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net/tls: Remove the context from the list in tls_device_down

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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: 3740651bf7 ("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>
This commit is contained in:
Maxim Mikityanskiy 2022-07-21 12:11:27 +03:00 committed by David S. Miller
parent 4d8f24eeed
commit f6336724a4
1 changed files with 6 additions and 1 deletions
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7
net/tls/tls_device.c
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@ -1376,8 +1376,13 @@ 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);