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net: netlink: Update attr validation to require exact length for some types

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Attributes using NLA_U* and NLA_S* (where * is 8, 16,32 and 64) are
expected to be an exact length. Split these data types from
nla_attr_minlen into nla_attr_len and update validate_nla to require
the attribute to have exact length for them.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2017-11-07 21:59:40 -08:00 committed by David S. Miller
parent 2210d6b2f2
commit 28033ae4e0
1 changed files with 16 additions and 3 deletions
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19
lib/nlattr.c
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@ -15,19 +15,23 @@
#include <linux/types.h>
#include <net/netlink.h>
static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = {
/* for these data types attribute length must be exactly given size */
static const u8 nla_attr_len[NLA_TYPE_MAX+1] = {
[NLA_U8] = sizeof(u8),
[NLA_U16] = sizeof(u16),
[NLA_U32] = sizeof(u32),
[NLA_U64] = sizeof(u64),
[NLA_MSECS] = sizeof(u64),
[NLA_NESTED] = NLA_HDRLEN,
[NLA_S8] = sizeof(s8),
[NLA_S16] = sizeof(s16),
[NLA_S32] = sizeof(s32),
[NLA_S64] = sizeof(s64),
};
static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = {
[NLA_MSECS] = sizeof(u64),
[NLA_NESTED] = NLA_HDRLEN,
};
static int validate_nla_bitfield32(const struct nlattr *nla,
u32 *valid_flags_allowed)
{
@ -65,6 +69,13 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
BUG_ON(pt->type > NLA_TYPE_MAX);
/* for data types NLA_U* and NLA_S* require exact length */
if (nla_attr_len[pt->type]) {
if (attrlen != nla_attr_len[pt->type])
return -ERANGE;
return 0;
}
switch (pt->type) {
case NLA_FLAG:
if (attrlen > 0)
@ -191,6 +202,8 @@ nla_policy_len(const struct nla_policy *p, int n)
for (i = 0; i < n; i++, p++) {
if (p->len)
len += nla_total_size(p->len);
else if (nla_attr_len[p->type])
len += nla_total_size(nla_attr_len[p->type]);
else if (nla_attr_minlen[p->type])
len += nla_total_size(nla_attr_minlen[p->type]);
}