From 115e9870358ba08ec8921ff8f459d379522f0368 Mon Sep 17 00:00:00 2001 From: Alexander Mikhalitsyn Date: Sun, 11 Jul 2021 14:15:46 +0300 Subject: [PATCH] libnetlink: check error handler is present before a call Fix nullptr dereference of errhndlr from rtnl_dump_filter_arg struct in rtnl_dump_done and rtnl_dump_error functions. Fixes: 459ce6e3d792 ("ip route: ignore ENOENT during save if RT_TABLE_MAIN is being dumped") Cc: Stephen Hemminger Cc: Roi Dayan Cc: Alexander Mikhalitsyn Reported-by: Roi Dayan Signed-off-by: Alexander Mikhalitsyn Reviewed-by: Roi Dayan Signed-off-by: Stephen Hemminger --- lib/libnetlink.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/lib/libnetlink.c b/lib/libnetlink.c index 5f062c7d..6836c21c 100644 --- a/lib/libnetlink.c +++ b/lib/libnetlink.c @@ -731,7 +731,7 @@ static int rtnl_dump_done(struct nlmsghdr *h, if (len < 0) { errno = -len; - if (a->errhndlr(h, a->arg2) & RTNL_SUPPRESS_NLMSG_DONE_NLERR) + if (a->errhndlr && (a->errhndlr(h, a->arg2) & RTNL_SUPPRESS_NLMSG_DONE_NLERR)) return 0; /* check for any messages returned from kernel */ @@ -774,7 +774,7 @@ static int rtnl_dump_error(const struct rtnl_handle *rth, errno == EOPNOTSUPP)) return -1; - if (a->errhndlr(h, a->arg2) & RTNL_SUPPRESS_NLMSG_ERROR_NLERR) + if (a->errhndlr && (a->errhndlr(h, a->arg2) & RTNL_SUPPRESS_NLMSG_ERROR_NLERR)) return 0; if (!(rth->flags & RTNL_HANDLE_F_SUPPRESS_NLERR))