pkg/sentry/fsimpl/kernfs/symlink.go
index 64731a3e4..a9812fcef 100644
--- a/pkg/sentry/fsimpl/kernfs/symlink.go
+++ b/pkg/sentry/fsimpl/kernfs/symlink.go
@@ -52,7 +52,7 @@ func (s *StaticSymlink) Init(creds *auth.Credentials, devMajor uint32, devMinor
}
// Readlink implements Inode.
-func (s *StaticSymlink) Readlink(_ context.Context) (string, error) {
+func (s *StaticSymlink) Readlink(_ context.Context, _ *vfs.Mount) (string, error) {
return s.target, nil
}
diff --git a/pkg/sentry/fsimpl/proc/task_fds.go b/pkg/sentry/fsimpl/proc/task_fds.go
index 94ec2ff69..47d744a57 100644
--- a/pkg/sentry/fsimpl/proc/task_fds.go
+++ b/pkg/sentry/fsimpl/proc/task_fds.go
@@ -214,7 +214,7 @@ func (fs *filesystem) newFDSymlink(task *kernel.Task, fd int32, ino uint64) *ker
return d
}
-func (s *fdSymlink) Readlink(ctx context.Context) (string, error) {
+func (s *fdSymlink) Readlink(ctx context.Context, _ *vfs.Mount) (string, error) {
file, _ := getTaskFD(s.task, s.fd)
if file == nil {
return "", syserror.ENOENT
diff --git a/pkg/sentry/fsimpl/proc/task_files.go b/pkg/sentry/fsimpl/proc/task_files.go
index ce87b0d47..87726d8f7 100644
--- a/pkg/sentry/fsimpl/proc/task_files.go
+++ b/pkg/sentry/fsimpl/proc/task_files.go
@@ -668,7 +668,7 @@ func (fs *filesystem) newExeSymlink(task *kernel.Task, ino uint64) *kernfs.Dentr
}
// Readlink implements kernfs.Inode.
-func (s *exeSymlink) Readlink(ctx context.Context) (string, error) {
+func (s *exeSymlink) Readlink(ctx context.Context, _ *vfs.Mount) (string, error) {
if !kernel.ContextCanTrace(ctx, s.task, false) {
return "", syserror.EACCES
}
@@ -808,11 +808,11 @@ func (fs *filesystem) newNamespaceSymlink(task *kernel.Task, ino uint64, ns stri
}
// Readlink implements Inode.
-func (s *namespaceSymlink) Readlink(ctx context.Context) (string, error) {
+func (s *namespaceSymlink) Readlink(ctx context.Context, mnt *vfs.Mount) (string, error) {
if err := checkTaskState(s.task); err != nil {
return "", err
}
- return s.StaticSymlink.Readlink(ctx)
+ return s.StaticSymlink.Readlink(ctx, mnt)
}
// Getlink implements Inode.Getlink.
diff --git a/pkg/sentry/fsimpl/proc/tasks_files.go b/pkg/sentry/fsimpl/proc/tasks_files.go
index 8c41729e4..68c541046 100644
--- a/pkg/sentry/fsimpl/proc/tasks_files.go
+++ b/pkg/sentry/fsimpl/proc/tasks_files.go
@@ -51,7 +51,7 @@ func (fs *filesystem) newSelfSymlink(creds *auth.Credentials, ino uint64, pidns
return d
}
-func (s *selfSymlink) Readlink(ctx context.Context) (string, error) {
+func (s *selfSymlink) Readlink(ctx context.Context, _ *vfs.Mount) (string, error) {
t := kernel.TaskFromContext(ctx)
if t == nil {
// Who is reading this link?
@@ -64,8 +64,8 @@ func (s *selfSymlink) Readlink(ctx context.Context) (string, error) {
return strconv.FormatUint(uint64(tgid), 10), nil
}
-func (s *selfSymlink) Getlink(ctx context.Context, _ *vfs.Mount) (vfs.VirtualDentry, string, error) {
- target, err := s.Readlink(ctx)
+func (s *selfSymlink) Getlink(ctx context.Context, mnt *vfs.Mount) (vfs.VirtualDentry, string, error) {
+ target, err := s.Readlink(ctx, mnt)
return vfs.VirtualDentry{}, target, err
}
@@ -94,7 +94,7 @@ func (fs *filesystem) newThreadSelfSymlink(creds *auth.Credentials, ino uint64,
return d
}
-func (s *threadSelfSymlink) Readlink(ctx context.Context) (string, error) {
+func (s *threadSelfSymlink) Readlink(ctx context.Context, _ *vfs.Mount) (string, error) {
t := kernel.TaskFromContext(ctx)
if t == nil {
// Who is reading this link?
@@ -108,8 +108,8 @@ func (s *threadSelfSymlink) Readlink(ctx context.Context) (string, error) {
return fmt.Sprintf("%d/task/%d", tgid, tid), nil
}
-func (s *threadSelfSymlink) Getlink(ctx context.Context, _ *vfs.Mount) (vfs.VirtualDentry, string, error) {
- target, err := s.Readlink(ctx)
+func (s *threadSelfSymlink) Getlink(ctx context.Context, mnt *vfs.Mount) (vfs.VirtualDentry, string, error) {
+ target, err := s.Readlink(ctx, mnt)
return vfs.VirtualDentry{}, target, err
}
diff --git a/test/fuse/BUILD b/test/fuse/BUILD
index 2f91fe2c7..c2bdcf1ba 100644
--- a/test/fuse/BUILD
+++ b/test/fuse/BUILD
@@ -26,3 +26,8 @@ syscall_test(
fuse = "True",
test = "//test/fuse/linux:symlink_test",
)
+
+syscall_test(
+ fuse = "True",
+ test = "//test/fuse/linux:readlink_test",
+)
diff --git a/test/fuse/linux/BUILD b/test/fuse/linux/BUILD
index df42857f6..d3e8ca148 100644
--- a/test/fuse/linux/BUILD
+++ b/test/fuse/linux/BUILD
@@ -71,6 +71,19 @@ cc_binary(
],
)
+cc_binary(
+ name = "readlink_test",
+ testonly = 1,
+ srcs = ["readlink_test.cc"],
+ deps = [
+ gtest,
+ ":fuse_base",
+ "//test/util:fuse_util",
+ "//test/util:test_main",
+ "//test/util:test_util",
+ ],
+)
+
cc_library(
name = "fuse_base",
testonly = 1,
diff --git a/test/fuse/linux/readlink_test.cc b/test/fuse/linux/readlink_test.cc
new file mode 100644
index 000000000..2cba8fc23
--- /dev/null
+++ b/test/fuse/linux/readlink_test.cc
@@ -0,0 +1,85 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/fuse_util.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class ReadlinkTest : public FuseTest {
+ protected:
+ const std::string test_file_ = "test_file_";
+ const mode_t perms_ = S_IRWXU | S_IRWXG | S_IRWXO;
+};
+
+TEST_F(ReadlinkTest, ReadSymLink) {
+ const std::string symlink_path =
+ JoinPath(mount_point_.path().c_str(), test_file_);
+ SetServerInodeLookup(test_file_, S_IFLNK | perms_);
+
+ struct fuse_out_header out_header = {
+ .len = static_cast<uint32_t>(sizeof(struct fuse_out_header)) +
+ static_cast<uint32_t>(test_file_.length()) + 1,
+ };
+ std::string link = test_file_;
+ auto iov_out = FuseGenerateIovecs(out_header, link);
+ SetServerResponse(FUSE_READLINK, iov_out);
+ const std::string actual_link =
+ ASSERT_NO_ERRNO_AND_VALUE(ReadLink(symlink_path));
+
+ struct fuse_in_header in_header;
+ auto iov_in = FuseGenerateIovecs(in_header);
+ GetServerActualRequest(iov_in);
+
+ EXPECT_EQ(in_header.len, sizeof(in_header));
+ EXPECT_EQ(in_header.opcode, FUSE_READLINK);
+ EXPECT_EQ(0, memcmp(actual_link.c_str(), link.data(), link.size()));
+
+ // next readlink should have link cached, so shouldn't have new request to
+ // server.
+ uint32_t recieved_before = GetServerTotalReceivedBytes();
+ ASSERT_NO_ERRNO(ReadLink(symlink_path));
+ EXPECT_EQ(GetServerTotalReceivedBytes(), recieved_before);
+}
+
+TEST_F(ReadlinkTest, NotSymlink) {
+ const std::string test_file_path =
+ JoinPath(mount_point_.path().c_str(), test_file_);
+ SetServerInodeLookup(test_file_, S_IFREG | perms_);
+
+ std::vector<char> buf(PATH_MAX + 1);
+ ASSERT_THAT(readlink(test_file_path.c_str(), buf.data(), PATH_MAX),
+ SyscallFailsWithErrno(EINVAL));
+}
+
+} // namespace
+
+} // namespace testing
+} // namespace gvisor
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 10:55:41 +0000