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-rw-r--r--kernel/kallsyms.c49
1 files changed, 47 insertions, 2 deletions
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 127e7cfafa55..51b49ed452e4 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -480,6 +480,7 @@ 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)
@@ -580,14 +581,23 @@ static void s_stop(struct seq_file *m, void *p)
{
}
+#ifndef CONFIG_64BIT
+# define KALLSYM_FMT "%08lx"
+#else
+# define KALLSYM_FMT "%016lx"
+#endif
+
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;
@@ -597,10 +607,10 @@ 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;
}
@@ -612,6 +622,40 @@ 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).
+ */
+static 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)
{
/*
@@ -625,6 +669,7 @@ static int kallsyms_open(struct inode *inode, struct file *file)
return -ENOMEM;
reset_iter(iter, 0);
+ iter->show_value = kallsyms_show_value();
return 0;
}