diff options
| -rw-r--r-- | pkg/p9/handlers.go | 70 |
1 files changed, 69 insertions, 1 deletions
diff --git a/pkg/p9/handlers.go b/pkg/p9/handlers.go index 83a66d3ae..7da9eff5f 100644 --- a/pkg/p9/handlers.go +++ b/pkg/p9/handlers.go @@ -17,6 +17,7 @@ package p9 import ( "io" "os" + "strings" "sync/atomic" "syscall" @@ -83,8 +84,24 @@ func (t *Tflush) handle(cs *connState) message { return &Rflush{} } +// isSafeName returns true iff the name does not contain directory characters. +// +// We permit walks only on safe names and store the sequence of paths used for +// any given walk in each FID. (This is immutable.) We use this to mark +// relevant FIDs as moved when a successful rename occurs. +func isSafeName(name string) bool { + return name != "" && !strings.Contains(name, "/") && name != "." && name != ".." +} + // handle implements handler.handle. func (t *Twalk) handle(cs *connState) message { + // Check the names. + for _, name := range t.Names { + if !isSafeName(name) { + return newErr(syscall.EINVAL) + } + } + // Lookup the FID. ref, ok := cs.LookupFID(t.FID) if !ok { @@ -200,6 +217,11 @@ func (t *Tlopen) handle(cs *connState) message { } func (t *Tlcreate) do(cs *connState, uid UID) (*Rlcreate, error) { + // Don't allow complex names. + if !isSafeName(t.Name) { + return nil, syscall.EINVAL + } + // Lookup the FID. ref, ok := cs.LookupFID(t.FID) if !ok { @@ -216,7 +238,11 @@ func (t *Tlcreate) do(cs *connState, uid UID) (*Rlcreate, error) { // Replace the FID reference. // // The new file will be opened already. - cs.InsertFID(t.FID, &fidRef{file: nsf, opened: true, openFlags: t.OpenFlags}) + cs.InsertFID(t.FID, &fidRef{ + file: nsf, + opened: true, + openFlags: t.OpenFlags, + }) return &Rlcreate{Rlopen: Rlopen{QID: qid, IoUnit: ioUnit, File: osFile}}, nil } @@ -240,6 +266,11 @@ func (t *Tsymlink) handle(cs *connState) message { } func (t *Tsymlink) do(cs *connState, uid UID) (*Rsymlink, error) { + // Don't allow complex names. + if !isSafeName(t.Name) { + return nil, syscall.EINVAL + } + // Lookup the FID. ref, ok := cs.LookupFID(t.Directory) if !ok { @@ -258,6 +289,11 @@ func (t *Tsymlink) do(cs *connState, uid UID) (*Rsymlink, error) { // handle implements handler.handle. func (t *Tlink) handle(cs *connState) message { + // Don't allow complex names. + if !isSafeName(t.Name) { + return newErr(syscall.EINVAL) + } + // Lookup the FID. ref, ok := cs.LookupFID(t.Directory) if !ok { @@ -282,6 +318,11 @@ func (t *Tlink) handle(cs *connState) message { // handle implements handler.handle. func (t *Trenameat) handle(cs *connState) message { + // Don't allow complex names. + if !isSafeName(t.OldName) || !isSafeName(t.NewName) { + return newErr(syscall.EINVAL) + } + // Lookup the FID. ref, ok := cs.LookupFID(t.OldDirectory) if !ok { @@ -306,6 +347,11 @@ func (t *Trenameat) handle(cs *connState) message { // handle implements handler.handle. func (t *Tunlinkat) handle(cs *connState) message { + // Don't allow complex names. + if !isSafeName(t.Name) { + return newErr(syscall.EINVAL) + } + // Lookup the FID. ref, ok := cs.LookupFID(t.Directory) if !ok { @@ -323,6 +369,11 @@ func (t *Tunlinkat) handle(cs *connState) message { // handle implements handler.handle. func (t *Trename) handle(cs *connState) message { + // Don't allow complex names. + if !isSafeName(t.Name) { + return newErr(syscall.EINVAL) + } + // Lookup the FID. ref, ok := cs.LookupFID(t.FID) if !ok { @@ -437,6 +488,11 @@ func (t *Tmknod) handle(cs *connState) message { } func (t *Tmknod) do(cs *connState, uid UID) (*Rmknod, error) { + // Don't allow complex names. + if !isSafeName(t.Name) { + return nil, syscall.EINVAL + } + // Lookup the FID. ref, ok := cs.LookupFID(t.Directory) if !ok { @@ -463,6 +519,11 @@ func (t *Tmkdir) handle(cs *connState) message { } func (t *Tmkdir) do(cs *connState, uid UID) (*Rmkdir, error) { + // Don't allow complex names. + if !isSafeName(t.Name) { + return nil, syscall.EINVAL + } + // Lookup the FID. ref, ok := cs.LookupFID(t.Directory) if !ok { @@ -619,6 +680,13 @@ func (t *Tflushf) handle(cs *connState) message { // handle implements handler.handle. func (t *Twalkgetattr) handle(cs *connState) message { + // Check the names. + for _, name := range t.Names { + if !isSafeName(name) { + return newErr(syscall.EINVAL) + } + } + // Lookup the FID. ref, ok := cs.LookupFID(t.FID) if !ok { |