kernel.git/net/tls/tls_device.c, branch linux-5.18.y

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

2022-08-03T10:05:23Z

commit f6336724a4d4220c89a4ec38bca84b03b178b1a3 upstream. 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 Reviewed-by: Tariq Toukan Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net/tls: Fix race in TLS device down flow

2022-07-29T15:28:03Z

[ Upstream commit f08d8c1bb97c48f24a82afaa2fd8c140f8d3da8b ] Socket destruction flow and tls_device_down function sync against each other using tls_device_lock and the context refcount, to guarantee the device resources are freed via tls_dev_del() by the end of tls_device_down. In the following unfortunate flow, this won't happen: - refcount is decreased to zero in tls_device_sk_destruct. - tls_device_down starts, skips the context as refcount is zero, going all the way until it flushes the gc work, and returns without freeing the device resources. - only then, tls_device_queue_ctx_destruction is called, queues the gc work and frees the context's device resources. Solve it by decreasing the refcount in the socket's destruction flow under the tls_device_lock, for perfect synchronization. This does not slow down the common likely destructor flow, in which both the refcount is decreased and the spinlock is acquired, anyway. Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure") Reviewed-by: Maxim Mikityanskiy Signed-off-by: Tariq Toukan Reviewed-by: Jakub Kicinski Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net/tls: Check for errors in tls_device_init

2022-07-22T08:21:44Z

[ Upstream commit 3d8c51b25a235e283e37750943bbf356ef187230 ] Add missing error checks in tls_device_init. Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure") Reported-by: Jakub Kicinski Reviewed-by: Maxim Mikityanskiy Signed-off-by: Tariq Toukan Link: https://lore.kernel.org/r/20220714070754.1428-1-tariqt@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

tls: Fix context leak on tls_device_down

2022-05-12T17:01:36Z

The commit cited below claims to fix a use-after-free condition after tls_device_down. Apparently, the description wasn't fully accurate. The context stayed alive, but ctx->netdev became NULL, and the offload was torn down without a proper fallback, so a bug was present, but a different kind of bug. Due to misunderstanding of the issue, the original patch dropped the refcount_dec_and_test line for the context to avoid the alleged premature deallocation. That line has to be restored, because it matches the refcount_inc_not_zero from the same function, otherwise the contexts that survived tls_device_down are leaked. This patch fixes the described issue by restoring refcount_dec_and_test. After this change, there is no leak anymore, and the fallback to software kTLS still works. Fixes: c55dcdd435aa ("net/tls: Fix use-after-free after the TLS device goes down and up") Signed-off-by: Maxim Mikityanskiy Reviewed-by: Tariq Toukan Link: https://lore.kernel.org/r/20220512091830.678684-1-maximmi@nvidia.com Signed-off-by: Jakub Kicinski

tls: Skip tls_append_frag on zero copy size

2022-04-27T22:25:20Z

Calling tls_append_frag when max_open_record_len == record->len might add an empty fragment to the TLS record if the call happens to be on the page boundary. Normally tls_append_frag coalesces the zero-sized fragment to the previous one, but not if it's on page boundary. If a resync happens then, the mlx5 driver posts dump WQEs in tx_post_resync_dump, and the empty fragment may become a data segment with byte_count == 0, which will confuse the NIC and lead to a CQE error. This commit fixes the described issue by skipping tls_append_frag on zero size to avoid adding empty fragments. The fix is not in the driver, because an empty fragment is hardly the desired behavior. Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure") Signed-off-by: Maxim Mikityanskiy Reviewed-by: Tariq Toukan Link: https://lore.kernel.org/r/20220426154949.159055-1-maximmi@nvidia.com Signed-off-by: Jakub Kicinski

net/tls: optimize judgement processes in tls_set_device_offload()

2022-03-21T21:58:16Z

It is known that priority setting HW offload when set tls TX/RX offload by setsockopt(). Check netdevice whether support NETIF_F_HW_TLS_TX or not at the later stages in the whole tls_set_device_offload() process, some memory allocations have been done before that. We must release those memory and return error if we judge the netdevice not support NETIF_F_HW_TLS_TX. It is redundant. Move NETIF_F_HW_TLS_TX judgement forward, and move start_marker_record and offload_ctx memory allocation back slightly. Thus, we can get simpler exception handling process. Signed-off-by: Ziyang Xuan Signed-off-by: Jakub Kicinski

skbuff: add a parameter to __skb_frag_unref

2021-06-07T21:11:47Z

This is a prerequisite patch, the next one is enabling recycling of skbs and fragments. Add an extra argument on __skb_frag_unref() to handle recycling, and update the current users of the function with that. Signed-off-by: Matteo Croce Signed-off-by: David S. Miller

net/tls: Fix use-after-free after the TLS device goes down and up

2021-06-01T22:58:05Z

When a netdev with active TLS offload goes down, tls_device_down is called to stop the offload and tear down the TLS context. However, the socket stays alive, and it still points to the TLS context, which is now deallocated. If a netdev goes up, while the connection is still active, and the data flow resumes after a number of TCP retransmissions, it will lead to a use-after-free of the TLS context. This commit addresses this bug by keeping the context alive until its normal destruction, and implements the necessary fallbacks, so that the connection can resume in software (non-offloaded) kTLS mode. On the TX side tls_sw_fallback is used to encrypt all packets. The RX side already has all the necessary fallbacks, because receiving non-decrypted packets is supported. The thing needed on the RX side is to block resync requests, which are normally produced after receiving non-decrypted packets. The necessary synchronization is implemented for a graceful teardown: first the fallbacks are deployed, then the driver resources are released (it used to be possible to have a tls_dev_resync after tls_dev_del). A new flag called TLS_RX_DEV_DEGRADED is added to indicate the fallback mode. It's used to skip the RX resync logic completely, as it becomes useless, and some objects may be released (for example, resync_async, which is allocated and freed by the driver). Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure") Signed-off-by: Maxim Mikityanskiy Reviewed-by: Tariq Toukan Signed-off-by: David S. Miller

net/tls: Replace TLS_RX_SYNC_RUNNING with RCU

2021-06-01T22:58:05Z

RCU synchronization is guaranteed to finish in finite time, unlike a busy loop that polls a flag. This patch is a preparation for the bugfix in the next patch, where the same synchronize_net() call will also be used to sync with the TX datapath. Signed-off-by: Maxim Mikityanskiy Reviewed-by: Tariq Toukan Signed-off-by: David S. Miller

net/tls: Remove redundant initialization of record

2021-04-27T21:15:19Z

record is being initialized to ctx->open_record but this is never read as record is overwritten later on. Remove the redundant initialization. Cleans up the following clang-analyzer warning: net/tls/tls_device.c:421:26: warning: Value stored to 'record' during its initialization is never read [clang-analyzer-deadcode.DeadStores]. Reported-by: Abaci Robot Signed-off-by: Jiapeng Chong Signed-off-by: David S. Miller