Messages in this thread | | | Date | Fri, 29 Oct 2021 21:12:04 +0800 | From | Herbert Xu <> | Subject | Re: [PATCH] crypto: pcrypt - Delay write to padata->info |
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On Thu, Oct 21, 2021 at 02:30:28PM -0400, Daniel Jordan wrote: > 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> > --- > > So, pcrypt(pcrypt(...)) doesn't make all that much sense, but apparently > there's not an easy way to prevent it [1], so I'm going with the minimal > fix. > > [1] https://lkml.kernel.org/20171230083744.vuclnbs677tj7pi2@gauss3.secunet.de/ > > crypto/pcrypt.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-)
Patch applied. Thanks. -- Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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