From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7D0FE6FAF; Tue, 5 Dec 2023 03:23:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="DgALJY2y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF692C433C8; Tue, 5 Dec 2023 03:23:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1701746636; bh=BCE6cCf1Fzpmfap0k83PkY+nJPwmFfk+PnTfgGC7hdc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DgALJY2yYjRNhJl1srUNke2mli/8xQGMl1+KDdNVWlWKIwgCwhSf253ZNFBeyzmii HmYal8AboORBus+HUdaJSxnBZ9Wm+OKWWkg3Agwwx+4ayIIouoiBW85+CfTNuSXC8n xms7EdW0zrgdGEb1BC6sprBBUT169xvMWmIwnoO0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Gustavo A. R. Silva" , Kees Cook , Joey Gouly , Paolo Abeni , Sasha Levin Subject: [PATCH 6.6 099/134] neighbour: Fix __randomize_layout crash in struct neighbour Date: Tue, 5 Dec 2023 12:16:11 +0900 Message-ID: <20231205031541.718578042@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231205031535.163661217@linuxfoundation.org> References: <20231205031535.163661217@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gustavo A. R. Silva [ Upstream commit 45b3fae4675dc1d4ee2d7aefa19d85ee4f891377 ] Previously, one-element and zero-length arrays were treated as true flexible arrays, even though they are actually "fake" flex arrays. The __randomize_layout would leave them untouched at the end of the struct, similarly to proper C99 flex-array members. However, this approach changed with commit 1ee60356c2dc ("gcc-plugins: randstruct: Only warn about true flexible arrays"). Now, only C99 flexible-array members will remain untouched at the end of the struct, while one-element and zero-length arrays will be subject to randomization. Fix a `__randomize_layout` crash in `struct neighbour` by transforming zero-length array `primary_key` into a proper C99 flexible-array member. Fixes: 1ee60356c2dc ("gcc-plugins: randstruct: Only warn about true flexible arrays") Closes: https://lore.kernel.org/linux-hardening/20231124102458.GB1503258@e124191.cambridge.arm.com/ Signed-off-by: Gustavo A. R. Silva Reviewed-by: Kees Cook Tested-by: Joey Gouly Link: https://lore.kernel.org/r/ZWJoRsJGnCPdJ3+2@work Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- include/net/neighbour.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/neighbour.h b/include/net/neighbour.h index 07022bb0d44d4..0d28172193fa6 100644 --- a/include/net/neighbour.h +++ b/include/net/neighbour.h @@ -162,7 +162,7 @@ struct neighbour { struct rcu_head rcu; struct net_device *dev; netdevice_tracker dev_tracker; - u8 primary_key[0]; + u8 primary_key[]; } __randomize_layout; struct neigh_ops { -- 2.42.0