From 4da245c69d7994efec75e1deaef56a03020d39db Mon Sep 17 00:00:00 2001 From: Jakob Unterwurzacher Date: Sun, 1 Oct 2017 13:50:25 +0200 Subject: fusefrontend_reverse: fix 176-byte names A file with a name of exactly 176 bytes length caused this error: ls: cannot access ./tmp/dsg/sXSGJLTuZuW1FarwIkJs0w/b6mGjdxIRpaeanTo0rbh0A/QjMRrQZC_4WLhmHI1UOBcA/gocryptfs.longname.QV-UipdDXeUVdl05WruoEzBNPrQCfpu6OzJL0_QnDKY: No such file or directory ls: cannot access ./tmp/dsg/sXSGJLTuZuW1FarwIkJs0w/b6mGjdxIRpaeanTo0rbh0A/QjMRrQZC_4WLhmHI1UOBcA/gocryptfs.longname.QV-UipdDXeUVdl05WruoEzBNPrQCfpu6OzJL0_QnDKY.name: No such file or directory -????????? ? ? ? ? ? gocryptfs.longname.QV-UipdDXeUVdl05WruoEzBNPrQCfpu6OzJL0_QnDKY -????????? ? ? ? ? ? gocryptfs.longname.QV-UipdDXeUVdl05WruoEzBNPrQCfpu6OzJL0_QnDKY.name Root cause was a wrong shortNameMax constant that failed to account for the obligatory padding byte. Fix the constant and also expand the TestLongnameStat test case to test ALL file name lengths from 1-255 bytes. Fixes https://github.com/rfjakob/gocryptfs/issues/143 . --- internal/fusefrontend_reverse/reverse_longnames.go | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'internal/fusefrontend_reverse') diff --git a/internal/fusefrontend_reverse/reverse_longnames.go b/internal/fusefrontend_reverse/reverse_longnames.go index ec164f1..3bfe3af 100644 --- a/internal/fusefrontend_reverse/reverse_longnames.go +++ b/internal/fusefrontend_reverse/reverse_longnames.go @@ -17,7 +17,14 @@ import ( ) const ( - shortNameMax = 176 + // File names are padded to 16-byte multiples, encrypted and + // base64-encoded. We can encode at most 176 bytes to stay below the 255 + // bytes limit: + // * base64(176 bytes) = 235 bytes + // * base64(192 bytes) = 256 bytes (over 255!) + // But the PKCS#7 padding is at least one byte. This means we can only use + // 175 bytes for the file name. + shortNameMax = 175 ) var longnameParentCache map[string]string @@ -57,6 +64,7 @@ func (rfs *ReverseFS) findLongnameParent(dir string, dirIV []byte, longname stri } dirEntries, err := dirfd.Readdirnames(-1) if err != nil { + tlog.Warn.Printf("findLongnameParent: Readdirnames failed: %v\n", err) return "", err } longnameCacheLock.Lock() @@ -78,7 +86,6 @@ func (rfs *ReverseFS) findLongnameParent(dir string, dirIV []byte, longname stri if hit == "" { return "", syscall.ENOENT } - return hit, nil } -- cgit v1.2.3