diff options
Diffstat (limited to 'kernel/kallsyms.c')
| -rw-r--r-- | kernel/kallsyms.c | 43 |
1 files changed, 41 insertions, 2 deletions
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 1966fe1c2b57..531ffa984bc2 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -486,6 +486,7 @@ struct kallsym_iter { char name[KSYM_NAME_LEN]; char module_name[MODULE_NAME_LEN]; int exported; + int show_value; }; static int get_ksymbol_mod(struct kallsym_iter *iter) @@ -613,12 +614,15 @@ static void s_stop(struct seq_file *m, void *p) static int s_show(struct seq_file *m, void *p) { + unsigned long value; struct kallsym_iter *iter = m->private; /* Some debugging symbols have no name. Ignore them. */ if (!iter->name[0]) return 0; + value = iter->show_value ? iter->value : 0; + if (iter->module_name[0]) { char type; @@ -628,10 +632,10 @@ static int s_show(struct seq_file *m, void *p) */ type = iter->exported ? toupper(iter->type) : tolower(iter->type); - seq_printf(m, "%pK %c %s\t[%s]\n", (void *)iter->value, + seq_printf(m, KALLSYM_FMT " %c %s\t[%s]\n", value, type, iter->name, iter->module_name); } else - seq_printf(m, "%pK %c %s\n", (void *)iter->value, + seq_printf(m, KALLSYM_FMT " %c %s\n", value, iter->type, iter->name); return 0; } @@ -643,6 +647,40 @@ static const struct seq_operations kallsyms_op = { .show = s_show }; +static inline int kallsyms_for_perf(void) +{ +#ifdef CONFIG_PERF_EVENTS + extern int sysctl_perf_event_paranoid; + if (sysctl_perf_event_paranoid <= 1) + return 1; +#endif + return 0; +} + +/* + * We show kallsyms information even to normal users if we've enabled + * kernel profiling and are explicitly not paranoid (so kptr_restrict + * is clear, and sysctl_perf_event_paranoid isn't set). + * + * Otherwise, require CAP_SYSLOG (assuming kptr_restrict isn't set to + * block even that). + */ +int kallsyms_show_value(void) +{ + switch (kptr_restrict) { + case 0: + if (kallsyms_for_perf()) + return 1; + /* fallthrough */ + case 1: + if (has_capability_noaudit(current, CAP_SYSLOG)) + return 1; + /* fallthrough */ + default: + return 0; + } +} + static int kallsyms_open(struct inode *inode, struct file *file) { /* @@ -656,6 +694,7 @@ static int kallsyms_open(struct inode *inode, struct file *file) return -ENOMEM; reset_iter(iter, 0); + iter->show_value = kallsyms_show_value(); return 0; } |