Commit 5a8a0765 authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by Herbert Xu
Browse files

crypto: 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 76497732 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: default avatarHoria Geantă <horia.geanta@nxp.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent d282eeeb

drivers/crypto/caam/caamalg.c

+1 −1
Original line number Diff line number Diff line
@@ -909,7 +909,7 @@ struct skcipher_edesc { 
	bool bklog;

	dma_addr_t sec4_sg_dma;

	struct sec4_sg_entry *sec4_sg;

	u32 hw_desc[0];

	u32 hw_desc[];

};



static void caam_unmap(struct device *dev, struct scatterlist *src,

drivers/crypto/caam/caamalg_qi.c

+2 −2
Original line number Diff line number Diff line
@@ -783,7 +783,7 @@ struct aead_edesc { 
	unsigned int assoclen;

	dma_addr_t assoclen_dma;

	struct caam_drv_req drv_req;

	struct qm_sg_entry sgt[0];

	struct qm_sg_entry sgt[];

};



/*
@@ -803,7 +803,7 @@ struct skcipher_edesc { 
	int qm_sg_bytes;

	dma_addr_t qm_sg_dma;

	struct caam_drv_req drv_req;

	struct qm_sg_entry sgt[0];

	struct qm_sg_entry sgt[];

};



static struct caam_drv_ctx *get_drv_ctx(struct caam_ctx *ctx,

drivers/crypto/caam/caamalg_qi2.h

+3 −3
Original line number Diff line number Diff line
@@ -114,7 +114,7 @@ struct aead_edesc { 
	dma_addr_t qm_sg_dma;

	unsigned int assoclen;

	dma_addr_t assoclen_dma;

	struct dpaa2_sg_entry sgt[0];

	struct dpaa2_sg_entry sgt[];

};



/*
@@ -132,7 +132,7 @@ struct skcipher_edesc { 
	dma_addr_t iv_dma;

	int qm_sg_bytes;

	dma_addr_t qm_sg_dma;

	struct dpaa2_sg_entry sgt[0];

	struct dpaa2_sg_entry sgt[];

};



/*
@@ -146,7 +146,7 @@ struct ahash_edesc { 
	dma_addr_t qm_sg_dma;

	int src_nents;

	int qm_sg_bytes;

	struct dpaa2_sg_entry sgt[0];

	struct dpaa2_sg_entry sgt[];

};



/**

drivers/crypto/caam/caamhash.c

+1 −1
Original line number Diff line number Diff line
@@ -536,7 +536,7 @@ struct ahash_edesc { 
	int sec4_sg_bytes;

	bool bklog;

	u32 hw_desc[DESC_JOB_IO_LEN_MAX / sizeof(u32)] ____cacheline_aligned;

	struct sec4_sg_entry sec4_sg[0];

	struct sec4_sg_entry sec4_sg[];

};



static inline void ahash_unmap(struct device *dev,

drivers/crypto/cavium/nitrox/nitrox_main.c

+1 −1
Original line number Diff line number Diff line
@@ -71,7 +71,7 @@ struct ucode { 
	char version[VERSION_LEN - 1];

	__be32 code_size;

	u8 raz[12];

	u64 code[0];

	u64 code[];

};



/**

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