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Commit 9834a2bb authored by Vlad Yasevich's avatar Vlad Yasevich Committed by Sridhar Samudrala
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[SCTP]: Fix sctp_cookie alignment in the packet. 



On 64 bit architectures, sctp_cookie sent as part of INIT-ACK is not
aligned on a 64 bit boundry and thus causes unaligned access exceptions.

The layout of the cookie prameter is this:
|<----- Parameter Header --------------------|<--- Cookie DATA --------
-----------------------------------------------------------------------
| param type (16 bits) | param len (16 bits) | sig [32 bytes] | cookie..
-----------------------------------------------------------------------

The cookie data portion contains 64 bit values on 64 bit architechtures
(timeval) that fall on a 32 bit alignment boundry when used as part of
the on-wire format, but align correctly when used in internal
structures.  This patch explicitely pads the on-wire format so that
it is properly aligned.

Signed-off-by: default avatarVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: default avatarSridhar Samudrala <sri@us.ibm.com>
parent 7a48f923

include/net/sctp/structs.h

+2 −1
Original line number Diff line number Diff line
@@ -405,8 +405,9 @@ struct sctp_cookie { 
/* The format of our cookie that we send to our peer. */

struct sctp_signed_cookie {

	__u8 signature[SCTP_SECRET_SIZE];

	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */

	struct sctp_cookie c;

};

} __attribute__((packed));



/* This is another convenience type to allocate memory for address

 * params for the maximum size and pass such structures around

net/sctp/sm_make_chunk.c

+12 −2
Original line number Diff line number Diff line
@@ -1275,7 +1275,12 @@ static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep, 
	unsigned int keylen;

	char *key;



	headersize = sizeof(sctp_paramhdr_t) + SCTP_SECRET_SIZE;

	/* Header size is static data prior to the actual cookie, including

	 * any padding.

	 */

	headersize = sizeof(sctp_paramhdr_t) + 

		     (sizeof(struct sctp_signed_cookie) - 

		      sizeof(struct sctp_cookie));

	bodysize = sizeof(struct sctp_cookie)

		+ ntohs(init_chunk->chunk_hdr->length) + addrs_len;
@@ -1362,7 +1367,12 @@ struct sctp_association *sctp_unpack_cookie( 
	struct sk_buff *skb = chunk->skb;

	struct timeval tv;



	headersize = sizeof(sctp_chunkhdr_t) + SCTP_SECRET_SIZE;

	/* Header size is static data prior to the actual cookie, including

	 * any padding.

	 */

	headersize = sizeof(sctp_chunkhdr_t) +

		     (sizeof(struct sctp_signed_cookie) - 

		      sizeof(struct sctp_cookie));

	bodysize = ntohs(chunk->chunk_hdr->length) - headersize;

	fixed_size = headersize + sizeof(struct sctp_cookie);