Line data    Source code

       1             : // SPDX-License-Identifier: GPL-2.0-only
       2             : /*
       3             :  * ksyms_common.c: A split of kernel/kallsyms.c
       4             :  * Contains a few generic function definations independent of config KALLSYMS.
       5             :  */
       6             : #include <linux/kallsyms.h>
       7             : #include <linux/security.h>
       8             : 
       9             : static inline int kallsyms_for_perf(void)
      10             : {
      11             : #ifdef CONFIG_PERF_EVENTS
      12             :         extern int sysctl_perf_event_paranoid;
      13             : 
      14             :         if (sysctl_perf_event_paranoid <= 1)
      15             :                 return 1;
      16             : #endif
      17             :         return 0;
      18             : }
      19             : 
      20             : /*
      21             :  * We show kallsyms information even to normal users if we've enabled
      22             :  * kernel profiling and are explicitly not paranoid (so kptr_restrict
      23             :  * is clear, and sysctl_perf_event_paranoid isn't set).
      24             :  *
      25             :  * Otherwise, require CAP_SYSLOG (assuming kptr_restrict isn't set to
      26             :  * block even that).
      27             :  */
      28           0 : bool kallsyms_show_value(const struct cred *cred)
      29             : {
      30           0 :         switch (kptr_restrict) {
      31             :         case 0:
      32             :                 if (kallsyms_for_perf())
      33             :                         return true;
      34             :                 fallthrough;
      35             :         case 1:
      36           0 :                 if (security_capable(cred, &init_user_ns, CAP_SYSLOG,
      37             :                                      CAP_OPT_NOAUDIT) == 0)
      38             :                         return true;
      39             :                 fallthrough;
      40             :         default:
      41             :                 return false;
      42             :         }
      43             : }