From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) by lore.proxmox.com (Postfix) with ESMTPS id CBCC31FF139 for ; Tue, 10 Feb 2026 16:07:02 +0100 (CET) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 779F16D1E; Tue, 10 Feb 2026 16:07:47 +0100 (CET) From: Robert Obkircher To: pbs-devel@lists.proxmox.com Subject: [PATCH v6 proxmox-backup 07/18] datastore: verify that chunk_size is a power of two Date: Tue, 10 Feb 2026 16:06:23 +0100 Message-ID: <20260210150642.469670-8-r.obkircher@proxmox.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260210150642.469670-1-r.obkircher@proxmox.com> References: <20260210150642.469670-1-r.obkircher@proxmox.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1770735948765 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.059 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 SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Message-ID-Hash: H7SS5FZ4NCDZNRGI5TTVAIPF6BA6SSWP X-Message-ID-Hash: H7SS5FZ4NCDZNRGI5TTVAIPF6BA6SSWP X-MailFrom: r.obkircher@proxmox.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.10 Precedence: list List-Id: Proxmox Backup Server development discussion List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Guarantee that the bitmasks used to compute the modulo actually yield the correct value and implicitly guard against divisions by zero. Signed-off-by: Robert Obkircher --- pbs-datastore/src/fixed_index.rs | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/pbs-datastore/src/fixed_index.rs b/pbs-datastore/src/fixed_index.rs index 7f0ef91c..953f4a20 100644 --- a/pbs-datastore/src/fixed_index.rs +++ b/pbs-datastore/src/fixed_index.rs @@ -86,6 +86,10 @@ impl FixedIndexReader { let ctime = i64::from_le(header.ctime); let chunk_size = u64::from_le(header.chunk_size); + if !chunk_size.is_power_of_two() { + bail!("got non-power-of-two chunk size: {chunk_size}"); + } + let index_length = size.div_ceil(chunk_size) as usize; let index_size = index_length * 32; @@ -98,6 +102,8 @@ impl FixedIndexReader { ); } + let chunk_size = usize::try_from(chunk_size)?; + let data = unsafe { nix::sys::mman::mmap( None, @@ -114,7 +120,7 @@ impl FixedIndexReader { Ok(Self { _file: file, - chunk_size: chunk_size as usize, + chunk_size, size, index_length, index: data, @@ -263,6 +269,9 @@ impl FixedIndexWriter { } let chunk_size = u64::from(chunk_size); + if !chunk_size.is_power_of_two() { + bail!("got non-power-of-two chunk size: {chunk_size}"); + } let ctime = proxmox_time::epoch_i64(); -- 2.47.3