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Thu, 16 Apr 2026 18:01:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776362521; bh=QOViSCcvUL9uyzox8/RADcIRKqDxy6ADtOAMBKvcXqE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UKTJpz1EAj5v6XqpXjYRWO2k81NaT8TbDwK6s2pv53HM7HaGAgCPS+XiXklModdHg iDJ9/fSyrZZzc+rFVaUmTdsdnSwpjP0ZLRBmtuX15LCWPG0EHIMBMtwLxY1mTMwwBt wDdhfZBJxCbsKeyO+1yi0Lw4EpD9HK7wDLG7mT0v3m787VKgIXpxE60KFFnAR/t+dS iZCJSpAsSzKgSUVKVZJ/SczeD46HhcPlVBjICZUKlAgjU/HW/Qi4IaRNHa8eTJZmRu yvFNhlNnDZoRs9N7euu8XylTXyNx/MmKUdTRJwXu1QAV4lZaZrCqwiXf+R8pyuZHev EtrfC/LJyfLoQ== From: =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= To: Bjorn Helgaas Cc: Bjorn Helgaas , Manivannan Sadhasivam , Lorenzo Pieralisi , Magnus Lindholm , Matt Turner , Richard Henderson , Christophe Leroy , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Dexuan Cui , =?UTF-8?q?Krzysztof=20Ha=C5=82asa?= , Lukas Wunner , "Oliver O'Halloran" , Saurabh Singh Sengar , Shuan He , Srivatsa Bhat , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , linux-pci@vger.kernel.org, linux-alpha@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v5 14/23] alpha/PCI: Fix __pci_mmap_fits() overflow for zero-length BARs Date: Thu, 16 Apr 2026 18:00:58 +0000 Message-ID: <20260416180107.777065-15-kwilczynski@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260416180107.777065-1-kwilczynski@kernel.org> References: <20260416180107.777065-1-kwilczynski@kernel.org> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, __pci_mmap_fits() computes the BAR size using pci_resource_len() - 1, which wraps to a large value when the BAR length is zero, causing the bounds check to incorrectly succeed. Thus, add an early return for empty resources. Fixes: 10a0ef39fbd1 ("PCI/alpha: pci sysfs resources") Tested-by: Magnus Lindholm Reviewed-by: Ilpo Järvinen Acked-by: Magnus Lindholm Signed-off-by: Krzysztof Wilczyński --- arch/alpha/kernel/pci-sysfs.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/alpha/kernel/pci-sysfs.c b/arch/alpha/kernel/pci-sysfs.c index 5c29f1d2821c..8802f955256e 100644 --- a/arch/alpha/kernel/pci-sysfs.c +++ b/arch/alpha/kernel/pci-sysfs.c @@ -37,12 +37,16 @@ static int hose_mmap_page_range(struct pci_controller *hose, static int __pci_mmap_fits(struct pci_dev *pdev, int num, struct vm_area_struct *vma, int sparse) { + resource_size_t len = pci_resource_len(pdev, num); unsigned long nr, start, size; int shift = sparse ? 5 : 0; + if (!len) + return 0; + nr = vma_pages(vma); start = vma->vm_pgoff; - size = ((pci_resource_len(pdev, num) - 1) >> (PAGE_SHIFT - shift)) + 1; + size = ((len - 1) >> (PAGE_SHIFT - shift)) + 1; if (start < size && size - start >= nr) return 1; -- 2.53.0