commit 8c2f1288250a90a4b5cabed5d888d7e3aeed4035 upstream.

Yiming reports an integer underflow in mpi_read_raw_from_sgl() when
subtracting "lzeros" from the unsigned "nbytes".

For this to happen, the scatterlist "sgl" needs to occupy more bytes
than the "nbytes" parameter and the first "nbytes + 1" bytes of the
scatterlist must be zero.  Under these conditions, the while loop
iterating over the scatterlist will count more zeroes than "nbytes",
subtract the number of zeroes from "nbytes" and cause the underflow.

When commit 2d4d1eea540b ("lib/mpi: Add mpi sgl helpers") originally
introduced the bug, it couldn't be triggered because all callers of
mpi_read_raw_from_sgl() passed a scatterlist whose length was equal to
"nbytes".

However since commit 63ba4d67594a ("KEYS: asymmetric: Use new crypto
interface without scatterlists"), the underflow can now actually be
triggered.  When invoking a KEYCTL_PKEY_ENCRYPT system call with a
larger "out_len" than "in_len" and filling the "in" buffer with zeroes,
crypto_akcipher_sync_prep() will create an all-zero scatterlist used for
both the "src" and "dst" member of struct akcipher_request and thereby
fulfil the conditions to trigger the bug:

  sys_keyctl()
    keyctl_pkey_e_d_s()
      asymmetric_key_eds_op()
        software_key_eds_op()
          crypto_akcipher_sync_encrypt()
            crypto_akcipher_sync_prep()
              crypto_akcipher_encrypt()
                rsa_enc()
                  mpi_read_raw_from_sgl()

To the user this will be visible as a DoS as the kernel spins forever,
causing soft lockup splats as a side effect.

Fix it.

Reported-by: Yiming Qian <yimingqian591@gmail.com> # off-list
Fixes: 2d4d1eea540b ("lib/mpi: Add mpi sgl helpers")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v4.4+
Reviewed-by: Ignat Korchagin <ignat@linux.win>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lore.kernel.org/r/59eca92ff4f87e2081777f1423a0efaaadcfdb39.1776003111.git.lukas@wunner.de
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit ba3c5574203034781ac4231acf117da917efcd2a upstream.

When the mpi_ec_ctx structure is initialized, some fields are not
cleared, causing a crash when referencing the field when the
structure was released. Initially, this issue was ignored because
memory for mpi_ec_ctx is allocated with the __GFP_ZERO flag.
For example, this error will be triggered when calculating the
Za value for SM2 separately.

Fixes: d58bb7e55a8a ("lib/mpi: Introduce ec implementation to MPI library")
Cc: stable@vger.kernel.org # v6.5
Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

During NVMeTCP Authentication a controller can trigger a kernel
oops by specifying the 8192 bit Diffie Hellman group and passing
a correctly sized, but zeroed Diffie Hellamn value.
mpi_cmp_ui() was detecting this if the second parameter was 0,
but 1 is passed from dh_is_pubkey_valid(). This causes the null
pointer u->d to be dereferenced towards the end of mpi_cmp_ui()

Signed-off-by: Mark O'Donovan <shiftee@posteo.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

As lib/mpi is mostly used by crypto code, move it under lib/crypto
so that patches touching it get directed to the right mailing list.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>