Calculate sequence length properly.

Use correct length in old ASN.1 indefinite length sequence decoder
(only used by SSL_SESSION).

This bug was discovered by Hanno Böck using libfuzzer.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(cherry picked from commit 436dead2e2a157fa501a7538a77b6078391b477f)

diff --git a/crypto/asn1/asn1_lib.c b/crypto/asn1/asn1_lib.c
index 87526541035c6bf6a60b92a0b4aeeacb9c82ca43..80f5f2b014947472c75574a4e93e9f0bbf931ed8 100644 (file)
--- a/crypto/asn1/asn1_lib.c
+++ b/crypto/asn1/asn1_lib.c
@@ -328,7 +328,7 @@ int asn1_GetSequence(ASN1_const_CTX *c, long *length)
         return (0);
     }
     if (c->inf == (1 | V_ASN1_CONSTRUCTED))
-        c->slen = *length + *(c->pp) - c->p;
+        c->slen = *length;
     c->eos = 0;
     return (1);
 }