The asymmetric key type allows an X.509 certificate to be added even if
its signature's hash algorithm is not available in the crypto API.  In
that case 'payload.data[asym_auth]' will be NULL.  But the key
restriction code failed to check for this case before trying to use the
signature, resulting in a NULL pointer dereference in
key_or_keyring_common() or in restrict_link_by_signature().

Fix this by returning -ENOPKG when the signature is unsupported.

Reproducer when all the CONFIG_CRYPTO_SHA512* options are disabled and
keyctl has support for the 'restrict_keyring' command:

    keyctl new_session
    keyctl restrict_keyring @s asymmetric builtin_trusted
    openssl req -new -sha512 -x509 -batch -nodes -outform der \
        | keyctl padd asymmetric desc @s

Fixes: a511e1af8b12 ("KEYS: Move the point of trust determination to __key_link()")
Cc: <stable@vger.kernel.org> # v4.7+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>

The X.509 parser mishandles the case where the certificate's signature's
hash algorithm is not available in the crypto API.  In this case,
x509_get_sig_params() doesn't allocate the cert->sig->digest buffer;
this part seems to be intentional.  However,
public_key_verify_signature() is still called via
x509_check_for_self_signed(), which triggers the 'BUG_ON(!sig->digest)'.

Fix this by making public_key_verify_signature() return -ENOPKG if the
hash buffer has not been allocated.

Reproducer when all the CONFIG_CRYPTO_SHA512* options are disabled:

    openssl req -new -sha512 -x509 -batch -nodes -outform der \
        | keyctl padd asymmetric desc @s

Fixes: 6c2dc5ae4ab7 ("X.509: Extract signature digest and make self-signed cert checks earlier")
Reported-by: Paolo Valente <paolo.valente@linaro.org>
Cc: Paolo Valente <paolo.valente@linaro.org>
Cc: <stable@vger.kernel.org> # v4.7+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>

If none of the certificates in a SignerInfo's certificate chain match a
trusted key, nor is the last certificate signed by a trusted key, then
pkcs7_validate_trust_one() tries to check whether the SignerInfo's
signature was made directly by a trusted key.  But, it actually fails to
set the 'sig' variable correctly, so it actually verifies the last
signature seen.  That will only be the SignerInfo's signature if the
certificate chain is empty; otherwise it will actually be the last
certificate's signature.

This is not by itself a security problem, since verifying any of the
certificates in the chain should be sufficient to verify the SignerInfo.
Still, it's not working as intended so it should be fixed.

Fix it by setting 'sig' correctly for the direct verification case.

Fixes: 757932e6da6d ("PKCS#7: Handle PKCS#7 messages that contain no X.509 certs")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>

If there is a blacklisted certificate in a SignerInfo's certificate
chain, then pkcs7_verify_sig_chain() sets sinfo->blacklisted and returns
0.  But, pkcs7_verify() fails to handle this case appropriately, as it
actually continues on to the line 'actual_ret = 0;', indicating that the
SignerInfo has passed verification.  Consequently, PKCS#7 signature
verification ignores the certificate blacklist.

Fix this by not considering blacklisted SignerInfos to have passed
verification.

Also fix the function comment with regards to when 0 is returned.

Fixes: 03bb79315ddc ("PKCS#7: Handle blacklisted certificates")
Cc: <stable@vger.kernel.org> # v4.12+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>

When pkcs7_verify_sig_chain() is building the certificate chain for a
SignerInfo using the certificates in the PKCS#7 message, it is passing
the wrong arguments to public_key_verify_signature().  Consequently,
when the next certificate is supposed to be used to verify the previous
certificate, the next certificate is actually used to verify itself.

An attacker can use this bug to create a bogus certificate chain that
has no cryptographic relationship between the beginning and end.

Fortunately I couldn't quite find a way to use this to bypass the
overall signature verification, though it comes very close.  Here's the
reasoning: due to the bug, every certificate in the chain beyond the
first actually has to be self-signed (where "self-signed" here refers to
the actual key and signature; an attacker might still manipulate the
certificate fields such that the self_signed flag doesn't actually get
set, and thus the chain doesn't end immediately).  But to pass trust
validation (pkcs7_validate_trust()), either the SignerInfo or one of the
certificates has to actually be signed by a trusted key.  Since only
self-signed certificates can be added to the chain, the only way for an
attacker to introduce a trusted signature is to include a self-signed
trusted certificate.

But, when pkcs7_validate_trust_one() reaches that certificate, instead
of trying to verify the signature on that certificate, it will actually
look up the corresponding trusted key, which will succeed, and then try
to verify the *previous* certificate, which will fail.  Thus, disaster
is narrowly averted (as far as I could tell).

Fixes: 6c2dc5ae4ab7 ("X.509: Extract signature digest and make self-signed cert checks earlier")
Cc: <stable@vger.kernel.org> # v4.7+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>

Pull crypto fixes from Herbert Xu:
 "This fixes the following issues:

   - oversize stack frames on mn10300 in sha3-generic

   - warning on old compilers in sha3-generic

   - API error in sun4i_ss_prng

   - potential dead-lock in sun4i_ss_prng

   - null-pointer dereference in sha512-mb

   - endless loop when DECO acquire fails in caam

   - kernel oops when hashing empty message in talitos"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: sun4i_ss_prng - convert lock to _bh in sun4i_ss_prng_generate
  crypto: sun4i_ss_prng - fix return value of sun4i_ss_prng_generate
  crypto: caam - fix endless loop when DECO acquire fails
  crypto: sha3-generic - Use __optimize to support old compilers
  compiler-gcc.h: __nostackprotector needs gcc-4.4 and up
  compiler-gcc.h: Introduce __optimize function attribute
  crypto: sha3-generic - deal with oversize stack frames
  crypto: talitos - fix Kernel Oops on hashing an empty file
  crypto: sha512-mb - initialize pending lengths correctly

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

With gcc-4.1.2:

    crypto/sha3_generic.c:39: warning: ‘__optimize__’ attribute directive ignored

Use the newly introduced __optimize macro to fix this.

Fixes: 83dee2ce1ae791c3 ("crypto: sha3-generic - rewrite KECCAK transform to help the compiler optimize")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

As reported by kbuild test robot, the optimized SHA3 C implementation
compiles to mn10300 code that uses a disproportionate amount of stack
space, i.e.,

  crypto/sha3_generic.c: In function 'keccakf':
  crypto/sha3_generic.c:147:1: warning: the frame size of 1232 bytes is larger than 1024 bytes [-Wframe-larger-than=]

As kindly diagnosed by Arnd, this does not only occur when building for
the mn10300 architecture (which is what the report was about) but also
for h8300, and builds for other 32-bit architectures show an increase in
stack space utilization as well.

Given that SHA3 operates on 64-bit quantities, and keeps a state matrix
of 25 64-bit words, it is not surprising that 32-bit architectures with
few general purpose registers are impacted the most by this, and it is
therefore reasonable to implement a workaround that distinguishes between
32-bit and 64-bit architectures.

Arnd figured out that taking the round calculation out of the loop, and
inlining it explicitly but only on 64-bit architectures preserves most
of the performance gain achieved by the rewrite, and also gets rid of
the excessive use of stack space.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Pull crypto updates from Herbert Xu:
 "API:
   - Enforce the setting of keys for keyed aead/hash/skcipher
     algorithms.
   - Add multibuf speed tests in tcrypt.

  Algorithms:
   - Improve performance of sha3-generic.
   - Add native sha512 support on arm64.
   - Add v8.2 Crypto Extentions version of sha3/sm3 on arm64.
   - Avoid hmac nesting by requiring underlying algorithm to be unkeyed.
   - Add cryptd_max_cpu_qlen module parameter to cryptd.

  Drivers:
   - Add support for EIP97 engine in inside-secure.
   - Add inline IPsec support to chelsio.
   - Add RevB core support to crypto4xx.
   - Fix AEAD ICV check in crypto4xx.
   - Add stm32 crypto driver.
   - Add support for BCM63xx platforms in bcm2835 and remove bcm63xx.
   - Add Derived Key Protocol (DKP) support in caam.
   - Add Samsung Exynos True RNG driver.
   - Add support for Exynos5250+ SoCs in exynos PRNG driver"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (166 commits)
  crypto: picoxcell - Fix error handling in spacc_probe()
  crypto: arm64/sha512 - fix/improve new v8.2 Crypto Extensions code
  crypto: arm64/sm3 - new v8.2 Crypto Extensions implementation
  crypto: arm64/sha3 - new v8.2 Crypto Extensions implementation
  crypto: testmgr - add new testcases for sha3
  crypto: sha3-generic - export init/update/final routines
  crypto: sha3-generic - simplify code
  crypto: sha3-generic - rewrite KECCAK transform to help the compiler optimize
  crypto: sha3-generic - fixes for alignment and big endian operation
  crypto: aesni - handle zero length dst buffer
  crypto: artpec6 - remove select on non-existing CRYPTO_SHA384
  hwrng: bcm2835 - Remove redundant dev_err call in bcm2835_rng_probe()
  crypto: stm32 - remove redundant dev_err call in stm32_cryp_probe()
  crypto: axis - remove unnecessary platform_get_resource() error check
  crypto: testmgr - test misuse of result in ahash
  crypto: inside-secure - make function safexcel_try_push_requests static
  crypto: aes-generic - fix aes-generic regression on powerpc
  crypto: chelsio - Fix indentation warning
  crypto: arm64/sha1-ce - get rid of literal pool
  crypto: arm64/sha2-ce - move the round constant table to .rodata section
  ...