linux/crypto/kpp.c

151 lines
3.6 KiB
C
Raw Normal View History

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Key-agreement Protocol Primitives (KPP)
*
* Copyright (c) 2016, Intel Corporation
* Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>
*/
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/crypto.h>
#include <crypto/algapi.h>
#include <linux/cryptouser.h>
#include <linux/compiler.h>
#include <net/netlink.h>
#include <crypto/kpp.h>
#include <crypto/internal/kpp.h>
#include "internal.h"
#ifdef CONFIG_NET
static int crypto_kpp_report(struct sk_buff *skb, struct crypto_alg *alg)
{
struct crypto_report_kpp rkpp;
crypto: user - clean up report structure copying There have been a pretty ridiculous number of issues with initializing the report structures that are copied to userspace by NETLINK_CRYPTO. Commit 4473710df1f8 ("crypto: user - Prepare for CRYPTO_MAX_ALG_NAME expansion") replaced some strncpy()s with strlcpy()s, thereby introducing information leaks. Later two other people tried to replace other strncpy()s with strlcpy() too, which would have introduced even more information leaks: - https://lore.kernel.org/patchwork/patch/954991/ - https://patchwork.kernel.org/patch/10434351/ Commit cac5818c25d0 ("crypto: user - Implement a generic crypto statistics") also uses the buggy strlcpy() approach and therefore leaks uninitialized memory to userspace. A fix was proposed, but it was originally incomplete. Seeing as how apparently no one can get this right with the current approach, change all the reporting functions to: - Start by memsetting the report structure to 0. This guarantees it's always initialized, regardless of what happens later. - Initialize all strings using strscpy(). This is safe after the memset, ensures null termination of long strings, avoids unnecessary work, and avoids the -Wstringop-truncation warnings from gcc. - Use sizeof(var) instead of sizeof(type). This is more robust against copy+paste errors. For simplicity, also reuse the -EMSGSIZE return value from nla_put(). Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-11-03 21:56:03 +00:00
memset(&rkpp, 0, sizeof(rkpp));
crypto: user - clean up report structure copying There have been a pretty ridiculous number of issues with initializing the report structures that are copied to userspace by NETLINK_CRYPTO. Commit 4473710df1f8 ("crypto: user - Prepare for CRYPTO_MAX_ALG_NAME expansion") replaced some strncpy()s with strlcpy()s, thereby introducing information leaks. Later two other people tried to replace other strncpy()s with strlcpy() too, which would have introduced even more information leaks: - https://lore.kernel.org/patchwork/patch/954991/ - https://patchwork.kernel.org/patch/10434351/ Commit cac5818c25d0 ("crypto: user - Implement a generic crypto statistics") also uses the buggy strlcpy() approach and therefore leaks uninitialized memory to userspace. A fix was proposed, but it was originally incomplete. Seeing as how apparently no one can get this right with the current approach, change all the reporting functions to: - Start by memsetting the report structure to 0. This guarantees it's always initialized, regardless of what happens later. - Initialize all strings using strscpy(). This is safe after the memset, ensures null termination of long strings, avoids unnecessary work, and avoids the -Wstringop-truncation warnings from gcc. - Use sizeof(var) instead of sizeof(type). This is more robust against copy+paste errors. For simplicity, also reuse the -EMSGSIZE return value from nla_put(). Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-11-03 21:56:03 +00:00
strscpy(rkpp.type, "kpp", sizeof(rkpp.type));
crypto: user - clean up report structure copying There have been a pretty ridiculous number of issues with initializing the report structures that are copied to userspace by NETLINK_CRYPTO. Commit 4473710df1f8 ("crypto: user - Prepare for CRYPTO_MAX_ALG_NAME expansion") replaced some strncpy()s with strlcpy()s, thereby introducing information leaks. Later two other people tried to replace other strncpy()s with strlcpy() too, which would have introduced even more information leaks: - https://lore.kernel.org/patchwork/patch/954991/ - https://patchwork.kernel.org/patch/10434351/ Commit cac5818c25d0 ("crypto: user - Implement a generic crypto statistics") also uses the buggy strlcpy() approach and therefore leaks uninitialized memory to userspace. A fix was proposed, but it was originally incomplete. Seeing as how apparently no one can get this right with the current approach, change all the reporting functions to: - Start by memsetting the report structure to 0. This guarantees it's always initialized, regardless of what happens later. - Initialize all strings using strscpy(). This is safe after the memset, ensures null termination of long strings, avoids unnecessary work, and avoids the -Wstringop-truncation warnings from gcc. - Use sizeof(var) instead of sizeof(type). This is more robust against copy+paste errors. For simplicity, also reuse the -EMSGSIZE return value from nla_put(). Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-11-03 21:56:03 +00:00
return nla_put(skb, CRYPTOCFGA_REPORT_KPP, sizeof(rkpp), &rkpp);
}
#else
static int crypto_kpp_report(struct sk_buff *skb, struct crypto_alg *alg)
{
return -ENOSYS;
}
#endif
static void crypto_kpp_show(struct seq_file *m, struct crypto_alg *alg)
__maybe_unused;
static void crypto_kpp_show(struct seq_file *m, struct crypto_alg *alg)
{
seq_puts(m, "type : kpp\n");
}
static void crypto_kpp_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_kpp *kpp = __crypto_kpp_tfm(tfm);
struct kpp_alg *alg = crypto_kpp_alg(kpp);
alg->exit(kpp);
}
static int crypto_kpp_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_kpp *kpp = __crypto_kpp_tfm(tfm);
struct kpp_alg *alg = crypto_kpp_alg(kpp);
if (alg->exit)
kpp->base.exit = crypto_kpp_exit_tfm;
if (alg->init)
return alg->init(kpp);
return 0;
}
crypto: kpp - provide support for KPP template instances The upcoming support for the RFC 7919 ffdhe group parameters will be made available in the form of templates like "ffdhe2048(dh)", "ffdhe3072(dh)" and so on. Template instantiations thereof would wrap the inner "dh" kpp_alg and also provide kpp_alg services to the outside again. Furthermore, it might be perhaps be desirable to provide KDF templates in the future, which would similarly wrap an inner kpp_alg and present themselves to the outside as another kpp_alg, transforming the shared secret on its way out. Introduce the bits needed for supporting KPP template instances. Everything related to inner kpp_alg spawns potentially being held by such template instances will be deferred to a subsequent patch in order to facilitate review. Define struct struct kpp_instance in close analogy to the already existing skcipher_instance, shash_instance and alike, but wrapping a struct kpp_alg. Implement the new kpp_register_instance() template instance registration primitive. Provide some helper functions for - going back and forth between a generic struct crypto_instance and the new struct kpp_instance, - obtaining the instantiating kpp_instance from a crypto_kpp transform and - for accessing a given kpp_instance's implementation specific context data. Annotate everything with proper kernel-doc comments, even though include/crypto/internal/kpp.h is not considered for the generated docs. 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>
2022-02-21 12:10:47 +00:00
static void crypto_kpp_free_instance(struct crypto_instance *inst)
{
struct kpp_instance *kpp = kpp_instance(inst);
kpp->free(kpp);
}
static const struct crypto_type crypto_kpp_type = {
.extsize = crypto_alg_extsize,
.init_tfm = crypto_kpp_init_tfm,
crypto: kpp - provide support for KPP template instances The upcoming support for the RFC 7919 ffdhe group parameters will be made available in the form of templates like "ffdhe2048(dh)", "ffdhe3072(dh)" and so on. Template instantiations thereof would wrap the inner "dh" kpp_alg and also provide kpp_alg services to the outside again. Furthermore, it might be perhaps be desirable to provide KDF templates in the future, which would similarly wrap an inner kpp_alg and present themselves to the outside as another kpp_alg, transforming the shared secret on its way out. Introduce the bits needed for supporting KPP template instances. Everything related to inner kpp_alg spawns potentially being held by such template instances will be deferred to a subsequent patch in order to facilitate review. Define struct struct kpp_instance in close analogy to the already existing skcipher_instance, shash_instance and alike, but wrapping a struct kpp_alg. Implement the new kpp_register_instance() template instance registration primitive. Provide some helper functions for - going back and forth between a generic struct crypto_instance and the new struct kpp_instance, - obtaining the instantiating kpp_instance from a crypto_kpp transform and - for accessing a given kpp_instance's implementation specific context data. Annotate everything with proper kernel-doc comments, even though include/crypto/internal/kpp.h is not considered for the generated docs. 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>
2022-02-21 12:10:47 +00:00
.free = crypto_kpp_free_instance,
#ifdef CONFIG_PROC_FS
.show = crypto_kpp_show,
#endif
.report = crypto_kpp_report,
.maskclear = ~CRYPTO_ALG_TYPE_MASK,
.maskset = CRYPTO_ALG_TYPE_MASK,
.type = CRYPTO_ALG_TYPE_KPP,
.tfmsize = offsetof(struct crypto_kpp, base),
};
struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask)
{
return crypto_alloc_tfm(alg_name, &crypto_kpp_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_kpp);
int crypto_grab_kpp(struct crypto_kpp_spawn *spawn,
struct crypto_instance *inst,
const char *name, u32 type, u32 mask)
{
spawn->base.frontend = &crypto_kpp_type;
return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_grab_kpp);
int crypto_has_kpp(const char *alg_name, u32 type, u32 mask)
{
return crypto_type_has_alg(alg_name, &crypto_kpp_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_has_kpp);
static void kpp_prepare_alg(struct kpp_alg *alg)
{
struct crypto_alg *base = &alg->base;
base->cra_type = &crypto_kpp_type;
base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
base->cra_flags |= CRYPTO_ALG_TYPE_KPP;
}
int crypto_register_kpp(struct kpp_alg *alg)
{
struct crypto_alg *base = &alg->base;
kpp_prepare_alg(alg);
return crypto_register_alg(base);
}
EXPORT_SYMBOL_GPL(crypto_register_kpp);
void crypto_unregister_kpp(struct kpp_alg *alg)
{
crypto_unregister_alg(&alg->base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_kpp);
crypto: kpp - provide support for KPP template instances The upcoming support for the RFC 7919 ffdhe group parameters will be made available in the form of templates like "ffdhe2048(dh)", "ffdhe3072(dh)" and so on. Template instantiations thereof would wrap the inner "dh" kpp_alg and also provide kpp_alg services to the outside again. Furthermore, it might be perhaps be desirable to provide KDF templates in the future, which would similarly wrap an inner kpp_alg and present themselves to the outside as another kpp_alg, transforming the shared secret on its way out. Introduce the bits needed for supporting KPP template instances. Everything related to inner kpp_alg spawns potentially being held by such template instances will be deferred to a subsequent patch in order to facilitate review. Define struct struct kpp_instance in close analogy to the already existing skcipher_instance, shash_instance and alike, but wrapping a struct kpp_alg. Implement the new kpp_register_instance() template instance registration primitive. Provide some helper functions for - going back and forth between a generic struct crypto_instance and the new struct kpp_instance, - obtaining the instantiating kpp_instance from a crypto_kpp transform and - for accessing a given kpp_instance's implementation specific context data. Annotate everything with proper kernel-doc comments, even though include/crypto/internal/kpp.h is not considered for the generated docs. 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>
2022-02-21 12:10:47 +00:00
int kpp_register_instance(struct crypto_template *tmpl,
struct kpp_instance *inst)
{
if (WARN_ON(!inst->free))
return -EINVAL;
kpp_prepare_alg(&inst->alg);
return crypto_register_instance(tmpl, kpp_crypto_instance(inst));
}
EXPORT_SYMBOL_GPL(kpp_register_instance);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Key-agreement Protocol Primitives");