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authorCong Wang <cong.wang@bytedance.com>2020-12-26 16:50:20 -0800
committerSteffen Klassert <steffen.klassert@secunet.com>2021-01-04 10:05:50 +0100
commitafbc293add6466f8f3f0c3d944d85f53709c170f (patch)
tree97288782f050eb5a58aa1ecb6149a23bef333dff /net/key/af_key.c
parent9f8550e4bd9d78a8436c2061ad2530215f875376 (diff)
af_key: relax availability checks for skb size calculation
xfrm_probe_algs() probes kernel crypto modules and changes the availability of struct xfrm_algo_desc. But there is a small window where ealg->available and aalg->available get changed between count_ah_combs()/count_esp_combs() and dump_ah_combs()/dump_esp_combs(), in this case we may allocate a smaller skb but later put a larger amount of data and trigger the panic in skb_put(). Fix this by relaxing the checks when counting the size, that is, skipping the test of ->available. We may waste some memory for a few of sizeof(struct sadb_comb), but it is still much better than a panic. Reported-by: syzbot+b2bf2652983d23734c5c@syzkaller.appspotmail.com Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'net/key/af_key.c')
-rw-r--r--net/key/af_key.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/key/af_key.c b/net/key/af_key.c
index c12dbc51ef5f..ef9b4ac03e7b 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -2902,7 +2902,7 @@ static int count_ah_combs(const struct xfrm_tmpl *t)
break;
if (!aalg->pfkey_supported)
continue;
- if (aalg_tmpl_set(t, aalg) && aalg->available)
+ if (aalg_tmpl_set(t, aalg))
sz += sizeof(struct sadb_comb);
}
return sz + sizeof(struct sadb_prop);
@@ -2920,7 +2920,7 @@ static int count_esp_combs(const struct xfrm_tmpl *t)
if (!ealg->pfkey_supported)
continue;
- if (!(ealg_tmpl_set(t, ealg) && ealg->available))
+ if (!(ealg_tmpl_set(t, ealg)))
continue;
for (k = 1; ; k++) {
@@ -2931,7 +2931,7 @@ static int count_esp_combs(const struct xfrm_tmpl *t)
if (!aalg->pfkey_supported)
continue;
- if (aalg_tmpl_set(t, aalg) && aalg->available)
+ if (aalg_tmpl_set(t, aalg))
sz += sizeof(struct sadb_comb);
}
}