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2022-03-03crypto: dh - constify struct dh's pointer membersNicolai Stange1-1/+1
struct dh contains several pointer members corresponding to DH parameters: ->key, ->p and ->g. 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. These templates will need to set the group parameter related members of the (serialized) struct dh instance passed to the inner "dh" kpp_alg instance, i.e. ->p and ->g, to some constant, static storage arrays. Turn the struct dh pointer members' types into "pointer to const" in preparation for this. 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>
2021-11-26security: DH - use KDF implementation from crypto APIStephan Müller1-91/+18
The kernel crypto API provides the SP800-108 counter KDF implementation. Thus, the separate implementation provided as part of the keys subsystem can be replaced with calls to the KDF offered by the kernel crypto API. The keys subsystem uses the counter KDF with a hash primitive. Thus, it only uses the call to crypto_kdf108_ctr_generate. Signed-off-by: Stephan Mueller <smueller@chronox.de> Acked-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2021-11-26security: DH - remove dead code for zero paddingStephan Müller1-21/+4
Remove the specific code that adds a zero padding that was intended to be invoked when the DH operation result was smaller than the modulus. However, this cannot occur any more these days because the function mpi_write_to_sgl is used in the code path that calculates the shared secret in dh_compute_value. This MPI service function guarantees that leading zeros are introduced as needed to ensure the resulting data is exactly as long as the modulus. This implies that the specific code to add zero padding is dead code which can be safely removed. Signed-off-by: Stephan Mueller <smueller@chronox.de> Acked-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-08-07mm, treewide: rename kzfree() to kfree_sensitive()Waiman Long1-7/+7
As said by Linus: A symmetric naming is only helpful if it implies symmetries in use. Otherwise it's actively misleading. In "kzalloc()", the z is meaningful and an important part of what the caller wants. In "kzfree()", the z is actively detrimental, because maybe in the future we really _might_ want to use that "memfill(0xdeadbeef)" or something. The "zero" part of the interface isn't even _relevant_. The main reason that kzfree() exists is to clear sensitive information that should not be leaked to other future users of the same memory objects. Rename kzfree() to kfree_sensitive() to follow the example of the recently added kvfree_sensitive() and make the intention of the API more explicit. In addition, memzero_explicit() is used to clear the memory to make sure that it won't get optimized away by the compiler. The renaming is done by using the command sequence: git grep -w --name-only kzfree |\ xargs sed -i 's/kzfree/kfree_sensitive/' followed by some editing of the kfree_sensitive() kerneldoc and adding a kzfree backward compatibility macro in slab.h. [akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h] [akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more] Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Joe Perches <joe@perches.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner1-5/+1
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>
2019-04-25crypto: shash - remove shash_desc::flagsEric Biggers1-1/+0
The flags field in 'struct shash_desc' never actually does anything. The only ostensibly supported flag is CRYPTO_TFM_REQ_MAY_SLEEP. However, no shash algorithm ever sleeps, making this flag a no-op. With this being the case, inevitably some users who can't sleep wrongly pass MAY_SLEEP. These would all need to be fixed if any shash algorithm actually started sleeping. For example, the shash_ahash_*() functions, which wrap a shash algorithm with the ahash API, pass through MAY_SLEEP from the ahash API to the shash API. However, the shash functions are called under kmap_atomic(), so actually they're assumed to never sleep. Even if it turns out that some users do need preemption points while hashing large buffers, we could easily provide a helper function crypto_shash_update_large() which divides the data into smaller chunks and calls crypto_shash_update() and cond_resched() for each chunk. It's not necessary to have a flag in 'struct shash_desc', nor is it necessary to make individual shash algorithms aware of this at all. Therefore, remove shash_desc::flags, and document that the crypto_shash_*() functions can be called from any context. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-09-25Revert "uapi/linux/keyctl.h: don't use C++ reserved keyword as a struct member name"Lubomir Rintel1-1/+1
This changes UAPI, breaking iwd and libell: ell/key.c: In function 'kernel_dh_compute': ell/key.c:205:38: error: 'struct keyctl_dh_params' has no member named 'private'; did you mean 'dh_private'? struct keyctl_dh_params params = { .private = private, ^~~~~~~ dh_private This reverts commit 8a2336e549d385bb0b46880435b411df8d8200e8. Fixes: 8a2336e549d3 ("uapi/linux/keyctl.h: don't use C++ reserved keyword as a struct member name") Signed-off-by: Lubomir Rintel <lkundrak@v3.sk> Signed-off-by: David Howells <dhowells@redhat.com> cc: Randy Dunlap <rdunlap@infradead.org> cc: Mat Martineau <mathew.j.martineau@linux.intel.com> cc: Stephan Mueller <smueller@chronox.de> cc: James Morris <jmorris@namei.org> cc: "Serge E. Hallyn" <serge@hallyn.com> cc: Mat Martineau <mathew.j.martineau@linux.intel.com> cc: Andrew Morton <akpm@linux-foundation.org> cc: Linus Torvalds <torvalds@linux-foundation.org> cc: <stable@vger.kernel.org> Signed-off-by: James Morris <james.morris@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-04uapi/linux/keyctl.h: don't use C++ reserved keyword as a struct member nameRandy Dunlap1-1/+1
Since this header is in "include/uapi/linux/", apparently people want to use it in userspace programs -- even in C++ ones. However, the header uses a C++ reserved keyword ("private"), so change that to "dh_private" instead to allow the header file to be used in C++ userspace. Fixes https://bugzilla.kernel.org/show_bug.cgi?id=191051 Link: http://lkml.kernel.org/r/0db6c314-1ef4-9bfa-1baa-7214dd2ee061@infradead.org Fixes: ddbb41148724 ("KEYS: Add KEYCTL_DH_COMPUTE command") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: David Howells <dhowells@redhat.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Mat Martineau <mathew.j.martineau@linux.intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-03Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linuxHerbert Xu1-2/+4
Merge mainline to pick up c7513c2a2714 ("crypto/arm64: aes-ce-gcm - add missing kernel_neon_begin/end pair").
2018-07-09crypto: remove redundant type flags from tfm allocationEric Biggers1-1/+1
Some crypto API users allocating a tfm with crypto_alloc_$FOO() are also specifying the type flags for $FOO, e.g. crypto_alloc_shash() with CRYPTO_ALG_TYPE_SHASH. But, that's redundant since the crypto API will override any specified type flag/mask with the correct ones. So, remove the unneeded flags. This patch shouldn't change any actual behavior. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-06-26dh key: fix rounding up KDF output lengthEric Biggers1-2/+4
Commit 383203eff718 ("dh key: get rid of stack allocated array") changed kdf_ctr() to assume that the length of key material to derive is a multiple of the digest size. The length was supposed to be rounded up accordingly. However, the round_up() macro was used which only gives the correct result on power-of-2 arguments, whereas not all hash algorithms have power-of-2 digest sizes. In some cases this resulted in a write past the end of the 'outbuf' buffer. Fix it by switching to roundup(), which works for non-power-of-2 inputs. Reported-by: syzbot+486f97f892efeb2075a3@syzkaller.appspotmail.com Reported-by: syzbot+29d17b7898b41ee120a5@syzkaller.appspotmail.com Reported-by: syzbot+8a608baf8751184ec727@syzkaller.appspotmail.com Reported-by: syzbot+d04e58bd384f1fe0b112@syzkaller.appspotmail.com Fixes: 383203eff718 ("dh key: get rid of stack allocated array") Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Tycho Andersen <tycho@tycho.ws> Signed-off-by: James Morris <james.morris@microsoft.com>
2018-05-11dh key: get rid of stack allocated array for zeroesTycho Andersen1-3/+3
We're interested in getting rid of all of the stack allocated arrays in the kernel: https://lkml.org/lkml/2018/3/7/621 This case is interesting, since we really just need an array of bytes that are zero. The loop already ensures that if the array isn't exactly the right size that enough zero bytes will be copied in. So, instead of choosing this value to be the size of the hash, let's just choose it to be 32, since that is a common size, is not too big, and will not result in too many extra iterations of the loop. v2: split out from other patch, just hardcode array size instead of dynamically allocating something the right size v3: fix typo of 256 -> 32 Signed-off-by: Tycho Andersen <tycho@tycho.ws> Reviewed-by: Kees Cook <keescook@chromium.org> CC: David Howells <dhowells@redhat.com> CC: James Morris <jmorris@namei.org> CC: "Serge E. Hallyn" <serge@hallyn.com> CC: Eric Biggers <ebiggers3@gmail.com> Signed-off-by: James Morris <james.morris@microsoft.com>
2018-05-11dh key: get rid of stack allocated arrayTycho Andersen1-19/+10
We're interested in getting rid of all of the stack allocated arrays in the kernel: https://lkml.org/lkml/2018/3/7/621 This particular vla is used as a temporary output buffer in case there is too much hash output for the destination buffer. Instead, let's just allocate a buffer that's big enough initially, but only copy back to userspace the amount that was originally asked for. v2: allocate enough in the original output buffer vs creating a temporary output buffer Signed-off-by: Tycho Andersen <tycho@tycho.ws> Reviewed-by: Kees Cook <keescook@chromium.org> CC: David Howells <dhowells@redhat.com> CC: James Morris <jmorris@namei.org> CC: "Serge E. Hallyn" <serge@hallyn.com> CC: Eric Biggers <ebiggers3@gmail.com> Signed-off-by: James Morris <james.morris@microsoft.com>
2017-07-14KEYS: DH: validate __spare fieldEric Biggers1-0/+5
Syscalls must validate that their reserved arguments are zero and return EINVAL otherwise. Otherwise, it will be impossible to actually use them for anything in the future because existing programs may be passing garbage in. This is standard practice when adding new APIs. Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-06-09KEYS: Convert KEYCTL_DH_COMPUTE to use the crypto KPP APIMat Martineau1-102/+170
The initial Diffie-Hellman computation made direct use of the MPI library because the crypto module did not support DH at the time. Now that KPP is implemented, KEYCTL_DH_COMPUTE should use it to get rid of duplicate code and leverage possible hardware acceleration. This fixes an issue whereby the input to the KDF computation would include additional uninitialized memory when the result of the Diffie-Hellman computation was shorter than the input prime number. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-06-09KEYS: DH: ensure the KDF counter is properly alignedEric Biggers1-13/+3
Accessing a 'u8[4]' through a '__be32 *' violates alignment rules. Just make the counter a __be32 instead. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-06-09KEYS: DH: don't feed uninitialized "otherinfo" into KDFEric Biggers1-1/+1
If userspace called KEYCTL_DH_COMPUTE with kdf_params containing NULL otherinfo but nonzero otherinfolen, the kernel would allocate a buffer for the otherinfo, then feed it into the KDF without initializing it. Fix this by always doing the copy from userspace (which will fail with EFAULT in this scenario). Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-06-09KEYS: DH: forbid using digest_null as the KDF hashEric Biggers1-1/+11
Requesting "digest_null" in the keyctl_kdf_params caused an infinite loop in kdf_ctr() because the "null" hash has a digest size of 0. Fix it by rejecting hash algorithms with a digest size of 0. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-04-04KEYS: add SP800-56A KDF support for DHStephan Mueller1-12/+208
SP800-56A defines the use of DH with key derivation function based on a counter. The input to the KDF is defined as (DH shared secret || other information). The value for the "other information" is to be provided by the caller. The KDF is implemented using the hash support from the kernel crypto API. The implementation uses the symmetric hash support as the input to the hash operation is usually very small. The caller is allowed to specify the hash name that he wants to use to derive the key material allowing the use of all supported hashes provided with the kernel crypto API. As the KDF implements the proper truncation of the DH shared secret to the requested size, this patch fills the caller buffer up to its size. The patch is tested with a new test added to the keyutils user space code which uses a CAVS test vector testing the compliance with SP800-56A. Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: David Howells <dhowells@redhat.com>
2017-03-02KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload()David Howells1-1/+1
rcu_dereference_key() and user_key_payload() are currently being used in two different, incompatible ways: (1) As a wrapper to rcu_dereference() - when only the RCU read lock used to protect the key. (2) As a wrapper to rcu_dereference_protected() - when the key semaphor is used to protect the key and the may be being modified. Fix this by splitting both of the key wrappers to produce: (1) RCU accessors for keys when caller has the key semaphore locked: dereference_key_locked() user_key_payload_locked() (2) RCU accessors for keys when caller holds the RCU read lock: dereference_key_rcu() user_key_payload_rcu() This should fix following warning in the NFS idmapper =============================== [ INFO: suspicious RCU usage. ] 4.10.0 #1 Tainted: G W ------------------------------- ./include/keys/user-type.h:53 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 0 1 lock held by mount.nfs/5987: #0: (rcu_read_lock){......}, at: [<d000000002527abc>] nfs_idmap_get_key+0x15c/0x420 [nfsv4] stack backtrace: CPU: 1 PID: 5987 Comm: mount.nfs Tainted: G W 4.10.0 #1 Call Trace: dump_stack+0xe8/0x154 (unreliable) lockdep_rcu_suspicious+0x140/0x190 nfs_idmap_get_key+0x380/0x420 [nfsv4] nfs_map_name_to_uid+0x2a0/0x3b0 [nfsv4] decode_getfattr_attrs+0xfac/0x16b0 [nfsv4] decode_getfattr_generic.constprop.106+0xbc/0x150 [nfsv4] nfs4_xdr_dec_lookup_root+0xac/0xb0 [nfsv4] rpcauth_unwrap_resp+0xe8/0x140 [sunrpc] call_decode+0x29c/0x910 [sunrpc] __rpc_execute+0x140/0x8f0 [sunrpc] rpc_run_task+0x170/0x200 [sunrpc] nfs4_call_sync_sequence+0x68/0xa0 [nfsv4] _nfs4_lookup_root.isra.44+0xd0/0xf0 [nfsv4] nfs4_lookup_root+0xe0/0x350 [nfsv4] nfs4_lookup_root_sec+0x70/0xa0 [nfsv4] nfs4_find_root_sec+0xc4/0x100 [nfsv4] nfs4_proc_get_rootfh+0x5c/0xf0 [nfsv4] nfs4_get_rootfh+0x6c/0x190 [nfsv4] nfs4_server_common_setup+0xc4/0x260 [nfsv4] nfs4_create_server+0x278/0x3c0 [nfsv4] nfs4_remote_mount+0x50/0xb0 [nfsv4] mount_fs+0x74/0x210 vfs_kern_mount+0x78/0x220 nfs_do_root_mount+0xb0/0x140 [nfsv4] nfs4_try_mount+0x60/0x100 [nfsv4] nfs_fs_mount+0x5ec/0xda0 [nfs] mount_fs+0x74/0x210 vfs_kern_mount+0x78/0x220 do_mount+0x254/0xf70 SyS_mount+0x94/0x100 system_call+0x38/0xe0 Reported-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
2016-06-03KEYS: Add placeholder for KDF usage with DHStephan Mueller1-1/+7
The values computed during Diffie-Hellman key exchange are often used in combination with key derivation functions to create cryptographic keys. Add a placeholder for a later implementation to configure a key derivation function that will transform the Diffie-Hellman result returned by the KEYCTL_DH_COMPUTE command. [This patch was stripped down from a patch produced by Mat Martineau that had a bug in the compat code - so for the moment Stephan's patch simply requires that the placeholder argument must be NULL] Original-signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
2016-04-12KEYS: Add KEYCTL_DH_COMPUTE commandMat Martineau1-0/+160
This adds userspace access to Diffie-Hellman computations through a new keyctl() syscall command to calculate shared secrets or public keys using input parameters stored in the keyring. Input key ids are provided in a struct due to the current 5-arg limit for the keyctl syscall. Only user keys are supported in order to avoid exposing the content of logon or encrypted keys. The output is written to the provided buffer, based on the assumption that the values are only needed in userspace. Future support for other types of key derivation would involve a new command, like KEYCTL_ECDH_COMPUTE. Once Diffie-Hellman support is included in the crypto API, this code can be converted to use the crypto API to take advantage of possible hardware acceleration and reduce redundant code. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David Howells <dhowells@redhat.com>