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path: root/net/tls/tls_device_fallback.c
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2021-06-01net/tls: Fix use-after-free after the TLS device goes down and upMaxim Mikityanskiy
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 <maximmi@nvidia.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-01-18net/tls: Except bond interface from some TLS checksTariq Toukan
In the tls_dev_event handler, ignore tlsdev_ops requirement for bond interfaces, they do not exist as the interaction is done directly with the lower device. Also, make the validate function pass when it's called with the upper bond interface. Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Reviewed-by: Boris Pismenny <borisp@nvidia.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-11-27net/tls: make inline helpers protocol-awareVadim Fedorenko
Inline functions defined in tls.h have a lot of AES-specific constants. Remove these constants and change argument to struct tls_prot_info to have an access to cipher type in later patches Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2019-07-30net: Use skb_frag_off accessorsJonathan Lemon
Use accessor functions for skb fragment's page_offset instead of direct references, in preparation for bvec conversion. Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-07-08net/tls: fix socket wmem accounting on fallback with netemJakub Kicinski
netem runs skb_orphan_partial() which "disconnects" the skb from normal TCP write memory accounting. We should not adjust sk->sk_wmem_alloc on the fallback path for such skbs. Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure") Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-06net/tls: export TLS per skb encryptionDirk van der Merwe
While offloading TLS connections, drivers need to handle the case where out of order packets need to be transmitted. Other drivers obtain the entire TLS record for the specific skb to provide as context to hardware for encryption. However, other designs may also want to keep the hardware state intact and perform the out of order encryption entirely on the host. To achieve this, export the already existing software encryption fallback path so drivers could access this. Signed-off-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-04net/tls: remove false positive warningJakub Kicinski
It's possible that TCP stack will decide to retransmit a packet right when that packet's data gets acked, especially in presence of packet reordering. This means that packets may be in flight, even though tls_device code has already freed their record state. Make fill_sg_in() and in turn tls_sw_fallback() not generate a warning in that case, and quietly proceed to drop such frames. Make the exit path from tls_sw_fallback() drop monitor friendly, for users to be able to troubleshoot dropped retransmissions. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-01net/tls: avoid NULL pointer deref on nskb->sk in fallbackJakub Kicinski
update_chksum() accesses nskb->sk before it has been set by complete_skb(), move the init up. Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure") Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Simon Horman <simon.horman@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-18net/tls: fix refcount adjustment in fallbackJakub Kicinski
Unlike atomic_add(), refcount_add() does not deal well with a negative argument. TLS fallback code reallocates the skb and is very likely to shrink the truesize, leading to: [ 189.513254] WARNING: CPU: 5 PID: 0 at lib/refcount.c:81 refcount_add_not_zero_checked+0x15c/0x180 Call Trace: refcount_add_checked+0x6/0x40 tls_enc_skb+0xb93/0x13e0 [tls] Once wmem_allocated count saturates the application can no longer send data on the socket. This is similar to Eric's fixes for GSO, TCP: commit 7ec318feeed1 ("tcp: gso: avoid refcount_t warning from tcp_gso_segment()") and UDP: commit 575b65bc5bff ("udp: avoid refcount_t saturation in __udp_gso_segment()"). Unlike the GSO case, for TLS fallback it's likely that the skb has shrunk, so the "likely" annotation is the other way around (likely branch being "sub"). Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure") Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: John Hurley <john.hurley@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-01net: tls: Add tls 1.3 supportDave Watson
TLS 1.3 has minor changes from TLS 1.2 at the record layer. * Header now hardcodes the same version and application content type in the header. * The real content type is appended after the data, before encryption (or after decryption). * The IV is xored with the sequence number, instead of concatinating four bytes of IV with the explicit IV. * Zero-padding: No exlicit length is given, we search backwards from the end of the decrypted data for the first non-zero byte, which is the content type. Currently recv supports reading zero-padding, but there is no way for send to add zero padding. Signed-off-by: Dave Watson <davejwatson@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-13tls: zero the crypto information from tls_context before freeingSabrina Dubroca
This contains key material in crypto_send_aes_gcm_128 and crypto_recv_aes_gcm_128. Introduce union tls_crypto_context, and replace the two identical unions directly embedded in struct tls_context with it. We can then use this union to clean up the memory in the new tls_ctx_free() function. Fixes: 3c4d7559159b ("tls: kernel TLS support") Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-15Merge branch 'linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 Pull crypto updates from Herbert Xu: "API: - Fix dcache flushing crash in skcipher. - Add hash finup self-tests. - Reschedule during speed tests. Algorithms: - Remove insecure vmac and replace it with vmac64. - Add public key verification for DH/ECDH. Drivers: - Decrease priority of sha-mb on x86. - Improve NEON latency/throughput on ARM64. - Add md5/sha384/sha512/des/3des to inside-secure. - Support eip197d in inside-secure. - Only register algorithms supported by the host in virtio. - Add cts and remove incompatible cts1 from ccree. - Add hisilicon SEC security accelerator driver. - Replace msm hwrng driver with qcom pseudo rng driver. Misc: - Centralize CRC polynomials" * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (121 commits) crypto: arm64/ghash-ce - implement 4-way aggregation crypto: arm64/ghash-ce - replace NEON yield check with block limit crypto: hisilicon - sec_send_request() can be static lib/mpi: remove redundant variable esign crypto: arm64/aes-ce-gcm - don't reload key schedule if avoidable crypto: arm64/aes-ce-gcm - implement 2-way aggregation crypto: arm64/aes-ce-gcm - operate on two input blocks at a time crypto: dh - make crypto_dh_encode_key() make robust crypto: dh - fix calculating encoded key size crypto: ccp - Check for NULL PSP pointer at module unload crypto: arm/chacha20 - always use vrev for 16-bit rotates crypto: ccree - allow bigger than sector XTS op crypto: ccree - zero all of request ctx before use crypto: ccree - remove cipher ivgen left overs crypto: ccree - drop useless type flag during reg crypto: ablkcipher - fix crash flushing dcache in error path crypto: blkcipher - fix crash flushing dcache in error path crypto: skcipher - fix crash flushing dcache in error path crypto: skcipher - remove unnecessary setting of walk->nbytes crypto: scatterwalk - remove scatterwalk_samebuf() ...
2018-08-03crypto: scatterwalk - remove 'chain' argument from scatterwalk_crypto_chain()Eric Biggers
All callers pass chain=0 to scatterwalk_crypto_chain(). Remove this unneeded parameter. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-07-16tls: Add rx inline crypto offloadBoris Pismenny
This patch completes the generic infrastructure to offload TLS crypto to a network device. It enables the kernel to skip decryption and authentication of some skbs marked as decrypted by the NIC. In the fast path, all packets received are decrypted by the NIC and the performance is comparable to plain TCP. This infrastructure doesn't require a TCP offload engine. Instead, the NIC only decrypts packets that contain the expected TCP sequence number. Out-Of-Order TCP packets are provided unmodified. As a result, at the worst case a received TLS record consists of both plaintext and ciphertext packets. These partially decrypted records must be reencrypted, only to be decrypted. The notable differences between SW KTLS Rx and this offload are as follows: 1. Partial decryption - Software must handle the case of a TLS record that was only partially decrypted by HW. This can happen due to packet reordering. 2. Resynchronization - tls_read_size calls the device driver to resynchronize HW after HW lost track of TLS record framing in the TCP stream. Signed-off-by: Boris Pismenny <borisp@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-16tls: Refactor tls_offload variable namesBoris Pismenny
For symmetry, we rename tls_offload_context to tls_offload_context_tx before we add tls_offload_context_rx. Signed-off-by: Boris Pismenny <borisp@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-01net/tls: Add generic NIC offload infrastructureIlya Lesokhin
This patch adds a generic infrastructure to offload TLS crypto to a network device. It enables the kernel TLS socket to skip encryption and authentication operations on the transmit side of the data path. Leaving those computationally expensive operations to the NIC. The NIC offload infrastructure builds TLS records and pushes them to the TCP layer just like the SW KTLS implementation and using the same API. TCP segmentation is mostly unaffected. Currently the only exception is that we prevent mixed SKBs where only part of the payload requires offload. In the future we are likely to add a similar restriction following a change cipher spec record. The notable differences between SW KTLS and NIC offloaded TLS implementations are as follows: 1. The offloaded implementation builds "plaintext TLS record", those records contain plaintext instead of ciphertext and place holder bytes instead of authentication tags. 2. The offloaded implementation maintains a mapping from TCP sequence number to TLS records. Thus given a TCP SKB sent from a NIC offloaded TLS socket, we can use the tls NIC offload infrastructure to obtain enough context to encrypt the payload of the SKB. A TLS record is released when the last byte of the record is ack'ed, this is done through the new icsk_clean_acked callback. The infrastructure should be extendable to support various NIC offload implementations. However it is currently written with the implementation below in mind: The NIC assumes that packets from each offloaded stream are sent as plaintext and in-order. It keeps track of the TLS records in the TCP stream. When a packet marked for offload is transmitted, the NIC encrypts the payload in-place and puts authentication tags in the relevant place holders. The responsibility for handling out-of-order packets (i.e. TCP retransmission, qdisc drops) falls on the netdev driver. The netdev driver keeps track of the expected TCP SN from the NIC's perspective. If the next packet to transmit matches the expected TCP SN, the driver advances the expected TCP SN, and transmits the packet with TLS offload indication. If the next packet to transmit does not match the expected TCP SN. The driver calls the TLS layer to obtain the TLS record that includes the TCP of the packet for transmission. Using this TLS record, the driver posts a work entry on the transmit queue to reconstruct the NIC TLS state required for the offload of the out-of-order packet. It updates the expected TCP SN accordingly and transmits the now in-order packet. The same queue is used for packet transmission and TLS context reconstruction to avoid the need for flushing the transmit queue before issuing the context reconstruction request. Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com> Signed-off-by: Boris Pismenny <borisp@mellanox.com> Signed-off-by: Aviad Yehezkel <aviadye@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>