30a87f150b
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>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
67 lines
1.9 KiB
C
67 lines
1.9 KiB
C
/* SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 */
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/* Copyright (c) 2017-2019 Mellanox Technologies. All rights reserved */
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#ifndef _MLXFW_MFA2_TLV_H
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#define _MLXFW_MFA2_TLV_H
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#include <linux/kernel.h>
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#include "mlxfw_mfa2_file.h"
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struct mlxfw_mfa2_tlv {
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u8 version;
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u8 type;
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__be16 len;
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u8 data[];
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} __packed;
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static inline const struct mlxfw_mfa2_tlv *
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mlxfw_mfa2_tlv_get(const struct mlxfw_mfa2_file *mfa2_file, const void *ptr)
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{
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if (!mlxfw_mfa2_valid_ptr(mfa2_file, ptr) ||
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!mlxfw_mfa2_valid_ptr(mfa2_file, ptr + sizeof(struct mlxfw_mfa2_tlv)))
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return NULL;
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return ptr;
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}
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static inline const void *
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mlxfw_mfa2_tlv_payload_get(const struct mlxfw_mfa2_file *mfa2_file,
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const struct mlxfw_mfa2_tlv *tlv, u8 payload_type,
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size_t payload_size, bool varsize)
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{
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void *tlv_top;
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tlv_top = (void *) tlv + be16_to_cpu(tlv->len) - 1;
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if (!mlxfw_mfa2_valid_ptr(mfa2_file, tlv) ||
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!mlxfw_mfa2_valid_ptr(mfa2_file, tlv_top))
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return NULL;
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if (tlv->type != payload_type)
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return NULL;
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if (varsize && (be16_to_cpu(tlv->len) < payload_size))
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return NULL;
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if (!varsize && (be16_to_cpu(tlv->len) != payload_size))
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return NULL;
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return tlv->data;
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}
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#define MLXFW_MFA2_TLV(name, payload_type, tlv_type) \
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static inline const payload_type * \
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mlxfw_mfa2_tlv_ ## name ## _get(const struct mlxfw_mfa2_file *mfa2_file, \
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const struct mlxfw_mfa2_tlv *tlv) \
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{ \
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return mlxfw_mfa2_tlv_payload_get(mfa2_file, tlv, \
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tlv_type, sizeof(payload_type), \
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false); \
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}
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#define MLXFW_MFA2_TLV_VARSIZE(name, payload_type, tlv_type) \
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static inline const payload_type * \
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mlxfw_mfa2_tlv_ ## name ## _get(const struct mlxfw_mfa2_file *mfa2_file, \
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const struct mlxfw_mfa2_tlv *tlv) \
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{ \
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return mlxfw_mfa2_tlv_payload_get(mfa2_file, tlv, \
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tlv_type, sizeof(payload_type), \
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true); \
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}
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#endif
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