diff options
| author | Jakob Unterwurzacher | 2017-03-06 23:50:17 +0100 |
|---|---|---|
| committer | Jakob Unterwurzacher | 2017-03-07 20:56:50 +0100 |
| commit | 2f953fdb95f44078895fec9bc4d542cd371126be (patch) | |
| tree | da1a2cf8fa8f438f27193ce09b8ef2017a54bbb8 /internal/contentenc/offsets.go | |
| parent | efc88346bec52675d5243f988aa3386d617ee1c4 (diff) | |
contentenc: catch integer underflow in file size calculation
If you truncate a ciphertext file to 19 bytes, you could get the
impression that the plaintext is 18446744073709551585 bytes long,
as reported by "ls -l".
Fix it by clamping the value to zero.
Diffstat (limited to 'internal/contentenc/offsets.go')
| -rw-r--r-- | internal/contentenc/offsets.go | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/internal/contentenc/offsets.go b/internal/contentenc/offsets.go index 97d7116..5ad0da4 100644 --- a/internal/contentenc/offsets.go +++ b/internal/contentenc/offsets.go @@ -54,6 +54,11 @@ func (be *ContentEnc) CipherSizeToPlainSize(cipherSize uint64) uint64 { overhead := be.BlockOverhead()*blockCount + HeaderLen + if overhead > cipherSize { + tlog.Warn.Printf("cipherSize %d < overhead %d: corrupt file\n", cipherSize, overhead) + return 0 + } + return cipherSize - overhead } |