[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>
This commit is contained in:
Thomas Graf
2006-08-26 20:11:47 -07:00
committed by David S. Miller
parent e3b4eadbea
commit a5531a5d85
2 changed files with 50 additions and 14 deletions

View File

@@ -167,6 +167,7 @@ enum {
NLA_FLAG,
NLA_MSECS,
NLA_NESTED,
NLA_NUL_STRING,
__NLA_TYPE_MAX,
};
@@ -175,21 +176,27 @@ enum {
/**
* struct nla_policy - attribute validation policy
* @type: Type of attribute or NLA_UNSPEC
* @minlen: Minimal length of payload required to be available
* @len: Type specific length of payload
*
* Policies are defined as arrays of this struct, the array must be
* accessible by attribute type up to the highest identifier to be expected.
*
* Meaning of `len' field:
* NLA_STRING Maximum length of string
* NLA_NUL_STRING Maximum length of string (excluding NUL)
* NLA_FLAG Unused
* All other Exact length of attribute payload
*
* Example:
* static struct nla_policy my_policy[ATTR_MAX+1] __read_mostly = {
* [ATTR_FOO] = { .type = NLA_U16 },
* [ATTR_BAR] = { .type = NLA_STRING },
* [ATTR_BAZ] = { .minlen = sizeof(struct mystruct) },
* [ATTR_BAR] = { .type = NLA_STRING, len = BARSIZ },
* [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
* };
*/
struct nla_policy {
u16 type;
u16 minlen;
u16 len;
};
/**