4.19-stable review patch. If anyone has any objections, please let me know.
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From: Sabrina Dubroca sd@queasysnail.net
[ 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@syzkaller.appspotmail.com Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Sabrina Dubroca sd@queasysnail.net Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Antony Antony antony.antony@secunet.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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;