From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 343AE6929C for ; Mon, 13 Sep 2021 09:54:26 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 1D89526A4C for ; Mon, 13 Sep 2021 09:53:56 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id 023C226A3E for ; Mon, 13 Sep 2021 09:53:54 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id B55AE4477A; Mon, 13 Sep 2021 09:53:53 +0200 (CEST) Message-ID: <7e3bcd21-b93f-eb58-ee4f-673796ea271b@proxmox.com> Date: Mon, 13 Sep 2021 09:53:51 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:92.0) Gecko/20100101 Thunderbird/92.0 Content-Language: en-US To: Thomas Lamprecht , Proxmox Backup Server development discussion References: <20210910090948.2145523-1-d.csapak@proxmox.com> <60f030f0-c15a-0b2f-6bf6-1a243f042f0c@proxmox.com> <758f28ef-4c6c-ccaf-54a7-17e4c0f8b10c@proxmox.com> <916d18cc-b4ac-ff07-e0fe-6c4dab61105d@proxmox.com> From: Dominik Csapak In-Reply-To: <916d18cc-b4ac-ff07-e0fe-6c4dab61105d@proxmox.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL 2.203 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment NICE_REPLY_A -3.584 Looks like a legit reply (A) SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: Re: [pbs-devel] [RFC PATCH proxmox-backup] pbs-tools: zip: add EFS flag to zip files X-BeenThere: pbs-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox Backup Server development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 13 Sep 2021 07:54:26 -0000 On 9/13/21 09:25, Thomas Lamprecht wrote: > On 13.09.21 09:14, Dominik Csapak wrote: >> On 9/11/21 17:08, Thomas Lamprecht wrote: >>> On 10.09.21 11:09, Dominik Csapak wrote: >>> Also interesting, just below above quote: >>> >>>> D.3 Applications MAY choose to supplement this file name storage through the use >>>> of the 0x0008 Extra Field.  Storage for this optional field is currently >>>> undefined, however it will be used to allow storing extended information >>>> on source or target encoding that MAY further assist applications with file >>>> name, or file content encoding tasks.  Please contact PKWARE with any >>>> requirements on how this field SHOULD be used. >> >> AFAIU, that part of the 'spec' is not open and would require a license of PKWARE > > yeah that's what I figured, but observe and replicate could in theory still be OK I guess? > >> >>> >>> >>> So I'd like to know what standard tools like info-zip (i.e., Debian's "zip" package) or >>> other cross-platform tools like 7zip do. >>> >>> It seems that at least Debian's version of info zip had some thoughts about this and can >>> (or always does, did not checked that closely) safe utf8 filenames in an extra field, one >>> that some other tools maybe check for? >>> >>> https://sources.debian.org/src/zip/3.0-12/zip.c/#L967 >>> >>> I say Debian's version, as upstream still talks about Unicode support on their home page, >>> which itself may be just outdated too, but it could also be that Debian patched that in. >>> >>> Any how, it seems to me that there'd be some more compatible options that do not plainly >>> state that they're 100% utf-8 while actually not being so sure of that, so I'd explore that >>> angle quite some more; data restoration is probably the most important aspect of a backup >>> system - so every way we expose doing so should work as as good as possible - even if going >>> outside our Linux bubble. >> >> I tested it with debians zip (Info-Zip), and despite was the spec says, >> i could not get it to write an 'extra-field' with the filenames. >> > > hmm, meh... > >> Instead, when it finds a filename that has a filename with any byte that >> has the high-bit set (>127) it sets the EFS bit in the filename iff >> the filename is valid utf-8, and does nothing if not. >> >> IMHO, that sounds like a reasonable thing to do, so i'd suggest >> that we test each filename for valid UTF-8, and set the bit >> if that's true. This marks ASCII only filenames also as UTF-8, >> but thats technically true and simplifies the rust code a bit >> (and should be faster for UTF-8 Filenames, >> since we do not have to check for a high bit first and then try to >> convert...) >> >> Does that sound ok to you? > > Yes, sounds reasonable to me for nwo. It'd be an improvement and we basically only use > this for on-the-fly generation, so if we find a possible "better" (hard to measure that > with such a mess of format) approach in the future it would help all users immediately > too then. > >> >> For non-valid UTF-8 filenames that have a high bit i'd produce >> CP437 filenames on windows, and on linux it'd just be the >> byte value. > > just to be sure: what does "i'd produce" mean here? As we certainly do not differ ZIP > generation semantics by user OS (thank goodness), this means that a unzip by most > reasonable tools would produce the outcome you described, or? oops, this should say "it'd" so "it would". To be completely clear, such ZIPs extracts as * Windows(built-in + 7zip): UTF-8 filenames get correctly encoded, all other filenames interpreted as CP437 * Debian(zip): filenames as bytes in any case * Debian(7z): weirdly it uses valid utf-8 as utf-8 bytes, but other filenames, it interprets as Windows 1252 and encodes as UTF-8.. i'll send a v2 with this semantic though, as i don't think we can do much better for now > >> >>> >>>>   pbs-tools/src/zip.rs | 6 ++++-- >>>>   1 file changed, 4 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/pbs-tools/src/zip.rs b/pbs-tools/src/zip.rs >>>> index 605480a8..88eea07b 100644 >>>> --- a/pbs-tools/src/zip.rs >>>> +++ b/pbs-tools/src/zip.rs >>>> @@ -34,6 +34,8 @@ const VERSION_MADE_BY: u16 = 0x032d; >>>>   const ZIP64_EOCD_RECORD: u32 = 0x06064B50; >>>>   const ZIP64_EOCD_LOCATOR: u32 = 0x07064B50; >>>>   +const GENERAL_PURUPOSE_FLAGS: u16 = (1 << 3) | (1 << 11); // EFS + Data Descriptor >>>> + >>> >>> - typo in constant name: purupose vs. purpose >> >> yeah thanks... >> >>> - comment order do not match the bits used, bit 11 is EFS and bit 3 is telling >>>    the parser that the crc32 is not in the header but in the data descriptor after >>>    the compressed data; your bitwise-OR+comment order suggests different. >> >> sorry >> >>> - isn't this related to BZ entry #3618, but that is neither mentioned here nor in the >>>    bug report... >> >> that bug-report wasn't there when i wrote the patch. > > I naturally only compared mail vs BZ time and missed the date difference of one day, > argh, sorry. > >> >>> >>> _If_ we'd go down this way then the following const name and formatting would make this >>> easier to read IMO: >>> >>> const LFH_GENERAL_PURPOSE_FLAGS: u16 = (1 << 3) // we place crc32 in data descriptor >>>      | (1 << 11); // EFS, mark filenames & comments as UTF-8 (not guaranteed but more often OK than CP437) >>> >> >> makes, sense, though if we only set it conditionally i'd split the >> EFS_MARK into its own constant. >> > > sounds good to me. >