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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	syzbot+b2bf2652983d23734c5c@syzkaller.appspotmail.com,
	Steffen Klassert <steffen.klassert@secunet.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Cong Wang <cong.wang@bytedance.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 06/24] af_key: relax availability checks for skb size calculation
Date: Thu, 11 Feb 2021 16:02:40 +0100
Message-ID: <20210211150148.026903055@linuxfoundation.org> (raw)
In-Reply-To: <20210211150147.743660073@linuxfoundation.org>

From: Cong Wang <cong.wang@bytedance.com>

[ Upstream commit afbc293add6466f8f3f0c3d944d85f53709c170f ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/key/af_key.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/key/af_key.c b/net/key/af_key.c
index e340e97224c3a..c7d5a6015389b 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -2908,7 +2908,7 @@ 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);
@@ -2926,7 +2926,7 @@ 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++) {
@@ -2937,7 +2937,7 @@ 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);
 		}
 	}
-- 
2.27.0




  parent reply index

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-11 15:02 [PATCH 4.19 00/24] 4.19.176-rc1 review Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 01/24] tracing/kprobe: Fix to support kretprobe events on unloaded modules Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 02/24] block: fix NULL pointer dereference in register_disk Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 03/24] fgraph: Initialize tracing_graph_pause at task creation Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 04/24] remoteproc: qcom_q6v5_mss: Validate modem blob firmware size before load Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 05/24] remoteproc: qcom_q6v5_mss: Validate MBA " Greg Kroah-Hartman
2021-02-11 15:02 ` Greg Kroah-Hartman [this message]
2021-02-11 15:02 ` [PATCH 4.19 07/24] regulator: core: avoid regulator_resolve_supply() race condition Greg Kroah-Hartman
2021-02-11 15:26   ` Mark Brown
2021-02-11 15:38     ` Greg Kroah-Hartman
2021-02-11 15:40       ` Mark Brown
2021-02-11 18:06         ` Sasha Levin
2021-02-11 15:02 ` [PATCH 4.19 08/24] chtls: Fix potential resource leak Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 09/24] pNFS/NFSv4: Try to return invalid layout in pnfs_layout_process() Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 10/24] iwlwifi: mvm: take mutex for calling iwl_mvm_get_sync_time() Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 11/24] iwlwifi: pcie: add a NULL check in iwl_pcie_txq_unmap Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 12/24] iwlwifi: pcie: fix context info memory leak Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 13/24] iwlwifi: mvm: guard against device removal in reprobe Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 14/24] SUNRPC: Move simple_get_bytes and simple_get_netobj into private header Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 15/24] SUNRPC: Handle 0 length opaque XDR object data properly Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 16/24] lib/string: Add strscpy_pad() function Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 17/24] include/trace/events/writeback.h: fix -Wstringop-truncation warnings Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 18/24] memcg: fix a crash in wb_workfn when a device disappears Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 19/24] Fix unsynchronized access to sev members through svm_register_enc_region Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 20/24] block: dont hold q->sysfs_lock in elevator_init_mq Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 21/24] blk-mq: dont hold q->sysfs_lock in blk_mq_map_swqueue Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 22/24] squashfs: add more sanity checks in id lookup Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 23/24] squashfs: add more sanity checks in inode lookup Greg Kroah-Hartman
2021-02-11 15:02 ` [PATCH 4.19 24/24] squashfs: add more sanity checks in xattr id lookup Greg Kroah-Hartman
2021-02-12  4:46 ` [PATCH 4.19 00/24] 4.19.176-rc1 review Naresh Kamboju
2021-02-12  7:42   ` Greg Kroah-Hartman
2021-02-12 10:29     ` Naresh Kamboju
2021-02-12 11:00       ` Greg Kroah-Hartman
2021-02-12 16:18 ` Shuah Khan

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