GIT: unionfs2-2.6.27.y: sctp: fix append error cause to ERROR chunk correctly

[Erez Zadok]

commit 7694247af71eb2a9067c07ee716ea2ead7bd8fe2
Author: Wei Yongjun <yjwei at cn.fujitsu.com>
Date:   Mon May 17 22:51:58 2010 -0700

    sctp: fix append error cause to ERROR chunk correctly
    
    commit 2e3219b5c8a2e44e0b83ae6e04f52f20a82ac0f2 upstream.
    
    commit 5fa782c2f5ef6c2e4f04d3e228412c9b4a4c8809
      sctp: Fix skb_over_panic resulting from multiple invalid \
        parameter errors (CVE-2010-1173) (v4)
    
    cause 'error cause' never be add the the ERROR chunk due to
    some typo when check valid length in sctp_init_cause_fixed().
    
    Signed-off-by: Wei Yongjun <yjwei at cn.fujitsu.com>
    Reviewed-by: Neil Horman <nhorman at tuxdriver.com>
    Acked-by: Vlad Yasevich <vladislav.yasevich at hp.com>
    Signed-off-by: David S. Miller <davem at davemloft.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 8018d4b..baf2fa4 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -140,7 +140,7 @@ int sctp_init_cause_fixed(struct sctp_chunk *chunk, __be16 cause_code,
 	len = sizeof(sctp_errhdr_t) + paylen;
 	err.length  = htons(len);
 
-	if (skb_tailroom(chunk->skb) >  len)
+	if (skb_tailroom(chunk->skb) < len)
 		return -ENOSPC;
 	chunk->subh.err_hdr = sctp_addto_chunk_fixed(chunk,
 						     sizeof(sctp_errhdr_t),
@@ -1401,7 +1401,7 @@ void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
 void *sctp_addto_chunk_fixed(struct sctp_chunk *chunk,
 			     int len, const void *data)
 {
-	if (skb_tailroom(chunk->skb) > len)
+	if (skb_tailroom(chunk->skb) >= len)
 		return sctp_addto_chunk(chunk, len, data);
 	else
 		return NULL;