FAILED: patch "[PATCH] lib/crypto: poly1305: Use memzero_explicit() in" failed to apply to 6.12-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x da619121a5d271e78ec709a1f9a3c5f99b9e10ad
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026102149-couch-tile-803f@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From da619121a5d271e78ec709a1f9a3c5f99b9e10ad Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@kernel.org>
Date: Tue, 6 Oct 2026 10:34:32 +0200
Subject: [PATCH] lib/crypto: poly1305: Use memzero_explicit() in
 poly1305_final()

Use memzero_explicit() instead of a plain struct assignment to guarantee
zeroization of the 'struct poly1305_desc_ctx'.

Note that dead store elimination was only theoretically possible with
link-time optimization here.  But it's still worth fixing.

Fixes: a1d93064094c ("crypto: poly1305 - expose init/update/final library interface")
Cc: stable@vger.kernel.org
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/bug/linux-c3a6bd76-f6ab-4203-892a-cd06f7aa0c34
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://patch.msgid.link/20261006083432.16328-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

diff --git a/lib/crypto/poly1305.c b/lib/crypto/poly1305.c
index f313ccc4b4dd..048c7afe8613 100644
--- a/lib/crypto/poly1305.c
+++ b/lib/crypto/poly1305.c
@@ -78,7 +78,7 @@ void poly1305_final(struct poly1305_desc_ctx *desc, u8 *dst)
 	}
 
 	poly1305_emit(&desc->state.h, dst, desc->s);
-	*desc = (struct poly1305_desc_ctx){};
+	memzero_explicit(desc, sizeof(*desc));
 }
 EXPORT_SYMBOL(poly1305_final);