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2022-03-03crypto: dh - split out deserialization code from crypto_dh_decode()Nicolai Stange
A subsequent commit will introduce "dh" wrapping templates of the form "ffdhe2048(dh)", "ffdhe3072(dh)" and so on in order to provide built-in support for the well-known safe-prime ffdhe group parameters specified in RFC 7919. Those templates' ->set_secret() will wrap the inner "dh" implementation's ->set_secret() and set the ->p and ->g group parameters as appropriate on the way inwards. More specifically, - A ffdheXYZ(dh) user would call crypto_dh_encode() on a struct dh instance having ->p == ->g == NULL as well as ->p_size == ->g_size == 0 and pass the resulting buffer to the outer ->set_secret(). - This outer ->set_secret() would then decode the struct dh via crypto_dh_decode_key(), set ->p, ->g, ->p_size as well as ->g_size as appropriate for the group in question and encode the struct dh again before passing it further down to the inner "dh"'s ->set_secret(). The problem is that crypto_dh_decode_key() implements some basic checks which would reject parameter sets with ->p_size == 0 and thus, the ffdheXYZ templates' ->set_secret() cannot use it as-is for decoding the passed buffer. As the inner "dh"'s ->set_secret() will eventually conduct said checks on the final parameter set anyway, the outer ->set_secret() really only needs the decoding functionality. Split out the pure struct dh decoding part from crypto_dh_decode_key() into the new __crypto_dh_decode_key(). __crypto_dh_decode_key() gets defined in crypto/dh_helper.c, but will have to get called from crypto/dh.c and thus, its declaration must be somehow made available to the latter. Strictly speaking, __crypto_dh_decode_key() is internal to the dh_generic module, yet it would be a bit over the top to introduce a new header like e.g. include/crypto/internal/dh.h containing just a single prototype. Add the __crypto_dh_decode_key() declaration to include/crypto/dh.h instead. Provide a proper kernel-doc annotation, even though __crypto_dh_decode_key() is purposedly not on the function list specified in Documentation/crypto/api-kpp.rst. Signed-off-by: Nicolai Stange <nstange@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-03-03crypto: dh - remove struct dh's ->q memberNicolai Stange
The only current user of the DH KPP algorithm, the keyctl(KEYCTL_DH_COMPUTE) syscall, doesn't set the domain parameter ->q in struct dh. Remove it and any associated (de)serialization code in crypto_dh_encode_key() and crypto_dh_decode_key. Adjust the encoded ->secret values in testmgr's DH test vectors accordingly. Note that the dh-generic implementation would have initialized its struct dh_ctx's ->q from the decoded struct dh's ->q, if present. If this struct dh_ctx's ->q would ever have been non-NULL, it would have enabled a full key validation as specified in NIST SP800-56A in dh_is_pubkey_valid(). However, as outlined above, ->q is always NULL in practice and the full key validation code is effectively dead. A later patch will make dh_is_pubkey_valid() to calculate Q from P on the fly, if possible, so don't remove struct dh_ctx's ->q now, but leave it there until that has happened. Signed-off-by: Nicolai Stange <nstange@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-03crypto: dh - make crypto_dh_encode_key() make robustEric Biggers
Make it return -EINVAL if crypto_dh_key_len() is incorrect rather than overflowing the buffer. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-08-03crypto: dh - fix calculating encoded key sizeEric Biggers
It was forgotten to increase DH_KPP_SECRET_MIN_SIZE to include 'q_size', causing an out-of-bounds write of 4 bytes in crypto_dh_encode_key(), and an out-of-bounds read of 4 bytes in crypto_dh_decode_key(). Fix it, and fix the lengths of the test vectors to match this. Reported-by: syzbot+6d38d558c25b53b8f4ed@syzkaller.appspotmail.com Fixes: e3fe0ae12962 ("crypto: dh - add public key verification test") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-07-09crypto: dh - add public key verification testStephan Mueller
According to SP800-56A section 5.6.2.1, the public key to be processed for the DH operation shall be checked for appropriateness. The check shall covers the full verification test in case the domain parameter Q is provided as defined in SP800-56A section 5.6.2.3.1. If Q is not provided, the partial check according to SP800-56A section 5.6.2.3.2 is performed. The full verification test requires the presence of the domain parameter Q. Thus, the patch adds the support to handle Q. It is permissible to not provide the Q value as part of the domain parameters. This implies that the interface is still backwards-compatible where so far only P and G are to be provided. However, if Q is provided, it is imported. Without the test, the NIST ACVP testing fails. After adding this check, the NIST ACVP testing passes. Testing without providing the Q domain parameter has been performed to verify the interface has not changed. Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-11-10crypto: dh - Don't permit 'key' or 'g' size longer than 'p'Eric Biggers
The "qat-dh" DH implementation assumes that 'key' and 'g' can be copied into a buffer with size 'p_size'. However it was never checked that that was actually the case, which most likely allowed users to cause a buffer underflow via KEYCTL_DH_COMPUTE. Fix this by updating crypto_dh_decode_key() to verify this precondition for all DH implementations. Fixes: c9839143ebbf ("crypto: qat - Add DH support") Cc: <stable@vger.kernel.org> # v4.8+ Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-11-10crypto: dh - Don't permit 'p' to be 0Eric Biggers
If 'p' is 0 for the software Diffie-Hellman implementation, then dh_max_size() returns 0. In the case of KEYCTL_DH_COMPUTE, this causes ZERO_SIZE_PTR to be passed to sg_init_one(), which with CONFIG_DEBUG_SG=y triggers the 'BUG_ON(!virt_addr_valid(buf));' in sg_set_buf(). Fix this by making crypto_dh_decode_key() reject 0 for 'p'. p=0 makes no sense for any DH implementation because 'p' is supposed to be a prime number. Moreover, 'mod 0' is not mathematically defined. Bug report: kernel BUG at ./include/linux/scatterlist.h:140! invalid opcode: 0000 [#1] SMP KASAN CPU: 0 PID: 27112 Comm: syz-executor2 Not tainted 4.14.0-rc7-00010-gf5dbb5d0ce32-dirty #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.3-20171021_125229-anatol 04/01/2014 task: ffff88006caac0c0 task.stack: ffff88006c7c8000 RIP: 0010:sg_set_buf include/linux/scatterlist.h:140 [inline] RIP: 0010:sg_init_one+0x1b3/0x240 lib/scatterlist.c:156 RSP: 0018:ffff88006c7cfb08 EFLAGS: 00010216 RAX: 0000000000010000 RBX: ffff88006c7cfe30 RCX: 00000000000064ee RDX: ffffffff81cf64c3 RSI: ffffc90000d72000 RDI: ffffffff92e937e0 RBP: ffff88006c7cfb30 R08: ffffed000d8f9fab R09: ffff88006c7cfd30 R10: 0000000000000005 R11: ffffed000d8f9faa R12: ffff88006c7cfd30 R13: 0000000000000000 R14: 0000000000000010 R15: ffff88006c7cfc50 FS: 00007fce190fa700(0000) GS:ffff88003ea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fffc6b33db8 CR3: 000000003cf64000 CR4: 00000000000006f0 Call Trace: __keyctl_dh_compute+0xa95/0x19b0 security/keys/dh.c:360 keyctl_dh_compute+0xac/0x100 security/keys/dh.c:434 SYSC_keyctl security/keys/keyctl.c:1745 [inline] SyS_keyctl+0x72/0x2c0 security/keys/keyctl.c:1641 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x4585c9 RSP: 002b:00007fce190f9bd8 EFLAGS: 00000216 ORIG_RAX: 00000000000000fa RAX: ffffffffffffffda RBX: 0000000000738020 RCX: 00000000004585c9 RDX: 000000002000d000 RSI: 0000000020000ff4 RDI: 0000000000000017 RBP: 0000000000000046 R08: 0000000020008000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000216 R12: 00007fff6e610cde R13: 00007fff6e610cdf R14: 00007fce190fa700 R15: 0000000000000000 Code: 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 33 5b 45 89 6c 24 14 41 5c 41 5d 41 5e 41 5f 5d c3 e8 fd 8f 68 ff <0f> 0b e8 f6 8f 68 ff 0f 0b e8 ef 8f 68 ff 0f 0b e8 e8 8f 68 ff 20 RIP: sg_set_buf include/linux/scatterlist.h:140 [inline] RSP: ffff88006c7cfb08 RIP: sg_init_one+0x1b3/0x240 lib/scatterlist.c:156 RSP: ffff88006c7cfb08 Fixes: 802c7f1c84e4 ("crypto: dh - Add DH software implementation") Cc: <stable@vger.kernel.org> # v4.8+ Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-10-12crypto: dh - return unsigned value for crypto_dh_key_len()Tudor-Dan Ambarus
DH_KPP_SECRET_MIN_SIZE and dh_data_size() are both returning unsigned values. Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-10-12crypto: dh - return unsigned int for dh_data_size()Tudor-Dan Ambarus
p->key_size, p->p_size, p->g_size are all of unsigned int type. Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-06-10crypto: kpp, (ec)dh - fix typosTudor-Dan Ambarus
While here, add missing argument description (ndigits). Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-06-23crypto: dh - Add DH software implementationSalvatore Benedetto
* Implement MPI based Diffie-Hellman under kpp API * Test provided uses data generad by OpenSSL Signed-off-by: Salvatore Benedetto <salvatore.benedetto@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>