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Diffstat (limited to 'runsc/fsgofer/fsgofer.go')
-rw-r--r--runsc/fsgofer/fsgofer.go148
1 files changed, 98 insertions, 50 deletions
diff --git a/runsc/fsgofer/fsgofer.go b/runsc/fsgofer/fsgofer.go
index 74977c313..82a46910e 100644
--- a/runsc/fsgofer/fsgofer.go
+++ b/runsc/fsgofer/fsgofer.go
@@ -132,19 +132,19 @@ func (a *attachPoint) Attach() (p9.File, error) {
return nil, fmt.Errorf("attach point already attached, prefix: %s", a.prefix)
}
- f, err := openAnyFile(a.prefix, func(mode int) (*fd.FD, error) {
+ f, readable, err := openAnyFile(a.prefix, func(mode int) (*fd.FD, error) {
return fd.Open(a.prefix, openFlags|mode, 0)
})
if err != nil {
return nil, fmt.Errorf("unable to open %q: %v", a.prefix, err)
}
- stat, err := stat(f.FD())
+ stat, err := fstat(f.FD())
if err != nil {
return nil, fmt.Errorf("unable to stat %q: %v", a.prefix, err)
}
- lf, err := newLocalFile(a, f, a.prefix, stat)
+ lf, err := newLocalFile(a, f, a.prefix, readable, stat)
if err != nil {
return nil, fmt.Errorf("unable to create localFile %q: %v", a.prefix, err)
}
@@ -212,6 +212,10 @@ type localFile struct {
// opened with.
file *fd.FD
+ // controlReadable tells whether 'file' was opened with read permissions
+ // during a walk.
+ controlReadable bool
+
// mode is the mode in which the file was opened. Set to invalidMode
// if localFile isn't opened.
mode p9.OpenFlags
@@ -251,49 +255,57 @@ func reopenProcFd(f *fd.FD, mode int) (*fd.FD, error) {
return fd.New(d), nil
}
-func openAnyFileFromParent(parent *localFile, name string) (*fd.FD, string, error) {
+func openAnyFileFromParent(parent *localFile, name string) (*fd.FD, string, bool, error) {
path := path.Join(parent.hostPath, name)
- f, err := openAnyFile(path, func(mode int) (*fd.FD, error) {
+ f, readable, err := openAnyFile(path, func(mode int) (*fd.FD, error) {
return fd.OpenAt(parent.file, name, openFlags|mode, 0)
})
- return f, path, err
+ return f, path, readable, err
}
// openAnyFile attempts to open the file in O_RDONLY and if it fails fallsback
// to O_PATH. 'path' is used for logging messages only. 'fn' is what does the
// actual file open and is customizable by the caller.
-func openAnyFile(path string, fn func(mode int) (*fd.FD, error)) (*fd.FD, error) {
+func openAnyFile(path string, fn func(mode int) (*fd.FD, error)) (*fd.FD, bool, error) {
// Attempt to open file in the following mode in order:
// 1. RDONLY | NONBLOCK: for all files, directories, ro mounts, FIFOs.
// Use non-blocking to prevent getting stuck inside open(2) for
// FIFOs. This option has no effect on regular files.
// 2. PATH: for symlinks, sockets.
- modes := []int{syscall.O_RDONLY | syscall.O_NONBLOCK, unix.O_PATH}
+ options := []struct {
+ mode int
+ readable bool
+ }{
+ {
+ mode: syscall.O_RDONLY | syscall.O_NONBLOCK,
+ readable: true,
+ },
+ {
+ mode: unix.O_PATH,
+ readable: false,
+ },
+ }
var err error
- var file *fd.FD
- for i, mode := range modes {
- file, err = fn(mode)
+ for i, option := range options {
+ var file *fd.FD
+ file, err = fn(option.mode)
if err == nil {
- // openat succeeded, we're done.
- break
+ // Succeeded opening the file, we're done.
+ return file, option.readable, nil
}
switch e := extractErrno(err); e {
case syscall.ENOENT:
// File doesn't exist, no point in retrying.
- return nil, e
+ return nil, false, e
}
- // openat failed. Try again with next mode, preserving 'err' in case this
- // was the last attempt.
- log.Debugf("Attempt %d to open file failed, mode: %#x, path: %q, err: %v", i, openFlags|mode, path, err)
- }
- if err != nil {
- // All attempts to open file have failed, return the last error.
- log.Debugf("Failed to open file, path: %q, err: %v", path, err)
- return nil, extractErrno(err)
+ // File failed to open. Try again with next mode, preserving 'err' in case
+ // this was the last attempt.
+ log.Debugf("Attempt %d to open file failed, mode: %#x, path: %q, err: %v", i, openFlags|option.mode, path, err)
}
-
- return file, nil
+ // All attempts to open file have failed, return the last error.
+ log.Debugf("Failed to open file, path: %q, err: %v", path, err)
+ return nil, false, extractErrno(err)
}
func getSupportedFileType(stat syscall.Stat_t, permitSocket bool) (fileType, error) {
@@ -316,18 +328,19 @@ func getSupportedFileType(stat syscall.Stat_t, permitSocket bool) (fileType, err
return ft, nil
}
-func newLocalFile(a *attachPoint, file *fd.FD, path string, stat syscall.Stat_t) (*localFile, error) {
+func newLocalFile(a *attachPoint, file *fd.FD, path string, readable bool, stat syscall.Stat_t) (*localFile, error) {
ft, err := getSupportedFileType(stat, a.conf.HostUDS)
if err != nil {
return nil, err
}
return &localFile{
- attachPoint: a,
- hostPath: path,
- file: file,
- mode: invalidMode,
- ft: ft,
+ attachPoint: a,
+ hostPath: path,
+ file: file,
+ mode: invalidMode,
+ ft: ft,
+ controlReadable: readable,
}, nil
}
@@ -352,7 +365,7 @@ func newFDMaybe(file *fd.FD) *fd.FD {
return dup
}
-func stat(fd int) (syscall.Stat_t, error) {
+func fstat(fd int) (syscall.Stat_t, error) {
var stat syscall.Stat_t
if err := syscall.Fstat(fd, &stat); err != nil {
return syscall.Stat_t{}, err
@@ -360,6 +373,14 @@ func stat(fd int) (syscall.Stat_t, error) {
return stat, nil
}
+func stat(path string) (syscall.Stat_t, error) {
+ var stat syscall.Stat_t
+ if err := syscall.Stat(path, &stat); err != nil {
+ return syscall.Stat_t{}, err
+ }
+ return stat, nil
+}
+
func fchown(fd int, uid p9.UID, gid p9.GID) error {
return syscall.Fchownat(fd, "", int(uid), int(gid), linux.AT_EMPTY_PATH|unix.AT_SYMLINK_NOFOLLOW)
}
@@ -372,7 +393,7 @@ func (l *localFile) Open(flags p9.OpenFlags) (*fd.FD, p9.QID, uint32, error) {
// Check if control file can be used or if a new open must be created.
var newFile *fd.FD
- if flags == p9.ReadOnly {
+ if flags == p9.ReadOnly && l.controlReadable {
log.Debugf("Open reusing control file, flags: %v, %q", flags, l.hostPath)
newFile = l.file
} else {
@@ -388,7 +409,7 @@ func (l *localFile) Open(flags p9.OpenFlags) (*fd.FD, p9.QID, uint32, error) {
}
}
- stat, err := stat(newFile.FD())
+ stat, err := fstat(newFile.FD())
if err != nil {
if newFile != l.file {
newFile.Close()
@@ -449,7 +470,7 @@ func (l *localFile) Create(name string, mode p9.OpenFlags, perm p9.FileMode, uid
if err := fchown(child.FD(), uid, gid); err != nil {
return nil, nil, p9.QID{}, 0, extractErrno(err)
}
- stat, err := stat(child.FD())
+ stat, err := fstat(child.FD())
if err != nil {
return nil, nil, p9.QID{}, 0, extractErrno(err)
}
@@ -497,7 +518,7 @@ func (l *localFile) Mkdir(name string, perm p9.FileMode, uid p9.UID, gid p9.GID)
if err := fchown(f.FD(), uid, gid); err != nil {
return p9.QID{}, extractErrno(err)
}
- stat, err := stat(f.FD())
+ stat, err := fstat(f.FD())
if err != nil {
return p9.QID{}, extractErrno(err)
}
@@ -510,24 +531,25 @@ func (l *localFile) Mkdir(name string, perm p9.FileMode, uid p9.UID, gid p9.GID)
func (l *localFile) Walk(names []string) ([]p9.QID, p9.File, error) {
// Duplicate current file if 'names' is empty.
if len(names) == 0 {
- newFile, err := openAnyFile(l.hostPath, func(mode int) (*fd.FD, error) {
+ newFile, readable, err := openAnyFile(l.hostPath, func(mode int) (*fd.FD, error) {
return reopenProcFd(l.file, openFlags|mode)
})
if err != nil {
return nil, nil, extractErrno(err)
}
- stat, err := stat(newFile.FD())
+ stat, err := fstat(newFile.FD())
if err != nil {
newFile.Close()
return nil, nil, extractErrno(err)
}
c := &localFile{
- attachPoint: l.attachPoint,
- hostPath: l.hostPath,
- file: newFile,
- mode: invalidMode,
+ attachPoint: l.attachPoint,
+ hostPath: l.hostPath,
+ file: newFile,
+ mode: invalidMode,
+ controlReadable: readable,
}
return []p9.QID{l.attachPoint.makeQID(stat)}, c, nil
}
@@ -535,19 +557,19 @@ func (l *localFile) Walk(names []string) ([]p9.QID, p9.File, error) {
var qids []p9.QID
last := l
for _, name := range names {
- f, path, err := openAnyFileFromParent(last, name)
+ f, path, readable, err := openAnyFileFromParent(last, name)
if last != l {
last.Close()
}
if err != nil {
return nil, nil, extractErrno(err)
}
- stat, err := stat(f.FD())
+ stat, err := fstat(f.FD())
if err != nil {
f.Close()
return nil, nil, extractErrno(err)
}
- c, err := newLocalFile(last.attachPoint, f, path, stat)
+ c, err := newLocalFile(last.attachPoint, f, path, readable, stat)
if err != nil {
f.Close()
return nil, nil, extractErrno(err)
@@ -592,7 +614,7 @@ func (l *localFile) FSync() error {
// GetAttr implements p9.File.
func (l *localFile) GetAttr(_ p9.AttrMask) (p9.QID, p9.AttrMask, p9.Attr, error) {
- stat, err := stat(l.file.FD())
+ stat, err := fstat(l.file.FD())
if err != nil {
return p9.QID{}, p9.AttrMask{}, p9.Attr{}, extractErrno(err)
}
@@ -880,7 +902,7 @@ func (l *localFile) Symlink(target, newName string, uid p9.UID, gid p9.GID) (p9.
if err := fchown(f.FD(), uid, gid); err != nil {
return p9.QID{}, extractErrno(err)
}
- stat, err := stat(f.FD())
+ stat, err := fstat(f.FD())
if err != nil {
return p9.QID{}, extractErrno(err)
}
@@ -907,13 +929,39 @@ func (l *localFile) Link(target p9.File, newName string) error {
}
// Mknod implements p9.File.
-//
-// Not implemented.
-func (*localFile) Mknod(_ string, _ p9.FileMode, _ uint32, _ uint32, _ p9.UID, _ p9.GID) (p9.QID, error) {
+func (l *localFile) Mknod(name string, mode p9.FileMode, _ uint32, _ uint32, uid p9.UID, gid p9.GID) (p9.QID, error) {
+ conf := l.attachPoint.conf
+ if conf.ROMount {
+ if conf.PanicOnWrite {
+ panic("attempt to write to RO mount")
+ }
+ return p9.QID{}, syscall.EROFS
+ }
+
+ hostPath := path.Join(l.hostPath, name)
+
+ // Return EEXIST if the file already exists.
+ if _, err := stat(hostPath); err == nil {
+ return p9.QID{}, syscall.EEXIST
+ }
+
// From mknod(2) man page:
// "EPERM: [...] if the filesystem containing pathname does not support
// the type of node requested."
- return p9.QID{}, syscall.EPERM
+ if mode.FileType() != p9.ModeRegular {
+ return p9.QID{}, syscall.EPERM
+ }
+
+ // Allow Mknod to create regular files.
+ if err := syscall.Mknod(hostPath, uint32(mode), 0); err != nil {
+ return p9.QID{}, err
+ }
+
+ stat, err := stat(hostPath)
+ if err != nil {
+ return p9.QID{}, extractErrno(err)
+ }
+ return l.attachPoint.makeQID(stat), nil
}
// UnlinkAt implements p9.File.
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-22 08:18:42 +0000