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Date: Wed, 26 Sep 2018 11:15:32 +0200
From: Johannes Berg <johannes@...solutions.net>
To: netdev@...r.kernel.org
Cc: David Ahern <dsahern@...il.com>,
Johannes Berg <johannes.berg@...el.com>
Subject: [PATCH v3 3/5] netlink: move extack setting into validate_nla()
From: Johannes Berg <johannes.berg@...el.com>
This unifies the code between nla_parse() which sets the bad
attribute pointer and an error message, and nla_validate()
which only sets the bad attribute pointer.
It also cleans up the code for NLA_REJECT and paves the way
for nested policy validation, as it will allow us to easily
skip setting the "generic" message without any extra args
like the **error_msg now, just passing the extack through is
now enough.
While at it, remove the unnecessary label in nla_parse().
Suggested-by: David Ahern <dsahern@...il.com>
Signed-off-by: Johannes Berg <johannes.berg@...el.com>
---
lib/nlattr.c | 68 ++++++++++++++++++++++++++++++++----------------------------
1 file changed, 36 insertions(+), 32 deletions(-)
diff --git a/lib/nlattr.c b/lib/nlattr.c
index e2e5b38394d5..6e03d650bec4 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -69,10 +69,11 @@ static int validate_nla_bitfield32(const struct nlattr *nla,
static int validate_nla(const struct nlattr *nla, int maxtype,
const struct nla_policy *policy,
- const char **error_msg)
+ struct netlink_ext_ack *extack)
{
const struct nla_policy *pt;
int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
+ int err = -ERANGE;
if (type <= 0 || type > maxtype)
return 0;
@@ -90,24 +91,31 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
switch (pt->type) {
case NLA_EXACT_LEN:
if (attrlen != pt->len)
- return -ERANGE;
+ goto out_err;
break;
case NLA_REJECT:
- if (pt->validation_data && error_msg)
- *error_msg = pt->validation_data;
- return -EINVAL;
+ if (extack && pt->validation_data) {
+ NL_SET_BAD_ATTR(extack, nla);
+ extack->_msg = pt->validation_data;
+ return -EINVAL;
+ }
+ err = -EINVAL;
+ goto out_err;
case NLA_FLAG:
if (attrlen > 0)
- return -ERANGE;
+ goto out_err;
break;
case NLA_BITFIELD32:
if (attrlen != sizeof(struct nla_bitfield32))
- return -ERANGE;
+ goto out_err;
- return validate_nla_bitfield32(nla, pt->validation_data);
+ err = validate_nla_bitfield32(nla, pt->validation_data);
+ if (err)
+ goto out_err;
+ break;
case NLA_NUL_STRING:
if (pt->len)
@@ -115,13 +123,15 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
else
minlen = attrlen;
- if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL)
- return -EINVAL;
+ if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL) {
+ err = -EINVAL;
+ goto out_err;
+ }
/* fall through */
case NLA_STRING:
if (attrlen < 1)
- return -ERANGE;
+ goto out_err;
if (pt->len) {
char *buf = nla_data(nla);
@@ -130,13 +140,13 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
attrlen--;
if (attrlen > pt->len)
- return -ERANGE;
+ goto out_err;
}
break;
case NLA_BINARY:
if (pt->len && attrlen > pt->len)
- return -ERANGE;
+ goto out_err;
break;
case NLA_NESTED:
@@ -152,10 +162,13 @@ static int validate_nla(const struct nlattr *nla, int maxtype,
minlen = nla_attr_minlen[pt->type];
if (attrlen < minlen)
- return -ERANGE;
+ goto out_err;
}
return 0;
+out_err:
+ NL_SET_ERR_MSG_ATTR(extack, nla, "Attribute failed policy validation");
+ return err;
}
/**
@@ -180,12 +193,10 @@ int nla_validate(const struct nlattr *head, int len, int maxtype,
int rem;
nla_for_each_attr(nla, head, len, rem) {
- int err = validate_nla(nla, maxtype, policy, NULL);
+ int err = validate_nla(nla, maxtype, policy, extack);
- if (err < 0) {
- NL_SET_BAD_ATTR(extack, nla);
+ if (err < 0)
return err;
- }
}
return 0;
@@ -241,7 +252,7 @@ int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
struct netlink_ext_ack *extack)
{
const struct nlattr *nla;
- int rem, err;
+ int rem;
memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
@@ -249,17 +260,12 @@ int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
u16 type = nla_type(nla);
if (type > 0 && type <= maxtype) {
- static const char _msg[] = "Attribute failed policy validation";
- const char *msg = _msg;
-
if (policy) {
- err = validate_nla(nla, maxtype, policy, &msg);
- if (err < 0) {
- NL_SET_BAD_ATTR(extack, nla);
- if (extack)
- extack->_msg = msg;
- goto errout;
- }
+ int err = validate_nla(nla, maxtype, policy,
+ extack);
+
+ if (err < 0)
+ return err;
}
tb[type] = (struct nlattr *)nla;
@@ -270,9 +276,7 @@ int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
rem, current->comm);
- err = 0;
-errout:
- return err;
+ return 0;
}
EXPORT_SYMBOL(nla_parse);
--
2.14.4
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