Hello Luiz,
Is there any comment on this patch?
Thanks,
Miao
On Sat, Dec 10, 2016 at 4:59 AM, <mcchou@xxxxxxxxxxxx> wrote:
> From: Miao-chen Chou <mcchou@xxxxxxxxxxxx>
>
> This patch removes "packed" attribute from the definition of struct rfcomm_rpn
> to prevent the access to an unaligned struct member in mmc_rpn(). This patch
> also introduces a temp variable in mcc_pn() to prevent unaligned access without
> touching the definition of struct rfcomm_pn, since struct rfcomm_pn is used as
> a PDU.
> ---
> monitor/rfcomm.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/monitor/rfcomm.c b/monitor/rfcomm.c
> index b32ad40..08f3e36 100644
> --- a/monitor/rfcomm.c
> +++ b/monitor/rfcomm.c
> @@ -106,7 +106,7 @@ struct rfcomm_rpn {
> uint8_t xon;
> uint8_t xoff;
> uint16_t pm;
> -} __attribute__ ((packed));
> +};
>
> struct rfcomm_rls {
> uint8_t dlci;
> @@ -232,8 +232,7 @@ static inline bool mcc_rpn(struct rfcomm_frame *rfcomm_frame, uint8_t indent)
>
> print_field("%*crtri %d rtro %d rtci %d rtco %d xon %d xoff %d",
> indent, ' ', GET_RPN_RTRI(rpn.io), GET_RPN_RTRO(rpn.io),
> - GET_RPN_RTCI(rpn.io), GET_RPN_RTCO(rpn.io), rpn.xon,
> - rpn.xoff);
> + GET_RPN_RTCI(rpn.io), GET_RPN_RTCO(rpn.io), rpn.xon, rpn.xoff);
>
> if (!l2cap_frame_get_le16(frame, &rpn.pm))
> return false;
> @@ -265,6 +264,7 @@ static inline bool mcc_pn(struct rfcomm_frame *rfcomm_frame, uint8_t indent)
> {
> struct l2cap_frame *frame = &rfcomm_frame->l2cap_frame;
> struct rfcomm_pn pn;
> + uint16_t mtu;
>
> /* rfcomm_pn struct is defined in rfcomm.h */
>
> @@ -284,8 +284,10 @@ static inline bool mcc_pn(struct rfcomm_frame *rfcomm_frame, uint8_t indent)
> if (!l2cap_frame_get_u8(frame, &pn.ack_timer))
> return false;
>
> - if (!l2cap_frame_get_le16(frame, &pn.mtu))
> + /* prevent unaligned memory access */
> + if (!l2cap_frame_get_le16(frame, &mtu))
> return false;
> + pn.mtu = mtu;
>
> if (!l2cap_frame_get_u8(frame, &pn.max_retrans))
> return false;
> --
> 2.8.0.rc3.226.g39d4020
>
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