Re: [PATCH 1/3] crypto: caam: Fix DMA mapping leak in the cbc(paes) job path

[Herbert Xu <herbert@gondor.apana.org.au>]

On Sun, Jul 26, 2026 at 10:15:02AM +0200, Richard Weinberger wrote:
> For a protected key, init_skcipher_job() maps the second job descriptor
> so that the blob decapsulation descriptor can jump to it, but keeps the
> address in a local variable. Nothing can ever unmap it, and the buffer
> it covers lives in edesc, which skcipher_crypt_done() frees while the
> mapping is still live. The mapping error is not checked either.
> 
> cbc(paes) is reachable through AF_ALG, so an unprivileged process leaks
> one mapping per request, exhausting IOVA space or swiotlb buffers.
> 
> Store the mapping in the extended descriptor, release it in
> skcipher_unmap() and propagate mapping failures to the caller.
> 
> Assisted-by: Claude-Code:claude-fable-5
> Reported-by: Eric Biggers <ebiggers@kernel.org>
> Signed-off-by: Richard Weinberger <richard@nod.at>
> ---
>  drivers/crypto/caam/caamalg.c | 31 +++++++++++++++++++++++++++----
>  1 file changed, 27 insertions(+), 4 deletions(-)

Please check the Sashiko comments:

https://sashiko.dev/#/patchset/20260726081504.2182951-1-richard%40nod.at

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