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pci: use security_capable() when checking capablities during config space read

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This reintroduces commit 47970b1b which was subsequently reverted
as f00eaeea.  The original change was broken and caused X startup
failures and generally made privileged processes incapable of reading
device dependent config space.  The normal capable() interface returns
true on success, but the LSM interface returns 0 on success.  This thinko
is now fixed in this patch, and has been confirmed to work properly.

So, once again...Eric Paris noted that commit de139a3 ("pci: check caps
from sysfs file open to read device dependent config space") caused the
capability check to bypass security modules and potentially auditing.
Rectify this by calling security_capable() when checking the open file's
capabilities for config space reads.

Reported-by: Eric Paris <eparis@redhat.com>
Tested-by: Dave Young <hidave.darkstar@gmail.com>
Acked-by: James Morris <jmorris@namei.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Alex Riesen <raa.lkml@gmail.com>
Cc: Sedat Dilek <sedat.dilek@googlemail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Chris Wright 2011-02-14 17:21:49 -08:00 committed by James Morris
parent 795abaf1e4
commit a628e7b87e
1 changed files with 2 additions and 1 deletions
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3
drivers/pci/pci-sysfs.c
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@ -23,6 +23,7 @@
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/capability.h>
#include <linux/security.h>
#include <linux/pci-aspm.h>
#include <linux/slab.h>
#include "pci.h"
@ -368,7 +369,7 @@ pci_read_config(struct file *filp, struct kobject *kobj,
u8 *data = (u8*) buf;
/* Several chips lock up trying to read undefined config space */
if (cap_raised(filp->f_cred->cap_effective, CAP_SYS_ADMIN)) {
if (security_capable(filp->f_cred, CAP_SYS_ADMIN) == 0) {
size = dev->cfg_size;
} else if (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS) {
size = 128;