This patch introduces within_kprobe_blacklist_early(), which will be
used when registering early kprobes.
In init_kprobes(), populate_kprobe_blacklist() is the only function
which rely on memory system so unable to be executed at very early
stage. Following patches will move other parts of init_kprobes() to
early stage and leave populate_kprobe_blacklist() at its original
position. Before populate_kprobe_blacklist(), within_kprobe_blacklist_early()
can be used for checking blacklist.
Signed-off-by: Wang Nan <wangn...@huawei.com>
---
kernel/kprobes.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index c90e417..427d761 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -68,6 +68,7 @@
#endif
static int kprobes_initialized;
+static int kprobes_blacklist_initialized;
static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
@@ -1332,12 +1333,41 @@ bool __weak arch_within_kprobe_blacklist(unsigned long
addr)
addr < (unsigned long)__kprobes_text_end;
}
+
+static bool within_kprobe_blacklist_early(unsigned long addr)
+{
+ /* Markers of _kprobe_blacklist section */
+ extern unsigned long __start_kprobe_blacklist[];
+ extern unsigned long __stop_kprobe_blacklist[];
+
+ unsigned long *start = __start_kprobe_blacklist;
+ unsigned long *end = __stop_kprobe_blacklist;
+ unsigned long *iter;
+ unsigned long entry, offset = 0, size = 0;
+
+ for (iter = start; iter < end; iter++) {
+ entry = arch_deref_entry_point((void *)*iter);
+
+ if (!kernel_text_address(entry) ||
+ !kallsyms_lookup_size_offset(entry, &size, &offset))
+ continue;
+ if (addr >= entry && addr < entry + size)
+ return true;
+ }
+
+ return false;
+}
+
static bool within_kprobe_blacklist(unsigned long addr)
{
struct kprobe_blacklist_entry *ent;
if (arch_within_kprobe_blacklist(addr))
return true;
+
+ if (!kprobes_blacklist_initialized)
+ return within_kprobe_blacklist_early(addr);
+
/*
* If there exists a kprobe_blacklist, verify and
* fail any probe registration in the prohibited area
@@ -2147,6 +2177,7 @@ static int __init init_kprobes(void)
pr_err("kprobes: failed to populate blacklist: %d\n", err);
pr_err("Please take care of using kprobes.\n");
}
+ kprobes_blacklist_initialized = (err == 0);
if (kretprobe_blacklist_size) {
/* lookup the function address from its name */
--
1.8.4
--
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