5.4-stable review patch. If anyone has any objections, please let me know.
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From: Liu Jian liujian56@huawei.com
[ Upstream commit cfaa80c91f6f99b9342b6557f0f0e1143e434066 ]
I got the below warning when do fuzzing test: BUG: KASAN: null-ptr-deref in scatterwalk_copychunks+0x320/0x470 Read of size 4 at addr 0000000000000008 by task kworker/u8:1/9
CPU: 0 PID: 9 Comm: kworker/u8:1 Tainted: G OE Hardware name: linux,dummy-virt (DT) Workqueue: pencrypt_parallel padata_parallel_worker Call trace: dump_backtrace+0x0/0x420 show_stack+0x34/0x44 dump_stack+0x1d0/0x248 __kasan_report+0x138/0x140 kasan_report+0x44/0x6c __asan_load4+0x94/0xd0 scatterwalk_copychunks+0x320/0x470 skcipher_next_slow+0x14c/0x290 skcipher_walk_next+0x2fc/0x480 skcipher_walk_first+0x9c/0x110 skcipher_walk_aead_common+0x380/0x440 skcipher_walk_aead_encrypt+0x54/0x70 ccm_encrypt+0x13c/0x4d0 crypto_aead_encrypt+0x7c/0xfc pcrypt_aead_enc+0x28/0x84 padata_parallel_worker+0xd0/0x2dc process_one_work+0x49c/0xbdc worker_thread+0x124/0x880 kthread+0x210/0x260 ret_from_fork+0x10/0x18
This is because the value of rec_seq of tls_crypto_info configured by the user program is too large, for example, 0xffffffffffffff. In addition, TLS is asynchronously accelerated. When tls_do_encryption() returns -EINPROGRESS and sk->sk_err is set to EBADMSG due to rec_seq overflow, skmsg is released before the asynchronous encryption process ends. As a result, the UAF problem occurs during the asynchronous processing of the encryption module.
If the operation is asynchronous and the encryption module returns EINPROGRESS, do not free the record information.
Fixes: 635d93981786 ("net/tls: free record only on encryption error") Signed-off-by: Liu Jian liujian56@huawei.com Reviewed-by: Sabrina Dubroca sd@queasysnail.net Link: https://lore.kernel.org/r/20230909081434.2324940-1-liujian56@huawei.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/tls/tls_sw.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index f4091fba4c722..62bc7e5c58e53 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -807,7 +807,7 @@ static int bpf_exec_tx_verdict(struct sk_msg *msg, struct sock *sk, psock = sk_psock_get(sk); if (!psock || !policy) { err = tls_push_record(sk, flags, record_type); - if (err && sk->sk_err == EBADMSG) { + if (err && err != -EINPROGRESS && sk->sk_err == EBADMSG) { *copied -= sk_msg_free(sk, msg); tls_free_open_rec(sk); err = -sk->sk_err; @@ -836,7 +836,7 @@ static int bpf_exec_tx_verdict(struct sk_msg *msg, struct sock *sk, switch (psock->eval) { case __SK_PASS: err = tls_push_record(sk, flags, record_type); - if (err && sk->sk_err == EBADMSG) { + if (err && err != -EINPROGRESS && sk->sk_err == EBADMSG) { *copied -= sk_msg_free(sk, msg); tls_free_open_rec(sk); err = -sk->sk_err;