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 811F11FF139 for ; Tue, 10 Feb 2026 16:07:21 +0100 (CET) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 3567C6FF4; Tue, 10 Feb 2026 16:08:06 +0100 (CET) From: Robert Obkircher To: pbs-devel@lists.proxmox.com Subject: [PATCH v6 proxmox-backup 16/18] datastore: compute fidx file size with overflow checks Date: Tue, 10 Feb 2026 16:06:32 +0100 Message-ID: <20260210150642.469670-17-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: 1770735968033 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.056 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: OHOGKNSK64XTVEZGFGAQI3MGYE76F4GQ X-Message-ID-Hash: OHOGKNSK64XTVEZGFGAQI3MGYE76F4GQ 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: Handle overflows and prevent potential inconsistencies by performing the calcualtion in one place. This also serves as a preparation for mmapping the entire file. Signed-off-by: Robert Obkircher --- pbs-datastore/src/fixed_index.rs | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/pbs-datastore/src/fixed_index.rs b/pbs-datastore/src/fixed_index.rs index e6d6f3df..372d4d91 100644 --- a/pbs-datastore/src/fixed_index.rs +++ b/pbs-datastore/src/fixed_index.rs @@ -313,7 +313,8 @@ impl FixedIndexWriter { }; let index_size = index_capacity * 32; - nix::unistd::ftruncate(&file, (header_size + index_size) as i64)?; + let file_size = Self::file_size(index_capacity)?; + nix::unistd::ftruncate(&file, file_size)?; let data = unsafe { nix::sys::mman::mmap( @@ -345,6 +346,22 @@ impl FixedIndexWriter { }) } + /// Computes the size of a fidx file containing `index_length` + /// chunk digests. + /// + /// Guarantees that the size fits into usize, isize and i64. + fn file_size(index_length: usize) -> Result { + if index_length == 0 { + bail!("fidx file must have at least one chunk"); + } + index_length + .checked_mul(32) + .and_then(|s| s.checked_add(size_of::())) + .filter(|s| *s <= isize::MAX as usize) + .and_then(|s| i64::try_from(s).ok()) + .ok_or_else(|| format_err!("fidx file size overflow for {index_length} chunks")) + } + /// If this returns an error, the sizes may be out of sync, /// which is especially bad if the capacity was reduced. fn set_index_capacity(&mut self, new_capacity: usize) -> Result<(), Error> { @@ -353,7 +370,7 @@ impl FixedIndexWriter { } let old_index_size = self.index_capacity * 32; let new_index_size = new_capacity * 32; - let new_file_size = (size_of::() + new_index_size) as i64; + let new_file_size = Self::file_size(new_capacity)?; let index_addr = NonNull::new(self.index as *mut std::ffi::c_void).ok_or_else(|| { format_err!("Can't resize FixedIndexWriter index because the index pointer is null.") @@ -456,11 +473,9 @@ impl FixedIndexWriter { self.unmap()?; - if self.index_length == 0 { - bail!("refusing to close empty fidx file {:?}", self.tmp_filename); - } else if self.index_length < self.index_capacity { - let file_size = size_of::() + index_size; - nix::unistd::ftruncate(&self.file, file_size as i64)?; + if self.index_length < self.index_capacity { + let file_size = Self::file_size(self.index_length)?; + nix::unistd::ftruncate(&self.file, file_size)?; self.index_capacity = self.index_length; } -- 2.47.3