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authorLinus Torvalds <torvalds@linux-foundation.org>2008-10-15 18:09:14 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2008-10-22 14:13:27 -0700
commitfe2615638c671468e28b15d5e15f9b594b1fa23c (patch)
parent76d8cb9a1e102231935e586e888b10ea6ca41101 (diff)
Check mapped ranges on sysfs resource files
commit b5ff7df3df9efab511244d5a299fce706c71af48 upstream Check mapped ranges on sysfs resource files This is loosely based on a patch by Jesse Barnes to check the user-space PCI mappings though the sysfs interfaces. Quoting Jesse's original explanation: It's fairly common for applications to map PCI resources through sysfs. However, with the current implementation, it's possible for an application to map far more than the range corresponding to the resourceN file it opened. This patch plugs that hole by checking the range at mmap time, similar to what is done on platforms like sparc64 in their lower level PCI remapping routines. It was initially put together to help debug the e1000e NVRAM corruption problem, since we initially thought an X driver might be walking past the end of one of its mappings and clobbering the NVRAM. It now looks like that's not the case, but doing the check is still important for obvious reasons. and this version of the patch differs in that it uses a helper function to clarify the code, and does all the checks in pages (instead of bytes) in order to avoid overflows when doing "<< PAGE_SHIFT" etc. [cebbert@redhat.com: backport, changing WARN() to printk()] Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Chuck Ebbert <cebbert@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 9c718583a237..96c47509d6ec 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -16,6 +16,7 @@
#include <linux/kernel.h>
+#include <linux/sched.h>
#include <linux/pci.h>
#include <linux/stat.h>
#include <linux/topology.h>
@@ -484,6 +485,21 @@ pci_mmap_legacy_mem(struct kobject *kobj, struct bin_attribute *attr,
#endif /* HAVE_PCI_LEGACY */
+static int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vma)
+ unsigned long nr, start, size;
+ nr = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+ start = vma->vm_pgoff;
+ size = pci_resource_len(pdev, resno) >> PAGE_SHIFT;
+ if (start < size && size - start >= nr)
+ return 1;
+ printk(KERN_WARNING "WARNING: process \"%s\" tried to map 0x%08lx-0x%08lx on %s BAR %d (size 0x%08lx)\n",
+ current->comm, start, start+nr, pci_name(pdev), resno, size);
+ return 0;
* pci_mmap_resource - map a PCI resource into user memory space
* @kobj: kobject for mapping
@@ -510,6 +526,9 @@ pci_mmap_resource(struct kobject *kobj, struct bin_attribute *attr,
return -ENODEV;
+ if (!pci_mmap_fits(pdev, i, vma))
+ return -EINVAL;
/* pci_mmap_page_range() expects the same kind of entry as coming
* from /proc/bus/pci/ which is a "user visible" value. If this is
* different from the resource itself, arch will do necessary fixup.