* [PATCH] dlm: Split memcpy() of struct dlm_message flexible array
@ 2022-09-24 3:52 Kees Cook
2022-09-24 4:03 ` Gustavo A. R. Silva
0 siblings, 1 reply; 2+ messages in thread
From: Kees Cook @ 2022-09-24 3:52 UTC (permalink / raw)
To: Christine Caulfield
Cc: Kees Cook, David Teigland, cluster-devel, Gustavo A. R. Silva,
linux-kernel, linux-hardening
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.
[1] https://lore.kernel.org/linux-hardening/20220901065914.1417829-2-keescook@chromium.org/
Cc: Christine Caulfield <ccaulfie@redhat.com>
Cc: David Teigland <teigland@redhat.com>
Cc: cluster-devel@redhat.com
Reported-by: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
fs/dlm/requestqueue.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/dlm/requestqueue.c b/fs/dlm/requestqueue.c
index 036a9a0078f6..63f45c3c53a2 100644
--- a/fs/dlm/requestqueue.c
+++ b/fs/dlm/requestqueue.c
@@ -44,7 +44,8 @@ void dlm_add_requestqueue(struct dlm_ls *ls, int nodeid, struct dlm_message *ms)
e->recover_seq = ls->ls_recover_seq & 0xFFFFFFFF;
e->nodeid = nodeid;
- memcpy(&e->request, ms, le16_to_cpu(ms->m_header.h_length));
+ e->request = *ms;
+ memcpy(&e->request.m_extra, ms->m_extra, length);
atomic_inc(&ls->ls_requestqueue_cnt);
mutex_lock(&ls->ls_requestqueue_mutex);
--
2.34.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] dlm: Split memcpy() of struct dlm_message flexible array
2022-09-24 3:52 [PATCH] dlm: Split memcpy() of struct dlm_message flexible array Kees Cook
@ 2022-09-24 4:03 ` Gustavo A. R. Silva
0 siblings, 0 replies; 2+ messages in thread
From: Gustavo A. R. Silva @ 2022-09-24 4:03 UTC (permalink / raw)
To: Kees Cook
Cc: Christine Caulfield, David Teigland, cluster-devel, linux-kernel,
linux-hardening
On Fri, Sep 23, 2022 at 08:52:26PM -0700, Kees Cook wrote:
> 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.
>
> [1] https://lore.kernel.org/linux-hardening/20220901065914.1417829-2-keescook@chromium.org/
>
> Cc: Christine Caulfield <ccaulfie@redhat.com>
> Cc: David Teigland <teigland@redhat.com>
> Cc: cluster-devel@redhat.com
> Reported-by: "Gustavo A. R. Silva" <gustavoars@kernel.org>
> Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Thanks!
--
Gustavo
> ---
> fs/dlm/requestqueue.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/dlm/requestqueue.c b/fs/dlm/requestqueue.c
> index 036a9a0078f6..63f45c3c53a2 100644
> --- a/fs/dlm/requestqueue.c
> +++ b/fs/dlm/requestqueue.c
> @@ -44,7 +44,8 @@ void dlm_add_requestqueue(struct dlm_ls *ls, int nodeid, struct dlm_message *ms)
>
> e->recover_seq = ls->ls_recover_seq & 0xFFFFFFFF;
> e->nodeid = nodeid;
> - memcpy(&e->request, ms, le16_to_cpu(ms->m_header.h_length));
> + e->request = *ms;
> + memcpy(&e->request.m_extra, ms->m_extra, length);
>
> atomic_inc(&ls->ls_requestqueue_cnt);
> mutex_lock(&ls->ls_requestqueue_mutex);
> --
> 2.34.1
>
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