diff options
| author | Thomas Graf <tgraf@suug.ch> | 2006-08-27 03:11:47 (GMT) |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2006-09-22 22:18:24 (GMT) |
| commit | a5531a5d852008be40811496029012f4ad3093d1 (patch) | |
| tree | f59a1b240753ef4f0a672f256fc01d8a965793d1 /net/netlink | |
| parent | e3b4eadbea77ecb3c3a74d1bc81b392f454c7f2e (diff) | |
| download | linux-a5531a5d852008be40811496029012f4ad3093d1.tar.xz | |
[NETLINK]: Improve string attribute validation
Introduces a new attribute type NLA_NUL_STRING to support NUL
terminated strings. Attributes of this kind require to carry
a terminating NUL within the maximum specified in the policy.
The `old' NLA_STRING which is not required to be NUL terminated
is extended to provide means to specify a maximum length of the
string.
Aims at easing the pain with using nla_strlcpy() on temporary
buffers.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netlink')
| -rw-r--r-- | net/netlink/attr.c | 49 |
1 files changed, 39 insertions, 10 deletions
diff --git a/net/netlink/attr.c b/net/netlink/attr.c index 136e529..0041395 100644 --- a/net/netlink/attr.c +++ b/net/netlink/attr.c @@ -20,7 +20,6 @@ static u16 nla_attr_minlen[NLA_TYPE_MAX+1] __read_mostly = { [NLA_U16] = sizeof(u16), [NLA_U32] = sizeof(u32), [NLA_U64] = sizeof(u64), - [NLA_STRING] = 1, [NLA_NESTED] = NLA_HDRLEN, }; @@ -28,7 +27,7 @@ static int validate_nla(struct nlattr *nla, int maxtype, struct nla_policy *policy) { struct nla_policy *pt; - int minlen = 0; + int minlen = 0, attrlen = nla_len(nla); if (nla->nla_type <= 0 || nla->nla_type > maxtype) return 0; @@ -37,16 +36,46 @@ static int validate_nla(struct nlattr *nla, int maxtype, BUG_ON(pt->type > NLA_TYPE_MAX); - if (pt->minlen) - minlen = pt->minlen; - else if (pt->type != NLA_UNSPEC) - minlen = nla_attr_minlen[pt->type]; + switch (pt->type) { + case NLA_FLAG: + if (attrlen > 0) + return -ERANGE; + break; - if (pt->type == NLA_FLAG && nla_len(nla) > 0) - return -ERANGE; + case NLA_NUL_STRING: + if (pt->len) + minlen = min_t(int, attrlen, pt->len + 1); + else + minlen = attrlen; - if (nla_len(nla) < minlen) - return -ERANGE; + if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL) + return -EINVAL; + /* fall through */ + + case NLA_STRING: + if (attrlen < 1) + return -ERANGE; + + if (pt->len) { + char *buf = nla_data(nla); + + if (buf[attrlen - 1] == '\0') + attrlen--; + + if (attrlen > pt->len) + return -ERANGE; + } + break; + + default: + if (pt->len) + minlen = pt->len; + else if (pt->type != NLA_UNSPEC) + minlen = nla_attr_minlen[pt->type]; + + if (attrlen < minlen) + return -ERANGE; + } return 0; } |