On 5/20/19 11:45 AM, Chris Packham wrote:
> TLV_SET is called with a data pointer and a len parameter that tells us
> how many bytes are pointed to by data. When invoking memcpy() we need
> to careful to only copy len bytes.
>
> Previously we would copy TLV_LENGTH(len) bytes which would copy an extra
> 4 bytes past the end of the data pointer which newer GCC versions
> complain about.
>
> In file included from test.c:17:
> In function 'TLV_SET',
> inlined from 'test' at test.c:186:5:
> /usr/include/linux/tipc_config.h:317:3:
> warning: 'memcpy' forming offset [33, 36] is out of the bounds [0, 32]
> of object 'bearer_name' with type 'char[32]' [-Warray-bounds]
> memcpy(TLV_DATA(tlv_ptr), data, tlv_len);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> test.c: In function 'test':
> test.c::161:10: note:
> 'bearer_name' declared here
> char bearer_name[TIPC_MAX_BEARER_NAME];
> ^~~~~~~~~~~
>
> We still want to ensure any padding bytes at the end are initialised, do
> this with a explicit memset() rather than copy bytes past the end of
> data. Apply the same logic to TCM_SET.
>
> Signed-off-by: Chris Packham <chris.pack...@alliedtelesis.co.nz>
Acked-by: Ying Xue <ying....@windriver.com>
But please make the same changes in usr/include/linux/tipc_config.h
> ---
>
> Changes in v2:
> - Ensure padding bytes are initialised in both TLV_SET and TCM_SET
>
> include/uapi/linux/tipc_config.h | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/include/uapi/linux/tipc_config.h
> b/include/uapi/linux/tipc_config.h
> index 4b2c93b1934c..4955e1a9f1bc 100644
> --- a/include/uapi/linux/tipc_config.h
> +++ b/include/uapi/linux/tipc_config.h
> @@ -307,8 +307,10 @@ static inline int TLV_SET(void *tlv, __u16 type, void
> *data, __u16 len)
> tlv_ptr = (struct tlv_desc *)tlv;
> tlv_ptr->tlv_type = htons(type);
> tlv_ptr->tlv_len = htons(tlv_len);
> - if (len && data)
> - memcpy(TLV_DATA(tlv_ptr), data, tlv_len);
> + if (len && data) {
> + memcpy(TLV_DATA(tlv_ptr), data, len);
> + memset(TLV_DATA(tlv_ptr) + len, 0, TLV_SPACE(len) - tlv_len);
> + }
> return TLV_SPACE(len);
> }
>
> @@ -405,8 +407,10 @@ static inline int TCM_SET(void *msg, __u16 cmd, __u16
> flags,
> tcm_hdr->tcm_len = htonl(msg_len);
> tcm_hdr->tcm_type = htons(cmd);
> tcm_hdr->tcm_flags = htons(flags);
> - if (data_len && data)
> + if (data_len && data) {
> memcpy(TCM_DATA(msg), data, data_len);
> + memset(TCM_DATA(msg) + data_len, 0, TCM_SPACE(data_len) -
> msg_len);
> + }
> return TCM_SPACE(data_len);
> }
>
>
