From 3aaf8bda00988f21f4a83affff47bafc74a745a0 Mon Sep 17 00:00:00 2001 From: Daniel Alvarez Date: Fri, 29 Jun 2018 17:23:13 +0200 Subject: [PATCH] getifaddrs: Don't return ifa entries with NULL names [BZ #21812] A lookup operation in map_newlink could turn into an insert because of holes in the interface part of the map. This leads to incorrectly set the name of the interface to NULL when the interface is not present for the address being processed (most likely because the interface was added between the RTM_GETLINK and RTM_GETADDR calls to the kernel). When such changes are detected by the kernel, it'll mark the dump as "inconsistent" by setting NLM_F_DUMP_INTR flag on the next netlink message. This patch checks this condition and retries the whole operation. Hopes are that next time the interface corresponding to the address entry is present in the list and correct name is returned. (cherry picked from commit c1f86a33ca32e26a9d6e29fc961e5ecb5e2e5eb4) --- ChangeLog | 7 +++++++ NEWS | 1 + sysdeps/unix/sysv/linux/ifaddrs.c | 8 ++++++++ 3 files changed, 16 insertions(+) diff --git a/ChangeLog b/ChangeLog index 0981fcaf716..c502aceddb3 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,10 @@ +2018-06-29 Daniel Alvarez + Jakub Sitnicki + + [BZ #21812] + * sysdeps/unix/sysv/linux/ifaddrs.c (getifaddrs_internal): Retry + on NLM_F_DUMP_INTR. + 2018-06-28 Florian Weimer [BZ #23349] diff --git a/NEWS b/NEWS index c34c6393eec..db43d87ee01 100644 --- a/NEWS +++ b/NEWS @@ -93,6 +93,7 @@ The following bugs are resolved with this release: [21265] x86-64: Use fxsave/xsave/xsavec in _dl_runtime_resolve [21269] i386 sigaction sa_restorer handling is wrong [21780] posix: Set p{read,write}v2 to return ENOTSUP + [21812] getifaddrs: Don't return ifa entries with NULL names [21871] x86-64: Use _dl_runtime_resolve_opt only with AVX512F [21885] getaddrinfo: Release resolver context on error in gethosts [21915] getaddrinfo: incorrect result handling for NSS service modules diff --git a/sysdeps/unix/sysv/linux/ifaddrs.c b/sysdeps/unix/sysv/linux/ifaddrs.c index 3bc99028639..4f75401850f 100644 --- a/sysdeps/unix/sysv/linux/ifaddrs.c +++ b/sysdeps/unix/sysv/linux/ifaddrs.c @@ -371,6 +371,14 @@ getifaddrs_internal (struct ifaddrs **ifap) if ((pid_t) nlh->nlmsg_pid != nh.pid || nlh->nlmsg_seq != nlp->seq) continue; + /* If the dump got interrupted, we can't rely on the results + so try again. */ + if (nlh->nlmsg_flags & NLM_F_DUMP_INTR) + { + result = -EAGAIN; + goto exit_free; + } + if (nlh->nlmsg_type == NLMSG_DONE) break; /* ok */ -- 2.47.2