From: Eric Biggers <ebiggers@xxxxxxxxxx> Add helper functions for creating and using AF_ALG sockets. AF_ALG is the userspace interface to algorithms in the Linux kernel's crypto API. See https://www.kernel.org/doc/html/latest/crypto/userspace-if.html for more information about this interface. Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> --- configure.ac | 1 + include/lapi/if_alg.h | 40 ++++++++++++ include/tst_af_alg.h | 136 ++++++++++++++++++++++++++++++++++++++ lib/tst_af_alg.c | 147 ++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 324 insertions(+) create mode 100644 include/lapi/if_alg.h create mode 100644 include/tst_af_alg.h create mode 100644 lib/tst_af_alg.c diff --git a/configure.ac b/configure.ac index caea34462f..229815694c 100644 --- a/configure.ac +++ b/configure.ac @@ -40,6 +40,7 @@ AC_CHECK_HEADERS([ \ linux/cryptouser.h \ linux/genetlink.h \ linux/keyctl.h \ + linux/if_alg.h \ linux/if_packet.h \ linux/if_ether.h \ linux/mempolicy.h \ diff --git a/include/lapi/if_alg.h b/include/lapi/if_alg.h new file mode 100644 index 0000000000..2fc5e7b5e3 --- /dev/null +++ b/include/lapi/if_alg.h @@ -0,0 +1,40 @@ +#ifndef IF_ALG_H__ +#define IF_ALG_H__ + +#ifdef HAVE_LINUX_IF_ALG_H +# include <linux/if_alg.h> +#else +# include <stdint.h> + +struct sockaddr_alg { + uint16_t salg_family; + uint8_t salg_type[14]; + uint32_t salg_feat; + uint32_t salg_mask; + uint8_t salg_name[64]; +}; + +struct af_alg_iv { + uint32_t ivlen; + uint8_t iv[0]; +}; + +/* Socket options */ +#define ALG_SET_KEY 1 +#define ALG_SET_IV 2 +#define ALG_SET_OP 3 +#define ALG_SET_AEAD_ASSOCLEN 4 +#define ALG_SET_AEAD_AUTHSIZE 5 + +/* Operations */ +#define ALG_OP_DECRYPT 0 +#define ALG_OP_ENCRYPT 1 + +#endif /* !HAVE_LINUX_IF_ALG_H */ + +/* This isn't in any UAPI header */ +#ifndef SOL_ALG +# define SOL_ALG 279 +#endif + +#endif /* IF_ALG_H__ */ diff --git a/include/tst_af_alg.h b/include/tst_af_alg.h new file mode 100644 index 0000000000..55f080a574 --- /dev/null +++ b/include/tst_af_alg.h @@ -0,0 +1,136 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright 2019 Google LLC + */ +/** + * @file tst_af_alg.h + * + * Library for accessing kernel crypto algorithms via AF_ALG. + * + * See https://www.kernel.org/doc/html/latest/crypto/userspace-if.html + * for more information about AF_ALG. + */ + +#ifndef TST_AF_ALG_H +#define TST_AF_ALG_H + +#include "lapi/if_alg.h" +#include <stdbool.h> + +/** + * Create an AF_ALG algorithm socket. + * + * This creates an AF_ALG algorithm socket that is initially not bound to any + * particular algorithm. On failure, tst_brk() is called with TCONF if the + * kernel doesn't support AF_ALG, otherwise TBROK. + * + * @return a new AF_ALG algorithm socket + */ +int tst_alg_create(void); + +/** + * Bind an AF_ALG algorithm socket to an algorithm. + * + * @param alg_fd An AF_ALG algorithm socket + * @param addr A structure which specifies the algorithm to use + * + * On failure, tst_brk() is called with TCONF if the kernel doesn't support the + * specified algorithm, otherwise TBROK. + */ +void tst_alg_bind_addr(int alg_fd, const struct sockaddr_alg *addr); + +/** + * Bind an AF_ALG algorithm socket to an algorithm. + * + * @param alg_fd An AF_ALG algorithm socket + * @param algtype The type of algorithm, such as "hash" or "skcipher" + * @param algname The name of the algorithm, such as "sha256" or "xts(aes)" + * + * Like tst_alg_bind_addr(), except this just takes in the algorithm type and + * name. The 'feat' and 'mask' fields are left 0. + * + * On failure, tst_brk() is called with TCONF if the kernel doesn't support the + * specified algorithm, otherwise TBROK. + */ +void tst_alg_bind(int alg_fd, const char *algtype, const char *algname); + +/** + * Check for the availability of an algorithm. + * + * @param algtype The type of algorithm, such as "hash" or "skcipher" + * @param algname The name of the algorithm, such as "sha256" or "xts(aes)" + * + * Return true if the algorithm is available, or false if unavailable. + * If another error occurs, tst_brk() is called with TBROK. + */ +bool tst_have_alg(const char *algtype, const char *algname); + +/** + * Require the availability of an algorithm. + * + * @param algtype The type of algorithm, such as "hash" or "skcipher" + * @param algname The name of the algorithm, such as "sha256" or "xts(aes)" + * + * If the algorithm is unavailable, tst_brk() is called with TCONF. + * If another error occurs, tst_brk() is called with TBROK. + */ +void tst_require_alg(const char *algtype, const char *algname); + +/** + * Assign a cryptographic key to an AF_ALG algorithm socket. + * + * @param alg_fd An AF_ALG algorithm socket + * @param key Pointer to the key. If NULL, a random key is generated. + * @param keylen Length of the key in bytes + * + * On failure, tst_brk() is called with TBROK. + */ +void tst_alg_setkey(int alg_fd, const uint8_t *key, unsigned int keylen); + +/** + * Create an AF_ALG request socket for the given algorithm socket. + * + * @param alg_fd An AF_ALG algorithm socket + * + * This creates a request socket for the given algorithm socket, which must be + * bound to an algorithm. The same algorithm socket can have many request + * sockets used concurrently to perform independent cryptographic operations, + * e.g. hashing or encryption/decryption. But the key, if any, that has been + * assigned to the algorithm is shared by all request sockets. + * + * On failure, tst_brk() is called with TBROK. + * + * @return a new AF_ALG request socket + */ +int tst_alg_accept(int alg_fd); + +/** + * Set up an AF_ALG algorithm socket for the given algorithm w/ given key. + * + * @param algtype The type of algorithm, such as "hash" or "skcipher" + * @param algname The name of the algorithm, such as "sha256" or "xts(aes)" + * @param key The key to use (optional) + * @param keylen The length of the key in bytes (optional) + * + * This is a helper function which creates an AF_ALG algorithm socket, binds it + * to the specified algorithm, and optionally sets a key. If keylen is 0 then + * no key is set; otherwise if key is NULL a key of the given length is randomly + * generated and set; otherwise the given key is set. + * + * @return the AF_ALG algorithm socket that was set up + */ +int tst_alg_setup(const char *algtype, const char *algname, + const uint8_t *key, unsigned int keylen); + +/** + * Set up an AF_ALG request socket for the given algorithm w/ given key. + * + * This is like tst_alg_setup(), except this returns a request fd instead of the + * alg fd. The alg fd is closed, so it doesn't need to be kept track of. + * + * @return the AF_ALG request socket that was set up + */ +int tst_alg_setup_reqfd(const char *algtype, const char *algname, + const uint8_t *key, unsigned int keylen); + +#endif /* TST_AF_ALG_H */ diff --git a/lib/tst_af_alg.c b/lib/tst_af_alg.c new file mode 100644 index 0000000000..8702185d6f --- /dev/null +++ b/lib/tst_af_alg.c @@ -0,0 +1,147 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright 2019 Google LLC + */ + +#include <errno.h> +#include <stdlib.h> + +#define TST_NO_DEFAULT_MAIN +#include "tst_test.h" +#include "tst_af_alg.h" + +int tst_alg_create(void) +{ + TEST(socket(AF_ALG, SOCK_SEQPACKET, 0)); + if (TST_RET >= 0) + return TST_RET; + if (TST_ERR == EPROTONOSUPPORT) + tst_brk(TCONF, "kernel doesn't support AF_ALG"); + tst_brk(TBROK | TTERRNO, "unexpected error creating AF_ALG socket"); + return -1; +} + +void tst_alg_bind_addr(int algfd, const struct sockaddr_alg *addr) +{ + TEST(bind(algfd, (const struct sockaddr *)addr, sizeof(*addr))); + if (TST_RET == 0) + return; + if (TST_ERR == ENOENT) { + tst_brk(TCONF, "kernel doesn't support %s algorithm '%s'", + addr->salg_type, addr->salg_name); + } + tst_brk(TBROK | TTERRNO, + "unexpected error binding to AF_ALG socket for %s algorithm '%s'", + addr->salg_type, addr->salg_name); +} + +static void init_sockaddr_alg(struct sockaddr_alg *addr, + const char *algtype, const char *algname) +{ + memset(addr, 0, sizeof(*addr)); + + addr->salg_family = AF_ALG; + + strncpy((char *)addr->salg_type, algtype, sizeof(addr->salg_type)); + if (addr->salg_type[sizeof(addr->salg_type) - 1] != '\0') + tst_brk(TBROK, "algorithm type too long: '%s'", algtype); + + strncpy((char *)addr->salg_name, algname, sizeof(addr->salg_name)); + if (addr->salg_name[sizeof(addr->salg_name) - 1] != '\0') + tst_brk(TBROK, "algorithm name too long: '%s'", algname); +} + +void tst_alg_bind(int algfd, const char *algtype, const char *algname) +{ + struct sockaddr_alg addr; + + init_sockaddr_alg(&addr, algtype, algname); + + tst_alg_bind_addr(algfd, &addr); +} + +bool tst_have_alg(const char *algtype, const char *algname) +{ + int algfd; + struct sockaddr_alg addr; + bool have_alg = true; + + algfd = tst_alg_create(); + + init_sockaddr_alg(&addr, algtype, algname); + + TEST(bind(algfd, (const struct sockaddr *)&addr, sizeof(addr))); + if (TST_RET != 0) { + if (TST_ERR != ENOENT) { + tst_brk(TBROK | TTERRNO, + "unexpected error binding to AF_ALG socket for %s algorithm '%s'", + algtype, algname); + } + have_alg = false; + } + + close(algfd); + return have_alg; +} + +void tst_require_alg(const char *algtype, const char *algname) +{ + int algfd = tst_alg_create(); + + tst_alg_bind(algfd, algtype, algname); + + close(algfd); +} + +void tst_alg_setkey(int algfd, const uint8_t *key, unsigned int keylen) +{ + uint8_t *keybuf = NULL; + unsigned int i; + + if (key == NULL) { + /* generate a random key */ + keybuf = SAFE_MALLOC(keylen); + for (i = 0; i < keylen; i++) + keybuf[i] = rand(); + key = keybuf; + } + TEST(setsockopt(algfd, SOL_ALG, ALG_SET_KEY, key, keylen)); + if (TST_RET != 0) { + tst_brk(TBROK | TTERRNO, + "unexpected error setting key (len=%u)", keylen); + } + free(keybuf); +} + +int tst_alg_accept(int algfd) +{ + TEST(accept(algfd, NULL, NULL)); + if (TST_RET < 0) { + tst_brk(TBROK | TTERRNO, + "unexpected error accept()ing AF_ALG request socket"); + } + return TST_RET; +} + +int tst_alg_setup(const char *algtype, const char *algname, + const uint8_t *key, unsigned int keylen) +{ + int algfd = tst_alg_create(); + + tst_alg_bind(algfd, algtype, algname); + + if (keylen != 0) + tst_alg_setkey(algfd, key, keylen); + + return algfd; +} + +int tst_alg_setup_reqfd(const char *algtype, const char *algname, + const uint8_t *key, unsigned int keylen) +{ + int algfd = tst_alg_setup(algtype, algname, key, keylen); + int req_fd = tst_alg_accept(algfd); + + close(algfd); + return req_fd; +} -- 2.20.1
