From c5d18e984a313adf5a1a4ae69e0b1d93cf410229 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Tue, 22 Apr 2008 00:46:42 -0700 Subject: [PATCH] [IPSEC]: Fix catch-22 with algorithm IDs above 31 As it stands it's impossible to use any authentication algorithms with an ID above 31 portably. It just happens to work on x86 but fails miserably on ppc64. The reason is that we're using a bit mask to check the algorithm ID but the mask is only 32 bits wide. After looking at how this is used in the field, I have concluded that in the long term we should phase out state matching by IDs because this is made superfluous by the reqid feature. For current applications, the best solution IMHO is to allow all algorithms when the bit masks are all ~0. The following patch does exactly that. This bug was identified by IBM when testing on the ppc64 platform using the NULL authentication algorithm which has an ID of 251. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- include/net/xfrm.h | 3 +++ net/key/af_key.c | 2 +- net/xfrm/xfrm_policy.c | 2 +- net/xfrm/xfrm_user.c | 2 ++ 4 files changed, 7 insertions(+), 2 deletions(-) diff --git a/include/net/xfrm.h b/include/net/xfrm.h index b56b6a10fe5e..baa9f372cfd1 100644 --- a/include/net/xfrm.h +++ b/include/net/xfrm.h @@ -436,6 +436,9 @@ struct xfrm_tmpl /* May skip this transfomration if no SA is found */ __u8 optional; +/* Skip aalgos/ealgos/calgos checks. */ + __u8 allalgs; + /* Bit mask of algos allowed for acquisition */ __u32 aalgos; __u32 ealgos; diff --git a/net/key/af_key.c b/net/key/af_key.c index 1fb0fe42a72e..81a8e5297ad1 100644 --- a/net/key/af_key.c +++ b/net/key/af_key.c @@ -1907,7 +1907,7 @@ parse_ipsecrequest(struct xfrm_policy *xp, struct sadb_x_ipsecrequest *rq) t->encap_family = xp->family; /* No way to set this via kame pfkey */ - t->aalgos = t->ealgos = t->calgos = ~0; + t->allalgs = 1; xp->xfrm_nr++; return 0; } diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index ab4d0e598a2c..e0c0390613c0 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -1819,7 +1819,7 @@ xfrm_state_ok(struct xfrm_tmpl *tmpl, struct xfrm_state *x, (x->id.spi == tmpl->id.spi || !tmpl->id.spi) && (x->props.reqid == tmpl->reqid || !tmpl->reqid) && x->props.mode == tmpl->mode && - ((tmpl->aalgos & (1<props.aalgo)) || + (tmpl->allalgs || (tmpl->aalgos & (1<props.aalgo)) || !(xfrm_id_proto_match(tmpl->id.proto, IPSEC_PROTO_ANY))) && !(x->props.mode != XFRM_MODE_TRANSPORT && xfrm_state_addr_cmp(tmpl, x, family)); diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index 1810f5645bb5..22a30ae582a2 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -981,6 +981,8 @@ static void copy_templates(struct xfrm_policy *xp, struct xfrm_user_tmpl *ut, t->aalgos = ut->aalgos; t->ealgos = ut->ealgos; t->calgos = ut->calgos; + /* If all masks are ~0, then we allow all algorithms. */ + t->allalgs = !~(t->aalgos & t->ealgos & t->calgos); t->encap_family = ut->family; } } -- 2.20.1