| Message ID | 20200224162100.GA25697@embeddedor (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | crypto: Replace zero-length array with flexible-array member | expand |
On 2/24/2020 6:18 PM, Gustavo A. R. Silva wrote: > 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 76497732932f ("cxgb3/l2t: Fix undefined behaviour") > > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by: Horia Geantă <horia.geanta@nxp.com> for caam driver: > drivers/crypto/caam/caamalg.c | 2 +- > drivers/crypto/caam/caamalg_qi.c | 4 ++-- > drivers/crypto/caam/caamalg_qi2.h | 6 +++--- > drivers/crypto/caam/caamhash.c | 2 +- Thanks, Horia
On 2/25/20 07:44, Horia Geanta wrote: > On 2/24/2020 6:18 PM, Gustavo A. R. Silva wrote: >> 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 76497732932f ("cxgb3/l2t: Fix undefined behaviour") >> >> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> > Reviewed-by: Horia Geantă <horia.geanta@nxp.com> > Thank you, Horia. -- Gustavo > for caam driver: > >> drivers/crypto/caam/caamalg.c | 2 +- >> drivers/crypto/caam/caamalg_qi.c | 4 ++-- >> drivers/crypto/caam/caamalg_qi2.h | 6 +++--- >> drivers/crypto/caam/caamhash.c | 2 +- > > Thanks, > Horia >
On Mon, Feb 24, 2020 at 10:21:00AM -0600, Gustavo A. R. Silva wrote: > 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 76497732932f ("cxgb3/l2t: Fix undefined behaviour") > > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> > --- > drivers/crypto/caam/caamalg.c | 2 +- > drivers/crypto/caam/caamalg_qi.c | 4 ++-- > drivers/crypto/caam/caamalg_qi2.h | 6 +++--- > drivers/crypto/caam/caamhash.c | 2 +- > drivers/crypto/cavium/nitrox/nitrox_main.c | 2 +- > drivers/crypto/chelsio/chcr_core.h | 2 +- > drivers/crypto/mediatek/mtk-sha.c | 2 +- > drivers/crypto/nx/nx.h | 2 +- > drivers/crypto/omap-sham.c | 4 ++-- > include/crypto/if_alg.h | 2 +- > 10 files changed, 14 insertions(+), 14 deletions(-) Patch applied. Thanks.
diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c index 03797f9b1050..b7bb7c30adeb 100644 --- a/drivers/crypto/caam/caamalg.c +++ b/drivers/crypto/caam/caamalg.c @@ -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, diff --git a/drivers/crypto/caam/caamalg_qi.c b/drivers/crypto/caam/caamalg_qi.c index 4a29e0ef9d63..27e36bdf6163 100644 --- a/drivers/crypto/caam/caamalg_qi.c +++ b/drivers/crypto/caam/caamalg_qi.c @@ -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, diff --git a/drivers/crypto/caam/caamalg_qi2.h b/drivers/crypto/caam/caamalg_qi2.h index 706736776b47..f29cb7bd7dd3 100644 --- a/drivers/crypto/caam/caamalg_qi2.h +++ b/drivers/crypto/caam/caamalg_qi2.h @@ -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[]; }; /** diff --git a/drivers/crypto/caam/caamhash.c b/drivers/crypto/caam/caamhash.c index 2fe852853d40..943bc0296267 100644 --- a/drivers/crypto/caam/caamhash.c +++ b/drivers/crypto/caam/caamhash.c @@ -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, diff --git a/drivers/crypto/cavium/nitrox/nitrox_main.c b/drivers/crypto/cavium/nitrox/nitrox_main.c index c4632d84c9a1..e91be9b8b083 100644 --- a/drivers/crypto/cavium/nitrox/nitrox_main.c +++ b/drivers/crypto/cavium/nitrox/nitrox_main.c @@ -71,7 +71,7 @@ struct ucode { char version[VERSION_LEN - 1]; __be32 code_size; u8 raz[12]; - u64 code[0]; + u64 code[]; }; /** diff --git a/drivers/crypto/chelsio/chcr_core.h b/drivers/crypto/chelsio/chcr_core.h index b41ef1abfe74..e480096754b5 100644 --- a/drivers/crypto/chelsio/chcr_core.h +++ b/drivers/crypto/chelsio/chcr_core.h @@ -68,7 +68,7 @@ struct _key_ctx { __be32 ctx_hdr; u8 salt[MAX_SALT]; __be64 iv_to_auth; - unsigned char key[0]; + unsigned char key[]; }; #define KEYCTX_TX_WR_IV_S 55 diff --git a/drivers/crypto/mediatek/mtk-sha.c b/drivers/crypto/mediatek/mtk-sha.c index 9e9f48bb7f85..bd6309e57ab8 100644 --- a/drivers/crypto/mediatek/mtk-sha.c +++ b/drivers/crypto/mediatek/mtk-sha.c @@ -107,7 +107,7 @@ struct mtk_sha_ctx { u8 id; u8 buf[SHA_BUF_SIZE] __aligned(sizeof(u32)); - struct mtk_sha_hmac_ctx base[0]; + struct mtk_sha_hmac_ctx base[]; }; struct mtk_sha_drv { diff --git a/drivers/crypto/nx/nx.h b/drivers/crypto/nx/nx.h index 91c54289124a..c6233173c612 100644 --- a/drivers/crypto/nx/nx.h +++ b/drivers/crypto/nx/nx.h @@ -37,7 +37,7 @@ struct max_sync_cop { u32 fc; u32 mode; u32 triplets; - struct msc_triplet trip[0]; + struct msc_triplet trip[]; } __packed; struct alg_props { diff --git a/drivers/crypto/omap-sham.c b/drivers/crypto/omap-sham.c index 4f915a4ef5b0..e4072cd38585 100644 --- a/drivers/crypto/omap-sham.c +++ b/drivers/crypto/omap-sham.c @@ -159,7 +159,7 @@ struct omap_sham_reqctx { int sg_len; unsigned int total; /* total request */ - u8 buffer[0] OMAP_ALIGNED; + u8 buffer[] OMAP_ALIGNED; }; struct omap_sham_hmac_ctx { @@ -176,7 +176,7 @@ struct omap_sham_ctx { /* fallback stuff */ struct crypto_shash *fallback; - struct omap_sham_hmac_ctx base[0]; + struct omap_sham_hmac_ctx base[]; }; #define OMAP_SHAM_QUEUE_LENGTH 10 diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h index 24cfa96f98ea..56527c85d122 100644 --- a/include/crypto/if_alg.h +++ b/include/crypto/if_alg.h @@ -66,7 +66,7 @@ struct af_alg_sgl { struct af_alg_tsgl { struct list_head list; unsigned int cur; /* Last processed SG entry */ - struct scatterlist sg[0]; /* Array of SGs forming the SGL */ + struct scatterlist sg[]; /* Array of SGs forming the SGL */ }; #define MAX_SGL_ENTS ((4096 - sizeof(struct af_alg_tsgl)) / \
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 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- drivers/crypto/caam/caamalg.c | 2 +- drivers/crypto/caam/caamalg_qi.c | 4 ++-- drivers/crypto/caam/caamalg_qi2.h | 6 +++--- drivers/crypto/caam/caamhash.c | 2 +- drivers/crypto/cavium/nitrox/nitrox_main.c | 2 +- drivers/crypto/chelsio/chcr_core.h | 2 +- drivers/crypto/mediatek/mtk-sha.c | 2 +- drivers/crypto/nx/nx.h | 2 +- drivers/crypto/omap-sham.c | 4 ++-- include/crypto/if_alg.h | 2 +- 10 files changed, 14 insertions(+), 14 deletions(-)