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37db69e0b4
There have been a pretty ridiculous number of issues with initializing the report structures that are copied to userspace by NETLINK_CRYPTO. Commit4473710df1("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/ Commitcac5818c25("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>
121 lines
2.9 KiB
C
121 lines
2.9 KiB
C
/*
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* Key-agreement Protocol Primitives (KPP)
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*
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* Copyright (c) 2016, Intel Corporation
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* Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/seq_file.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/crypto.h>
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#include <crypto/algapi.h>
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#include <linux/cryptouser.h>
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#include <linux/compiler.h>
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#include <net/netlink.h>
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#include <crypto/kpp.h>
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#include <crypto/internal/kpp.h>
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#include "internal.h"
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#ifdef CONFIG_NET
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static int crypto_kpp_report(struct sk_buff *skb, struct crypto_alg *alg)
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{
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struct crypto_report_kpp rkpp;
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memset(&rkpp, 0, sizeof(rkpp));
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strscpy(rkpp.type, "kpp", sizeof(rkpp.type));
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return nla_put(skb, CRYPTOCFGA_REPORT_KPP, sizeof(rkpp), &rkpp);
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}
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#else
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static int crypto_kpp_report(struct sk_buff *skb, struct crypto_alg *alg)
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{
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return -ENOSYS;
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}
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#endif
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static void crypto_kpp_show(struct seq_file *m, struct crypto_alg *alg)
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__maybe_unused;
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static void crypto_kpp_show(struct seq_file *m, struct crypto_alg *alg)
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{
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seq_puts(m, "type : kpp\n");
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}
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static void crypto_kpp_exit_tfm(struct crypto_tfm *tfm)
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{
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struct crypto_kpp *kpp = __crypto_kpp_tfm(tfm);
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struct kpp_alg *alg = crypto_kpp_alg(kpp);
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alg->exit(kpp);
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}
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static int crypto_kpp_init_tfm(struct crypto_tfm *tfm)
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{
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struct crypto_kpp *kpp = __crypto_kpp_tfm(tfm);
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struct kpp_alg *alg = crypto_kpp_alg(kpp);
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if (alg->exit)
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kpp->base.exit = crypto_kpp_exit_tfm;
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if (alg->init)
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return alg->init(kpp);
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return 0;
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}
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static const struct crypto_type crypto_kpp_type = {
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.extsize = crypto_alg_extsize,
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.init_tfm = crypto_kpp_init_tfm,
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#ifdef CONFIG_PROC_FS
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.show = crypto_kpp_show,
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#endif
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.report = crypto_kpp_report,
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.maskclear = ~CRYPTO_ALG_TYPE_MASK,
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.maskset = CRYPTO_ALG_TYPE_MASK,
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.type = CRYPTO_ALG_TYPE_KPP,
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.tfmsize = offsetof(struct crypto_kpp, base),
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};
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struct crypto_kpp *crypto_alloc_kpp(const char *alg_name, u32 type, u32 mask)
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{
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return crypto_alloc_tfm(alg_name, &crypto_kpp_type, type, mask);
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}
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EXPORT_SYMBOL_GPL(crypto_alloc_kpp);
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static void kpp_prepare_alg(struct kpp_alg *alg)
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{
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struct crypto_alg *base = &alg->base;
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base->cra_type = &crypto_kpp_type;
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base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
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base->cra_flags |= CRYPTO_ALG_TYPE_KPP;
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}
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int crypto_register_kpp(struct kpp_alg *alg)
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{
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struct crypto_alg *base = &alg->base;
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kpp_prepare_alg(alg);
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return crypto_register_alg(base);
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}
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EXPORT_SYMBOL_GPL(crypto_register_kpp);
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void crypto_unregister_kpp(struct kpp_alg *alg)
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{
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crypto_unregister_alg(&alg->base);
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}
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EXPORT_SYMBOL_GPL(crypto_unregister_kpp);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Key-agreement Protocol Primitives");
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