| Message ID | 20220927003927.1942170-1-keescook@chromium.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 7cd04013fbf3e6dcb67ca6b59aa813269a2ad9ce |
| Headers | show |
| Series | w1: Split memcpy() of struct cn_msg flexible array | expand |
On Mon, Sep 26, 2022 at 05:39:27PM -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: Evgeniy Polyakov <zbr@ioremap.net> > Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Thanks! -- Gustavo > --- > drivers/w1/w1_netlink.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c > index fa490aa4407c..db110cc442b1 100644 > --- a/drivers/w1/w1_netlink.c > +++ b/drivers/w1/w1_netlink.c > @@ -611,7 +611,8 @@ static void w1_cn_callback(struct cn_msg *cn, struct netlink_skb_parms *nsp) > } > atomic_set(&block->refcnt, 1); > block->portid = nsp->portid; > - memcpy(&block->request_cn, cn, sizeof(*cn) + cn->len); > + block->request_cn = *cn; > + memcpy(block->request_cn.data, cn->data, cn->len); > node = (struct w1_cb_node *)(block->request_cn.data + cn->len); > > /* Sneeky, when not bundling, reply_size is the allocated space > -- > 2.34.1 >
diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c index fa490aa4407c..db110cc442b1 100644 --- a/drivers/w1/w1_netlink.c +++ b/drivers/w1/w1_netlink.c @@ -611,7 +611,8 @@ static void w1_cn_callback(struct cn_msg *cn, struct netlink_skb_parms *nsp) } atomic_set(&block->refcnt, 1); block->portid = nsp->portid; - memcpy(&block->request_cn, cn, sizeof(*cn) + cn->len); + block->request_cn = *cn; + memcpy(block->request_cn.data, cn->data, cn->len); node = (struct w1_cb_node *)(block->request_cn.data + cn->len); /* Sneeky, when not bundling, reply_size is the allocated space
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: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: Kees Cook <keescook@chromium.org> --- drivers/w1/w1_netlink.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)