Commit 3f0ab59e authored by Sabrina Dubroca's avatar Sabrina Dubroca Committed by Steffen Klassert
Browse files

xfrm: validate new SA's prefixlen using SA family when sel.family is unset 



This expands the validation introduced in commit 07bf7908 ("xfrm:
Validate address prefix lengths in the xfrm selector.")

syzbot created an SA with
    usersa.sel.family = AF_UNSPEC
    usersa.sel.prefixlen_s = 128
    usersa.family = AF_INET

Because of the AF_UNSPEC selector, verify_newsa_info doesn't put
limits on prefixlen_{s,d}. But then copy_from_user_state sets
x->sel.family to usersa.family (AF_INET). Do the same conversion in
verify_newsa_info before validating prefixlen_{s,d}, since that's how
prefixlen is going to be used later on.

Reported-by: default avatar <syzbot+cc39f136925517aed571@syzkaller.appspotmail.com>
Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: default avatarSabrina Dubroca <sd@queasysnail.net>
Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
parent 645546a0

net/xfrm/xfrm_user.c

+5 −1
Original line number Diff line number Diff line
@@ -201,6 +201,7 @@ static int verify_newsa_info(struct xfrm_usersa_info *p, 
{

	int err;

	u8 sa_dir = attrs[XFRMA_SA_DIR] ? nla_get_u8(attrs[XFRMA_SA_DIR]) : 0;

	u16 family = p->sel.family;



	err = -EINVAL;

	switch (p->family) {
@@ -221,7 +222,10 @@ static int verify_newsa_info(struct xfrm_usersa_info *p, 
		goto out;

	}



	switch (p->sel.family) {

	if (!family && !(p->flags & XFRM_STATE_AF_UNSPEC))

		family = p->family;



	switch (family) {

	case AF_UNSPEC:

		break;