From 4476d16b033341be5b0a884425cff19b0358ea25 Mon Sep 17 00:00:00 2001 From: Daniel Alvarez Date: Fri, 29 Jun 2018 17:23:52 +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 371ae547c4d..40383d9ee3a 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 f6e33734c8e..501d97bc7af 100644 --- a/NEWS +++ b/NEWS @@ -45,6 +45,7 @@ The following bugs are resolved with this release: [18018] Additional $ORIGIN handling issues (CVE-2011-0536) [20419] files with large allocated notes crash in open_verify [21269] i386 sigaction sa_restorer handling is wrong + [21812] getifaddrs: Don't return ifa entries with NULL names [21942] _dl_dst_substitute incorrectly handles $ORIGIN: with AT_SECURE=1 [22342] NSCD not properly caching netgroup [22638] sparc: static binaries are broken if glibc is built by gcc diff --git a/sysdeps/unix/sysv/linux/ifaddrs.c b/sysdeps/unix/sysv/linux/ifaddrs.c index 32381f54e4e..ac0e1e5738f 100644 --- a/sysdeps/unix/sysv/linux/ifaddrs.c +++ b/sysdeps/unix/sysv/linux/ifaddrs.c @@ -370,6 +370,14 @@ 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