| Message ID | 20211207063217.2591451-1-keescook@chromium.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | c0e084e342a8046d06c4172b6ccb4db5d7633156 |
| Headers | show |
| Series | hv_sock: Extract hvs_send_data() helper that takes only header | expand |
On Mon, Dec 06, 2021 at 10:32:17PM -0800, Kees Cook wrote: > When building under -Warray-bounds, the compiler is especially > conservative when faced with casts from a smaller object to a larger > object. While this has found many real bugs, there are some cases that > are currently false positives (like here). With this as one of the last > few instances of the warning in the kernel before -Warray-bounds can be > enabled globally, rearrange the functions so that there is a header-only > version of hvs_send_data(). Silences this warning: > > net/vmw_vsock/hyperv_transport.c: In function 'hvs_shutdown_lock_held.constprop': > net/vmw_vsock/hyperv_transport.c:231:32: warning: array subscript 'struct hvs_send_buf[0]' is partly outside array bounds of 'struct vmpipe_proto_header[1]' [-Warray-bounds] > 231 | send_buf->hdr.pkt_type = 1; > | ~~~~~~~~~~~~~~~~~~~~~~~^~~ > net/vmw_vsock/hyperv_transport.c:465:36: note: while referencing 'hdr' > 465 | struct vmpipe_proto_header hdr; > | ^~~ > > This change results in no executable instruction differences. > > Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Wei Liu <wei.liu@kernel.org>
Hello: This patch was applied to netdev/net-next.git (master) by Jakub Kicinski <kuba@kernel.org>: On Mon, 6 Dec 2021 22:32:17 -0800 you wrote: > When building under -Warray-bounds, the compiler is especially > conservative when faced with casts from a smaller object to a larger > object. While this has found many real bugs, there are some cases that > are currently false positives (like here). With this as one of the last > few instances of the warning in the kernel before -Warray-bounds can be > enabled globally, rearrange the functions so that there is a header-only > version of hvs_send_data(). Silences this warning: > > [...] Here is the summary with links: - hv_sock: Extract hvs_send_data() helper that takes only header https://git.kernel.org/netdev/net-next/c/c0e084e342a8 You are awesome, thank you!
diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c index 19189cf30a72..e111e13b6660 100644 --- a/net/vmw_vsock/hyperv_transport.c +++ b/net/vmw_vsock/hyperv_transport.c @@ -225,14 +225,20 @@ static size_t hvs_channel_writable_bytes(struct vmbus_channel *chan) return round_down(ret, 8); } +static int __hvs_send_data(struct vmbus_channel *chan, + struct vmpipe_proto_header *hdr, + size_t to_write) +{ + hdr->pkt_type = 1; + hdr->data_size = to_write; + return vmbus_sendpacket(chan, hdr, sizeof(*hdr) + to_write, + 0, VM_PKT_DATA_INBAND, 0); +} + static int hvs_send_data(struct vmbus_channel *chan, struct hvs_send_buf *send_buf, size_t to_write) { - send_buf->hdr.pkt_type = 1; - send_buf->hdr.data_size = to_write; - return vmbus_sendpacket(chan, &send_buf->hdr, - sizeof(send_buf->hdr) + to_write, - 0, VM_PKT_DATA_INBAND, 0); + return __hvs_send_data(chan, &send_buf->hdr, to_write); } static void hvs_channel_cb(void *ctx) @@ -468,7 +474,7 @@ static void hvs_shutdown_lock_held(struct hvsock *hvs, int mode) return; /* It can't fail: see hvs_channel_writable_bytes(). */ - (void)hvs_send_data(hvs->chan, (struct hvs_send_buf *)&hdr, 0); + (void)__hvs_send_data(hvs->chan, &hdr, 0); hvs->fin_sent = true; }
When building under -Warray-bounds, the compiler is especially conservative when faced with casts from a smaller object to a larger object. While this has found many real bugs, there are some cases that are currently false positives (like here). With this as one of the last few instances of the warning in the kernel before -Warray-bounds can be enabled globally, rearrange the functions so that there is a header-only version of hvs_send_data(). Silences this warning: net/vmw_vsock/hyperv_transport.c: In function 'hvs_shutdown_lock_held.constprop': net/vmw_vsock/hyperv_transport.c:231:32: warning: array subscript 'struct hvs_send_buf[0]' is partly outside array bounds of 'struct vmpipe_proto_header[1]' [-Warray-bounds] 231 | send_buf->hdr.pkt_type = 1; | ~~~~~~~~~~~~~~~~~~~~~~~^~~ net/vmw_vsock/hyperv_transport.c:465:36: note: while referencing 'hdr' 465 | struct vmpipe_proto_header hdr; | ^~~ This change results in no executable instruction differences. Signed-off-by: Kees Cook <keescook@chromium.org> --- net/vmw_vsock/hyperv_transport.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-)