4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>
[ Upstream commit 3f0ab59e6537c6a8f9e1b355b48f9c05a76e8563 ]
This expands the validation introduced in commit 07bf7908950a ("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: syzbot+cc39f136925517aed571@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Antony Antony <antony.antony@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/xfrm/xfrm_user.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 5892ff68d1680..8146ef538ab3d 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -148,6 +148,7 @@ static int verify_newsa_info(struct xfrm_usersa_info *p,
struct nlattr **attrs)
{
int err;
+ u16 family = p->sel.family;
err = -EINVAL;
switch (p->family) {
@@ -166,7 +167,10 @@ 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;
--
2.43.0
