From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [IPv6:2a01:7e0:0:424::9]) by lore.proxmox.com (Postfix) with ESMTPS id 1D09B1FF16B for ; Thu, 29 Aug 2024 12:31:28 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 48DE61A229; Thu, 29 Aug 2024 12:31:56 +0200 (CEST) Date: Thu, 29 Aug 2024 12:31:22 +0200 From: Gabriel Goller To: Wolfgang Bumiller Message-ID: <20240829103122.ainqdg2k3ewqfd5y@luna.proxmox.com> References: <20240823091215.124453-1-g.goller@proxmox.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20220429 X-SPAM-LEVEL: Spam detection results: 0 AWL -0.042 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment RCVD_IN_VALIDITY_CERTIFIED_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. 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SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record T_SCC_BODY_TEXT_LINE -0.01 - Subject: Re: [pbs-devel] [PATCH proxmox-backup] proxy: check permissions on proxy.key and proxy.pem 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: , Reply-To: Proxmox Backup Server development discussion Cc: pbs-devel@lists.proxmox.com Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: pbs-devel-bounces@lists.proxmox.com Sender: "pbs-devel" On 27.08.2024 11:37, Wolfgang Bumiller wrote: >NAK > >On Fri, Aug 23, 2024 at 11:12:15AM GMT, Gabriel Goller wrote: >> Check the owner and permission of the proxy.key and proxy.pem files. >> This avoids openssl's unhelpful error message and prints a nicer one. >> >> Motivation: https://forum.proxmox.com/threads/proxmox-backup-tailscale-proxmox-backup-proxy-service-wont-boot.153204 >> >> Signed-off-by: Gabriel Goller >> --- >> >> Note: not sure about the correct permissions, we currently default to >> 640, but maybe a minimum of 400 is enough? >> >> src/bin/proxmox-backup-proxy.rs | 27 +++++++++++++++++++++++++++ >> 1 file changed, 27 insertions(+) >> >> diff --git a/src/bin/proxmox-backup-proxy.rs b/src/bin/proxmox-backup-proxy.rs >> index 041f3aff999c..544196b8bc5d 100644 >> --- a/src/bin/proxmox-backup-proxy.rs >> +++ b/src/bin/proxmox-backup-proxy.rs >> @@ -367,6 +367,30 @@ async fn run() -> Result<(), Error> { >> Ok(()) >> } >> >> +/// Check permissions and owner of passed path. >> +fn check_permissions>(path: T, file_mode: u32) -> Result<(), Error> { >> + match nix::sys::stat::stat(path.as_ref()) { >> + Ok(stat) => { >> + if stat.st_uid != u32::from(pbs_config::backup_user()?.uid) >> + || stat.st_gid != u32::from(pbs_config::backup_group()?.gid) >> + || stat.st_mode & 0o770 < file_mode > >If you want to test whether you can open a file, you should either just >`open(2)` it, or, if you really want to avoid it, use `access(2)`. >You do not ever want to attempt to try to perform the kernel's >permission checks yourself. There could be ACLs, AppArmor profiles, ... >and while we can say that, for now, this is not supposed to be the case, >it's bad practice in general. > >Also note that this only covers the case at a point in time where the >certificate isn't actually loaded, and won't help with changes to the >permissions while a daemon is already running. > >A better approach to handle this specific case would be to adapt >`proxmox-rest-server`'s handling of `Tls::PemFiles` so that instead of >using `openssl`'s ".set_private_key_file()` convenience methods, it >loads the files, and handles `EPERM`/`ENOENT`/... with useful error >messags, and then uses >`acceptor.set_private_key(PKey::private_key_from_pem(data)?)` I agree. We can use the function you mentioned for the private key (and it works!), but not for the certificate. AFAICT (and I know nothing about openssl) there is no use_certificate_chain() function, so the certificate chain can only be loaded using a path [0]. This seems kinda weird, as all the other functions have path and file-content flavors, but this one hasn't. Nevertheless we could just forget about the certificate or we could do a open() and close() to check the permissions? [0]: https://github.com/openssl/openssl/blob/14c45338e986d5827f1e944d0cffe54a7f4697ea/ssl/ssl_rsa.c#L437 _______________________________________________ pbs-devel mailing list pbs-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pbs-devel