kernel_optimize_test/include/linux/digsig.h
Gustavo A. R. Silva 1fa0949bed digsig.h: Replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
2020-04-18 15:44:54 -05:00

61 lines
1.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2011 Nokia Corporation
* Copyright (C) 2011 Intel Corporation
*
* Author:
* Dmitry Kasatkin <dmitry.kasatkin@nokia.com>
* <dmitry.kasatkin@intel.com>
*/
#ifndef _DIGSIG_H
#define _DIGSIG_H
#include <linux/key.h>
enum pubkey_algo {
PUBKEY_ALGO_RSA,
PUBKEY_ALGO_MAX,
};
enum digest_algo {
DIGEST_ALGO_SHA1,
DIGEST_ALGO_SHA256,
DIGEST_ALGO_MAX
};
struct pubkey_hdr {
uint8_t version; /* key format version */
uint32_t timestamp; /* key made, always 0 for now */
uint8_t algo;
uint8_t nmpi;
char mpi[];
} __packed;
struct signature_hdr {
uint8_t version; /* signature format version */
uint32_t timestamp; /* signature made */
uint8_t algo;
uint8_t hash;
uint8_t keyid[8];
uint8_t nmpi;
char mpi[];
} __packed;
#if defined(CONFIG_SIGNATURE) || defined(CONFIG_SIGNATURE_MODULE)
int digsig_verify(struct key *keyring, const char *sig, int siglen,
const char *digest, int digestlen);
#else
static inline int digsig_verify(struct key *keyring, const char *sig,
int siglen, const char *digest, int digestlen)
{
return -EOPNOTSUPP;
}
#endif /* CONFIG_SIGNATURE */
#endif /* _DIGSIG_H */