From 9f66764e308e9c645b3fb2d1cfbb7fb207eb5de1 Mon Sep 17 00:00:00 2001 From: Cyrill Gorcunov Date: Wed, 2 Nov 2016 16:14:55 +0300 Subject: [PATCH] libnetlink: Add test for error code returned from netlink reply In case if some diag module is not present in the system, say the kernel is not modern enough, we simply skip the error code reported. Instead we should check for data length in NLMSG_DONE and process unsupported case. Signed-off-by: Cyrill Gorcunov --- lib/libnetlink.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/lib/libnetlink.c b/lib/libnetlink.c index 21a763632..a5db168e5 100644 --- a/lib/libnetlink.c +++ b/lib/libnetlink.c @@ -319,6 +319,22 @@ int rtnl_dump_filter_l(struct rtnl_handle *rth, dump_intr = 1; if (h->nlmsg_type == NLMSG_DONE) { + if (rth->proto == NETLINK_SOCK_DIAG) { + if (h->nlmsg_len < NLMSG_LENGTH(sizeof(int))) { + fprintf(stderr, "DONE truncated\n"); + return -1; + } else { + int len = *(int *)NLMSG_DATA(h); + if (len < 0) { + errno = -len; + if (errno == ENOENT || + errno == EOPNOTSUPP) + return -1; + perror("RTNETLINK answers"); + return len; + } + } + } found_done = 1; break; /* process next filter */ } -- 2.47.2