crypto/rsa: improve error message for keys too short for PSS

Fixes #23736

Change-Id: I850d91a512394c4292927d51c475064bfa4e3053
Reviewed-on: https://go-review.googlesource.com/92815
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

diff --git a/src/crypto/rsa/pss.go b/src/crypto/rsa/pss.go
index 75558a92cf1918f3e49e6c23f5e03c27d167321a..3ff0c2f4d0076912c0144fd5e0befaccd9abf7ac 100644 (file)
--- a/src/crypto/rsa/pss.go
+++ b/src/crypto/rsa/pss.go
@@ -36,7 +36,7 @@ func emsaPSSEncode(mHash []byte, emBits int, salt []byte, hash hash.Hash) ([]byt
        // 3.  If emLen < hLen + sLen + 2, output "encoding error" and stop.
 
        if emLen < hLen+sLen+2 {
-               return nil, errors.New("crypto/rsa: encoding error")
+               return nil, errors.New("crypto/rsa: key size too small for PSS signature")
        }
 
        em := make([]byte, emLen)