diff options
author | Jamal Hadi Salim <jhs@mojatatu.com> | 2017-07-30 13:24:49 -0400 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2017-07-30 19:28:08 -0700 |
commit | 64c83d837329531252a1a0f0dfdd4fd607e1d8e9 (patch) | |
tree | a764214643c24db912ab942efd1aa47365d179c9 /lib | |
parent | fbbeefdd21049fcf9437c809da3828b210577f36 (diff) |
net netlink: Add new type NLA_BITFIELD32
Generic bitflags attribute content sent to the kernel by user.
With this netlink attr type the user can either set or unset a
flag in the kernel.
The value is a bitmap that defines the bit values being set
The selector is a bitmask that defines which value bit is to be
considered.
A check is made to ensure the rules that a kernel subsystem always
conforms to bitflags the kernel already knows about. i.e
if the user tries to set a bit flag that is not understood then
the _it will be rejected_.
In the most basic form, the user specifies the attribute policy as:
[ATTR_GOO] = { .type = NLA_BITFIELD32, .validation_data = &myvalidflags },
where myvalidflags is the bit mask of the flags the kernel understands.
If the user _does not_ provide myvalidflags then the attribute will
also be rejected.
Examples:
value = 0x0, and selector = 0x1
implies we are selecting bit 1 and we want to set its value to 0.
value = 0x2, and selector = 0x2
implies we are selecting bit 2 and we want to set its value to 1.
Suggested-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'lib')
-rw-r--r-- | lib/nlattr.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/lib/nlattr.c b/lib/nlattr.c index fb52435be42d..ee79b7a3c6b0 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -27,6 +27,30 @@ static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = { [NLA_S64] = sizeof(s64), }; +static int validate_nla_bitfield32(const struct nlattr *nla, + u32 *valid_flags_allowed) +{ + const struct nla_bitfield32 *bf = nla_data(nla); + u32 *valid_flags_mask = valid_flags_allowed; + + if (!valid_flags_allowed) + return -EINVAL; + + /*disallow invalid bit selector */ + if (bf->selector & ~*valid_flags_mask) + return -EINVAL; + + /*disallow invalid bit values */ + if (bf->value & ~*valid_flags_mask) + return -EINVAL; + + /*disallow valid bit values that are not selected*/ + if (bf->value & ~bf->selector) + return -EINVAL; + + return 0; +} + static int validate_nla(const struct nlattr *nla, int maxtype, const struct nla_policy *policy) { @@ -46,6 +70,12 @@ static int validate_nla(const struct nlattr *nla, int maxtype, return -ERANGE; break; + case NLA_BITFIELD32: + if (attrlen != sizeof(struct nla_bitfield32)) + return -ERANGE; + + return validate_nla_bitfield32(nla, pt->validation_data); + case NLA_NUL_STRING: if (pt->len) minlen = min_t(int, attrlen, pt->len + 1); |