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 8878E35292A; Tue, 16 Jun 2026 18:19:09 +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=1781633950; cv=none; b=P1zY//f44EHJWs73x2pVDaMh+Sqb4GUplQ3sk5ZSB69lMuZhUy98gECqFjVmW3ExOK0t2te5x/vvC1MVu3U2rcitEPX5oeWDV7L26gsIAjDUnn0pl9D5dIqgrJPAJ3gRDw1xf1T02fiKCL8f3ov35QCkcA6bfwlwiGBMrgRX+OE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781633950; c=relaxed/simple; bh=5ZrAqZUIJ+VOp0Thdj1Yo8hYZDGMuNyZ9z9FA9bAcqQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XvNaMXNmGldxY6cecBQNdawSOVQLwYOGcmA/kV0JdSyxPsTJjwerCW8x6Hzm75kpM7yZT1bsl2ia2+loTmxZOJpxm6QKAVii/IWA9CG1g67crC9PipPb+gON0HlCNT0UVPMruauSCVxtTSwMdOdd3Bxx6sJPKX2qJUk0yiH2MSk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=CnsK5mUm; 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="CnsK5mUm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 000751F000E9; Tue, 16 Jun 2026 18:19:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781633949; bh=IVVfQgzIL86T6cLt5ZlbUx4avH8RIvTJeVaHKNZNWRw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CnsK5mUmnpRhDDaC9xGZjRZtD8uzQJPev0bmsVYcwcphUzti28boSwcasElfrowuP cbWFh7O2QkOJXA6UbRpLvse3keY7nqxQgPoJe0eSZH/cSzDhfZ6F7rSxYvmKo1Lcul pnnAKAWaGXm+MKmvkBY/CuNnXdRoH97Rqyb3MPWM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+04c4e65cab786a2e5b7e@syzkaller.appspotmail.com, Tejas Bharambe , Theodore Tso , stable@kernel.org, Alexey Panov , Sasha Levin Subject: [PATCH 5.15 174/411] ext4: validate p_idx bounds in ext4_ext_correct_indexes Date: Tue, 16 Jun 2026 20:26:52 +0530 Message-ID: <20260616145109.910023187@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145100.376842714@linuxfoundation.org> References: <20260616145100.376842714@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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tejas Bharambe commit 2acb5c12ebd860f30e4faf67e6cc8c44ddfe5fe8 upstream. ext4_ext_correct_indexes() walks up the extent tree correcting index entries when the first extent in a leaf is modified. Before accessing path[k].p_idx->ei_block, there is no validation that p_idx falls within the valid range of index entries for that level. If the on-disk extent header contains a corrupted or crafted eh_entries value, p_idx can point past the end of the allocated buffer, causing a slab-out-of-bounds read. Fix this by validating path[k].p_idx against EXT_LAST_INDEX() at both access sites: before the while loop and inside it. Return -EFSCORRUPTED if the index pointer is out of range, consistent with how other bounds violations are handled in the ext4 extent tree code. Reported-by: syzbot+04c4e65cab786a2e5b7e@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=04c4e65cab786a2e5b7e Signed-off-by: Tejas Bharambe Link: https://patch.msgid.link/JH0PR06MB66326016F9B6AD24097D232B897CA@JH0PR06MB6632.apcprd06.prod.outlook.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org [ Alexey: Adapt goto clean to break because the clean error path is not present in linux-5.10.y and linux-5.15.y. ] Signed-off-by: Alexey Panov Signed-off-by: Sasha Levin --- fs/ext4/extents.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 80b7783c65b41e..e6dbb2dfb3318f 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -1736,6 +1736,13 @@ static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode, err = ext4_ext_get_access(handle, inode, path + k); if (err) return err; + if (unlikely(path[k].p_idx > EXT_LAST_INDEX(path[k].p_hdr))) { + EXT4_ERROR_INODE(inode, + "path[%d].p_idx %p > EXT_LAST_INDEX %p", + k, path[k].p_idx, + EXT_LAST_INDEX(path[k].p_hdr)); + return -EFSCORRUPTED; + } path[k].p_idx->ei_block = border; err = ext4_ext_dirty(handle, inode, path + k); if (err) @@ -1748,6 +1755,14 @@ static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode, err = ext4_ext_get_access(handle, inode, path + k); if (err) break; + if (unlikely(path[k].p_idx > EXT_LAST_INDEX(path[k].p_hdr))) { + EXT4_ERROR_INODE(inode, + "path[%d].p_idx %p > EXT_LAST_INDEX %p", + k, path[k].p_idx, + EXT_LAST_INDEX(path[k].p_hdr)); + err = -EFSCORRUPTED; + break; + } path[k].p_idx->ei_block = border; err = ext4_ext_dirty(handle, inode, path + k); if (err) -- 2.53.0