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 B7CDA2511F; Fri, 24 Nov 2023 19:25:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="aesNrUiD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0AD4C433C7; Fri, 24 Nov 2023 19:25:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700853943; bh=I/ZmqpcYb+0sD880xun09+KD5SlI5d36j8XczSJJ9yw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aesNrUiDMXdVL/DtyCc9hTGIlPyy4CKChaZDm/l1GXvO1Eo01Rr2bY8GZQN0xJWgn HaZTRf8uvg/jUfVsMqz2O8cdBuUT2fKojGDweOUfdPwLsWkrQRMqUq4U2kEeVNcGb4 rDiX4obK4FDFkPDIzJI2eaGLTSX/+gIPqtmLQd+w= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, linux-hardening@vger.kernel.org, Lukas Loidolt , Kees Cook Subject: [PATCH 5.4 068/159] randstruct: Fix gcc-plugin performance mode to stay in group Date: Fri, 24 Nov 2023 17:54:45 +0000 Message-ID: <20231124171944.785943949@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231124171941.909624388@linuxfoundation.org> References: <20231124171941.909624388@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 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook commit 381fdb73d1e2a48244de7260550e453d1003bb8e upstream. The performance mode of the gcc-plugin randstruct was shuffling struct members outside of the cache-line groups. Limit the range to the specified group indexes. Cc: linux-hardening@vger.kernel.org Cc: stable@vger.kernel.org Reported-by: Lukas Loidolt Closes: https://lore.kernel.org/all/f3ca77f0-e414-4065-83a5-ae4c4d25545d@student.tuwien.ac.at Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin") Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman --- scripts/gcc-plugins/randomize_layout_plugin.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/scripts/gcc-plugins/randomize_layout_plugin.c +++ b/scripts/gcc-plugins/randomize_layout_plugin.c @@ -209,12 +209,14 @@ static void partition_struct(tree *field static void performance_shuffle(tree *newtree, unsigned long length, ranctx *prng_state) { - unsigned long i, x; + unsigned long i, x, index; struct partition_group size_group[length]; unsigned long num_groups = 0; unsigned long randnum; partition_struct(newtree, length, (struct partition_group *)&size_group, &num_groups); + + /* FIXME: this group shuffle is currently a no-op. */ for (i = num_groups - 1; i > 0; i--) { struct partition_group tmp; randnum = ranval(prng_state) % (i + 1); @@ -224,11 +226,14 @@ static void performance_shuffle(tree *ne } for (x = 0; x < num_groups; x++) { - for (i = size_group[x].start + size_group[x].length - 1; i > size_group[x].start; i--) { + for (index = size_group[x].length - 1; index > 0; index--) { tree tmp; + + i = size_group[x].start + index; if (DECL_BIT_FIELD_TYPE(newtree[i])) continue; - randnum = ranval(prng_state) % (i + 1); + randnum = ranval(prng_state) % (index + 1); + randnum += size_group[x].start; // we could handle this case differently if desired if (DECL_BIT_FIELD_TYPE(newtree[randnum])) continue;