On Mon, Mar 25, 2024 at 03:01:56PM -0600, Gustavo A. R. Silva wrote: > -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting > ready to enable it globally. > > Use the `__struct_group()` helper to separate the flexible array > from the rest of the members in flexible `struct nx842_crypto_header`, > through tagged `struct nx842_crypto_header_hdr`, and avoid embedding > the flexible-array member in the middle of `struct nx842_crypto_ctx`. > > Also, use `container_of()` whenever we need to retrieve a pointer to > the flexible structure. > > This code was detected with the help of Coccinelle, and audited and > modified manually. > > Link: https://github.com/KSPP/linux/issues/202 > Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> > --- > drivers/crypto/nx/nx-842.c | 6 ++++-- > drivers/crypto/nx/nx-842.h | 11 +++++++---- > 2 files changed, 11 insertions(+), 6 deletions(-) > > diff --git a/drivers/crypto/nx/nx-842.c b/drivers/crypto/nx/nx-842.c > index 2ab90ec10e61..82214cde2bcd 100644 > --- a/drivers/crypto/nx/nx-842.c > +++ b/drivers/crypto/nx/nx-842.c > @@ -251,7 +251,9 @@ int nx842_crypto_compress(struct crypto_tfm *tfm, > u8 *dst, unsigned int *dlen) > { > struct nx842_crypto_ctx *ctx = crypto_tfm_ctx(tfm); > - struct nx842_crypto_header *hdr = &ctx->header; > + struct nx842_crypto_header *hdr = > + container_of(&ctx->header, > + struct nx842_crypto_header, hdr); > struct nx842_crypto_param p; > struct nx842_constraints c = *ctx->driver->constraints; > unsigned int groups, hdrsize, h; > @@ -490,7 +492,7 @@ int nx842_crypto_decompress(struct crypto_tfm *tfm, > } > > memcpy(&ctx->header, src, hdr_len); > - hdr = &ctx->header; > + hdr = container_of(&ctx->header, struct nx842_crypto_header, hdr); > > for (n = 0; n < hdr->groups; n++) { > /* ignore applies to last group */ > diff --git a/drivers/crypto/nx/nx-842.h b/drivers/crypto/nx/nx-842.h > index 7590bfb24d79..1f42c83d2683 100644 > --- a/drivers/crypto/nx/nx-842.h > +++ b/drivers/crypto/nx/nx-842.h > @@ -157,9 +157,12 @@ struct nx842_crypto_header_group { > } __packed; > > struct nx842_crypto_header { > - __be16 magic; /* NX842_CRYPTO_MAGIC */ > - __be16 ignore; /* decompressed end bytes to ignore */ > - u8 groups; /* total groups in this header */ > + /* New members must be added within the __struct_group() macro below. */ > + __struct_group(nx842_crypto_header_hdr, hdr, __packed, > + __be16 magic; /* NX842_CRYPTO_MAGIC */ > + __be16 ignore; /* decompressed end bytes to ignore */ > + u8 groups; /* total groups in this header */ > + ); > struct nx842_crypto_header_group group[]; > } __packed; > > @@ -171,7 +174,7 @@ struct nx842_crypto_ctx { > u8 *wmem; > u8 *sbounce, *dbounce; > > - struct nx842_crypto_header header; > + struct nx842_crypto_header_hdr header; > struct nx842_crypto_header_group group[NX842_CRYPTO_GROUP_MAX]; > > struct nx842_driver *driver; Hmm. I think commit 03952d980153 ("crypto: nx - make platform drivers directly register with crypto") incorrectly added "struct nx842_driver *driver" to the end of struct nx842_crypto_ctx. I think it should be before "header". Then I see: #define NX842_CRYPTO_HEADER_SIZE(g) \ (sizeof(struct nx842_crypto_header) + \ sizeof(struct nx842_crypto_header_group) * (g)) This is just struct_size(), really. And nothing uses: #define NX842_CRYPTO_HEADER_MAX_SIZE \ NX842_CRYPTO_HEADER_SIZE(NX842_CRYPTO_GROUP_MAX) And then looking for what uses struct nx842_crypto_ctx's "group" member, I don't see anything except some sizeof()s: drivers/crypto/nx/nx-common-powernv.c:1044: .cra_ctxsize = sizeof(struct nx842_crypto_ctx), drivers/crypto/nx/nx-common-pseries.c:1021: .cra_ctxsize = sizeof(struct nx842_crypto_ctx), This is just a maximally sized ctx (as if the group count were NX842_CRYPTO_GROUP_MAX), which we could use struct_size for again: .cra_ctxsize = struct_size_t(struct nx842_crypto_ctx, header.group, NX842_CRYPTO_GROUP_MAX), So then "group" can be entirely removed from struct nx842_crypto_ctx. The result means we can also add __counted_by: diff --git a/drivers/crypto/nx/nx-842.c b/drivers/crypto/nx/nx-842.c index 2ab90ec10e61..144972fe2e6f 100644 --- a/drivers/crypto/nx/nx-842.c +++ b/drivers/crypto/nx/nx-842.c @@ -62,10 +62,7 @@ */ #define NX842_CRYPTO_MAGIC (0xf842) #define NX842_CRYPTO_HEADER_SIZE(g) \ - (sizeof(struct nx842_crypto_header) + \ - sizeof(struct nx842_crypto_header_group) * (g)) -#define NX842_CRYPTO_HEADER_MAX_SIZE \ - NX842_CRYPTO_HEADER_SIZE(NX842_CRYPTO_GROUP_MAX) + struct_size_t(nx842_crypto_header, group, g) /* bounce buffer size */ #define BOUNCE_BUFFER_ORDER (2) diff --git a/drivers/crypto/nx/nx-842.h b/drivers/crypto/nx/nx-842.h index 7590bfb24d79..70d9f99a4595 100644 --- a/drivers/crypto/nx/nx-842.h +++ b/drivers/crypto/nx/nx-842.h @@ -160,7 +160,7 @@ struct nx842_crypto_header { __be16 magic; /* NX842_CRYPTO_MAGIC */ __be16 ignore; /* decompressed end bytes to ignore */ u8 groups; /* total groups in this header */ - struct nx842_crypto_header_group group[]; + struct nx842_crypto_header_group group[] __counted_by(groups); } __packed; #define NX842_CRYPTO_GROUP_MAX (0x20) @@ -171,10 +171,9 @@ struct nx842_crypto_ctx { u8 *wmem; u8 *sbounce, *dbounce; - struct nx842_crypto_header header; - struct nx842_crypto_header_group group[NX842_CRYPTO_GROUP_MAX]; - struct nx842_driver *driver; + + struct nx842_crypto_header header; }; int nx842_crypto_init(struct crypto_tfm *tfm, struct nx842_driver *driver); diff --git a/drivers/crypto/nx/nx-common-powernv.c b/drivers/crypto/nx/nx-common-powernv.c index 8c859872c183..22ab4a5885f2 100644 --- a/drivers/crypto/nx/nx-common-powernv.c +++ b/drivers/crypto/nx/nx-common-powernv.c @@ -1041,7 +1041,8 @@ static struct crypto_alg nx842_powernv_alg = { .cra_driver_name = "842-nx", .cra_priority = 300, .cra_flags = CRYPTO_ALG_TYPE_COMPRESS, - .cra_ctxsize = sizeof(struct nx842_crypto_ctx), + .cra_ctxsize = struct_size_t(struct nx842_crypto_ctx, header.group, + NX842_CRYPTO_GROUP_MAX), .cra_module = THIS_MODULE, .cra_init = nx842_powernv_crypto_init, .cra_exit = nx842_crypto_exit, diff --git a/drivers/crypto/nx/nx-common-pseries.c b/drivers/crypto/nx/nx-common-pseries.c index 35f2d0d8507e..fdf328eab6fc 100644 --- a/drivers/crypto/nx/nx-common-pseries.c +++ b/drivers/crypto/nx/nx-common-pseries.c @@ -1018,7 +1018,8 @@ static struct crypto_alg nx842_pseries_alg = { .cra_driver_name = "842-nx", .cra_priority = 300, .cra_flags = CRYPTO_ALG_TYPE_COMPRESS, - .cra_ctxsize = sizeof(struct nx842_crypto_ctx), + .cra_ctxsize = struct_size_t(struct nx842_crypto_ctx, header.group, + NX842_CRYPTO_GROUP_MAX), .cra_module = THIS_MODULE, .cra_init = nx842_pseries_crypto_init, .cra_exit = nx842_crypto_exit, -- Kees Cook
