Commit c10e6cf85e7d ("net: genetlink: push attrbuf allocation and parsing
to a separate function") moved attribute buffer allocation and attribute
parsing from genl_family_rcv_msg_doit() into a separate function
genl_family_rcv_msg_attrs_parse() which, unlike the previous code, calls
__nlmsg_parse() even if family->maxattr is 0 (i.e. the family does its own
parsing). The parser error is ignored and does not propagate out of
genl_family_rcv_msg_attrs_parse() but an error message ("Unknown attribute
type") is set in extack and if further processing generates no error or
warning, it stays there and is interpreted as a warning by userspace.
Dumpit requests are not affected as genl_family_rcv_msg_dumpit() bypasses
the call of genl_family_rcv_msg_doit() if family->maxattr is zero. Do the
same also in genl_family_rcv_msg_doit().
Fixes: c10e6cf85e7d ("net: genetlink: push attrbuf allocation and parsing to a separate function")
Signed-off-by: Michal Kubecek <[email protected]>
---
net/netlink/genetlink.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index ecc2bd3e73e4..c4bf8830eedf 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -639,21 +639,23 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family,
const struct genl_ops *ops,
int hdrlen, struct net *net)
{
- struct nlattr **attrbuf;
+ struct nlattr **attrbuf = NULL;
struct genl_info info;
int err;
if (!ops->doit)
return -EOPNOTSUPP;
+ if (!family->maxattr)
+ goto no_attrs;
attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
ops, hdrlen,
GENL_DONT_VALIDATE_STRICT,
- family->maxattr &&
family->parallel_ops);
if (IS_ERR(attrbuf))
return PTR_ERR(attrbuf);
+no_attrs:
info.snd_seq = nlh->nlmsg_seq;
info.snd_portid = NETLINK_CB(skb).portid;
info.nlhdr = nlh;
--
2.23.0
Wed, Oct 09, 2019 at 06:44:32PM CEST, [email protected] wrote:
>Commit c10e6cf85e7d ("net: genetlink: push attrbuf allocation and parsing
>to a separate function") moved attribute buffer allocation and attribute
>parsing from genl_family_rcv_msg_doit() into a separate function
>genl_family_rcv_msg_attrs_parse() which, unlike the previous code, calls
>__nlmsg_parse() even if family->maxattr is 0 (i.e. the family does its own
>parsing). The parser error is ignored and does not propagate out of
>genl_family_rcv_msg_attrs_parse() but an error message ("Unknown attribute
>type") is set in extack and if further processing generates no error or
>warning, it stays there and is interpreted as a warning by userspace.
>
>Dumpit requests are not affected as genl_family_rcv_msg_dumpit() bypasses
>the call of genl_family_rcv_msg_doit() if family->maxattr is zero. Do the
>same also in genl_family_rcv_msg_doit().
This is the original code before the changes:
if (ops->doit == NULL)
return -EOPNOTSUPP;
if (family->maxattr && family->parallel_ops) {
attrbuf = kmalloc_array(family->maxattr + 1,
sizeof(struct nlattr *),
GFP_KERNEL);
if (attrbuf == NULL)
return -ENOMEM;
} else
attrbuf = family->attrbuf;
if (attrbuf) {
enum netlink_validation validate = NL_VALIDATE_STRICT;
if (ops->validate & GENL_DONT_VALIDATE_STRICT)
validate = NL_VALIDATE_LIBERAL;
err = __nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
family->policy, validate, extack);
if (err < 0)
goto out;
}
Looks like the __nlmsg_parse() is called no matter if maxattr if 0 or
not. It is only considered for allocation of attrbuf. This is in-sync
with the current code.
For dumpit, the check was there:
if (family->maxattr) {
unsigned int validate = NL_VALIDATE_STRICT;
if (ops->validate &
GENL_DONT_VALIDATE_DUMP_STRICT)
validate = NL_VALIDATE_LIBERAL;
rc = __nla_validate(nlmsg_attrdata(nlh, hdrlen),
nlmsg_attrlen(nlh, hdrlen),
family->maxattr,
family->policy,
validate, extack);
if (rc)
return rc;
}
>
>Fixes: c10e6cf85e7d ("net: genetlink: push attrbuf allocation and parsing to a separate function")
>Signed-off-by: Michal Kubecek <[email protected]>
>---
> net/netlink/genetlink.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
>diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
>index ecc2bd3e73e4..c4bf8830eedf 100644
>--- a/net/netlink/genetlink.c
>+++ b/net/netlink/genetlink.c
>@@ -639,21 +639,23 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family,
> const struct genl_ops *ops,
> int hdrlen, struct net *net)
> {
>- struct nlattr **attrbuf;
>+ struct nlattr **attrbuf = NULL;
> struct genl_info info;
> int err;
>
> if (!ops->doit)
> return -EOPNOTSUPP;
>
>+ if (!family->maxattr)
>+ goto no_attrs;
> attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
> ops, hdrlen,
> GENL_DONT_VALIDATE_STRICT,
>- family->maxattr &&
> family->parallel_ops);
> if (IS_ERR(attrbuf))
> return PTR_ERR(attrbuf);
>
>+no_attrs:
> info.snd_seq = nlh->nlmsg_seq;
> info.snd_portid = NETLINK_CB(skb).portid;
> info.nlhdr = nlh;
>--
>2.23.0
>
On Thu, Oct 10, 2019 at 10:39:58AM +0200, Jiri Pirko wrote:
> Wed, Oct 09, 2019 at 06:44:32PM CEST, [email protected] wrote:
> >Commit c10e6cf85e7d ("net: genetlink: push attrbuf allocation and parsing
> >to a separate function") moved attribute buffer allocation and attribute
> >parsing from genl_family_rcv_msg_doit() into a separate function
> >genl_family_rcv_msg_attrs_parse() which, unlike the previous code, calls
> >__nlmsg_parse() even if family->maxattr is 0 (i.e. the family does its own
> >parsing). The parser error is ignored and does not propagate out of
> >genl_family_rcv_msg_attrs_parse() but an error message ("Unknown attribute
> >type") is set in extack and if further processing generates no error or
> >warning, it stays there and is interpreted as a warning by userspace.
> >
> >Dumpit requests are not affected as genl_family_rcv_msg_dumpit() bypasses
> >the call of genl_family_rcv_msg_doit() if family->maxattr is zero. Do the
> >same also in genl_family_rcv_msg_doit().
>
> This is the original code before the changes:
>
> if (ops->doit == NULL)
> return -EOPNOTSUPP;
>
> if (family->maxattr && family->parallel_ops) {
> attrbuf = kmalloc_array(family->maxattr + 1,
> sizeof(struct nlattr *),
> GFP_KERNEL);
> if (attrbuf == NULL)
> return -ENOMEM;
> } else
> attrbuf = family->attrbuf;
>
> if (attrbuf) {
> enum netlink_validation validate = NL_VALIDATE_STRICT;
>
> if (ops->validate & GENL_DONT_VALIDATE_STRICT)
> validate = NL_VALIDATE_LIBERAL;
>
> err = __nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
> family->policy, validate, extack);
> if (err < 0)
> goto out;
> }
>
> Looks like the __nlmsg_parse() is called no matter if maxattr if 0 or
> not. It is only considered for allocation of attrbuf. This is in-sync
> with the current code.
If family->maxattr is 0, genl_register_family() sets family->attrbuf to
NULL so that attrbuf is also NULL and the whole "if (attrbuf) { ... }"
block is not executed.
Michal
Thu, Oct 10, 2019 at 11:13:47AM CEST, [email protected] wrote:
>On Thu, Oct 10, 2019 at 10:39:58AM +0200, Jiri Pirko wrote:
>> Wed, Oct 09, 2019 at 06:44:32PM CEST, [email protected] wrote:
>> >Commit c10e6cf85e7d ("net: genetlink: push attrbuf allocation and parsing
>> >to a separate function") moved attribute buffer allocation and attribute
>> >parsing from genl_family_rcv_msg_doit() into a separate function
>> >genl_family_rcv_msg_attrs_parse() which, unlike the previous code, calls
>> >__nlmsg_parse() even if family->maxattr is 0 (i.e. the family does its own
>> >parsing). The parser error is ignored and does not propagate out of
>> >genl_family_rcv_msg_attrs_parse() but an error message ("Unknown attribute
>> >type") is set in extack and if further processing generates no error or
>> >warning, it stays there and is interpreted as a warning by userspace.
>> >
>> >Dumpit requests are not affected as genl_family_rcv_msg_dumpit() bypasses
>> >the call of genl_family_rcv_msg_doit() if family->maxattr is zero. Do the
>> >same also in genl_family_rcv_msg_doit().
>>
>> This is the original code before the changes:
>>
>> if (ops->doit == NULL)
>> return -EOPNOTSUPP;
>>
>> if (family->maxattr && family->parallel_ops) {
>> attrbuf = kmalloc_array(family->maxattr + 1,
>> sizeof(struct nlattr *),
>> GFP_KERNEL);
>> if (attrbuf == NULL)
>> return -ENOMEM;
>> } else
>> attrbuf = family->attrbuf;
>>
>> if (attrbuf) {
>> enum netlink_validation validate = NL_VALIDATE_STRICT;
>>
>> if (ops->validate & GENL_DONT_VALIDATE_STRICT)
>> validate = NL_VALIDATE_LIBERAL;
>>
>> err = __nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
>> family->policy, validate, extack);
>> if (err < 0)
>> goto out;
>> }
>>
>> Looks like the __nlmsg_parse() is called no matter if maxattr if 0 or
>> not. It is only considered for allocation of attrbuf. This is in-sync
>> with the current code.
>
>If family->maxattr is 0, genl_register_family() sets family->attrbuf to
>NULL so that attrbuf is also NULL and the whole "if (attrbuf) { ... }"
>block is not executed.
Ah, I missed that. Thanks!
>
>Michal
Wed, Oct 09, 2019 at 06:44:32PM CEST, [email protected] wrote:
>Commit c10e6cf85e7d ("net: genetlink: push attrbuf allocation and parsing
>to a separate function") moved attribute buffer allocation and attribute
>parsing from genl_family_rcv_msg_doit() into a separate function
>genl_family_rcv_msg_attrs_parse() which, unlike the previous code, calls
>__nlmsg_parse() even if family->maxattr is 0 (i.e. the family does its own
>parsing). The parser error is ignored and does not propagate out of
>genl_family_rcv_msg_attrs_parse() but an error message ("Unknown attribute
>type") is set in extack and if further processing generates no error or
>warning, it stays there and is interpreted as a warning by userspace.
>
>Dumpit requests are not affected as genl_family_rcv_msg_dumpit() bypasses
>the call of genl_family_rcv_msg_doit() if family->maxattr is zero. Do the
>same also in genl_family_rcv_msg_doit().
>
>Fixes: c10e6cf85e7d ("net: genetlink: push attrbuf allocation and parsing to a separate function")
>Signed-off-by: Michal Kubecek <[email protected]>
>---
> net/netlink/genetlink.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
>diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
>index ecc2bd3e73e4..c4bf8830eedf 100644
>--- a/net/netlink/genetlink.c
>+++ b/net/netlink/genetlink.c
>@@ -639,21 +639,23 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family,
> const struct genl_ops *ops,
> int hdrlen, struct net *net)
> {
>- struct nlattr **attrbuf;
>+ struct nlattr **attrbuf = NULL;
> struct genl_info info;
> int err;
>
> if (!ops->doit)
> return -EOPNOTSUPP;
>
>+ if (!family->maxattr)
>+ goto no_attrs;
> attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
> ops, hdrlen,
> GENL_DONT_VALIDATE_STRICT,
>- family->maxattr &&
> family->parallel_ops);
Please also adjust genl_family_rcv_msg_attrs_free() call arg
below in this function in the similar way.
> if (IS_ERR(attrbuf))
> return PTR_ERR(attrbuf);
>
>+no_attrs:
> info.snd_seq = nlh->nlmsg_seq;
> info.snd_portid = NETLINK_CB(skb).portid;
> info.nlhdr = nlh;
>--
>2.23.0
>
On Thu, Oct 10, 2019 at 11:31:53AM +0200, Jiri Pirko wrote:
> Wed, Oct 09, 2019 at 06:44:32PM CEST, [email protected] wrote:
> >Commit c10e6cf85e7d ("net: genetlink: push attrbuf allocation and parsing
> >to a separate function") moved attribute buffer allocation and attribute
> >parsing from genl_family_rcv_msg_doit() into a separate function
> >genl_family_rcv_msg_attrs_parse() which, unlike the previous code, calls
> >__nlmsg_parse() even if family->maxattr is 0 (i.e. the family does its own
> >parsing). The parser error is ignored and does not propagate out of
> >genl_family_rcv_msg_attrs_parse() but an error message ("Unknown attribute
> >type") is set in extack and if further processing generates no error or
> >warning, it stays there and is interpreted as a warning by userspace.
> >
> >Dumpit requests are not affected as genl_family_rcv_msg_dumpit() bypasses
> >the call of genl_family_rcv_msg_doit() if family->maxattr is zero. Do the
> >same also in genl_family_rcv_msg_doit().
> >
> >Fixes: c10e6cf85e7d ("net: genetlink: push attrbuf allocation and parsing to a separate function")
> >Signed-off-by: Michal Kubecek <[email protected]>
> >---
> > net/netlink/genetlink.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> >diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
> >index ecc2bd3e73e4..c4bf8830eedf 100644
> >--- a/net/netlink/genetlink.c
> >+++ b/net/netlink/genetlink.c
> >@@ -639,21 +639,23 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family,
> > const struct genl_ops *ops,
> > int hdrlen, struct net *net)
> > {
> >- struct nlattr **attrbuf;
> >+ struct nlattr **attrbuf = NULL;
> > struct genl_info info;
> > int err;
> >
> > if (!ops->doit)
> > return -EOPNOTSUPP;
> >
> >+ if (!family->maxattr)
> >+ goto no_attrs;
> > attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
> > ops, hdrlen,
> > GENL_DONT_VALIDATE_STRICT,
> >- family->maxattr &&
> > family->parallel_ops);
>
> Please also adjust genl_family_rcv_msg_attrs_free() call arg
> below in this function in the similar way.
Sent v2.
Michal