[PATCH 5.7 052/265] genetlink: clean up family attributes allocations

Sasha Levin
2020-06-29T21:53:50Z

From: Cong Wang <xiyou.wangcong@gmail.com>

[ Upstream commit b65ce380b754e77fbfdcfc83fd6e29c8ceedf431 ]

genl_family_rcv_msg_attrs_parse() and genl_family_rcv_msg_attrs_free()
take a boolean parameter to determine whether allocate/free the family
attrs. This is unnecessary as we can just check family->parallel_ops.
More importantly, callers would not need to worry about pairing these
parameters correctly after this patch.

And this fixes a memory leak, as after commit c36f05559104
("genetlink: fix memory leaks in genl_family_rcv_msg_dumpit()")
we call genl_family_rcv_msg_attrs_parse() for both parallel and
non-parallel cases.

Fixes: c36f05559104 ("genetlink: fix memory leaks in genl_family_rcv_msg_dumpit()")
Reported-by: Ido Schimmel <idosch@idosch.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Tested-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netlink/genetlink.c | 28 ++++++++++++----------------
1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index bcbba0bef1c2a..9c1c27f3a0894 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -474,8 +474,7 @@ genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
struct netlink_ext_ack *extack,
const struct genl_ops *ops,
int hdrlen,
- enum genl_validate_flags no_strict_flag,
- bool parallel)
+ enum genl_validate_flags no_strict_flag)
{
enum netlink_validation validate = ops->validate & no_strict_flag ?
NL_VALIDATE_LIBERAL :
@@ -486,7 +485,7 @@ genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
if (!family->maxattr)
return NULL;

- if (parallel) {
+ if (family->parallel_ops) {
attrbuf = kmalloc_array(family->maxattr + 1,
sizeof(struct nlattr *), GFP_KERNEL);
if (!attrbuf)
@@ -498,7 +497,7 @@ genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
err = __nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
family->policy, validate, extack);
if (err) {
- if (parallel)
+ if (family->parallel_ops)
kfree(attrbuf);
return ERR_PTR(err);
}
@@ -506,10 +505,9 @@ genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
}

static void genl_family_rcv_msg_attrs_free(const struct genl_family *family,
- struct nlattr **attrbuf,
- bool parallel)
+ struct nlattr **attrbuf)
{
- if (parallel)
+ if (family->parallel_ops)
kfree(attrbuf);
}

@@ -537,15 +535,14 @@ static int genl_start(struct netlink_callback *cb)

attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack,
ops, ctx->hdrlen,
- GENL_DONT_VALIDATE_DUMP_STRICT,
- true);
+ GENL_DONT_VALIDATE_DUMP_STRICT);
if (IS_ERR(attrs))
return PTR_ERR(attrs);

no_attrs:
info = genl_dumpit_info_alloc();
if (!info) {
- kfree(attrs);
+ genl_family_rcv_msg_attrs_free(ctx->family, attrs);
return -ENOMEM;
}
info->family = ctx->family;
@@ -562,7 +559,7 @@ no_attrs:
}

if (rc) {
- kfree(attrs);
+ genl_family_rcv_msg_attrs_free(info->family, info->attrs);
genl_dumpit_info_free(info);
cb->data = NULL;
}
@@ -591,7 +588,7 @@ static int genl_lock_done(struct netlink_callback *cb)
rc = ops->done(cb);
genl_unlock();
}
- genl_family_rcv_msg_attrs_free(info->family, info->attrs, false);
+ genl_family_rcv_msg_attrs_free(info->family, info->attrs);
genl_dumpit_info_free(info);
return rc;
}
@@ -604,7 +601,7 @@ static int genl_parallel_done(struct netlink_callback *cb)

if (ops->done)
rc = ops->done(cb);
- genl_family_rcv_msg_attrs_free(info->family, info->attrs, true);
+ genl_family_rcv_msg_attrs_free(info->family, info->attrs);
genl_dumpit_info_free(info);
return rc;
}
@@ -671,8 +668,7 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family,

attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
ops, hdrlen,
- GENL_DONT_VALIDATE_STRICT,
- family->parallel_ops);
+ GENL_DONT_VALIDATE_STRICT);
if (IS_ERR(attrbuf))
return PTR_ERR(attrbuf);

@@ -698,7 +694,7 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family,
family->post_doit(ops, skb, &info);

out:
- genl_family_rcv_msg_attrs_free(family, attrbuf, family->parallel_ops);
+ genl_family_rcv_msg_attrs_free(family, attrbuf);

return err;
}
--
2.25.1