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-rw-r--r--kernel/kallsyms.c86
1 files changed, 78 insertions, 8 deletions
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 127e7cfafa55..531ffa984bc2 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -24,6 +24,7 @@
#include <linux/ctype.h>
#include <linux/slab.h>
#include <linux/filter.h>
+#include <linux/ftrace.h>
#include <linux/compiler.h>
#include <asm/sections.h>
@@ -337,6 +338,10 @@ const char *kallsyms_lookup(unsigned long addr,
if (!ret)
ret = bpf_address_lookup(addr, symbolsize,
offset, modname, namebuf);
+
+ if (!ret)
+ ret = ftrace_mod_address_lookup(addr, symbolsize,
+ offset, modname, namebuf);
return ret;
}
@@ -474,12 +479,14 @@ EXPORT_SYMBOL(__print_symbol);
struct kallsym_iter {
loff_t pos;
loff_t pos_mod_end;
+ loff_t pos_ftrace_mod_end;
unsigned long value;
unsigned int nameoff; /* If iterating in core kernel symbols. */
char type;
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)
@@ -496,11 +503,25 @@ static int get_ksymbol_mod(struct kallsym_iter *iter)
return 1;
}
+static int get_ksymbol_ftrace_mod(struct kallsym_iter *iter)
+{
+ int ret = ftrace_mod_get_kallsym(iter->pos - iter->pos_mod_end,
+ &iter->value, &iter->type,
+ iter->name, iter->module_name,
+ &iter->exported);
+ if (ret < 0) {
+ iter->pos_ftrace_mod_end = iter->pos;
+ return 0;
+ }
+
+ return 1;
+}
+
static int get_ksymbol_bpf(struct kallsym_iter *iter)
{
iter->module_name[0] = '\0';
iter->exported = 0;
- return bpf_get_kallsym(iter->pos - iter->pos_mod_end,
+ return bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end,
&iter->value, &iter->type,
iter->name) < 0 ? 0 : 1;
}
@@ -525,20 +546,31 @@ static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
iter->name[0] = '\0';
iter->nameoff = get_symbol_offset(new_pos);
iter->pos = new_pos;
- if (new_pos == 0)
+ if (new_pos == 0) {
iter->pos_mod_end = 0;
+ iter->pos_ftrace_mod_end = 0;
+ }
}
static int update_iter_mod(struct kallsym_iter *iter, loff_t pos)
{
iter->pos = pos;
- if (iter->pos_mod_end > 0 &&
- iter->pos_mod_end < iter->pos)
+ if (iter->pos_ftrace_mod_end > 0 &&
+ iter->pos_ftrace_mod_end < iter->pos)
return get_ksymbol_bpf(iter);
- if (!get_ksymbol_mod(iter))
- return get_ksymbol_bpf(iter);
+ if (iter->pos_mod_end > 0 &&
+ iter->pos_mod_end < iter->pos) {
+ if (!get_ksymbol_ftrace_mod(iter))
+ return get_ksymbol_bpf(iter);
+ return 1;
+ }
+
+ if (!get_ksymbol_mod(iter)) {
+ if (!get_ksymbol_ftrace_mod(iter))
+ return get_ksymbol_bpf(iter);
+ }
return 1;
}
@@ -582,12 +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;
@@ -597,10 +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;
}
@@ -612,6 +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)
{
/*
@@ -625,6 +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;
}