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 1A19C3254BB; Tue, 25 Aug 2026 13:43:46 +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=1787665427; cv=none; b=hUU596+RJ9utB/av+UqvEzbxzL3HuefpTQB38vQf/uwIiEq71oWt06tDkTHvnTDEY627YthyPdmmMZ/p5bPR6uwLL1LG18UicL9ORpJ/qeLLynt2Bm1JjouAc8LqRZhWYmcra0KQ/qm8Icagn7kELihTYk94p3ilAGbG8IPXDfU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787665427; c=relaxed/simple; bh=DFsLkQ4+5twvVR/DEjF+Hny+/PSzdAtoInrqRkRiDZ4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=m2qSTSmH5KDQNoxduuYGCyQLx50YK3zBJ1/ZWlfzRZ3YACXh36cy0dfzXgOpsuBri2maymGszr6IJWlLgaJWebKNv0C6t6XyMXQohcL5VOYNHuL0sxzftPQY8y3tkIuTHie1eVSUqLVlfUpUjxz3EEgFElNSV8D5XxTQXrczPPY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=yLe2dUaN; 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="yLe2dUaN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D8861F000E9; Tue, 25 Aug 2026 13:43:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787665426; bh=WGZakjZspmRbx2CN5i5bXcM+uWpt+iLyUTxar29i/ZQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=yLe2dUaNm6FfCkpcLb7cxXV54pAsgMsjk0zSin+7n3lKadjkd1o6FrfcFLFx7e1m8 Pm2X769hdFcQABZlDEuMmr928BGdQebZ6dZy7XEAggtaTu+/ppK/AO3H7ItMQPP0kE Z2mhzfJ0OnffStSq/+WIZ03DpgY/vO0Kuzeb6PfE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ibrahim Hashimov , "Darrick J. Wong" , Brian Foster , Carlos Maiolino , Sasha Levin Subject: [PATCH 6.12 22/77] xfs: bounds-check buffer log items dirty bitmap Date: Tue, 25 Aug 2026 15:25:44 +0200 Message-ID: <20260825132542.436346419@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260825132541.580275153@linuxfoundation.org> References: <20260825132541.580275153@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: Ibrahim Hashimov [ Upstream commit 813f8136a2ce1fee266d02a7df73db6e8a541604 ] 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 Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/xfs/xfs_buf_item_recover.c | 57 ++++++++++++++++++++++++++++++------------ 1 file changed, 41 insertions(+), 16 deletions(-) --- a/fs/xfs/xfs_buf_item_recover.c +++ b/fs/xfs/xfs_buf_item_recover.c @@ -444,7 +444,7 @@ 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, @@ -472,8 +472,24 @@ 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 @@ -527,6 +543,7 @@ xlog_recover_do_reg_buffer( ASSERT(i == item->ri_total); xlog_recover_validate_buf_type(mp, bp, buf_f, current_lsn); + return 0; } /* @@ -535,10 +552,10 @@ 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, @@ -547,6 +564,7 @@ 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); @@ -554,7 +572,7 @@ 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) @@ -567,10 +585,12 @@ 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; } /* @@ -706,7 +726,9 @@ xlog_recover_do_primary_sb_buffer( xfs_agnumber_t orig_agcount = mp->m_sb.sb_agcount; 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"); @@ -1026,11 +1048,11 @@ 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, @@ -1038,7 +1060,10 @@ xlog_recover_buf_commit_pass2( if (error) goto out_writebuf; } 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; } /*