From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2210) id 956B4399203E; Wed, 28 Jul 2021 11:45:38 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 956B4399203E Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Ken Brown To: cygwin-cvs@sourceware.org Subject: [newlib-cygwin] Cygwin: getifaddrs: don't return a zero IPv4 address X-Act-Checkin: newlib-cygwin X-Git-Author: Ken Brown X-Git-Refname: refs/heads/master X-Git-Oldrev: c08ee10d6b9e9dc72c32387d42f3c55441657fdb X-Git-Newrev: b88d686a68d7bf2ff22d857a28d37fe4fdbafdf2 Message-Id: <20210728114538.956B4399203E@sourceware.org> Date: Wed, 28 Jul 2021 11:45:38 +0000 (GMT) X-BeenThere: cygwin-cvs@cygwin.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Cygwin core component git logs List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 Jul 2021 11:45:38 -0000 https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=b88d686a68d7bf2ff22d857a28d37fe4fdbafdf2 commit b88d686a68d7bf2ff22d857a28d37fe4fdbafdf2 Author: Ken Brown Date: Mon Jul 26 10:27:53 2021 -0400 Cygwin: getifaddrs: don't return a zero IPv4 address If an interface is disconnected, net.cc:get_ifs tries to fetch IPv4 addresses from the registry. If it fails, it currently returns pointers to sockaddr structs with zero address. Return a NULL pointer instead, to signal the caller of getifaddrs that we do not have a valid struct sockaddr. Partially addresses: https://cygwin.com/pipermail/cygwin/2021-July/248970.html Diff: --- winsup/cygwin/net.cc | 29 +++++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-) diff --git a/winsup/cygwin/net.cc b/winsup/cygwin/net.cc index 67dd7fc04..5bdc8709f 100644 --- a/winsup/cygwin/net.cc +++ b/winsup/cygwin/net.cc @@ -1595,6 +1595,7 @@ static void get_ipv4fromreg (struct ifall *ifp, const char *name, DWORD idx) { WCHAR regkey[256], *c; + bool got_addr = false, got_mask = false; c = wcpcpy (regkey, L"Tcpip\\Parameters\\Interfaces\\"); sys_mbstowcs (c, 220, name); @@ -1637,9 +1638,15 @@ get_ipv4fromreg (struct ifall *ifp, const char *name, DWORD idx) if (dhcp) { if (udipa.Buffer) - inet_uton (udipa.Buffer, &addr->sin_addr); + { + inet_uton (udipa.Buffer, &addr->sin_addr); + got_addr = true; + } if (udsub.Buffer) - inet_uton (udsub.Buffer, &mask->sin_addr); + { + inet_uton (udsub.Buffer, &mask->sin_addr); + got_mask = true; + } } else { @@ -1649,7 +1656,10 @@ get_ipv4fromreg (struct ifall *ifp, const char *name, DWORD idx) c += wcslen (c) + 1) ifs++; if (*c) - inet_uton (c, &addr->sin_addr); + { + inet_uton (c, &addr->sin_addr); + got_addr = true; + } } if (usub.Buffer) { @@ -1657,9 +1667,16 @@ get_ipv4fromreg (struct ifall *ifp, const char *name, DWORD idx) c += wcslen (c) + 1) ifs++; if (*c) - inet_uton (c, &mask->sin_addr); + { + inet_uton (c, &mask->sin_addr); + got_mask = true; + } } } + if (got_addr) + ifp->ifa_ifa.ifa_addr = (struct sockaddr *) addr; + if (got_mask) + ifp->ifa_ifa.ifa_netmask = (struct sockaddr *) mask; if (ifp->ifa_ifa.ifa_flags & IFF_BROADCAST) brdc->sin_addr.s_addr = (addr->sin_addr.s_addr & mask->sin_addr.s_addr) @@ -1800,13 +1817,13 @@ get_ifs (ULONG family) ifp->ifa_ifa.ifa_flags |= IFF_BROADCAST; /* Address */ ifp->ifa_addr.ss_family = AF_INET; - ifp->ifa_ifa.ifa_addr = (struct sockaddr *) &ifp->ifa_addr; + ifp->ifa_ifa.ifa_addr = NULL; /* Broadcast/Destination address */ ifp->ifa_brddstaddr.ss_family = AF_INET; ifp->ifa_ifa.ifa_dstaddr = NULL; /* Netmask */ ifp->ifa_netmask.ss_family = AF_INET; - ifp->ifa_ifa.ifa_netmask = (struct sockaddr *) &ifp->ifa_netmask; + ifp->ifa_ifa.ifa_netmask = NULL; /* Try to fetch real IPv4 address information from registry. */ get_ipv4fromreg (ifp, pap->AdapterName, idx); /* Hardware address */