Messages in this thread Patch in this message | | | Date | Fri, 14 May 2021 16:52:09 -0500 | From | "Gustavo A. R. Silva" <> | Subject | [PATCH][next] ceph: Replace zero-length array with flexible array member |
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There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2].
Notice that, in this case, sizeof(au->reply_buf) translates to zero, becase in the original code reply_buf is a zero-length array. Now that reply_buf is transformed into a flexible array, the mentioned line of code is now replaced by a literal 0.
Also, as a safeguard, explicitly assign NULL to auth->authorizer_reply_buf, as no heap is allocated for it, therefore it should not be accessible.
[1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.10/process/deprecated.html#zero-length-and-one-element-arrays
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> --- net/ceph/auth_none.c | 4 ++-- net/ceph/auth_none.h | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/net/ceph/auth_none.c b/net/ceph/auth_none.c index 70e86e462250..10ee16d2cbf0 100644 --- a/net/ceph/auth_none.c +++ b/net/ceph/auth_none.c @@ -111,8 +111,8 @@ static int ceph_auth_none_create_authorizer( auth->authorizer = (struct ceph_authorizer *) au; auth->authorizer_buf = au->buf; auth->authorizer_buf_len = au->buf_len; - auth->authorizer_reply_buf = au->reply_buf; - auth->authorizer_reply_buf_len = sizeof (au->reply_buf); + auth->authorizer_reply_buf_len = 0; + auth->authorizer_reply_buf = NULL; return 0; } diff --git a/net/ceph/auth_none.h b/net/ceph/auth_none.h index 4158f064302e..3c68c0ee3dab 100644 --- a/net/ceph/auth_none.h +++ b/net/ceph/auth_none.h @@ -16,7 +16,7 @@ struct ceph_none_authorizer { struct ceph_authorizer base; char buf[128]; int buf_len; - char reply_buf[0]; + char reply_buf[]; }; struct ceph_auth_none_info { -- 2.27.0
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