linux/crypto/rng.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Cryptographic API.
*
* RNG operations.
*
* Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
* Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
*/
#include <crypto/internal/rng.h>
#include <linux/atomic.h>
#include <linux/cryptouser.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/random.h>
#include <linux/seq_file.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include <linux/string.h>
#include <net/netlink.h>
#include "internal.h"
static DEFINE_MUTEX(crypto_default_rng_lock);
struct crypto_rng *crypto_default_rng;
EXPORT_SYMBOL_GPL(crypto_default_rng);
static int crypto_default_rng_refcnt;
int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen)
{
struct rng_alg *alg = crypto_rng_alg(tfm);
u8 *buf = NULL;
int err;
if (IS_ENABLED(CONFIG_CRYPTO_STATS))
atomic64_inc(&rng_get_stat(alg)->seed_cnt);
if (!seed && slen) {
buf = kmalloc(slen, GFP_KERNEL);
err = -ENOMEM;
if (!buf)
goto out;
err = get_random_bytes_wait(buf, slen);
if (err)
goto free_buf;
seed = buf;
}
err = alg->seed(tfm, seed, slen);
free_buf:
mm, treewide: rename kzfree() to kfree_sensitive() 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>
2020-08-07 06:18:13 +00:00
kfree_sensitive(buf);
out:
return crypto_rng_errstat(alg, err);
}
EXPORT_SYMBOL_GPL(crypto_rng_reset);
static int crypto_rng_init_tfm(struct crypto_tfm *tfm)
{
return 0;
}
static unsigned int seedsize(struct crypto_alg *alg)
{
struct rng_alg *ralg = container_of(alg, struct rng_alg, base);
return ralg->seedsize;
}
static int __maybe_unused crypto_rng_report(
struct sk_buff *skb, struct crypto_alg *alg)
{
struct crypto_report_rng rrng;
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(&rrng, 0, sizeof(rrng));
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(rrng.type, "rng", sizeof(rrng.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
rrng.seedsize = seedsize(alg);
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_RNG, sizeof(rrng), &rrng);
}
static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
__maybe_unused;
static void crypto_rng_show(struct seq_file *m, struct crypto_alg *alg)
{
seq_printf(m, "type : rng\n");
seq_printf(m, "seedsize : %u\n", seedsize(alg));
}
static int __maybe_unused crypto_rng_report_stat(
struct sk_buff *skb, struct crypto_alg *alg)
{
struct rng_alg *rng = __crypto_rng_alg(alg);
struct crypto_istat_rng *istat;
struct crypto_stat_rng rrng;
istat = rng_get_stat(rng);
memset(&rrng, 0, sizeof(rrng));
strscpy(rrng.type, "rng", sizeof(rrng.type));
rrng.stat_generate_cnt = atomic64_read(&istat->generate_cnt);
rrng.stat_generate_tlen = atomic64_read(&istat->generate_tlen);
rrng.stat_seed_cnt = atomic64_read(&istat->seed_cnt);
rrng.stat_err_cnt = atomic64_read(&istat->err_cnt);
return nla_put(skb, CRYPTOCFGA_STAT_RNG, sizeof(rrng), &rrng);
}
static const struct crypto_type crypto_rng_type = {
.extsize = crypto_alg_extsize,
.init_tfm = crypto_rng_init_tfm,
#ifdef CONFIG_PROC_FS
.show = crypto_rng_show,
#endif
#if IS_ENABLED(CONFIG_CRYPTO_USER)
.report = crypto_rng_report,
#endif
#ifdef CONFIG_CRYPTO_STATS
.report_stat = crypto_rng_report_stat,
#endif
.maskclear = ~CRYPTO_ALG_TYPE_MASK,
.maskset = CRYPTO_ALG_TYPE_MASK,
.type = CRYPTO_ALG_TYPE_RNG,
.tfmsize = offsetof(struct crypto_rng, base),
};
struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask)
{
return crypto_alloc_tfm(alg_name, &crypto_rng_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_rng);
int crypto_get_default_rng(void)
{
struct crypto_rng *rng;
int err;
mutex_lock(&crypto_default_rng_lock);
if (!crypto_default_rng) {
rng = crypto_alloc_rng("stdrng", 0, 0);
err = PTR_ERR(rng);
if (IS_ERR(rng))
goto unlock;
err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng));
if (err) {
crypto_free_rng(rng);
goto unlock;
}
crypto_default_rng = rng;
}
crypto_default_rng_refcnt++;
err = 0;
unlock:
mutex_unlock(&crypto_default_rng_lock);
return err;
}
EXPORT_SYMBOL_GPL(crypto_get_default_rng);
void crypto_put_default_rng(void)
{
mutex_lock(&crypto_default_rng_lock);
crypto_default_rng_refcnt--;
mutex_unlock(&crypto_default_rng_lock);
}
EXPORT_SYMBOL_GPL(crypto_put_default_rng);
#if defined(CONFIG_CRYPTO_RNG) || defined(CONFIG_CRYPTO_RNG_MODULE)
int crypto_del_default_rng(void)
{
int err = -EBUSY;
mutex_lock(&crypto_default_rng_lock);
if (crypto_default_rng_refcnt)
goto out;
crypto_free_rng(crypto_default_rng);
crypto_default_rng = NULL;
err = 0;
out:
mutex_unlock(&crypto_default_rng_lock);
return err;
}
EXPORT_SYMBOL_GPL(crypto_del_default_rng);
#endif
int crypto_register_rng(struct rng_alg *alg)
{
struct crypto_istat_rng *istat = rng_get_stat(alg);
struct crypto_alg *base = &alg->base;
if (alg->seedsize > PAGE_SIZE / 8)
return -EINVAL;
base->cra_type = &crypto_rng_type;
base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
base->cra_flags |= CRYPTO_ALG_TYPE_RNG;
if (IS_ENABLED(CONFIG_CRYPTO_STATS))
memset(istat, 0, sizeof(*istat));
return crypto_register_alg(base);
}
EXPORT_SYMBOL_GPL(crypto_register_rng);
void crypto_unregister_rng(struct rng_alg *alg)
{
crypto_unregister_alg(&alg->base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_rng);
int crypto_register_rngs(struct rng_alg *algs, int count)
{
int i, ret;
for (i = 0; i < count; i++) {
ret = crypto_register_rng(algs + i);
if (ret)
goto err;
}
return 0;
err:
for (--i; i >= 0; --i)
crypto_unregister_rng(algs + i);
return ret;
}
EXPORT_SYMBOL_GPL(crypto_register_rngs);
void crypto_unregister_rngs(struct rng_alg *algs, int count)
{
int i;
for (i = count - 1; i >= 0; --i)
crypto_unregister_rng(algs + i);
}
EXPORT_SYMBOL_GPL(crypto_unregister_rngs);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Random Number Generator");