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authorPatrick McHardy <kaber@trash.net>2008-11-28 03:05:19 -0800
committerDavid S. Miller <davem@davemloft.net>2008-11-28 03:05:19 -0800
commitea5693ccc553951ae44cb963b28cce85edc275c9 (patch)
tree44ca6da57e63035537d01cf58c24837067c2ec26
parented77a89c30fa03dcb234a84ddea710b3fb7b62da (diff)
netlink: allow empty nested attributes
validate_nla() currently doesn't allow empty nested attributes. This makes userspace code unnecessarily complicated when starting and ending the nested attribute is done by generic upper level code and the inner attributes are dumped by a module. Add a special case to accept empty nested attributes. When the nested attribute is non empty, the same checks as before are performed. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/netlink/attr.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/net/netlink/attr.c b/net/netlink/attr.c
index c83fea7da9a..56c3ce7fe29 100644
--- a/net/netlink/attr.c
+++ b/net/netlink/attr.c
@@ -83,6 +83,12 @@ static int validate_nla(struct nlattr *nla, int maxtype,
if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla))
return -ERANGE;
break;
+ case NLA_NESTED:
+ /* a nested attributes is allowed to be empty; if its not,
+ * it must have a size of at least NLA_HDRLEN.
+ */
+ if (attrlen == 0)
+ break;
default:
if (pt->len)
minlen = pt->len;