Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Kconfig: consolidate CONFIG_DEBUG_STRICT_USER_COPY_CHECKS

Browse source 
The help text for this config is duplicated across the x86, parisc, and
s390 Kconfig.debug files.  Arnd Bergman noted that the help text was
slightly misleading and should be fixed to state that enabling this
option isn't a problem when using pre 4.4 gcc.

To simplify the rewording, consolidate the text into lib/Kconfig.debug
and modify it there to be more explicit about when you should say N to
this config.

Also, make the text a bit more generic by stating that this option
enables compile time checks so we can cover architectures which emit
warnings vs.  ones which emit errors.  The details of how an
architecture decided to implement the checks isn't as important as the
concept of compile time checking of copy_from_user() calls.

While we're doing this, remove all the copy_from_user_overflow() code
that's duplicated many times and place it into lib/ so that any
architecture supporting this option can get the function for free.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Helge Deller <deller@gmx.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Stephen Boyd 2013-04-30 15:28:42 -07:00 committed by Linus Torvalds
parent a05342cbd6
commit 446f24d119
16 changed files with 31 additions and 76 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
arch/parisc/Kconfig
View file

@ -1,5 +1,6 @@
config PARISC
def_bool y
select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
select HAVE_IDE
select HAVE_OPROFILE
select HAVE_FUNCTION_TRACER if 64BIT

14
arch/parisc/Kconfig.debug
View file

@ -12,18 +12,4 @@ config DEBUG_RODATA
portion of the kernel code won't be covered by a TLB anymore.
If in doubt, say "N".
config DEBUG_STRICT_USER_COPY_CHECKS
bool "Strict copy size checks"
depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING
---help---
Enabling this option turns a certain set of sanity checks for user
copy operations into compile time failures.
The copy_from_user() etc checks are there to help test if there
are sufficient security checks on the length argument of
the copy operation, by having gcc prove that the argument is
within bounds.
If unsure, or if you run an older (pre 4.4) gcc, say N.
endmenu

1
arch/s390/Kconfig
View file

@ -91,6 +91,7 @@ config S390
select ARCH_INLINE_WRITE_UNLOCK_BH
select ARCH_INLINE_WRITE_UNLOCK_IRQ
select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
select ARCH_SAVE_PAGE_KEYS if HIBERNATION
select ARCH_WANT_IPC_PARSE_VERSION
select BUILDTIME_EXTABLE_SORT

14
arch/s390/Kconfig.debug
View file

@ -17,20 +17,6 @@ config STRICT_DEVMEM
If you are unsure, say Y.
config DEBUG_STRICT_USER_COPY_CHECKS
def_bool n
prompt "Strict user copy size checks"
---help---
Enabling this option turns a certain set of sanity checks for user
copy operations into compile time warnings.
The copy_from_user() etc checks are there to help test if there
are sufficient security checks on the length argument of
the copy operation, by having gcc prove that the argument is
within bounds.
If unsure, or if you run an older (pre 4.4) gcc, say N.
config S390_PTDUMP
bool "Export kernel pagetable layout to userspace via debugfs"
depends on DEBUG_KERNEL

1
arch/s390/lib/Makefile
View file

@ -3,7 +3,6 @@
#
lib-y += delay.o string.o uaccess_std.o uaccess_pt.o
obj-y += usercopy.o
obj-$(CONFIG_32BIT) += div64.o qrnnd.o ucmpdi2.o mem32.o
obj-$(CONFIG_64BIT) += mem64.o
lib-$(CONFIG_64BIT) += uaccess_mvcos.o

1
arch/sparc/lib/Makefile
View file

@ -45,4 +45,3 @@ obj-y += iomap.o
obj-$(CONFIG_SPARC32) += atomic32.o ucmpdi2.o
obj-y += ksyms.o
obj-$(CONFIG_SPARC64) += PeeCeeI.o
obj-y += usercopy.o

9
arch/sparc/lib/usercopy.c
View file

@ -1,9 +0,0 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/bug.h>
void copy_from_user_overflow(void)
{
WARN(1, "Buffer overflow detected!\n");
}
EXPORT_SYMBOL(copy_from_user_overflow);

8
arch/tile/Kconfig
View file

@ -19,6 +19,7 @@ config TILE
select HAVE_SYSCALL_WRAPPERS if TILEGX
select VIRT_TO_BUS
select SYS_HYPERVISOR
select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select GENERIC_CLOCKEVENTS
select MODULES_USE_ELF_RELA
@ -114,13 +115,6 @@ config STRICT_DEVMEM
config SMP
def_bool y
# Allow checking for compile-time determined overflow errors in
# copy_from_user(). There are still unprovable places in the
# generic code as of 2.6.34, so this option is not really compatible
# with -Werror, which is more useful in general.
config DEBUG_COPY_FROM_USER
def_bool n
config HVC_TILE
depends on TTY
select HVC_DRIVER

7
arch/tile/include/asm/uaccess.h
View file

@ -395,7 +395,12 @@ _copy_from_user(void *to, const void __user *from, unsigned long n)
return n;
}
#ifdef CONFIG_DEBUG_COPY_FROM_USER
#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
/*
* There are still unprovable places in the generic code as of 2.6.34, so this
* option is not really compatible with -Werror, which is more useful in
* general.
*/
extern void copy_from_user_overflow(void)
__compiletime_warning("copy_from_user() size is not provably correct");

8
arch/tile/lib/uaccess.c
View file

@ -22,11 +22,3 @@ int __range_ok(unsigned long addr, unsigned long size)
is_arch_mappable_range(addr, size));
}
EXPORT_SYMBOL(__range_ok);
#ifdef CONFIG_DEBUG_COPY_FROM_USER
void copy_from_user_overflow(void)
{
WARN(1, "Buffer overflow detected!\n");
}
EXPORT_SYMBOL(copy_from_user_overflow);
#endif

1
arch/x86/Kconfig
View file

@ -20,6 +20,7 @@ config X86_64
### Arch settings
config X86
def_bool y
select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
select HAVE_AOUT if X86_32
select HAVE_UNSTABLE_SCHED_CLOCK
select ARCH_SUPPORTS_NUMA_BALANCING

14
arch/x86/Kconfig.debug
View file

@ -292,20 +292,6 @@ config OPTIMIZE_INLINING
If unsure, say N.
config DEBUG_STRICT_USER_COPY_CHECKS
bool "Strict copy size checks"
depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING
---help---
Enabling this option turns a certain set of sanity checks for user
copy operations into compile time failures.
The copy_from_user() etc checks are there to help test if there
are sufficient security checks on the length argument of
the copy operation, by having gcc prove that the argument is
within bounds.
If unsure, or if you run an older (pre 4.4) gcc, say N.
config DEBUG_NMI_SELFTEST
bool "NMI Selftest"
depends on DEBUG_KERNEL && X86_LOCAL_APIC

6
arch/x86/lib/usercopy_32.c
View file

@ -689,9 +689,3 @@ _copy_from_user(void *to, const void __user *from, unsigned long n)
return n;
}
EXPORT_SYMBOL(_copy_from_user);
void copy_from_user_overflow(void)
{
WARN(1, "Buffer overflow detected!\n");
}
EXPORT_SYMBOL(copy_from_user_overflow);

18
lib/Kconfig.debug
View file

@ -1292,6 +1292,24 @@ config LATENCYTOP
Enable this option if you want to use the LatencyTOP tool
to find out which userspace is blocking on what kernel operations.
config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
bool
config DEBUG_STRICT_USER_COPY_CHECKS
bool "Strict user copy size checks"
depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING
help
Enabling this option turns a certain set of sanity checks for user
copy operations into compile time failures.
The copy_from_user() etc checks are there to help test if there
are sufficient security checks on the length argument of
the copy operation, by having gcc prove that the argument is
within bounds.
If unsure, say N.
source mm/Kconfig.debug
source kernel/trace/Kconfig

1
lib/Makefile
View file

@ -15,6 +15,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
is_single_threaded.o plist.o decompress.o kobject_uevent.o \
earlycpio.o
obj-$(CONFIG_ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS) += usercopy.o
lib-$(CONFIG_MMU) += ioremap.o
lib-$(CONFIG_SMP) += cpumask.o

3
arch/s390/lib/usercopy.c → lib/usercopy.c
View file

@ -1,5 +1,6 @@
#include <linux/module.h>
#include <linux/export.h>
#include <linux/bug.h>
#include <linux/uaccess.h>
void copy_from_user_overflow(void)
{