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.
error messages from LLVM build:
monitor/rfcomm.c:238:36: error: taking address of packed member 'pm' of class
or structure 'rfcomm_rpn' may result in an unaligned pointer value
[-Werror,-Waddress-of-packed-member]
if (!l2cap_frame_get_le16(frame, &rpn.pm))
monitor/rfcomm.c:287:36: error: taking address of packed member 'mtu' of class
or structure 'rfcomm_pn' may result in an unaligned pointer value
[-Werror,-Waddress-of-packed-member]
if (!l2cap_frame_get_le16(frame, &pn.mtu))
Currently there is no corresponding flag in GCC to generate the same error
messages. See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51628.
---
v5 adds more details about the error messages.
monitor/rfcomm.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/monitor/rfcomm.c b/monitor/rfcomm.c
index fd7bbdc..afeb5e1 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;
@@ -265,6 +265,7 @@ 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 +285,10 @@ 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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