From 957e971ed90cacdfdfc13c8a6e0def199735d9cb Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Mon, 2 Nov 2020 16:14:46 +0000 Subject: [PATCH] UPSTREAM: xfrm/compat: memset(0) 64-bit padding at right place 32-bit messages translated by xfrm_compat can have attributes attached. For all, but XFRMA_SA, XFRMA_POLICY the size of payload is the same in 32-bit UABI and 64-bit UABI. For XFRMA_SA (struct xfrm_usersa_info) and XFRMA_POLICY (struct xfrm_userpolicy_info) it's only tail-padding that is present in 64-bit payload, but not in 32-bit. The proper size for destination nlattr is already calculated by xfrm_user_rcv_calculate_len64() and allocated with kvmalloc(). xfrm_attr_cpy32() copies 32-bit copy_len into 64-bit attribute translated payload, zero-filling possible padding for SA/POLICY. Due to a typo, *pos already has 64-bit payload size, in a result next memset(0) is called on the memory after the translated attribute, not on the tail-padding of it. Fixes: 5106f4a8acff ("xfrm/compat: Add 32=>64-bit messages translator") Reported-by: syzbot+c43831072e7df506a646@syzkaller.appspotmail.com Signed-off-by: Dmitry Safonov Signed-off-by: Steffen Klassert (cherry picked from commit d1949d045fd67eab8a32a579a8c1ab1681330854) Bug: 187129171 Signed-off-by: Connor O'Brien Change-Id: Ic81e020da215c3fd093a76dc687abf5f86827283 --- net/xfrm/xfrm_compat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/xfrm/xfrm_compat.c b/net/xfrm/xfrm_compat.c index 0e7476e05f3a..48cbece14430 100644 --- a/net/xfrm/xfrm_compat.c +++ b/net/xfrm/xfrm_compat.c @@ -387,7 +387,7 @@ static int xfrm_attr_cpy32(void *dst, size_t *pos, const struct nlattr *src, memcpy(nla, src, nla_attr_size(copy_len)); nla->nla_len = nla_attr_size(payload); - *pos += nla_attr_size(payload); + *pos += nla_attr_size(copy_len); nlmsg->nlmsg_len += nla->nla_len; memset(dst + *pos, 0, payload - copy_len);