From: Maxim Mikityanskiy maximmi@nvidia.com
mainline inclusion from mainline-v5.19 commit f6336724a4d4220c89a4ec38bca84b03b178b1a3 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I990AF CVE: CVE-2021-47131
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tls_device_down takes a reference on all contexts it's going to move to the degraded state (software fallback). If sk_destruct runs afterwards, it can reduce the reference counter back to 1 and return early without destroying the context. Then tls_device_down will release the reference it took and call tls_device_free_ctx. However, the context will still stay in tls_device_down_list forever. The list will contain an item, memory for which is released, making a memory corruption possible.
Fix the above bug by properly removing the context from all lists before any call to tls_device_free_ctx.
Fixes: 3740651bf7e2 ("tls: Fix context leak on tls_device_down") Signed-off-by: Maxim Mikityanskiy maximmi@nvidia.com Reviewed-by: Tariq Toukan tariqt@nvidia.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Ziyang Xuan william.xuanziyang@huawei.com --- net/tls/tls_device.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c index 045f064b12ef2..8d7940a817694 100644 --- a/net/tls/tls_device.c +++ b/net/tls/tls_device.c @@ -1041,8 +1041,13 @@ static int tls_device_down(struct net_device *netdev) * by tls_device_free_ctx. rx_conf and tx_conf stay in TLS_HW. * Now release the ref taken above. */ - if (refcount_dec_and_test(&ctx->refcount)) + if (refcount_dec_and_test(&ctx->refcount)) { + /* sk_destruct ran after tls_device_down took a ref, and + * it returned early. Complete the destruction here. + */ + list_del(&ctx->list); tls_device_free_ctx(ctx); + } }
up_write(&device_offload_lock);