diff options
| author | Benjamin Tissoires <bentiss@kernel.org> | 2024-06-26 15:46:26 +0200 |
|---|---|---|
| committer | Benjamin Tissoires <bentiss@kernel.org> | 2024-06-27 11:00:12 +0200 |
| commit | 75839101ce52e319cb2154a027d14f1f0aa3be09 (patch) | |
| tree | 37b05cb095474429cd80940e2c7b2e6d6d3a92a7 /include/linux/hid.h | |
| parent | 8bd0488b5ea58655ad6fdcbe0408ef49b16882b1 (diff) | |
HID: bpf: prevent infinite recursions with hid_hw_raw_requests hooks
When we attach a sleepable hook to hid_hw_raw_requests, we can (and in
many cases should) call ourself hid_bpf_raw_request(), to actually fetch
data from the device itself.
However, this means that we might enter an infinite loop between
hid_hw_raw_requests hooks and hid_bpf_hw_request() call.
To prevent that, if a hid_bpf_hw_request() call is emitted, we prevent
any new call of this kfunc by storing the information in the context.
This way we can always trace/monitor/filter the incoming bpf requests,
while preventing those loops to happen.
I don't think exposing "from_bpf" is very interesting because while
writing such a bpf program, you need to match at least the report number
and/or the source of the call. So a blind "if there is a
hid_hw_raw_request() call, I'm emitting another one" makes no real
sense.
Link: https://patch.msgid.link/20240626-hid_hw_req_bpf-v2-5-cfd60fb6c79f@kernel.org
Acked-by: Jiri Kosina <jkosina@suse.com>
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Diffstat (limited to 'include/linux/hid.h')
| -rw-r--r-- | include/linux/hid.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/hid.h b/include/linux/hid.h index dac2804b4562..24d0d7c0bd33 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -1129,7 +1129,7 @@ int __hid_hw_raw_request(struct hid_device *hdev, unsigned char reportnum, __u8 *buf, size_t len, enum hid_report_type rtype, enum hid_class_request reqtype, - __u64 source); + __u64 source, bool from_bpf); int __hid_hw_output_report(struct hid_device *hdev, __u8 *buf, size_t len, __u64 source); int hid_hw_raw_request(struct hid_device *hdev, unsigned char reportnum, __u8 *buf, |