commit a9f7aa12f71d9b3956c76467b51cdec52f2bde73
from: Martijn van Duren <martijn@openbsd.org>
date: Thu Mar 24 13:50:31 2022 UTC

Make sure that l-tag is smaller than body

commit - cc08de5188216a473aabf44c48c9fb7fd2a41b62
commit + a9f7aa12f71d9b3956c76467b51cdec52f2bde73
blob - ba45b75d3c25b60268122aea78b84f68fd7800d1
blob + c38ca6ba2c1a95a3d5704989d6196790d0203016
--- main.c
+++ main.c
@@ -1464,6 +1464,11 @@ dkim_body_verify(struct signature *sig)
 			return;
 		}
 	}
+	if (sig->l > 0) {
+		dkim_signature_state(sig, DKIM_PERMERROR,
+		    "l tag larger than body");
+		return;
+	}
 
 	if (EVP_DigestFinal_ex(sig->bhctx, digest, &digestsz) == 0) {
 		dkim_errx(sig->header->msg, "Can't finalize hash context");