sysfs allows attribute files to be truncated, e.g. using ftruncate(), with the expected effect on their inode. For most attributes, this doesn't change the "real" size of the file i.e. how much can be read from it. However, the parameter validation for reading and writing binary attribute files is based on the inode size and not the size specified in the file's bin_attribute, so it can be broken by this. For example, if we try using dd to write to such a file: # pwd /sys/bus/pci/devices/0000:08:00.0 # ls -l config -rw-r--r-- 1 root root 4096 Feb 1 17:35 config # dd if=/dev/zero of=config bs=4 count=1 1+0 records in 1+0 records out # ls -l config -rw-r--r-- 1 root root 0 Feb 1 17:50 config # dd if=/dev/zero of=config bs=4 count=1 seek=128 dd: writing `config': No space left on device 1+0 records in 0+0 records out Also, after truncation to 0, parameter validation for read and write is disabled. Most bin_attribute read and write methods also validate the size and offset, but for some this will allow out-of-range access. This may be a security issue, though access to such files is often limited to root. In any case, the validation should remain for safety's sake!) This was previously reported in Bugzilla as bug 9867. sysfs should ignore size changes or else refuse them (by returning -EINVAL). This patch makes it ignore them. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
__FUNCTION__ is gcc-specific, use __func__ Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a new BDI capability flag: BDI_CAP_NO_ACCT_WB. If this flag is set, then don't update the per-bdi writeback stats from test_set_page_writeback() and test_clear_page_writeback(). Misc cleanups: - convert bdi_cap_writeback_dirty() and friends to static inline functions - create a flag that includes all three dirty/writeback related flags, since almst all users will want to have them toghether Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have a problem in scsi_transport_spi in that we need to customise not only the visibility of the attributes, but also their mode. Fix this by making the is_visible() callback return a mode, with 0 indicating is not visible. Also add a sysfs_update_group() API to allow us to change either the visibility or mode of the files at any time on the fly. Acked-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Requiring userspace to close and re-open sysfs attributes has been the policy since before 2.6.12. It allows userspace to get a consistent snapshot of kernel state and consume it with incremental reads and seeks. Now, if the file position is zero the kernel assumes userspace wants to see the new value. The application for this change is to allow a userspace RAID metadata handler to check the state of an array without causing any memory allocations. Thus not causing writeback to a raid array that might be blocked waiting for userspace to take action. Cc: Neil Brown <neilb@suse.de> Acked-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
After an experimental deletion of the unnecessary inclusion of <linux/slab.h> from the header file <linux/percpu.h>, the following files under fs/sysfs were exposed as needing to explicitly include <linux/slab.h>. Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Allow callers of sysfs_remove_link() to pass a NULL kobj, in which case sysfs_root will be used as the parent directory. This allows us to tear down top level symlinks created via sysfs_create_link(), which already has similar handling of a NULL parent object. Signed-off-by: Mark Fasheh <mfasheh@suse.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Try to find the culprit who caused http://bugzilla.kernel.org/show_bug.cgi?id=10150 Cc: <balajirrao@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
It's possible that the caller of sysfs_remove_group messed up and passed in an attribute group that was not really registered to this kobject. But don't panic for such a foolish error, spit out a warning about what happened, and continue on our way safely. Cc: Roland Dreier <rdreier@cisco.com> Cc: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (200 commits) [SCSI] usbstorage: use last_sector_bug flag universally [SCSI] libsas: abstract STP task status into a function [SCSI] ultrastor: clean up inline asm warnings [SCSI] aic7xxx: fix firmware build [SCSI] aacraid: fib context lock for management ioctls [SCSI] ch: remove forward declarations [SCSI] ch: fix device minor number management bug [SCSI] ch: handle class_device_create failure properly [SCSI] NCR5380: fix section mismatch [SCSI] sg: fix /proc/scsi/sg/devices when no SCSI devices [SCSI] IB/iSER: add logical unit reset support [SCSI] don't use __GFP_DMA for sense buffers if not required [SCSI] use dynamically allocated sense buffer [SCSI] scsi.h: add macro for enclosure bit of inquiry data [SCSI] sd: add fix for devices with last sector access problems [SCSI] fix pcmcia compile problem [SCSI] aacraid: add Voodoo Lite class of cards. [SCSI] aacraid: add new driver features flags [SCSI] qla2xxx: Update version number to 8.02.00-k7. [SCSI] qla2xxx: Issue correct MBC_INITIALIZE_FIRMWARE command. ...