Avoid undefined behaviour that results from negating a signed long with

minimum value.

Fixes oss-fuzz #14354.

ok beck@ bcook@ tb@

1 files changed, 2 insertions, 2 deletions

diff --git a/src/lib/libcrypto/asn1/x_long.c b/src/lib/libcrypto/asn1/x_long.c
index 8b11f14217..ff72338cc0 100644
--- a/src/lib/libcrypto/asn1/x_long.c
+++ b/src/lib/libcrypto/asn1/x_long.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: x_long.c,v 1.15 2019/04/15 17:46:02 jsing Exp $ */
+/* $OpenBSD: x_long.c,v 1.16 2019/04/20 11:13:15 jsing Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2000.
  */
@@ -142,7 +142,7 @@ long_i2c(ASN1_VALUE **pval, unsigned char *cont, int *putype,
          * octet is set.
          */
         if (ltmp < 0)
-                utmp = -ltmp - 1;
+                utmp = -(ltmp + 1);
         else
                 utmp = ltmp;
         clen = BN_num_bits_word(utmp);