From f1945c4daae65074cfca8f0ab5b97ac5a50c24a0 Mon Sep 17 00:00:00 2001
From: danim7
Date: Sat, 8 Apr 2017 02:09:28 +0200
Subject: Add -forcedecode

Force decode of encrypted files even if the integrity check fails, instead of
failing with an IO error. Warning messages are still printed to syslog if corrupted
files are encountered.
It can be useful to recover files from disks with bad sectors or other corrupted
media.

Closes https://github.com/rfjakob/gocryptfs/pull/102 .
---
 internal/fusefrontend/args.go | 2 ++
 internal/fusefrontend/file.go | 4 +++-
 internal/fusefrontend/fs.go   | 4 ++--
 3 files changed, 7 insertions(+), 3 deletions(-)

(limited to 'internal/fusefrontend')

diff --git a/internal/fusefrontend/args.go b/internal/fusefrontend/args.go
index ddfb9dc..5781db8 100644
--- a/internal/fusefrontend/args.go
+++ b/internal/fusefrontend/args.go
@@ -31,4 +31,6 @@ type Args struct {
 	HKDF bool
 	// Try to serialize read operations, "-serialize_reads"
 	SerializeReads bool
+	// Force decode even if integrity check fails (openSSL only)
+	ForceDecode bool
 }
diff --git a/internal/fusefrontend/file.go b/internal/fusefrontend/file.go
index 84ce058..4d75d64 100644
--- a/internal/fusefrontend/file.go
+++ b/internal/fusefrontend/file.go
@@ -202,7 +202,9 @@ func (f *file) doRead(off uint64, length uint64) ([]byte, fuse.Status) {
 	if err != nil {
 		curruptBlockNo := firstBlockNo + f.contentEnc.PlainOffToBlockNo(uint64(len(plaintext)))
 		tlog.Warn.Printf("ino%d: doRead: corrupt block #%d: %v", f.devIno.ino, curruptBlockNo, err)
-		return nil, fuse.EIO
+		if (f.fs.args.ForceDecode == false) {
+			return nil, fuse.EIO
+		}
 	}
 
 	// Crop down to the relevant part
diff --git a/internal/fusefrontend/fs.go b/internal/fusefrontend/fs.go
index 28c43b6..4aa4ffd 100644
--- a/internal/fusefrontend/fs.go
+++ b/internal/fusefrontend/fs.go
@@ -40,8 +40,8 @@ var _ pathfs.FileSystem = &FS{} // Verify that interface is implemented.
 
 // NewFS returns a new encrypted FUSE overlay filesystem.
 func NewFS(args Args) *FS {
-	cryptoCore := cryptocore.New(args.Masterkey, args.CryptoBackend, contentenc.DefaultIVBits, args.HKDF)
-	contentEnc := contentenc.New(cryptoCore, contentenc.DefaultBS)
+	cryptoCore := cryptocore.New(args.Masterkey, args.CryptoBackend, contentenc.DefaultIVBits, args.HKDF, args.ForceDecode)
+	contentEnc := contentenc.New(cryptoCore, contentenc.DefaultBS, args.ForceDecode)
 	nameTransform := nametransform.New(cryptoCore.EMECipher, args.LongNames, args.Raw64)
 
 	if args.SerializeReads {
-- 
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