From: Yochai Eisenrich Date: Tue, 24 Mar 2026 22:49:25 +0000 (+0200) Subject: net: ipv6: ndisc: fix ndisc_ra_useropt to initialize nduseropt_padX fields to zero... X-Git-Tag: v7.0-rc7~28^2~43 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ae05340ccaa9d347fe85415609e075545bec589f;p=thirdparty%2Fkernel%2Flinux.git net: ipv6: ndisc: fix ndisc_ra_useropt to initialize nduseropt_padX fields to zero to prevent an info-leak When processing Router Advertisements with user options the kernel builds an RTM_NEWNDUSEROPT netlink message. The nduseroptmsg struct has three padding fields that are never zeroed and can leak kernel data The fix is simple, just zeroes the padding fields. Fixes: 31910575a9de ("[IPv6]: Export userland ND options through netlink (RDNSS support)") Signed-off-by: Yochai Eisenrich Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260324224925.2437775-1-echelonh@gmail.com Signed-off-by: Jakub Kicinski --- diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index f6a5d8c73af9..186e60c79214 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1209,6 +1209,9 @@ static void ndisc_ra_useropt(struct sk_buff *ra, struct nd_opt_hdr *opt) ndmsg->nduseropt_icmp_type = icmp6h->icmp6_type; ndmsg->nduseropt_icmp_code = icmp6h->icmp6_code; ndmsg->nduseropt_opts_len = opt->nd_opt_len << 3; + ndmsg->nduseropt_pad1 = 0; + ndmsg->nduseropt_pad2 = 0; + ndmsg->nduseropt_pad3 = 0; memcpy(ndmsg + 1, opt, opt->nd_opt_len << 3);