From: Thomas Zimmermann tzimmermann@suse.de
mainline inclusion from mainline-v6.9-rc1 commit 4e754597d603c642869be9bffbb0ef49bf5f7bb8 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAR4KI CVE: CVE-2024-46698
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Test if the firmware framebuffer's parent PCI device, if any, has been enabled. If not, the firmware framebuffer is most likely not working. Hence, do not create a device for the firmware framebuffer on disabled PCI devices.
So far, efifb tracked the status of the PCI parent device internally and did not bind if it was disabled. This patch implements the functionality for all PCI-based firmware framebuffers.
v3: * make commit message more precise (Sui) v2: * rework sysfb_pci_dev_is_enabled() (Javier)
Signed-off-by: Thomas Zimmermann tzimmermann@suse.de Reviewed-by: Javier Martinez Canillas javierm@redhat.com Link: https://patchwork.freedesktop.org/patch/msgid/20240212090736.11464-6-tzimmer... Signed-off-by: dinglongwei dinglongwei1@huawei.com --- drivers/firmware/sysfb.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-)
diff --git a/drivers/firmware/sysfb.c b/drivers/firmware/sysfb.c index 6156baaa2e90..a6b48703dc9e 100644 --- a/drivers/firmware/sysfb.c +++ b/drivers/firmware/sysfb.c @@ -70,15 +70,41 @@ void sysfb_disable(void) } EXPORT_SYMBOL_GPL(sysfb_disable);
+#if defined(CONFIG_PCI) +static __init bool sysfb_pci_dev_is_enabled(struct pci_dev *pdev) +{ + /* + * TODO: Try to integrate this code into the PCI subsystem + */ + int ret; + u16 command; + + ret = pci_read_config_word(pdev, PCI_COMMAND, &command); + if (ret != PCIBIOS_SUCCESSFUL) + return false; + if (!(command & PCI_COMMAND_MEMORY)) + return false; + return true; +} +#else +static __init bool sysfb_pci_dev_is_enabled(struct pci_dev *pdev) +{ + return false; +} +#endif + static __init struct device *sysfb_parent_dev(const struct screen_info *si) { struct pci_dev *pdev;
pdev = screen_info_pci_dev(si); - if (IS_ERR(pdev)) + if (IS_ERR(pdev)) { return ERR_CAST(pdev); - else if (pdev) + } else if (pdev) { + if (!sysfb_pci_dev_is_enabled(pdev)) + return ERR_PTR(-ENODEV); return &pdev->dev; + }
return NULL; } @@ -101,6 +127,8 @@ static __init int sysfb_init(void) sysfb_apply_efi_quirks();
parent = sysfb_parent_dev(si); + if (IS_ERR(parent)) + goto unlock_mutex;
/* try to create a simple-framebuffer device */ compatible = sysfb_parse_mode(si, &mode);