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authorPřemysl Eric Janouch <p@janouch.name>2020-09-04 15:34:33 +0200
committerPřemysl Eric Janouch <p@janouch.name>2020-09-04 16:05:14 +0200
commit1224d9be47e5235f39556d9118c9893ee6e68a4c (patch)
tree4eb042d56f8baa5f036e9c327226523bd9719bb5 /pdf
parent486cafa6b447d7af296411f7c50d4c078f3eac34 (diff)
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Return errors rather than mangle documents
Diffstat (limited to 'pdf')
-rw-r--r--pdf/pdf.go15
1 files changed, 12 insertions, 3 deletions
diff --git a/pdf/pdf.go b/pdf/pdf.go
index ded8747..d9e4098 100644
--- a/pdf/pdf.go
+++ b/pdf/pdf.go
@@ -1,5 +1,5 @@
//
-// Copyright (c) 2018, Přemysl Eric Janouch <p@janouch.name>
+// Copyright (c) 2018 - 2020, Přemysl Eric Janouch <p@janouch.name>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted.
@@ -32,6 +32,7 @@ import (
"crypto/ecdsa"
"crypto/rsa"
"crypto/x509"
+
"go.mozilla.org/pkcs7"
"golang.org/x/crypto/pkcs12"
)
@@ -1166,9 +1167,13 @@ func Sign(document []byte,
return nil, errors.New("invalid or unsupported page tree")
}
- // XXX: Assuming this won't be an indirectly referenced array.
annots := page.Dict["Annots"]
if annots.Kind != Array {
+ // TODO(p): Indirectly referenced arrays might not be
+ // that hard to support.
+ if annots.Kind != End {
+ return nil, errors.New("unexpected Annots")
+ }
annots = NewArray(nil)
}
annots.Array = append(annots.Array, NewReference(sigfieldN, 0))
@@ -1179,7 +1184,11 @@ func Sign(document []byte,
})
// 8.6.1 Interactive Form Dictionary
- // XXX: Assuming there are no forms already, overwriting everything.
+ if _, ok := root.Dict["AcroForm"]; ok {
+ return nil, errors.New("the document already contains forms, " +
+ "they would be overwritten")
+ }
+
root.Dict["AcroForm"] = NewDict(map[string]Object{
"Fields": NewArray([]Object{NewReference(sigfieldN, 0)}),
"SigFlags": NewNumeric(3 /* SignaturesExist | AppendOnly */),