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Sat, 11 Apr 2026 08:02:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775894565; bh=DXESaPnzd7c3JQ2Cj6QdfGEnPi+ZFUUE0vNpiijc+CQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=URmQWa3q2QkaBIhjekHwjkIQ6ygmAcCk5P7N+qFY0DtVxyE4GgfwvJ3JEPbkiTZo0 OTIcElHxkmygEAmNHNZNqL58DBxmbgmSiRDcnnK9pATkqoFX11xo6/LTtY16Azxdck nPSw8oAsZf1/hN1NkW8rubQCLJH3CBftLKXXREIbbTKUVKN5BEOi94irqitjc/w6+d pRY5BdvzfBn/a8vSMcBxYI32ElWedqiNvwXzpJ8C7HHpOzIkl2ONIBwgq1Tzoex5y/ 3YyA+tPjvODPYccpayyfAriUwS/JE8X9pyCPNvMWzzI43+Mq4+tzaFzDNiUcCnyjw1 xdZXqbiut/HmA== 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 v4 15/24] alpha/PCI: Fix __pci_mmap_fits() overflow for zero-length BARs Date: Sat, 11 Apr 2026 08:01:39 +0000 Message-ID: <20260411080148.471335-16-kwilczynski@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260411080148.471335-1-kwilczynski@kernel.org> References: <20260411080148.471335-1-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") 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 6c011dab326d..2748000a7486 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