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 1366933F595 for ; Thu, 20 Aug 2026 11:48:42 +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=1787226523; cv=none; b=cZUPMqOjpGIH/6X+EQRtBgdxCL1gXZlG5pZO0pSE9V0QPRSlicUxQJgUbwq4o4P71VZ10DJodRvv60aMUtIfRgeYuXX9VtHOipygCOWxYpw0tG/Xk0I+QX6q6DpIC5l/lY6fD/6dwso4dWDs4zXtBw2nVvdg70cYCKdL+tKjIv4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787226523; c=relaxed/simple; bh=S9yptoGPbKC51hsmjyYTLqHWGaFpGyWxDtroE/WHdwk=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=PhBY9oVa6LmLWNn+i+tv7Cr5rf6hrggB9z1M0l/+qTDK6p28i705Fm6axIbmvbZI1UbnqzlvBYqDz0ur6O9pqAXt8S/JXmbbvEUAKZRJ1iD+VXHVrPQHHjCEtPZcocRU/aUs88QlCbBq3FCMDHep7XTsUVfYzvynsxWd7mz9Cfc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=GDpGEXbC; 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="GDpGEXbC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C6B041F000E9; Thu, 20 Aug 2026 11:48:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787226522; bh=cS8zetNeFoD4LwnJ831IigKM9Shyd+q4lJVbqQ5Z35I=; h=Subject:To:Cc:From:Date; b=GDpGEXbCqEtEpECG0id6LPz0Lf/mFSyKqx65ecv3wn1aDnzl/szLeN7KXOExJy2U0 dB30KhbpVp1VAGZnqHq4OFaQlbsqzls2sBCir2X9b0fZ4Gq3y7X6UIGc+cuT7L7/YL xcGO35731UDku90wbzX3rhc7DIvrRfHtYQrpY0kc= Subject: FAILED: patch "[PATCH] xfs: bounds-check buffer log item's dirty bitmap" failed to apply to 6.1-stable tree To: security@auditcode.ai,bfoster@redhat.com,cem@kernel.org,djwong@kernel.org Cc: From: Date: Thu, 20 Aug 2026 13:32:46 +0200 Message-ID: <2026082046-trophy-useable-6a71@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.1-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 . 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-6.1.y git checkout FETCH_HEAD git cherry-pick -x 813f8136a2ce1fee266d02a7df73db6e8a541604 # git commit -s git send-email --to '' --in-reply-to '2026082046-trophy-useable-6a71@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 813f8136a2ce1fee266d02a7df73db6e8a541604 Mon Sep 17 00:00:00 2001 From: Ibrahim Hashimov Date: Wed, 15 Jul 2026 09:17:23 +0200 Subject: [PATCH] xfs: bounds-check buffer log item's dirty bitmap xlog_recover_do_reg_buffer() replays each dirty region described by a buffer log item's bitmap into the buffer read for that item: memcpy(xfs_buf_offset(bp, (uint)bit << XFS_BLF_SHIFT), item->ri_buf[i].iov_base, nbits << XFS_BLF_SHIFT); The destination offset (bit/nbits, from the logged dirty bitmap) and the buffer size (from the logged blf_len) are both attacker-controlled and otherwise unrelated, yet the only thing bounding the copy is an ASSERT(), which compiles away on production kernels. A crafted image logging a small blf_len together with a bitmap bit past the end of that buffer drives the memcpy() past the buffer's allocation, corrupting adjacent kernel heap during mount-time log recovery. This is reachable by anyone who can get a crafted image mounted -- the malicious-filesystem threat model XFS already guards against elsewhere. Turn the ASSERT() into a real XFS_IS_CORRUPT() check that aborts recovery of the buffer with -EFSCORRUPTED, consistent with the validate-and-fail idiom already used in xlog_recover_do_inode_buffer() and xfs_dquot_item_recover.c. xlog_recover_do_reg_buffer() therefore becomes STATIC int and its three callers propagate the error. Found and confirmed with KASAN on a CONFIG_XFS_DEBUG=n build: the crafted image trips a slab-out-of-bounds write before this change and fails recovery cleanly with -EFSCORRUPTED after it. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Ibrahim Hashimov Reviewed-by: "Darrick J. Wong" Reviewed-by: Brian Foster Signed-off-by: Carlos Maiolino diff --git a/fs/xfs/xfs_buf_item_recover.c b/fs/xfs/xfs_buf_item_recover.c index 02b95b89d1b5..240deb3f7827 100644 --- a/fs/xfs/xfs_buf_item_recover.c +++ b/fs/xfs/xfs_buf_item_recover.c @@ -461,7 +461,7 @@ xlog_recover_validate_buf_type( * given buffer. The bitmap in the buf log format structure indicates * where to place the logged data. */ -STATIC void +STATIC int xlog_recover_do_reg_buffer( struct xfs_mount *mp, struct xlog_recover_item *item, @@ -489,8 +489,24 @@ xlog_recover_do_reg_buffer( ASSERT(nbits > 0); ASSERT(item->ri_buf[i].iov_base != NULL); ASSERT(item->ri_buf[i].iov_len % XFS_BLF_CHUNK == 0); - ASSERT(BBTOB(bp->b_length) >= - ((uint)bit << XFS_BLF_SHIFT) + (nbits << XFS_BLF_SHIFT)); + /* + * The bitmap is only trustworthy to the extent that it + * describes a region that actually fits inside the buffer we + * read in based on the (attacker-controlled) blf_len. Do not + * rely on an ASSERT() for this -- it compiles away entirely on + * non-DEBUG kernels, which is exactly where this matters, so + * validate it for real and abort recovery of this buffer rather + * than copying past the end of it. + */ + if (XFS_IS_CORRUPT(mp, BBTOB(bp->b_length) < + ((uint)bit << XFS_BLF_SHIFT) + + (nbits << XFS_BLF_SHIFT))) { + xfs_alert(mp, + "Bad buffer log item dirty bitmap (bit %d, nbits %d) for %d-byte buffer at daddr 0x%llx.", + bit, nbits, BBTOB(bp->b_length), + xfs_buf_daddr(bp)); + return -EFSCORRUPTED; + } /* * The dirty regions logged in the buffer, even though @@ -544,6 +560,7 @@ xlog_recover_do_reg_buffer( ASSERT(i == item->ri_total); xlog_recover_validate_buf_type(mp, bp, buf_f, current_lsn); + return 0; } /* @@ -552,10 +569,10 @@ xlog_recover_do_reg_buffer( * (ie. USR or GRP), then just toss this buffer away; don't recover it. * Else, treat it as a regular buffer and do recovery. * - * Return false if the buffer was tossed and true if we recovered the buffer to - * indicate to the caller if the buffer needs writing. + * Return 0 if the buffer was not recovered (tossed), 1 if it was recovered and + * needs writing, or a negative errno if recovery of the buffer failed. */ -STATIC bool +STATIC int xlog_recover_do_dquot_buffer( struct xfs_mount *mp, struct xlog *log, @@ -564,6 +581,7 @@ xlog_recover_do_dquot_buffer( struct xfs_buf_log_format *buf_f) { uint type; + int error; trace_xfs_log_recover_buf_dquot_buf(log, buf_f); @@ -571,7 +589,7 @@ xlog_recover_do_dquot_buffer( * Filesystems are required to send in quota flags at mount time. */ if (!mp->m_qflags) - return false; + return 0; type = 0; if (buf_f->blf_flags & XFS_BLF_UDQUOT_BUF) @@ -584,10 +602,12 @@ xlog_recover_do_dquot_buffer( * This type of quotas was turned off, so ignore this buffer */ if (log->l_quotaoffs_flag & type) - return false; + return 0; - xlog_recover_do_reg_buffer(mp, item, bp, buf_f, NULLCOMMITLSN); - return true; + error = xlog_recover_do_reg_buffer(mp, item, bp, buf_f, NULLCOMMITLSN); + if (error) + return error; + return 1; } /* @@ -724,7 +744,9 @@ xlog_recover_do_primary_sb_buffer( xfs_rgnumber_t orig_rgcount = mp->m_sb.sb_rgcount; int error; - xlog_recover_do_reg_buffer(mp, item, bp, buf_f, current_lsn); + error = xlog_recover_do_reg_buffer(mp, item, bp, buf_f, current_lsn); + if (error) + return error; if (orig_agcount == 0) { xfs_alert(mp, "Trying to grow file system without AGs"); @@ -1081,11 +1103,11 @@ xlog_recover_buf_commit_pass2( goto out_release; } else if (buf_f->blf_flags & (XFS_BLF_UDQUOT_BUF|XFS_BLF_PDQUOT_BUF|XFS_BLF_GDQUOT_BUF)) { - bool dirty; - - dirty = xlog_recover_do_dquot_buffer(mp, log, item, bp, buf_f); - if (!dirty) + error = xlog_recover_do_dquot_buffer(mp, log, item, bp, buf_f); + if (error <= 0) goto out_release; + /* write dirty buffer */ + error = 0; } else if ((xfs_blft_from_flags(buf_f) & XFS_BLFT_SB_BUF) && xfs_buf_daddr(bp) == 0) { error = xlog_recover_do_primary_sb_buffer(mp, item, bp, buf_f, @@ -1105,7 +1127,10 @@ xlog_recover_buf_commit_pass2( xfs_buf_relse(rtsb_bp); } } else { - xlog_recover_do_reg_buffer(mp, item, bp, buf_f, current_lsn); + error = xlog_recover_do_reg_buffer(mp, item, bp, buf_f, + current_lsn); + if (error) + goto out_release; } /*