2024-01-10 10:42:08

by Vasiliy Kovalev

Subject: [PATCH 1/1] misc/vmw_vmci: fix filling of the msg and msg_payload in dg_info struct

From: Vasiliy Kovalev <[email protected]>

Fix "detected field-spanning write" of memcpy warning that is issued by
the tracking mechanism __fortify_memcpy_chk, added 2021-04-20
(f68f2ff91512c199ec24883001245912afc17873 fortify: Detect struct member overflows in memcpy() at compile-time)

Fixes: a110b7ebb9c674 ("VMCI: datagram implementation.")
Signed-off-by: Vasiliy Kovalev <[email protected]>
---
drivers/misc/vmw_vmci/vmci_datagram.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/vmw_vmci/vmci_datagram.c b/drivers/misc/vmw_vmci/vmci_datagram.c
index f50d22882476f9..27853b31e288b1 100644
--- a/drivers/misc/vmw_vmci/vmci_datagram.c
+++ b/drivers/misc/vmw_vmci/vmci_datagram.c
@@ -234,7 +234,10 @@ static int dg_dispatch_as_host(u32 context_id, struct vmci_datagram *dg)

dg_info->in_dg_host_queue = true;
dg_info->entry = dst_entry;
- memcpy(&dg_info->msg, dg, dg_size);
+ memcpy(&dg_info->msg, dg, VMCI_DG_HEADERSIZE);
+ if (dg->payload_size) {
+ memcpy(dg_info->msg_payload, VMCI_DG_PAYLOAD(dg), dg->payload_size);
+ }

INIT_WORK(&dg_info->work, dg_delayed_dispatch);
schedule_work(&dg_info->work);
@@ -377,7 +380,10 @@ int vmci_datagram_invoke_guest_handler(struct vmci_datagram *dg)

dg_info->in_dg_host_queue = false;
dg_info->entry = dst_entry;
- memcpy(&dg_info->msg, dg, VMCI_DG_SIZE(dg));
+ memcpy(&dg_info->msg, dg, VMCI_DG_HEADERSIZE);
+ if (dg->payload_size) {
+ memcpy(dg_info->msg_payload, VMCI_DG_PAYLOAD(dg), dg->payload_size);
+ }

INIT_WORK(&dg_info->work, dg_delayed_dispatch);
schedule_work(&dg_info->work);
--
2.33.8

2024-01-10 10:55:08

by Greg Kroah-Hartman

Subject: Re: [PATCH 1/1] misc/vmw_vmci: fix filling of the msg and msg_payload in dg_info struct

On Wed, Jan 10, 2024 at 01:40:42PM +0300, [email protected] wrote:
> From: Vasiliy Kovalev <[email protected]>
>
> Fix "detected field-spanning write" of memcpy warning that is issued by
> the tracking mechanism __fortify_memcpy_chk, added 2021-04-20
> (f68f2ff91512c199ec24883001245912afc17873 fortify: Detect struct member overflows in memcpy() at compile-time)

Please properly quote commits.

> Fixes: a110b7ebb9c674 ("VMCI: datagram implementation.")

It's not really a bug to be "fixed", right? It's just a "shut up the
fortify checkers with this false-positive" type of thing.

Again, see the thread I pointed you at for this same discussion.

thanks,

greg k-h

2024-01-10 11:00:26

by Greg Kroah-Hartman

Subject: Re: [PATCH 1/1] misc/vmw_vmci: fix filling of the msg and msg_payload in dg_info struct

On Wed, Jan 10, 2024 at 01:40:42PM +0300, [email protected] wrote:
> From: Vasiliy Kovalev <[email protected]>
>
> Fix "detected field-spanning write" of memcpy warning that is issued by
> the tracking mechanism __fortify_memcpy_chk, added 2021-04-20
> (f68f2ff91512c199ec24883001245912afc17873 fortify: Detect struct member overflows in memcpy() at compile-time)
>
> Fixes: a110b7ebb9c674 ("VMCI: datagram implementation.")
> Signed-off-by: Vasiliy Kovalev <[email protected]>
> ---
> drivers/misc/vmw_vmci/vmci_datagram.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/misc/vmw_vmci/vmci_datagram.c b/drivers/misc/vmw_vmci/vmci_datagram.c
> index f50d22882476f9..27853b31e288b1 100644
> --- a/drivers/misc/vmw_vmci/vmci_datagram.c
> +++ b/drivers/misc/vmw_vmci/vmci_datagram.c
> @@ -234,7 +234,10 @@ static int dg_dispatch_as_host(u32 context_id, struct vmci_datagram *dg)
>
> dg_info->in_dg_host_queue = true;
> dg_info->entry = dst_entry;
> - memcpy(&dg_info->msg, dg, dg_size);
> + memcpy(&dg_info->msg, dg, VMCI_DG_HEADERSIZE);
> + if (dg->payload_size) {
> + memcpy(dg_info->msg_payload, VMCI_DG_PAYLOAD(dg), dg->payload_size);
> + }
>
> INIT_WORK(&dg_info->work, dg_delayed_dispatch);
> schedule_work(&dg_info->work);
> @@ -377,7 +380,10 @@ int vmci_datagram_invoke_guest_handler(struct vmci_datagram *dg)
>
> dg_info->in_dg_host_queue = false;
> dg_info->entry = dst_entry;
> - memcpy(&dg_info->msg, dg, VMCI_DG_SIZE(dg));
> + memcpy(&dg_info->msg, dg, VMCI_DG_HEADERSIZE);
> + if (dg->payload_size) {
> + memcpy(dg_info->msg_payload, VMCI_DG_PAYLOAD(dg), dg->payload_size);
> + }
>
> INIT_WORK(&dg_info->work, dg_delayed_dispatch);
> schedule_work(&dg_info->work);
> --
> 2.33.8
>

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman. You have sent him
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