6.5-stable review patch. If anyone has any objections, please let me know.
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From: David Howells dhowells@redhat.com
[ Upstream commit 6a4b8aa0a916b39a39175584c07222434fa6c6ef ]
Fix af_alg_alloc_areq() to initialise areq->first_rsgl.sgl.sgt.sgl to point to the scatterlist array in areq->first_rsgl.sgl.sgl.
Without this, the gcm-aes-s390 driver will oops when it tries to do gcm_walk_start() on req->dst because req->dst is set to the value of areq->first_rsgl.sgl.sgl by _aead_recvmsg() calling aead_request_set_crypt().
The problem comes if an empty ciphertext is passed: the loop in af_alg_get_rsgl() just passes straight out and doesn't set areq->first_rsgl up.
This isn't a problem on x86_64 using gcmaes_crypt_by_sg() because, as far as I can tell, that ignores req->dst and only uses req->src[*].
[*] Is this a bug in aesni-intel_glue.c?
The s390x oops looks something like:
Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 0000000a00000000 TEID: 0000000a00000803 Fault in home space mode while using kernel ASCE. AS:00000000a43a0007 R3:0000000000000024 Oops: 003b ilc:2 [#1] SMP ... Call Trace: [<000003ff7fc3d47e>] gcm_walk_start+0x16/0x28 [aes_s390] [<00000000a2a342f2>] crypto_aead_decrypt+0x9a/0xb8 [<00000000a2a60888>] aead_recvmsg+0x478/0x698 [<00000000a2e519a0>] sock_recvmsg+0x70/0xb0 [<00000000a2e51a56>] sock_read_iter+0x76/0xa0 [<00000000a273e066>] vfs_read+0x26e/0x2a8 [<00000000a273e8c4>] ksys_read+0xbc/0x100 [<00000000a311d808>] __do_syscall+0x1d0/0x1f8 [<00000000a312ff30>] system_call+0x70/0x98 Last Breaking-Event-Address: [<000003ff7fc3e6b4>] gcm_aes_crypt+0x104/0xa68 [aes_s390]
Fixes: c1abe6f570af ("crypto: af_alg: Use extract_iter_to_sg() to create scatterlists") Reported-by: Ondrej Mosnáček omosnacek@gmail.com Link: https://lore.kernel.org/r/CAAUqJDuRkHE8fPgZJGaKjUjd3QfGwzfumuJBmStPqBhubxyk_... Signed-off-by: David Howells dhowells@redhat.com cc: Herbert Xu herbert@gondor.apana.org.au cc: Sven Schnelle svens@linux.ibm.com cc: Harald Freudenberger freude@linux.vnet.ibm.com cc: "David S. Miller" davem@davemloft.net cc: Paolo Abeni pabeni@redhat.com cc: linux-crypto@vger.kernel.org cc: linux-s390@vger.kernel.org cc: regressions@lists.linux.dev Tested-by: Sven Schnelle svens@linux.ibm.com Tested-by: Ondrej Mosnáček omosnacek@gmail.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Sasha Levin sashal@kernel.org --- crypto/af_alg.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 10efb56d8b481..ad02ca0a8cdde 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -1192,6 +1192,7 @@ struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
areq->areqlen = areqlen; areq->sk = sk; + areq->first_rsgl.sgl.sgt.sgl = areq->first_rsgl.sgl.sgl; areq->last_rsgl = NULL; INIT_LIST_HEAD(&areq->rsgl_list); areq->tsgl = NULL;