diff options
| author | Demi Marie Obenour <demiobenour@gmail.com> | 2026-05-23 22:43:03 +0300 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2026-05-29 09:05:30 +0300 |
| commit | 7524070f26d8d347c26787dc297fb844baa26abf (patch) | |
| tree | 74f0a7b9a2e653829cdc6a4f2991458e6f5f6c0d /include | |
| parent | fcc77d33a34cf271702e8daafb6c593e4626776d (diff) | |
| download | linux-7524070f26d8d347c26787dc297fb844baa26abf.tar.xz | |
crypto: af_alg - Drop support for off-CPU cryptography
AF_ALG is deprecated and exposed to unprivileged userspace. Only
use the least buggy algorithm implementations: the pure software ones.
This removes one of the main advantages of AF_ALG, which is the
ability to use it with off-CPU accelerators. However, using off-CPU
accelerators has huge overheads, both in performance and attack surface.
I have yet to see real-world, performance-critical workloads where using
an accelerator via AF_ALG is actually a win over doing cryptography in
userspace.
If using an off-CPU accelerator really does turn out to be a win, a new
API should be developed that is actually a good fit for it.
Signed-off-by: Demi Marie Obenour <demiobenour@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'include')
| -rw-r--r-- | include/crypto/if_alg.h | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h index 62867daca47d..7643ba954125 100644 --- a/include/crypto/if_alg.h +++ b/include/crypto/if_alg.h @@ -41,7 +41,7 @@ struct af_alg_control { }; struct af_alg_type { - void *(*bind)(const char *name, u32 type, u32 mask); + void *(*bind)(const char *name); void (*release)(void *private); int (*setkey)(void *private, const u8 *key, unsigned int keylen); int (*setentropy)(void *private, sockptr_t entropy, unsigned int len); @@ -243,4 +243,16 @@ int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags, struct af_alg_async_req *areq, size_t maxsize, size_t *outlen); +/* + * Mask used to disable unsupported algorithm implementations. + * + * This is the same as FSCRYPT_CRYPTOAPI_MASK in fs/crypto/fscrypt_private.h. + * In additions to the motivations there, this API is exposed to userspace + * that might not be fully trusted. + */ +#define AF_ALG_CRYPTOAPI_MASK \ + (CRYPTO_ALG_ASYNC | CRYPTO_ALG_ALLOCATES_MEMORY | \ + CRYPTO_ALG_KERN_DRIVER_ONLY) + + #endif /* _CRYPTO_IF_ALG_H */ |