From d5bdae351ad5f820033f6c174272dfe6c4b85bf0 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Fri, 10 Feb 2023 01:12:01 +0100 Subject: [PATCH] libbpf: Fix alen calculation in libbpf_nla_dump_errormsg() [ Upstream commit 17bcd27a08a21397698edf143084d7c87ce17946 ] The code assumes that everything that comes after nlmsgerr are nlattrs. When calculating their size, it does not account for the initial nlmsghdr. This may lead to accessing uninitialized memory. Fixes: bbf48c18ee0c ("libbpf: add error reporting in XDP") Signed-off-by: Ilya Leoshkevich Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20230210001210.395194-8-iii@linux.ibm.com Signed-off-by: Sasha Levin --- tools/lib/bpf/nlattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/lib/bpf/nlattr.c b/tools/lib/bpf/nlattr.c index 4719434278b2..ac979b429055 100644 --- a/tools/lib/bpf/nlattr.c +++ b/tools/lib/bpf/nlattr.c @@ -170,7 +170,7 @@ int nla_dump_errormsg(struct nlmsghdr *nlh) hlen += nlmsg_len(&err->msg); attr = (struct nlattr *) ((void *) err + hlen); - alen = nlh->nlmsg_len - hlen; + alen = (void *)nlh + nlh->nlmsg_len - (void *)attr; if (nla_parse(tb, NLMSGERR_ATTR_MAX, attr, alen, extack_policy) != 0) { fprintf(stderr,