Re: [PATCH] sysctl: do not allow a 64bit value write in a 32bit knob

2018-08-28 Thread kbuild test robot 
Hi Aristeu,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v4.19-rc1 next-20180827]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:
https://github.com/0day-ci/linux/commits/Aristeu-Rozanski/sysctl-do-not-allow-a-64bit-value-write-in-a-32bit-knob/20180828-043801
config: i386-randconfig-x017-201834 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
reproduce:
# save the attached .config to linux build tree
make ARCH=i386 

All warnings (new ones prefixed by >>):

   In file included from include/linux/export.h:45:0,
from include/linux/linkage.h:7,
from include/linux/kernel.h:7,
from include/linux/list.h:9,
from include/linux/module.h:9,
from kernel/sysctl.c:21:
   kernel/sysctl.c: In function 'do_proc_dointvec_minmax_conv':
   kernel/sysctl.c:2558:14: warning: right shift count >= width of type 
[-Wshift-count-overflow]
  *lvalp >> (sizeof(int) * 8))
 ^
   include/linux/compiler.h:58:30: note: in definition of macro '__trace_if'
 if (__builtin_constant_p(!!(cond)) ? !!(cond) :   \
 ^~~~
>> kernel/sysctl.c:2556:3: note: in expansion of macro 'if'
  if ((param->min && *param->min > val) ||
  ^~
   kernel/sysctl.c:2558:14: warning: right shift count >= width of type 
[-Wshift-count-overflow]
  *lvalp >> (sizeof(int) * 8))
 ^
   include/linux/compiler.h:58:42: note: in definition of macro '__trace_if'
 if (__builtin_constant_p(!!(cond)) ? !!(cond) :   \
 ^~~~
>> kernel/sysctl.c:2556:3: note: in expansion of macro 'if'
  if ((param->min && *param->min > val) ||
  ^~
   kernel/sysctl.c:2558:14: warning: right shift count >= width of type 
[-Wshift-count-overflow]
  *lvalp >> (sizeof(int) * 8))
 ^
   include/linux/compiler.h:69:16: note: in definition of macro '__trace_if'
  __r = !!(cond); \
   ^~~~
>> kernel/sysctl.c:2556:3: note: in expansion of macro 'if'
  if ((param->min && *param->min > val) ||
  ^~

vim +/if +2556 kernel/sysctl.c

^1da177e Linus Torvalds   2005-04-16  2548  
00b7c339 Amerigo Wang 2010-05-05  2549  static int 
do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
^1da177e Linus Torvalds   2005-04-16  2550  
int *valp,
^1da177e Linus Torvalds   2005-04-16  2551  
int write, void *data)
^1da177e Linus Torvalds   2005-04-16  2552  {
^1da177e Linus Torvalds   2005-04-16  2553  struct 
do_proc_dointvec_minmax_conv_param *param = data;
^1da177e Linus Torvalds   2005-04-16  2554  if (write) {
^1da177e Linus Torvalds   2005-04-16  2555  int val = *negp ? 
-*lvalp : *lvalp;
^1da177e Linus Torvalds   2005-04-16 @2556  if ((param->min && 
*param->min > val) ||
b79ce51f Aristeu Rozanski 2018-08-27  2557  (param->max && 
*param->max < val) ||
b79ce51f Aristeu Rozanski 2018-08-27  2558  *lvalp >> 
(sizeof(int) * 8))
^1da177e Linus Torvalds   2005-04-16  2559  return -EINVAL;
^1da177e Linus Torvalds   2005-04-16  2560  *valp = val;
^1da177e Linus Torvalds   2005-04-16  2561  } else {
^1da177e Linus Torvalds   2005-04-16  2562  int val = *valp;
^1da177e Linus Torvalds   2005-04-16  2563  if (val < 0) {
00b7c339 Amerigo Wang 2010-05-05  2564  *negp = true;
9a5bc726 Ilya Dryomov 2015-09-09  2565  *lvalp = 
-(unsigned long)val;
^1da177e Linus Torvalds   2005-04-16  2566  } else {
00b7c339 Amerigo Wang 2010-05-05  2567  *negp = false;
^1da177e Linus Torvalds   2005-04-16  2568  *lvalp = 
(unsigned long)val;
^1da177e Linus Torvalds   2005-04-16  2569  }
^1da177e Linus Torvalds   2005-04-16  2570  }
^1da177e Linus Torvalds   2005-04-16  2571  return 0;
^1da177e Linus Torvalds   2005-04-16  2572  }
^1da177e Linus Torvalds   2005-04-16  2573  

:: The code at line 2556 was first introduced by commit
:: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2

:: TO: Linus Torvalds 
:: CC: Linus Torvalds 

---
0-DAY kernel test infrastructureOpen Source Technology Center
https://lists.01.org/pipermail/kbuild-all   Intel Corporation


.config.gz
Description: application/gzip

Re: [PATCH] sysctl: do not allow a 64bit value write in a 32bit knob

2018-08-27 Thread kbuild test robot 
Hi Aristeu,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v4.19-rc1 next-20180827]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:
https://github.com/0day-ci/linux/commits/Aristeu-Rozanski/sysctl-do-not-allow-a-64bit-value-write-in-a-32bit-knob/20180828-043801
config: microblaze-mmu_defconfig (attached as .config)
compiler: microblaze-linux-gcc (GCC) 8.1.0
reproduce:
wget 
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O 
~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=8.1.0 make.cross ARCH=microblaze 

All warnings (new ones prefixed by >>):

   kernel/sysctl.c: In function 'do_proc_dointvec_minmax_conv':
>> kernel/sysctl.c:2558:14: warning: right shift count >= width of type 
>> [-Wshift-count-overflow]
  *lvalp >> (sizeof(int) * 8))
 ^~

vim +2558 kernel/sysctl.c

  2548  
  2549  static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long 
*lvalp,
  2550  int *valp,
  2551  int write, void *data)
  2552  {
  2553  struct do_proc_dointvec_minmax_conv_param *param = data;
  2554  if (write) {
  2555  int val = *negp ? -*lvalp : *lvalp;
  2556  if ((param->min && *param->min > val) ||
  2557  (param->max && *param->max < val) ||
> 2558  *lvalp >> (sizeof(int) * 8))
  2559  return -EINVAL;
  2560  *valp = val;
  2561  } else {
  2562  int val = *valp;
  2563  if (val < 0) {
  2564  *negp = true;
  2565  *lvalp = -(unsigned long)val;
  2566  } else {
  2567  *negp = false;
  2568  *lvalp = (unsigned long)val;
  2569  }
  2570  }
  2571  return 0;
  2572  }
  2573  

---
0-DAY kernel test infrastructureOpen Source Technology Center
https://lists.01.org/pipermail/kbuild-all   Intel Corporation


.config.gz
Description: application/gzip

[PATCH] sysctl: do not allow a 64bit value write in a 32bit knob

2018-08-27 Thread Aristeu Rozanski 
Writing to a sysctl file that uses proc_dointvec_minmax like 
user/max_uts_namespaces
a larger than 32 bit value won't cause an error as expected but instead will 
zero
its value:
# echo 21474836480 > max_uts_namespaces
# cat max_uts_namespaces
0

This patches fixes it.

Signed-off-by: Aristeu Rozanski 
Cc: "Luis R. Rodriguez" 
Cc: Kees Cook 

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 4ac9b9a..243f277 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2486,7 +2486,8 @@ static int do_proc_dointvec_minmax_conv(bool *negp, 
unsigned long *lvalp,
if (write) {
int val = *negp ? -*lvalp : *lvalp;
if ((param->min && *param->min > val) ||
-   (param->max && *param->max < val))
+   (param->max && *param->max < val) ||
+   *lvalp >> (sizeof(int) * 8))
return -EINVAL;
*valp = val;
} else {