diff options
| author | Kees Cook <keescook@chromium.org> | 2022-09-27 14:17:36 -0700 |
|---|---|---|
| committer | Wei Liu <wei.liu@kernel.org> | 2022-09-28 13:35:26 +0000 |
| commit | fb2d14add4f813c73bd9d28b750315ccb3f5f0ea (patch) | |
| tree | 3b31973688a0f2aa4dcb6337b2c91aff2f2107f8 | |
| parent | 635b241d93010cbbbea3855e4f274c2621df7a19 (diff) | |
Drivers: hv: vmbus: Split memcpy of flex-array
To work around a misbehavior of the compiler's ability to see into
composite flexible array structs (as detailed in the coming memcpy()
hardening series[1]), split the memcpy() of the header and the payload
so no false positive run-time overflow warning will be generated. This
results in the already inlined memcpy getting unrolled a little more,
which very slightly increases text size:
$ size drivers/hv/vmbus_drv.o.before drivers/hv/vmbus_drv.o
text data bss dec hex filename
22968 5239 232 28439 6f17 drivers/hv/vmbus_drv.o.before
23032 5239 232 28503 6f57 drivers/hv/vmbus_drv.o
Avoids the run-time false-positive warning:
memcpy: detected field-spanning write (size 212) of single field "&ctx->msg" at drivers/hv/vmbus_drv.c:1133 (size 16)
[1] https://lore.kernel.org/linux-hardening/20220901065914.1417829-2-keescook@chromium.org/
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: linux-hyperv@vger.kernel.org
Reported-by: Nathan Chancellor <nathan@kernel.org>
Reported-by: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20220927211736.3241175-1-keescook@chromium.org
Signed-off-by: Wei Liu <wei.liu@kernel.org>
| -rw-r--r-- | drivers/hv/vmbus_drv.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index cfc231beb52a..bbbc92994e94 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -1130,7 +1130,8 @@ void vmbus_on_msg_dpc(unsigned long data) return; INIT_WORK(&ctx->work, vmbus_onmessage_work); - memcpy(&ctx->msg, &msg_copy, sizeof(msg->header) + payload_size); + ctx->msg.header = msg_copy.header; + memcpy(&ctx->msg.payload, msg_copy.u.payload, payload_size); /* * The host can generate a rescind message while we |