From: Guy Harris <guy@alum.mit.edu>
Date: Fri, 29 Jul 2016 07:31:10 +0000 (-0700)
Subject: Squelch warnings for negating an unsigned value.
X-Git-Tag: libpcap-1.8.1~119
X-Git-Url: https://git.tcpdump.org/libpcap/commitdiff_plain/2fc98f9a355a97a69f8701cd7822ed5d6537c579

Squelch warnings for negating an unsigned value.
---

diff --git a/bpf/net/bpf_filter.c b/bpf/net/bpf_filter.c
index 1ce22f4c..01a1b64e 100644
--- a/bpf/net/bpf_filter.c
+++ b/bpf/net/bpf_filter.c
@@ -579,7 +579,12 @@ bpf_filter_with_aux_data(pc, p, wirelen, buflen, aux_data)
 			continue;
 
 		case BPF_ALU|BPF_NEG:
-			A = -A;
+			/*
+			 * Most BPF arithmetic is unsigned, but negation
+			 * can't be unsigned; throw some casts to
+			 * specify what we're trying to do.
+			 */
+			A = (u_int32)(-(int32)A);
 			continue;
 
 		case BPF_MISC|BPF_TAX: