gcc 10.1.0 on Debian sid has a bug where the bounds checking gets confused beteen two branches: In file included from /usr/include/string.h:495, from ../../src/internal.h:28, from ../../src/util/virsocket.h:21, from ../../src/util/virsocketaddr.h:21, from ../../src/util/virnetdevip.h:21, from ../../src/util/virnetdevip.c:21: In function 'memcpy', inlined from 'virNetDevGetifaddrsAddress' at ../../src/util/virnetdevip.c:914:13, inlined from 'virNetDevIPAddrGet' at ../../src/util/virnetdevip.c:962:16: /usr/include/arm-linux-gnueabihf/bits/string_fortified.h:34:10: error: '__builtin_memcpy' offset [16, 27] from the object at 'addr' is out of the bounds of referenced subobject 'inet4' with type 'struct sockaddr_in' at offset 0 [-Werror=array-bounds] 34 | return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from ../../src/util/virnetdevip.h:21, from ../../src/util/virnetdevip.c:21: ../../src/util/virnetdevip.c: In function 'virNetDevIPAddrGet': ../../src/util/virsocketaddr.h:29:28: note: subobject 'inet4' declared here 29 | struct sockaddr_in inet4; | ^~~~~ cc1: all warnings being treated as errors Note the source location is pointing to the "inet6" / AF_INET6 branch of the "if", but is complaining about bounds of the "inet4" field. Changing the code into a switch() is sufficient to avoid triggering the bug and is arguably better code too. Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; --- src/util/virnetdevip.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/src/util/virnetdevip.c b/src/util/virnetdevip.c index ba9e567e5a..8b85c7beca 100644 --- a/src/util/virnetdevip.c +++ b/src/util/virnetdevip.c @@ -897,26 +897,25 @@ virNetDevGetifaddrsAddress(const char *ifname, } for (ifa = ifap; ifa; ifa = ifa->ifa_next) { - int family; - if (STRNEQ_NULLABLE(ifa->ifa_name, ifname)) continue; if (!ifa->ifa_addr) continue; - family = ifa->ifa_addr->sa_family; - - if (family != AF_INET6 && family != AF_INET) - continue; - if (family == AF_INET6) { + switch (ifa->ifa_addr->sa_family) { + case AF_INET6: addr->len = sizeof(addr->data.inet6); memcpy(&addr->data.inet6, ifa->ifa_addr, addr->len); - } else { + break; + case AF_INET: addr->len = sizeof(addr->data.inet4); memcpy(&addr->data.inet4, ifa->ifa_addr, addr->len); + break; + default: + continue; } - addr->data.stor.ss_family = family; + addr->data.stor.ss_family = ifa->ifa_addr->sa_family; ret = 0; goto cleanup; } -- 2.24.1