From 4232ecc9f617f380200e8baefefa53748a2c26ea Mon Sep 17 00:00:00 2001 From: Yasuaki Torimaru Date: Mon, 13 Apr 2026 18:12:15 -0400 Subject: [PATCH] xfrm: clear trailing padding in build_polexpire() [ Upstream commit 71a98248c63c535eaa4d4c22f099b68d902006d0 ] build_expire() clears the trailing padding bytes of struct xfrm_user_expire after setting the hard field via memset_after(), but the analogous function build_polexpire() does not do this for struct xfrm_user_polexpire. The padding bytes after the __u8 hard field are left uninitialized from the heap allocation, and are then sent to userspace via netlink multicast to XFRMNLGRP_EXPIRE listeners, leaking kernel heap memory contents. Add the missing memset_after() call, matching build_expire(). Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Yasuaki Torimaru Reviewed-by: Simon Horman Reviewed-by: Breno Leitao Signed-off-by: Steffen Klassert [ replaced `memset_after()` macro with equivalent manual `memset()` call ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ulrich Hecht --- net/xfrm/xfrm_user.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index f7226e00b98a..8acd4392fb06 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -3098,6 +3098,8 @@ static int build_polexpire(struct sk_buff *skb, struct xfrm_policy *xp, return err; } upe->hard = !!hard; + /* clear the padding bytes */ + memset(&upe->hard + 1, 0, sizeof(*upe) - offsetofend(typeof(*upe), hard)); nlmsg_end(skb, nlh); return 0;