diff options
author | Jakob Unterwurzacher | 2017-02-12 15:35:50 +0100 |
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committer | Jakob Unterwurzacher | 2017-02-12 17:59:09 +0100 |
commit | 8adfbf2dc34560df7436c89b59a9749d2dd3b78e (patch) | |
tree | b1f7a10f654a6c2e35fdc60f53770d83bff1267c /internal/readpassword | |
parent | 2dd90ac19ce97544c412d90a24df0f68e66311db (diff) |
Check for trailing garbage after the password
From the comment:
// CheckTrailingGarbage tries to read one byte from stdin and exits with a
// fatal error if the read returns any data.
// This is meant to be called after reading the password, when there is no more
// data expected. This helps to catch problems with third-party tools that
// interface with gocryptfs.
Diffstat (limited to 'internal/readpassword')
-rw-r--r-- | internal/readpassword/read.go | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/internal/readpassword/read.go b/internal/readpassword/read.go index 49cf8ef..fe9be45 100644 --- a/internal/readpassword/read.go +++ b/internal/readpassword/read.go @@ -7,6 +7,8 @@ import ( "os" "os/exec" "strings" + "sync" + "time" "golang.org/x/crypto/ssh/terminal" @@ -141,3 +143,33 @@ func readLineUnbuffered(r io.Reader) (l string) { l = l + string(b) } } + +// CheckTrailingGarbage tries to read one byte from stdin and exits with a +// fatal error if the read returns any data. +// This is meant to be called after reading the password, when there is no more +// data expected. This helps to catch problems with third-party tools that +// interface with gocryptfs. +// +// This is tested via TestInitTrailingGarbage() in tests/cli/cli_test.go. +func CheckTrailingGarbage() { + if terminal.IsTerminal(int(os.Stdin.Fd())) { + // Be lenient when interacting with a human. + return + } + var wg sync.WaitGroup + wg.Add(1) + go func() { + b := make([]byte, 1) + wg.Done() + n, _ := os.Stdin.Read(b) + if n > 0 { + tlog.Fatal.Printf("Received trailing garbage after the password") + os.Exit(exitCode) + } + }() + // Wait for the goroutine to start up plus one millisecond for the read to + // return. If there is data available, this SHOULD be plenty of time to + // read one byte. However, I don't see a way to be sure. + wg.Wait() + time.Sleep(1 * time.Millisecond) +} |