Messages in this thread | | | Subject | Re: [PATCH v2] tipc: Avoid copying bytes beyond the supplied data | From | Ying Xue <> | Date | Wed, 22 May 2019 15:47:46 +0800 |
| |
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.packham@alliedtelesis.co.nz>
Acked-by: Ying Xue <ying.xue@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); > } > >
| |