OrgGo/unipdf
1
0
Fork 0
mirror of https://github.com/unidoc/unipdf.git synced 2025-05-01 22:17:29 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

Improved crypto handling for encrypt dicts with references

Browse Source
This commit is contained in:
Gunnsteinn Hall 2017-03-29 15:54:50 +00:00
parent 698dbe3168
commit 90caacec66
2 changed files with 30 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
pdf/core/crypt.go
View File

@ -41,6 +41,8 @@ type PdfCrypt struct {
CryptFilters CryptFilters
StreamFilter string
StringFilter string
parser *PdfParser
}
type AccessPermissions struct {
@ -69,15 +71,36 @@ type CryptFilters map[string]CryptFilter
func (this *PdfCrypt) LoadCryptFilters(ed *PdfObjectDictionary) error {
this.CryptFilters = CryptFilters{}
cf, ok := (*ed)["CF"].(*PdfObjectDictionary)
obj := (*ed)["CF"]
obj = TraceToDirectObject(obj) // XXX may need to resolve reference...
if ref, isRef := obj.(*PdfObjectReference); isRef {
o, err := this.parser.LookupByReference(*ref)
if err != nil {
common.Log.Debug("Error looking up CF reference")
return err
}
obj = TraceToDirectObject(o)
}
cf, ok := obj.(*PdfObjectDictionary)
if !ok {
common.Log.Debug("Invalid CF, type: %T", obj)
return errors.New("Invalid CF")
}
for name, v := range *cf {
if ref, isRef := v.(*PdfObjectReference); isRef {
o, err := this.parser.LookupByReference(*ref)
if err != nil {
common.Log.Debug("Error lookup up dictionary reference")
return err
}
v = TraceToDirectObject(o)
}
dict, ok := v.(*PdfObjectDictionary)
if !ok {
return fmt.Errorf("Invalid dict in CF (name %s)", name)
return fmt.Errorf("Invalid dict in CF (name %s) - not a dictionary but %T", name, v)
}
if name == "Identity" {
@ -160,11 +183,12 @@ func (this *PdfCrypt) LoadCryptFilters(ed *PdfObjectDictionary) error {
// Prepare the document crypt handler based on the encryption dictionary
// and trailer dictionary.
func PdfCryptMakeNew(ed, trailer *PdfObjectDictionary) (PdfCrypt, error) {
func PdfCryptMakeNew(parser *PdfParser, ed, trailer *PdfObjectDictionary) (PdfCrypt, error) {
crypter := PdfCrypt{}
crypter.DecryptedObjects = map[PdfObject]bool{}
crypter.EncryptedObjects = map[PdfObject]bool{}
crypter.Authenticated = false
crypter.parser = parser
filter, ok := (*ed)["Filter"].(*PdfObjectName)
if !ok {
@ -261,12 +285,13 @@ func PdfCryptMakeNew(ed, trailer *PdfObjectDictionary) (PdfCrypt, error) {
// but clearly not everyone is following the specification.
id0 := PdfObjectString("")
if idArray, ok := (*trailer)["ID"].(*PdfObjectArray); ok {
common.Log.Debug("Trailer ID array missing!")
id0obj, ok := (*idArray)[0].(*PdfObjectString)
if !ok {
return crypter, errors.New("Invalid trailer ID")
}
id0 = *id0obj
} else {
common.Log.Debug("Trailer ID array missing or invalid!")
}
crypter.Id0 = string(id0)

2
pdf/core/parser.go
View File

@ -1404,7 +1404,7 @@ func (this *PdfParser) IsEncrypted() (bool, error) {
if !ok {
return false, errors.New("Trailer Encrypt object non dictionary")
}
crypter, err := PdfCryptMakeNew(encDict, this.trailer)
crypter, err := PdfCryptMakeNew(this, encDict, this.trailer)
if err != nil {
return false, err
}