| From f6fdfe0438535eb66a232986a47dc3ee41e6dbf3 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 21 Oct 2021 14:30:28 -0400 |
| Subject: crypto: pcrypt - Delay write to padata->info |
| |
| From: Daniel Jordan <daniel.m.jordan@oracle.com> |
| |
| [ Upstream commit 68b6dea802cea0dbdd8bd7ccc60716b5a32a5d8a ] |
| |
| These three events can race when pcrypt is used multiple times in a |
| template ("pcrypt(pcrypt(...))"): |
| |
| 1. [taskA] The caller makes the crypto request via crypto_aead_encrypt() |
| 2. [kworkerB] padata serializes the inner pcrypt request |
| 3. [kworkerC] padata serializes the outer pcrypt request |
| |
| 3 might finish before the call to crypto_aead_encrypt() returns in 1, |
| resulting in two possible issues. |
| |
| First, a use-after-free of the crypto request's memory when, for |
| example, taskA writes to the outer pcrypt request's padata->info in |
| pcrypt_aead_enc() after kworkerC completes the request. |
| |
| Second, the outer pcrypt request overwrites the inner pcrypt request's |
| return code with -EINPROGRESS, making a successful request appear to |
| fail. For instance, kworkerB writes the outer pcrypt request's |
| padata->info in pcrypt_aead_done() and then taskA overwrites it |
| in pcrypt_aead_enc(). |
| |
| Avoid both situations by delaying the write of padata->info until after |
| the inner crypto request's return code is checked. This prevents the |
| use-after-free by not touching the crypto request's memory after the |
| next-inner crypto request is made, and stops padata->info from being |
| overwritten. |
| |
| Fixes: 5068c7a883d16 ("crypto: pcrypt - Add pcrypt crypto parallelization wrapper") |
| Reported-by: syzbot+b187b77c8474f9648fae@syzkaller.appspotmail.com |
| Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com> |
| Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| crypto/pcrypt.c | 12 ++++++++---- |
| 1 file changed, 8 insertions(+), 4 deletions(-) |
| |
| diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c |
| index a4f3b3f342c8d..276d2fd9e911c 100644 |
| --- a/crypto/pcrypt.c |
| +++ b/crypto/pcrypt.c |
| @@ -79,12 +79,14 @@ static void pcrypt_aead_enc(struct padata_priv *padata) |
| { |
| struct pcrypt_request *preq = pcrypt_padata_request(padata); |
| struct aead_request *req = pcrypt_request_ctx(preq); |
| + int ret; |
| |
| - padata->info = crypto_aead_encrypt(req); |
| + ret = crypto_aead_encrypt(req); |
| |
| - if (padata->info == -EINPROGRESS) |
| + if (ret == -EINPROGRESS) |
| return; |
| |
| + padata->info = ret; |
| padata_do_serial(padata); |
| } |
| |
| @@ -124,12 +126,14 @@ static void pcrypt_aead_dec(struct padata_priv *padata) |
| { |
| struct pcrypt_request *preq = pcrypt_padata_request(padata); |
| struct aead_request *req = pcrypt_request_ctx(preq); |
| + int ret; |
| |
| - padata->info = crypto_aead_decrypt(req); |
| + ret = crypto_aead_decrypt(req); |
| |
| - if (padata->info == -EINPROGRESS) |
| + if (ret == -EINPROGRESS) |
| return; |
| |
| + padata->info = ret; |
| padata_do_serial(padata); |
| } |
| |
| -- |
| 2.33.0 |
| |