[PATCH] crypto: nx - Fix packed layout in struct nx842_crypto_header

[PATCH] crypto: nx - Fix packed layout in struct nx842_crypto_header

[Gustavo A. R. Silva]

struct nx842_crypto_header is declared with the __packed attribute,
however	the fields grouped with struct_group_tagged() were not packed.
This caused the grouped header portion of the structure to lose the
packed layout guarantees of the containing structure.

Fix this by replacing struct_group_tagged() with __struct_group(...,
..., __packed, ...) so the grouped fields are packed, and the original
layout is preserved, restoring the intended packed layout of the
structure.

Before changes:
struct nx842_crypto_header {
	union {
		struct {
			__be16     magic;                /*     0     2 */
			__be16     ignore;               /*     2     2 */
			u8         groups;               /*     4     1 */
		};                                       /*     0     6 */
		struct nx842_crypto_header_hdr hdr;      /*     0     6 */
	};                                               /*     0     6 */
	struct nx842_crypto_header_group group[];        /*     6     0 */

	/* size: 6, cachelines: 1, members: 2 */
	/* last cacheline: 6 bytes */
} __attribute__((__packed__));

After changes:
struct nx842_crypto_header {
	union {
		struct {
			__be16     magic;                /*     0     2 */
			__be16     ignore;               /*     2     2 */
			u8         groups;               /*     4     1 */
		} __attribute__((__packed__));           /*     0     5 */
		struct nx842_crypto_header_hdr hdr;      /*     0     5 */
	};                                               /*     0     5 */
	struct nx842_crypto_header_group group[];        /*     5     0 */

	/* size: 5, cachelines: 1, members: 2 */
	/* last cacheline: 5 bytes */
} __attribute__((__packed__));

Fixes: 1e6b251ce175 ("crypto: nx - Avoid -Wflex-array-member-not-at-end warning")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/crypto/nx/nx-842.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/nx/nx-842.h b/drivers/crypto/nx/nx-842.h
index f5e2c82ba876..cd3c1a433e8c 100644
--- a/drivers/crypto/nx/nx-842.h
+++ b/drivers/crypto/nx/nx-842.h
@@ -159,7 +159,7 @@ struct nx842_crypto_header_group {
 
 struct nx842_crypto_header {
 	/* New members MUST be added within the struct_group() macro below. */
-	struct_group_tagged(nx842_crypto_header_hdr, hdr,
+	__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 */
@@ -167,7 +167,7 @@ struct nx842_crypto_header {
 	struct nx842_crypto_header_group group[];
 } __packed;
 static_assert(offsetof(struct nx842_crypto_header, group) == sizeof(struct nx842_crypto_header_hdr),
-	      "struct member likely outside of struct_group_tagged()");
+	      "struct member likely outside of __struct_group()");
 
 #define NX842_CRYPTO_GROUP_MAX	(0x20)
 
-- 
2.43.0

Re: [PATCH] crypto: nx - Fix packed layout in struct nx842_crypto_header

[Thorsten Blum]

On Tue, Mar 17, 2026 at 05:40:02PM -0600, Gustavo A. R. Silva wrote:
> struct nx842_crypto_header is declared with the __packed attribute,
> however	the fields grouped with struct_group_tagged() were not packed.
> This caused the grouped header portion of the structure to lose the
> packed layout guarantees of the containing structure.
> 
> Fix this by replacing struct_group_tagged() with __struct_group(...,
> ..., __packed, ...) so the grouped fields are packed, and the original
> layout is preserved, restoring the intended packed layout of the
> structure.
> 
> Before changes:
> struct nx842_crypto_header {
> 	union {
> 		struct {
> 			__be16     magic;                /*     0     2 */
> 			__be16     ignore;               /*     2     2 */
> 			u8         groups;               /*     4     1 */
> 		};                                       /*     0     6 */
> 		struct nx842_crypto_header_hdr hdr;      /*     0     6 */
> 	};                                               /*     0     6 */
> 	struct nx842_crypto_header_group group[];        /*     6     0 */
> 
> 	/* size: 6, cachelines: 1, members: 2 */
> 	/* last cacheline: 6 bytes */
> } __attribute__((__packed__));
> 
> After changes:
> struct nx842_crypto_header {
> 	union {
> 		struct {
> 			__be16     magic;                /*     0     2 */
> 			__be16     ignore;               /*     2     2 */
> 			u8         groups;               /*     4     1 */
> 		} __attribute__((__packed__));           /*     0     5 */
> 		struct nx842_crypto_header_hdr hdr;      /*     0     5 */
> 	};                                               /*     0     5 */
> 	struct nx842_crypto_header_group group[];        /*     5     0 */
> 
> 	/* size: 5, cachelines: 1, members: 2 */
> 	/* last cacheline: 5 bytes */
> } __attribute__((__packed__));
> 
> Fixes: 1e6b251ce175 ("crypto: nx - Avoid -Wflex-array-member-not-at-end warning")
> Cc: stable@vger.kernel.org
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>  drivers/crypto/nx/nx-842.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Reviewed-by: Thorsten Blum <thorsten.blum@linux.dev>

Re: [PATCH] crypto: nx - Fix packed layout in struct nx842_crypto_header

[Herbert Xu]

On Tue, Mar 17, 2026 at 05:40:02PM -0600, Gustavo A. R. Silva wrote:
> struct nx842_crypto_header is declared with the __packed attribute,
> however	the fields grouped with struct_group_tagged() were not packed.
> This caused the grouped header portion of the structure to lose the
> packed layout guarantees of the containing structure.
> 
> Fix this by replacing struct_group_tagged() with __struct_group(...,
> ..., __packed, ...) so the grouped fields are packed, and the original
> layout is preserved, restoring the intended packed layout of the
> structure.
> 
> Before changes:
> struct nx842_crypto_header {
> 	union {
> 		struct {
> 			__be16     magic;                /*     0     2 */
> 			__be16     ignore;               /*     2     2 */
> 			u8         groups;               /*     4     1 */
> 		};                                       /*     0     6 */
> 		struct nx842_crypto_header_hdr hdr;      /*     0     6 */
> 	};                                               /*     0     6 */
> 	struct nx842_crypto_header_group group[];        /*     6     0 */
> 
> 	/* size: 6, cachelines: 1, members: 2 */
> 	/* last cacheline: 6 bytes */
> } __attribute__((__packed__));
> 
> After changes:
> struct nx842_crypto_header {
> 	union {
> 		struct {
> 			__be16     magic;                /*     0     2 */
> 			__be16     ignore;               /*     2     2 */
> 			u8         groups;               /*     4     1 */
> 		} __attribute__((__packed__));           /*     0     5 */
> 		struct nx842_crypto_header_hdr hdr;      /*     0     5 */
> 	};                                               /*     0     5 */
> 	struct nx842_crypto_header_group group[];        /*     5     0 */
> 
> 	/* size: 5, cachelines: 1, members: 2 */
> 	/* last cacheline: 5 bytes */
> } __attribute__((__packed__));
> 
> Fixes: 1e6b251ce175 ("crypto: nx - Avoid -Wflex-array-member-not-at-end warning")
> Cc: stable@vger.kernel.org
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>  drivers/crypto/nx/nx-842.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt