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authorArnd Bergmann <arnd@arndb.de>2023-07-05 17:02:24 +0300
committerBenjamin Tissoires <bentiss@kernel.org>2023-07-09 13:47:37 +0300
commit5f151364b1da6bd217632fd4ee8cc24eaf66a497 (patch)
treedecf1f0c4242d025fc72107ab43be7309963df02 /drivers/hid
parentf9abdcc617dad5f14bbc2ebe96ee99f3e6de0c4e (diff)
downloadlinux-5f151364b1da6bd217632fd4ee8cc24eaf66a497.tar.xz
HID: hyperv: avoid struct memcpy overrun warning
A previous patch addressed the fortified memcpy warning for most builds, but I still see this one with gcc-9: In file included from include/linux/string.h:254, from drivers/hid/hid-hyperv.c:8: In function 'fortify_memcpy_chk', inlined from 'mousevsc_on_receive' at drivers/hid/hid-hyperv.c:272:3: include/linux/fortify-string.h:583:4: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning] 583 | __write_overflow_field(p_size_field, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ My guess is that the WARN_ON() itself is what confuses gcc, so it no longer sees that there is a correct range check. Rework the code in a way that helps readability and avoids the warning. Fixes: 542f25a94471 ("HID: hyperv: Replace one-element array with flexible-array member") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20230705140242.844167-1-arnd@kernel.org Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Diffstat (limited to 'drivers/hid')
-rw-r--r--drivers/hid/hid-hyperv.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/drivers/hid/hid-hyperv.c b/drivers/hid/hid-hyperv.c
index 49d4a26895e7..f33485d83d24 100644
--- a/drivers/hid/hid-hyperv.c
+++ b/drivers/hid/hid-hyperv.c
@@ -258,19 +258,17 @@ static void mousevsc_on_receive(struct hv_device *device,
switch (hid_msg_hdr->type) {
case SYNTH_HID_PROTOCOL_RESPONSE:
+ len = struct_size(pipe_msg, data, pipe_msg->size);
+
/*
* While it will be impossible for us to protect against
* malicious/buggy hypervisor/host, add a check here to
* ensure we don't corrupt memory.
*/
- if (struct_size(pipe_msg, data, pipe_msg->size)
- > sizeof(struct mousevsc_prt_msg)) {
- WARN_ON(1);
+ if (WARN_ON(len > sizeof(struct mousevsc_prt_msg)))
break;
- }
- memcpy(&input_dev->protocol_resp, pipe_msg,
- struct_size(pipe_msg, data, pipe_msg->size));
+ memcpy(&input_dev->protocol_resp, pipe_msg, len);
complete(&input_dev->wait_event);
break;