LinuxPPC-Dev Archive mirror
 help / color / mirror / Atom feed
From: "Gustavo A. R. Silva" <gustavoars@kernel.org>
To: Haren Myneni <haren@us.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	"Aneesh Kumar K.V" <aneesh.kumar@kernel.org>,
	"Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>
Cc: linux-hardening@vger.kernel.org,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	linuxppc-dev@lists.ozlabs.org, linux-crypto@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH][next] crypto/nx: Avoid potential -Wflex-array-member-not-at-end warning
Date: Mon, 25 Mar 2024 15:01:56 -0600	[thread overview]
Message-ID: <ZgHmRNcR+a4EJX94@neat> (raw)

-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@kernel.org>
---
 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;
-- 
2.34.1


             reply	other threads:[~2024-03-25 21:02 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-25 21:01 Gustavo A. R. Silva [this message]
2024-04-29 17:05 ` [PATCH][next] crypto/nx: Avoid potential -Wflex-array-member-not-at-end warning Kees Cook

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=ZgHmRNcR+a4EJX94@neat \
    --to=gustavoars@kernel.org \
    --cc=aneesh.kumar@kernel.org \
    --cc=christophe.leroy@csgroup.eu \
    --cc=davem@davemloft.net \
    --cc=haren@us.ibm.com \
    --cc=herbert@gondor.apana.org.au \
    --cc=linux-crypto@vger.kernel.org \
    --cc=linux-hardening@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=mpe@ellerman.id.au \
    --cc=naveen.n.rao@linux.ibm.com \
    --cc=npiggin@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).