[glibc] Use unsigned constants for ICMP6 filters [BZ #22489]

[DJ Delorie <dj@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=c2d0411488c68a07cc22a5dd76fa37e952d2a66b

commit c2d0411488c68a07cc22a5dd76fa37e952d2a66b
Author: Sergey <s.korolev@ndmsystems.com>
Date:   Fri Apr 24 17:18:41 2020 -0400

    Use unsigned constants for ICMP6 filters [BZ #22489]
    
    The core problem here is that the filter array elements are unsigned
    but the computed constants are signed.  This both causes a
    signededness conversion at the &= step and may cause undefined
    behavior if the MSB is being modified.  This patch uses unsigned
    constants to avoid both cases. - DJ

Diff:
---
 inet/netinet/icmp6.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/inet/netinet/icmp6.h b/inet/netinet/icmp6.h
index a75722887d..5fed0fbca1 100644
--- a/inet/netinet/icmp6.h
+++ b/inet/netinet/icmp6.h
@@ -85,16 +85,16 @@ struct icmp6_hdr
 #define ICMP6_PARAMPROB_OPTION        2 /* unrecognized IPv6 option */
 
 #define ICMP6_FILTER_WILLPASS(type, filterp) \
-	((((filterp)->icmp6_filt[(type) >> 5]) & (1 << ((type) & 31))) == 0)
+	((((filterp)->icmp6_filt[(type) >> 5]) & (1U << ((type) & 31))) == 0)
 
 #define ICMP6_FILTER_WILLBLOCK(type, filterp) \
-	((((filterp)->icmp6_filt[(type) >> 5]) & (1 << ((type) & 31))) != 0)
+	((((filterp)->icmp6_filt[(type) >> 5]) & (1U << ((type) & 31))) != 0)
 
 #define ICMP6_FILTER_SETPASS(type, filterp) \
-	((((filterp)->icmp6_filt[(type) >> 5]) &= ~(1 << ((type) & 31))))
+	((((filterp)->icmp6_filt[(type) >> 5]) &= ~(1U << ((type) & 31))))
 
 #define ICMP6_FILTER_SETBLOCK(type, filterp) \
-	((((filterp)->icmp6_filt[(type) >> 5]) |=  (1 << ((type) & 31))))
+	((((filterp)->icmp6_filt[(type) >> 5]) |=  (1U << ((type) & 31))))
 
 #define ICMP6_FILTER_SETPASSALL(filterp) \
 	memset (filterp, 0, sizeof (struct icmp6_filter));