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authorSean Young <sean@mess.org>2017-09-27 16:00:49 -0400
committerMauro Carvalho Chehab <mchehab@s-opensource.com>2017-12-14 09:58:34 -0500
commit1d091b8aa0f06648b4667bad75d3c6e05eef1a14 (patch)
tree4822bad3ce79a70bc518556fcebf5095b6b04a56
parent80aa2db77634ede29813fdcd7000e0660be81cdb (diff)
media: lirc: validate scancode for transmit
Ensure we reject an attempt to transmit invalid scancodes. Signed-off-by: Sean Young <sean@mess.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
-rw-r--r--drivers/media/rc/ir-lirc-codec.c10
-rw-r--r--drivers/media/rc/rc-core-priv.h1
-rw-r--r--drivers/media/rc/rc-main.c53
3 files changed, 44 insertions, 20 deletions
diff --git a/drivers/media/rc/ir-lirc-codec.c b/drivers/media/rc/ir-lirc-codec.c
index aec0109b1a69..1ed69c9e64bf 100644
--- a/drivers/media/rc/ir-lirc-codec.c
+++ b/drivers/media/rc/ir-lirc-codec.c
@@ -126,6 +126,16 @@ static ssize_t ir_lirc_transmit_ir(struct file *file, const char __user *buf,
if (scan.flags || scan.keycode || scan.timestamp)
return -EINVAL;
+ /*
+ * The scancode field in lirc_scancode is 64-bit simply
+ * to future-proof it, since there are IR protocols encode
+ * use more than 32 bits. For now only 32-bit protocols
+ * are supported.
+ */
+ if (scan.scancode > U32_MAX ||
+ !rc_validate_scancode(scan.rc_proto, scan.scancode))
+ return -EINVAL;
+
raw = kmalloc_array(LIRCBUF_SIZE, sizeof(*raw), GFP_KERNEL);
if (!raw)
return -ENOMEM;
diff --git a/drivers/media/rc/rc-core-priv.h b/drivers/media/rc/rc-core-priv.h
index face39c3a96c..6d5a36b8b550 100644
--- a/drivers/media/rc/rc-core-priv.h
+++ b/drivers/media/rc/rc-core-priv.h
@@ -150,6 +150,7 @@ static inline bool is_timing_event(struct ir_raw_event ev)
#define TO_STR(is_pulse) ((is_pulse) ? "pulse" : "space")
/* functions for IR encoders */
+bool rc_validate_scancode(enum rc_proto proto, u32 scancode);
static inline void init_ir_raw_event_duration(struct ir_raw_event *ev,
unsigned int pulse,
diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c
index 56b322b3d325..ce8837b1facd 100644
--- a/drivers/media/rc/rc-main.c
+++ b/drivers/media/rc/rc-main.c
@@ -776,6 +776,37 @@ void rc_keydown_notimeout(struct rc_dev *dev, enum rc_proto protocol,
EXPORT_SYMBOL_GPL(rc_keydown_notimeout);
/**
+ * rc_validate_scancode() - checks that a scancode is valid for a protocol
+ * @proto: protocol
+ * @scancode: scancode
+ */
+bool rc_validate_scancode(enum rc_proto proto, u32 scancode)
+{
+ switch (proto) {
+ case RC_PROTO_NECX:
+ if ((((scancode >> 16) ^ ~(scancode >> 8)) & 0xff) == 0)
+ return false;
+ break;
+ case RC_PROTO_NEC32:
+ if ((((scancode >> 24) ^ ~(scancode >> 16)) & 0xff) == 0)
+ return false;
+ break;
+ case RC_PROTO_RC6_MCE:
+ if ((scancode & 0xffff0000) != 0x800f0000)
+ return false;
+ break;
+ case RC_PROTO_RC6_6A_32:
+ if ((scancode & 0xffff0000) == 0x800f0000)
+ return false;
+ break;
+ default:
+ break;
+ }
+
+ return true;
+}
+
+/**
* rc_validate_filter() - checks that the scancode and mask are valid and
* provides sensible defaults
* @dev: the struct rc_dev descriptor of the device
@@ -794,26 +825,8 @@ static int rc_validate_filter(struct rc_dev *dev,
mask = protocols[protocol].scancode_bits;
- switch (protocol) {
- case RC_PROTO_NECX:
- if ((((s >> 16) ^ ~(s >> 8)) & 0xff) == 0)
- return -EINVAL;
- break;
- case RC_PROTO_NEC32:
- if ((((s >> 24) ^ ~(s >> 16)) & 0xff) == 0)
- return -EINVAL;
- break;
- case RC_PROTO_RC6_MCE:
- if ((s & 0xffff0000) != 0x800f0000)
- return -EINVAL;
- break;
- case RC_PROTO_RC6_6A_32:
- if ((s & 0xffff0000) == 0x800f0000)
- return -EINVAL;
- break;
- default:
- break;
- }
+ if (!rc_validate_scancode(protocol, s))
+ return -EINVAL;
filter->data &= mask;
filter->mask &= mask;

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