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authorVladis Dronov <vdronov@redhat.com>2019-01-29 11:58:35 +0100
committerBenjamin Tissoires <benjamin.tissoires@redhat.com>2019-01-29 12:09:11 +0100
commit13054abbaa4f1fd4e6f3b4b63439ec033b4c8035 (patch)
treee1385b1d1ad52472b30ec37fb46358d4069f16a6 /include
parent1950f462916edc9581168ca8d5882a8101e8bbcf (diff)
HID: debug: fix the ring buffer implementation
Ring buffer implementation in hid_debug_event() and hid_debug_events_read() is strange allowing lost or corrupted data. After commit 717adfdaf147 ("HID: debug: check length before copy_to_user()") it is possible to enter an infinite loop in hid_debug_events_read() by providing 0 as count, this locks up a system. Fix this by rewriting the ring buffer implementation with kfifo and simplify the code. This fixes CVE-2019-3819. v2: fix an execution logic and add a comment v3: use __set_current_state() instead of set_current_state() Link: https://bugzilla.redhat.com/show_bug.cgi?id=1669187 Cc: stable@vger.kernel.org # v4.18+ Fixes: cd667ce24796 ("HID: use debugfs for events/reports dumping") Fixes: 717adfdaf147 ("HID: debug: check length before copy_to_user()") Signed-off-by: Vladis Dronov <vdronov@redhat.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Diffstat (limited to 'include')
-rw-r--r--include/linux/hid-debug.h9
1 files changed, 4 insertions, 5 deletions
diff --git a/include/linux/hid-debug.h b/include/linux/hid-debug.h
index 8663f216c563..2d6100edf204 100644
--- a/include/linux/hid-debug.h
+++ b/include/linux/hid-debug.h
@@ -24,7 +24,10 @@
#ifdef CONFIG_DEBUG_FS
+#include <linux/kfifo.h>
+
#define HID_DEBUG_BUFSIZE 512
+#define HID_DEBUG_FIFOSIZE 512
void hid_dump_input(struct hid_device *, struct hid_usage *, __s32);
void hid_dump_report(struct hid_device *, int , u8 *, int);
@@ -37,11 +40,8 @@ void hid_debug_init(void);
void hid_debug_exit(void);
void hid_debug_event(struct hid_device *, char *);
-
struct hid_debug_list {
- char *hid_debug_buf;
- int head;
- int tail;
+ DECLARE_KFIFO_PTR(hid_debug_fifo, char);
struct fasync_struct *fasync;
struct hid_device *hdev;
struct list_head node;
@@ -64,4 +64,3 @@ struct hid_debug_list {
#endif
#endif
-