[PATCH] virSocketAddrPrefixToNetmask: Prevent undefined behaviour on bitshifts on signed integer

From: Peter Krempa <pkrempa(a)redhat.com&gt; Shifting bits into the sign bit is undefined behaviour in C although both gcc and clang handle it as expected. Since the value is used as unsigned convert it to unsigned int. For code readability use 'if' statement instead of a ternary. Closes: https://gitlab.com/libvirt/libvirt/-/issues/785 Signed-off-by: Peter Krempa <pkrempa(a)redhat.com&gt; --- src/util/virsocketaddr.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/src/util/virsocketaddr.c b/src/util/virsocketaddr.c index a2e6701670..f53768878e 100644 --- a/src/util/virsocketaddr.c +++ b/src/util/virsocketaddr.c @@ -1144,12 +1144,14 @@ virSocketAddrPrefixToNetmask(unsigned int prefix, netmask->data.stor.ss_family = AF_UNSPEC; /* assume failure */ if (family == AF_INET) { - int ip; + unsigned int ip = 0; if (prefix > 32) return -1; - ip = prefix ? ~((1 << (32 - prefix)) - 1) : 0; + if (prefix > 0) + ip = ~((1U << (32 - prefix)) - 1); + netmask->data.inet4.sin_addr.s_addr = htonl(ip); netmask->data.stor.ss_family = AF_INET; netmask->len = sizeof(struct sockaddr_in); -- 2.49.0