* [PATCH][next] crypto: nx - Use static_assert() to check struct sizes
@ 2024-08-08 22:09 Gustavo A. R. Silva
2024-08-17 7:08 ` Herbert Xu
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2024-08-08 22:09 UTC (permalink / raw)
To: Haren Myneni, Michael Ellerman, Nicholas Piggin, Christophe Leroy,
Naveen N Rao, Herbert Xu, David S. Miller
Cc: linux-hardening, Gustavo A. R. Silva, linuxppc-dev, linux-crypto,
linux-kernel
Commit 1e6b251ce175 ("crypto: nx - Avoid -Wflex-array-member-not-at-end
warning") introduced tagged `struct nx842_crypto_header_hdr`. We want
to ensure that when new members need to be added to the flexible
structure, they are always included within this tagged struct.
So, we use `static_assert()` to ensure that the memory layout for
both the flexible structure and the tagged struct is the same after
any changes.
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
drivers/crypto/nx/nx-842.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/crypto/nx/nx-842.h b/drivers/crypto/nx/nx-842.h
index 25fa70b2112c..887d4ce3cb49 100644
--- a/drivers/crypto/nx/nx-842.h
+++ b/drivers/crypto/nx/nx-842.h
@@ -157,6 +157,7 @@ struct nx842_crypto_header_group {
} __packed;
struct nx842_crypto_header {
+ /* New members MUST be added within the struct_group() macro below. */
struct_group_tagged(nx842_crypto_header_hdr, hdr,
__be16 magic; /* NX842_CRYPTO_MAGIC */
__be16 ignore; /* decompressed end bytes to ignore */
@@ -164,6 +165,8 @@ 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()");
#define NX842_CRYPTO_GROUP_MAX (0x20)
--
2.34.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH][next] crypto: nx - Use static_assert() to check struct sizes
2024-08-08 22:09 [PATCH][next] crypto: nx - Use static_assert() to check struct sizes Gustavo A. R. Silva
@ 2024-08-17 7:08 ` Herbert Xu
0 siblings, 0 replies; 2+ messages in thread
From: Herbert Xu @ 2024-08-17 7:08 UTC (permalink / raw)
To: Gustavo A. R. Silva
Cc: Haren Myneni, Michael Ellerman, Nicholas Piggin, Christophe Leroy,
Naveen N Rao, David S. Miller, linuxppc-dev, linux-crypto,
linux-kernel, linux-hardening
On Thu, Aug 08, 2024 at 04:09:06PM -0600, Gustavo A. R. Silva wrote:
> Commit 1e6b251ce175 ("crypto: nx - Avoid -Wflex-array-member-not-at-end
> warning") introduced tagged `struct nx842_crypto_header_hdr`. We want
> to ensure that when new members need to be added to the flexible
> structure, they are always included within this tagged struct.
>
> So, we use `static_assert()` to ensure that the memory layout for
> both the flexible structure and the tagged struct is the same after
> any changes.
>
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
> drivers/crypto/nx/nx-842.h | 3 +++
> 1 file changed, 3 insertions(+)
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
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