From patchwork Wed Dec 23 13:49:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 11988363 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A15CC433E0 for ; Wed, 23 Dec 2020 13:51:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C64AB20773 for ; Wed, 23 Dec 2020 13:51:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728802AbgLWNvE (ORCPT ); Wed, 23 Dec 2020 08:51:04 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:43849 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728717AbgLWNvD (ORCPT ); Wed, 23 Dec 2020 08:51:03 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1608731376; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kWSTwe7BO+IAn1kJ/m6kiyZFGVqqtNUwNHZYMDzC0Vo=; b=FMCmy31Co5RHrb0A3je+0FkgrLk84SS+laAo5XaCo5RiFPwkYizZjvG9P22/G9zLdPQ9WX ZT6ICKUy8rRyvGdz6Yfhj2v3wrwGWYpFDv7IpyAfT8pzMTKCWoIXPN0dBAEIm4TCL1a8df hRohxQx4F+CoW47gqlbnErez7lzdN4w= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-213-AtMNMQXBNQGx9kshQLoCuw-1; Wed, 23 Dec 2020 08:49:34 -0500 X-MC-Unique: AtMNMQXBNQGx9kshQLoCuw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 508AD800D53; Wed, 23 Dec 2020 13:49:33 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-112-204.rdu2.redhat.com [10.10.112.204]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3B16863BA7; Wed, 23 Dec 2020 13:49:32 +0000 (UTC) Organization: Red Hat UK Ltd. 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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 2/2] afs: Fix directory entry size calculation From: David Howells To: linux-afs@lists.infradead.org Cc: dhowells@redhat.com, marc.dionne@auristor.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 23 Dec 2020 13:49:31 +0000 Message-ID: <160873137145.834177.6619912921657158513.stgit@warthog.procyon.org.uk> In-Reply-To: <160873136449.834177.8213549315585633735.stgit@warthog.procyon.org.uk> References: <160873136449.834177.8213549315585633735.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.23 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The number of dirent records used by an AFS directory entry should be calculated using the assumption that there is a 16-byte name field in the first block, rather than a 20-byte name field (which is actually the case). This miscalculation is historic and effectively standard, so we have to use it. The calculation we need to use is: 1 + (((strlen(name) + 1) + 15) >> 5) where we are adding one to the strlen() result to account for the NUL termination. Fix this by the following means: (1) Create an inline function to do the calculation for a given name length. (2) Use the function to calculate the number of records used for a dirent in afs_dir_iterate_block(). Use this to move the over-end check out of the loop since it only needs to be done once. Further use this to only go through the loop for the 2nd+ records composing an entry. The only test there now is for if the record is allocated - and we already checked the first block at the top of the outer loop. (3) Add a max name length check in afs_dir_iterate_block(). (4) Make afs_edit_dir_add() and afs_edit_dir_remove() use the function from (1) to calculate the number of blocks rather than doing it incorrectly themselves. Fixes: 63a4681ff39c ("afs: Locally edit directory data for mkdir/create/unlink/...") Fixes: ^1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: David Howells --- fs/afs/dir.c | 49 +++++++++++++++++++++++--------------------- fs/afs/dir_edit.c | 6 ++--- fs/afs/xdr_fs.h | 14 ++++++++++++- include/trace/events/afs.h | 2 ++ 4 files changed, 43 insertions(+), 28 deletions(-) diff --git a/fs/afs/dir.c b/fs/afs/dir.c index 9068d5578a26..7bd659ad959e 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -350,7 +350,7 @@ static int afs_dir_iterate_block(struct afs_vnode *dvnode, unsigned blkoff) { union afs_xdr_dirent *dire; - unsigned offset, next, curr; + unsigned offset, next, curr, nr_slots; size_t nlen; int tmp; @@ -363,13 +363,12 @@ static int afs_dir_iterate_block(struct afs_vnode *dvnode, offset < AFS_DIR_SLOTS_PER_BLOCK; offset = next ) { - next = offset + 1; - /* skip entries marked unused in the bitmap */ if (!(block->hdr.bitmap[offset / 8] & (1 << (offset % 8)))) { _debug("ENT[%zu.%u]: unused", blkoff / sizeof(union afs_xdr_dir_block), offset); + next = offset + 1; if (offset >= curr) ctx->pos = blkoff + next * sizeof(union afs_xdr_dirent); @@ -381,35 +380,39 @@ static int afs_dir_iterate_block(struct afs_vnode *dvnode, nlen = strnlen(dire->u.name, sizeof(*block) - offset * sizeof(union afs_xdr_dirent)); + if (nlen > AFSNAMEMAX - 1) { + _debug("ENT[%zu]: name too long (len %u/%zu)", + blkoff / sizeof(union afs_xdr_dir_block), + offset, nlen); + return afs_bad(dvnode, afs_file_error_dir_name_too_long); + } _debug("ENT[%zu.%u]: %s %zu \"%s\"", blkoff / sizeof(union afs_xdr_dir_block), offset, (offset < curr ? "skip" : "fill"), nlen, dire->u.name); - /* work out where the next possible entry is */ - for (tmp = nlen; tmp > 15; tmp -= sizeof(union afs_xdr_dirent)) { - if (next >= AFS_DIR_SLOTS_PER_BLOCK) { - _debug("ENT[%zu.%u]:" - " %u travelled beyond end dir block" - " (len %u/%zu)", - blkoff / sizeof(union afs_xdr_dir_block), - offset, next, tmp, nlen); - return afs_bad(dvnode, afs_file_error_dir_over_end); - } - if (!(block->hdr.bitmap[next / 8] & - (1 << (next % 8)))) { - _debug("ENT[%zu.%u]:" - " %u unmarked extension (len %u/%zu)", + nr_slots = afs_dir_calc_slots(nlen); + next = offset + nr_slots; + if (next > AFS_DIR_SLOTS_PER_BLOCK) { + _debug("ENT[%zu.%u]:" + " %u extends beyond end dir block" + " (len %zu)", + blkoff / sizeof(union afs_xdr_dir_block), + offset, next, nlen); + return afs_bad(dvnode, afs_file_error_dir_over_end); + } + + /* Check that the name-extension dirents are all allocated */ + for (tmp = 1; tmp < nr_slots; tmp++) { + unsigned int ix = offset + tmp; + if (!(block->hdr.bitmap[ix / 8] & (1 << (ix % 8)))) { + _debug("ENT[%zu.u]:" + " %u unmarked extension (%u/%u)", blkoff / sizeof(union afs_xdr_dir_block), - offset, next, tmp, nlen); + offset, tmp, nr_slots); return afs_bad(dvnode, afs_file_error_dir_unmarked_ext); } - - _debug("ENT[%zu.%u]: ext %u/%zu", - blkoff / sizeof(union afs_xdr_dir_block), - next, tmp, nlen); - next++; } /* skip if starts before the current position */ diff --git a/fs/afs/dir_edit.c b/fs/afs/dir_edit.c index 2ffe09abae7f..f4600c1353ad 100644 --- a/fs/afs/dir_edit.c +++ b/fs/afs/dir_edit.c @@ -215,8 +215,7 @@ void afs_edit_dir_add(struct afs_vnode *vnode, } /* Work out how many slots we're going to need. */ - need_slots = round_up(12 + name->len + 1 + 4, AFS_DIR_DIRENT_SIZE); - need_slots /= AFS_DIR_DIRENT_SIZE; + need_slots = afs_dir_calc_slots(name->len); meta_page = kmap(page0); meta = &meta_page->blocks[0]; @@ -393,8 +392,7 @@ void afs_edit_dir_remove(struct afs_vnode *vnode, } /* Work out how many slots we're going to discard. */ - need_slots = round_up(12 + name->len + 1 + 4, AFS_DIR_DIRENT_SIZE); - need_slots /= AFS_DIR_DIRENT_SIZE; + need_slots = afs_dir_calc_slots(name->len); meta_page = kmap(page0); meta = &meta_page->blocks[0]; diff --git a/fs/afs/xdr_fs.h b/fs/afs/xdr_fs.h index c926430fd08a..8ca868164507 100644 --- a/fs/afs/xdr_fs.h +++ b/fs/afs/xdr_fs.h @@ -58,7 +58,8 @@ union afs_xdr_dirent { /* When determining the number of dirent slots needed to * represent a directory entry, name should be assumed to be 16 * bytes, due to a now-standardised (mis)calculation, but it is - * in fact 20 bytes in size. + * in fact 20 bytes in size. afs_dir_calc_slots() should be + * used for this. * * For names longer than (16 or) 20 bytes, extra slots should * be annexed to this one using the extended_name format. @@ -101,4 +102,15 @@ struct afs_xdr_dir_page { union afs_xdr_dir_block blocks[AFS_DIR_BLOCKS_PER_PAGE]; }; +/* + * Calculate the number of dirent slots required for any given name length. + * The calculation is made assuming the part of the name in the first slot is + * 16 bytes, rather than 20, but this miscalculation is now standardised. + */ +static inline unsigned int afs_dir_calc_slots(size_t name_len) +{ + name_len++; /* NUL-terminated */ + return 1 + ((name_len + 15) / AFS_DIR_DIRENT_SIZE); +} + #endif /* XDR_FS_H */ diff --git a/include/trace/events/afs.h b/include/trace/events/afs.h index 4eef374d4413..4a5cc8c64be3 100644 --- a/include/trace/events/afs.h +++ b/include/trace/events/afs.h @@ -231,6 +231,7 @@ enum afs_file_error { afs_file_error_dir_bad_magic, afs_file_error_dir_big, afs_file_error_dir_missing_page, + afs_file_error_dir_name_too_long, afs_file_error_dir_over_end, afs_file_error_dir_small, afs_file_error_dir_unmarked_ext, @@ -488,6 +489,7 @@ enum afs_cb_break_reason { EM(afs_file_error_dir_bad_magic, "DIR_BAD_MAGIC") \ EM(afs_file_error_dir_big, "DIR_BIG") \ EM(afs_file_error_dir_missing_page, "DIR_MISSING_PAGE") \ + EM(afs_file_error_dir_name_too_long, "DIR_NAME_TOO_LONG") \ EM(afs_file_error_dir_over_end, "DIR_ENT_OVER_END") \ EM(afs_file_error_dir_small, "DIR_SMALL") \ EM(afs_file_error_dir_unmarked_ext, "DIR_UNMARKED_EXT") \