Commit Graph

7 Commits

Author SHA1 Message Date
Jason A. Donenfeld ac88c322d0 crypto: lib/chacha20poly1305 - define empty module exit function
With no mod_exit function, users are unable to unload the module after
use. I'm not aware of any reason why module unloading should be
prohibited for this one, so this commit simply adds an empty exit
function.

Reported-and-tested-by: John Donnelly <john.p.donnelly@oracle.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2021-01-22 14:58:03 +11:00
Herbert Xu 255f6c2e74 crypto: lib/chacha20poly1305 - Set SG_MITER_ATOMIC unconditionally
There is no reason for the chacha20poly1305 SG miter code to use
kmap instead of kmap_atomic as the critical section doesn't sleep
anyway.  So we can simply get rid of the preemptible check and
set SG_MITER_ATOMIC unconditionally.

Even if we need to reenable preemption to lower latency we should
be doing that by interrupting the SG miter walk rather than using
kmap.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-09-25 17:48:13 +10:00
Herbert Xu 06cc2afbbd crypto: lib/chacha20poly1305 - Add missing function declaration
This patch adds a declaration for chacha20poly1305_selftest to
silence a sparse warning.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-07-16 21:49:04 +10:00
Jason A. Donenfeld c9cc0517bb crypto: chacha20poly1305 - prevent integer overflow on large input
This code assigns src_len (size_t) to sl (int), which causes problems
when src_len is very large. Probably nobody in the kernel should be
passing this much data to chacha20poly1305 all in one go anyway, so I
don't think we need to change the algorithm or introduce larger types
or anything. But we should at least error out early in this case and
print a warning so that we get reports if this does happen and can look
into why anybody is possibly passing it that much data or if they're
accidently passing -1 or similar.

Fixes: d95312a3cc ("crypto: lib/chacha20poly1305 - reimplement crypt_from_sg() routine")
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: stable@vger.kernel.org # 5.5+
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-02-14 14:48:37 +08:00
Eric Biggers 413808b71e crypto: lib/chacha20poly1305 - use chacha20_crypt()
Use chacha20_crypt() instead of chacha_crypt(), since it's not really
appropriate for users of the ChaCha library API to be passing the number
of rounds as an argument.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2019-11-22 18:48:39 +08:00
Ard Biesheuvel d95312a3cc crypto: lib/chacha20poly1305 - reimplement crypt_from_sg() routine
Reimplement the library routines to perform chacha20poly1305 en/decryption
on scatterlists, without [ab]using the [deprecated] blkcipher interface,
which is rather heavyweight and does things we don't really need.

Instead, we use the sg_miter API in a novel and clever way, to iterate
over the scatterlist in-place (i.e., source == destination, which is the
only way this library is expected to be used). That way, we don't have to
iterate over two scatterlists in parallel.

Another optimization is that, instead of relying on the blkcipher walker
to present the input in suitable chunks, we recognize that ChaCha is a
streamcipher, and so we can simply deal with partial blocks by keeping a
block of cipherstream on the stack and use crypto_xor() to mix it with
the in/output.

Finally, we omit the scatterwalk_and_copy() call if the last element of
the scatterlist covers the MAC as well (which is the common case),
avoiding the need to walk the scatterlist and kmap() the page twice.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2019-11-17 09:02:44 +08:00
Ard Biesheuvel ed20078b7e crypto: chacha20poly1305 - import construction and selftest from Zinc
This incorporates the chacha20poly1305 from the Zinc library, retaining
the library interface, but replacing the implementation with calls into
the code that already existed in the kernel's crypto API.

Note that this library API does not implement RFC7539 fully, given that
it is limited to 64-bit nonces. (The 96-bit nonce version that was part
of the selftest only has been removed, along with the 96-bit nonce test
vectors that only tested the selftest but not the actual library itself)

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2019-11-17 09:02:44 +08:00