linux_old1/arch/parisc/include/asm
Josh Poimboeuf 0d025d271e mm/usercopy: get rid of CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
There are three usercopy warnings which are currently being silenced for
gcc 4.6 and newer:

1) "copy_from_user() buffer size is too small" compile warning/error

   This is a static warning which happens when object size and copy size
   are both const, and copy size > object size.  I didn't see any false
   positives for this one.  So the function warning attribute seems to
   be working fine here.

   Note this scenario is always a bug and so I think it should be
   changed to *always* be an error, regardless of
   CONFIG_DEBUG_STRICT_USER_COPY_CHECKS.

2) "copy_from_user() buffer size is not provably correct" compile warning

   This is another static warning which happens when I enable
   __compiletime_object_size() for new compilers (and
   CONFIG_DEBUG_STRICT_USER_COPY_CHECKS).  It happens when object size
   is const, but copy size is *not*.  In this case there's no way to
   compare the two at build time, so it gives the warning.  (Note the
   warning is a byproduct of the fact that gcc has no way of knowing
   whether the overflow function will be called, so the call isn't dead
   code and the warning attribute is activated.)

   So this warning seems to only indicate "this is an unusual pattern,
   maybe you should check it out" rather than "this is a bug".

   I get 102(!) of these warnings with allyesconfig and the
   __compiletime_object_size() gcc check removed.  I don't know if there
   are any real bugs hiding in there, but from looking at a small
   sample, I didn't see any.  According to Kees, it does sometimes find
   real bugs.  But the false positive rate seems high.

3) "Buffer overflow detected" runtime warning

   This is a runtime warning where object size is const, and copy size >
   object size.

All three warnings (both static and runtime) were completely disabled
for gcc 4.6 with the following commit:

  2fb0815c9e ("gcc4: disable __compiletime_object_size for GCC 4.6+")

That commit mistakenly assumed that the false positives were caused by a
gcc bug in __compiletime_object_size().  But in fact,
__compiletime_object_size() seems to be working fine.  The false
positives were instead triggered by #2 above.  (Though I don't have an
explanation for why the warnings supposedly only started showing up in
gcc 4.6.)

So remove warning #2 to get rid of all the false positives, and re-enable
warnings #1 and #3 by reverting the above commit.

Furthermore, since #1 is a real bug which is detected at compile time,
upgrade it to always be an error.

Having done all that, CONFIG_DEBUG_STRICT_USER_COPY_CHECKS is no longer
needed.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-30 10:10:21 -07:00
..
Kbuild mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
agp.h
asm-offsets.h
asmregs.h
assembly.h parisc: Use generic extable search and sort routines 2016-03-23 16:00:46 +01:00
atomic.h locking/atomic: Remove linux/atomic.h:atomic_fetch_or() 2016-06-16 10:48:32 +02:00
bitops.h arch,parisc: Convert smp_mb__*() 2014-04-18 14:20:41 +02:00
bug.h [PARISC] fix missing TAINT_WARN problem 2012-06-05 14:10:17 +09:00
bugs.h
cache.h arch: Introduce post-init read-only memory 2016-02-22 08:51:38 +01:00
cacheflush.h asm-generic: Consolidate mark_rodata_ro() 2016-02-22 08:51:37 +01:00
checksum.h ipv6: Pass proto to csum_ipv6_magic as __u8 instead of unsigned short 2016-03-13 23:55:13 -04:00
cmpxchg.h parisc: Add native high-resolution sched_clock() implementation 2016-05-22 21:39:25 +02:00
compat.h parisc: Fix SIGSYS signals in compat case 2016-03-31 12:28:37 +02:00
compat_ucontext.h
current.h
delay.h parisc: make udelay() SMP-safe 2013-11-07 22:28:26 +01:00
dma-mapping.h dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
dma.h Disintegrate asm/system.h for PA-RISC 2012-03-28 18:30:02 +01:00
eisa_bus.h
eisa_eeprom.h parisc: Fix typos in eisa_eeprom.h 2016-05-22 21:57:40 +02:00
elf.h parisc,metag: Fix crashes due to stack randomization on stack-grows-upwards architectures 2015-05-12 22:03:44 +02:00
fb.h
fixmap.h
floppy.h parisc: Use parentheses around expression in floppy.h 2016-03-01 22:51:04 +01:00
ftrace.h parisc: Add syscall tracepoint support 2016-05-22 21:38:47 +02:00
futex.h parisc: Update futex.h to match generic implementation 2016-05-22 21:48:54 +02:00
grfioctl.h
hardirq.h parisc: do not count IPI calls twice 2013-11-07 22:28:54 +01:00
hardware.h parisc: drop include of asm/pdc.h from asm/hardware.h 2012-05-10 15:12:08 -07:00
hash.h parisc: Add <asm/hash.h> 2016-08-02 16:44:29 +02:00
hugetlb.h parisc: Protect huge page pte changes with spinlocks 2016-01-16 19:19:14 +01:00
ide.h
io.h parisc: Define ioremap_uc and ioremap_wc 2015-09-08 15:30:37 +02:00
irq.h [PARISC] Convert to new irq_chip functions 2011-02-10 10:22:14 -06:00
irqflags.h Fix IRQ flag handling naming 2010-10-07 14:08:55 +01:00
kbdleds.h keyboard: Use BIOS Keyboard variable to set Numlock 2012-05-08 14:19:41 -07:00
kmap_types.h
ldcw.h parisc: Fix typo in ldcw.h 2016-05-22 21:56:37 +02:00
led.h
linkage.h
machdep.h
mckinley.h
mmu.h
mmu_context.h atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
mmzone.h parisc: fix kernel BUG at arch/parisc/include/asm/mmzone.h:50 (part 2) 2013-06-18 20:20:21 +02:00
module.h Make most arch asm/module.h files use asm-generic/module.h 2012-09-28 14:31:03 +09:30
page.h parisc: Add defines for Huge page support 2015-11-22 12:22:34 +01:00
parisc-device.h parisc: Fix interrupt routing for C8000 serial ports 2013-07-31 23:42:32 +02:00
parport.h ARCH: drivers remove __dev* attributes. 2013-01-03 15:57:13 -08:00
pci.h PCI: Move pci_dma_* helpers to common code 2016-03-07 10:40:02 -06:00
pdc.h parisc: Imporove debug info about space registers and TLB configuration 2016-01-12 22:12:09 +01:00
pdc_chassis.h
pdcpat.h
perf.h
perf_event.h irq_work: Add generic hardirq context callbacks 2010-10-18 19:58:50 +02:00
pgalloc.h parisc: get rid of superfluous __GFP_REPEAT 2016-06-24 17:23:52 -07:00
pgtable.h parisc: Disable huge pages on Mako machines 2015-12-12 16:45:23 +01:00
prefetch.h [PARISC] fix panic on prefetch(NULL) on PA7300LC 2012-05-16 13:15:21 +01:00
processor.h parisc: Reduce overhead of parisc_requires_coherency() 2016-01-12 22:03:36 +01:00
psw.h Disintegrate asm/system.h for PA-RISC 2012-03-28 18:30:02 +01:00
ptrace.h parisc: add kernel audit feature 2013-11-07 22:27:20 +01:00
ropes.h
rt_sigframe.h
runway.h
sections.h
serial.h parisc: remove empty SERIAL_PORT_DFNS in serial.h 2013-11-30 21:02:18 +01:00
shmparam.h parisc: change value of SHMLBA from 0x00400000 to PAGE_SIZE 2014-04-13 15:00:53 +02:00
signal.h Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2013-02-23 18:50:11 -08:00
smp.h [PARISC] Fix parisc compile failure after smp: Add task_struct argument to __cpu_up() 2012-05-25 12:35:45 +01:00
socket.h parisc: break out SOCK_NONBLOCK define to own asm header file 2013-11-19 23:36:17 +01:00
special_insns.h parisc: optimize mtsp(0,sr) inline assembly 2013-07-09 22:09:21 +02:00
spinlock.h locking/spinlock, arch: Update and fix spin_unlock_wait() implementations 2016-06-14 11:55:15 +02:00
spinlock_types.h
string.h
superio.h
switch_to.h Disintegrate asm/system.h for PA-RISC 2012-03-28 18:30:02 +01:00
syscall.h parisc: Add syscall tracepoint support 2016-05-22 21:38:47 +02:00
termios.h UAPI: (Scripted) Disintegrate arch/parisc/include/asm 2012-10-16 21:28:05 +01:00
thread_info.h parisc: Add syscall tracepoint support 2016-05-22 21:38:47 +02:00
timex.h Disintegrate asm/system.h for PA-RISC 2012-03-28 18:30:02 +01:00
tlb.h
tlbflush.h parisc: Fix some PTE/TLB race conditions and optimize __flush_tlb_range based on timing results 2015-07-10 21:47:47 +02:00
traps.h parisc: Move die_if_kernel() prototype into traps.h header 2016-06-05 08:49:01 +02:00
uaccess.h mm/usercopy: get rid of CONFIG_DEBUG_STRICT_USER_COPY_CHECKS 2016-08-30 10:10:21 -07:00
ucontext.h
unaligned.h
unistd.h sys_sgetmask/sys_ssetmask: add CONFIG_SGETMASK_SYSCALL 2014-06-04 16:54:14 -07:00
unwind.h