Re: [PATCH v9 09/11] AppArmor: Add selfattr hooks

[kernel test robot <lkp@intel.com>]

Hi Casey,

kernel test robot noticed the following build warnings:

[auto build test WARNING on tip/perf/core]
[also build test WARNING on acme/perf/core shuah-kselftest/next shuah-kselftest/fixes linus/master v6.3-rc7]
[cannot apply to next-20230421]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Casey-Schaufler/LSM-Maintain-a-table-of-LSM-attribute-data/20230422-024331
base:   tip/perf/core
patch link:    https://lore.kernel.org/r/20230421174259.2458-10-casey%40schaufler-ca.com
patch subject: [PATCH v9 09/11] AppArmor: Add selfattr hooks
config: x86_64-randconfig-a005 (https://download.01.org/0day-ci/archive/20230422/202304220930.OFrY92as-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/2628bfcd3ff1b12fbae522a5449a7344ffe6ecbd
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Casey-Schaufler/LSM-Maintain-a-table-of-LSM-attribute-data/20230422-024331
        git checkout 2628bfcd3ff1b12fbae522a5449a7344ffe6ecbd
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash security/apparmor/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202304220930.OFrY92as-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> security/apparmor/lsm.c:654:7: warning: variable 'total_len' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
                   if (error > 0) {
                       ^~~~~~~~~
   security/apparmor/lsm.c:666:10: note: uninitialized use occurs here
           *size = total_len;
                   ^~~~~~~~~
   security/apparmor/lsm.c:654:3: note: remove the 'if' if its condition is always true
                   if (error > 0) {
                   ^~~~~~~~~~~~~~~
   security/apparmor/lsm.c:652:6: warning: variable 'total_len' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
           if (label) {
               ^~~~~
   security/apparmor/lsm.c:666:10: note: uninitialized use occurs here
           *size = total_len;
                   ^~~~~~~~~
   security/apparmor/lsm.c:652:2: note: remove the 'if' if its condition is always true
           if (label) {
           ^~~~~~~~~~~
   security/apparmor/lsm.c:640:18: note: initialize the variable 'total_len' to silence this warning
           size_t total_len;
                           ^
                            = 0
   2 warnings generated.


vim +654 security/apparmor/lsm.c

   632	
   633	static int apparmor_getselfattr(unsigned int __user attr,
   634					struct lsm_ctx __user *lx, size_t *size,
   635					u32 __user flags)
   636	{
   637		int error = -ENOENT;
   638		struct aa_task_ctx *ctx = task_ctx(current);
   639		struct aa_label *label = NULL;
   640		size_t total_len;
   641		char *value;
   642	
   643		if (attr == LSM_ATTR_CURRENT)
   644			label = aa_get_newest_label(cred_label(current_cred()));
   645		else if (attr == LSM_ATTR_PREV && ctx->previous)
   646			label = aa_get_newest_label(ctx->previous);
   647		else if (attr == LSM_ATTR_EXEC && ctx->onexec)
   648			label = aa_get_newest_label(ctx->onexec);
   649		else
   650			error = -EOPNOTSUPP;
   651	
   652		if (label) {
   653			error = aa_getprocattr(label, &value, false);
 > 654			if (error > 0) {
   655				total_len = ALIGN(error + sizeof(*ctx), 8);
   656				if (total_len > *size)
   657					error = -E2BIG;
   658				else
   659					lsm_fill_user_ctx(lx, value, error,
   660							  LSM_ID_APPARMOR, 0);
   661			}
   662		}
   663	
   664		aa_put_label(label);
   665	
   666		*size = total_len;
   667		if (error > 0)
   668			return 1;
   669		return error;
   670	}
   671	

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https://github.com/intel/lkp-tests