From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 4044F478E5D; Sat, 12 Sep 2026 11:42:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789213378; cv=none; b=fQYnJLQFf2B8JmgZz9+U4kmySnL5Dp8OVoHmPfePSLb3Jfpnr4i8r+CoFxRMVMybjkhoUIlRyWnZ+vym5Rrrm2h/0MSruRK5rMxi1GLgJnQGwR0zCXKW78Dqdw1Y/5io6ybj25CrvjsQt7ZAenIPM4zPk24hgKi/znyYu0u18sw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789213378; c=relaxed/simple; bh=DgNdLe5yR4dINcclrv6M0daYT/POAAiHlVz8DfSc96Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hvj8rnIJxy8WO7wX6PkTU1g7+uKtZHIyrUucvZrWhvgBmFIhV3AtF+gz4yyFqqj7f4PqnW7iPelTXh53SHzBi3nP6MNPNeJOKUxIp8cIFkjp5jmurGT7Rm795a9fnPC65J+HjylHUM+7HHlFyu5xJmpSFIf+Ln6Vxe3bq+0S9I0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UnlaZL5h; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="UnlaZL5h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CAC161F000FF; Sat, 12 Sep 2026 11:42:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789213375; bh=gQeQIDGbcp5Zwgon/EpkBwFeWZ35USGKF+drcCmh1Jg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=UnlaZL5hLS1SwvbqUo+jvfCQ3NwJu8Y48zNkPwGcvvL0P2aih0Yda2a07lNpH/zjH Q40HudgVeQH0WBGZzC+Qq2yTAowFyZJA5pt/wi/xzP0Hlv/DbX6PC/ngqqFHezwGUE xohetcvUoP4z3yuPqV8UvoelylVAM5xpODwVu07o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Bryam Vargas , Alison Schofield Subject: [PATCH 6.12 0092/1376] nvdimm/btt: reject an arena whose nfree is below the lane count Date: Sat, 12 Sep 2026 08:41:58 +0200 Message-ID: <20260912065609.613227578@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.535295758@linuxfoundation.org> References: <20260912065607.535295758@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bryam Vargas commit 6a1f2e5ed9267ca19187038ac635393c165213ac upstream. The BTT info block's nfree field, the number of reserve free blocks, is read from the medium without validation. btt_freelist_init() and btt_rtt_init() size the per-lane freelist[] and rtt[] arrays by nfree, but the I/O path indexes them by the lane from nd_region_acquire_lane(), which is bounded by nd_region->num_lanes (ND_MAX_LANES), not by nfree. A crafted or foreign arena whose nfree is below the lane count makes freelist[lane]/rtt[lane] run past the allocation: an out-of-bounds write. btt.rst documents the nlanes = min(nfree, num_cpus) invariant, which the code does not currently honor: num_lanes is ND_MAX_LANES regardless of nfree. Reject an arena whose nfree is below num_lanes at discovery, before the per-lane arrays are allocated, enforcing that invariant. Fixes: 5212e11fde4d ("nd_btt: atomic sector updates") Cc: stable@vger.kernel.org Signed-off-by: Bryam Vargas Reviewed-by: Alison Schofield Tested-by: Alison Schofield Link: https://patch.msgid.link/20260620-b4-disp-88b2514b-v1-1-3834e707d232@proton.me Signed-off-by: Alison Schofield Signed-off-by: Greg Kroah-Hartman --- drivers/nvdimm/btt.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/drivers/nvdimm/btt.c +++ b/drivers/nvdimm/btt.c @@ -885,6 +885,14 @@ static int discover_arenas(struct btt *b arena->external_lba_start = cur_nlba; parse_arena_meta(arena, super, cur_off); + if (arena->nfree < btt->nd_region->num_lanes) { + dev_err(to_dev(arena), + "nfree %u smaller than lane count %d\n", + arena->nfree, btt->nd_region->num_lanes); + ret = -ENODEV; + goto out; + } + ret = log_set_indices(arena); if (ret) { dev_err(to_dev(arena),