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Subject[PATCH] [PATCH v3] sock: fix potential memory leak in proto_register()
Date
If protocols registered exceeded PROTO_INUSE_NR, prot will be
added to proto_list, but no available bit left for prot in
proto_inuse_idx.

Changes since v2:
* Propagate the error code properly

Signed-off-by: zhanglin <zhang.lin16@zte.com.cn>
---
net/core/sock.c | 31 +++++++++++++++++++++----------
1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/net/core/sock.c b/net/core/sock.c
index bc3512f230a3..f39163071384 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3139,16 +3139,17 @@ static __init int net_inuse_init(void)

core_initcall(net_inuse_init);

-static void assign_proto_idx(struct proto *prot)
+static int assign_proto_idx(struct proto *prot)
{
prot->inuse_idx = find_first_zero_bit(proto_inuse_idx, PROTO_INUSE_NR);

if (unlikely(prot->inuse_idx == PROTO_INUSE_NR - 1)) {
pr_err("PROTO_INUSE_NR exhausted\n");
- return;
+ return -ENOSPC;
}

set_bit(prot->inuse_idx, proto_inuse_idx);
+ return 0;
}

static void release_proto_idx(struct proto *prot)
@@ -3157,8 +3158,9 @@ static void release_proto_idx(struct proto *prot)
clear_bit(prot->inuse_idx, proto_inuse_idx);
}
#else
-static inline void assign_proto_idx(struct proto *prot)
+static inline int assign_proto_idx(struct proto *prot)
{
+ return 0;
}

static inline void release_proto_idx(struct proto *prot)
@@ -3207,6 +3209,8 @@ static int req_prot_init(const struct proto *prot)

int proto_register(struct proto *prot, int alloc_slab)
{
+ int ret = -ENOBUFS;
+
if (alloc_slab) {
prot->slab = kmem_cache_create_usercopy(prot->name,
prot->obj_size, 0,
@@ -3243,20 +3247,27 @@ int proto_register(struct proto *prot, int alloc_slab)
}

mutex_lock(&proto_list_mutex);
+ ret = assign_proto_idx(prot);
+ if (ret) {
+ mutex_unlock(&proto_list_mutex);
+ goto out_free_timewait_sock_slab_name;
+ }
list_add(&prot->node, &proto_list);
- assign_proto_idx(prot);
mutex_unlock(&proto_list_mutex);
- return 0;
+ return ret;

out_free_timewait_sock_slab_name:
- kfree(prot->twsk_prot->twsk_slab_name);
+ if (alloc_slab && prot->twsk_prot)
+ kfree(prot->twsk_prot->twsk_slab_name);
out_free_request_sock_slab:
- req_prot_cleanup(prot->rsk_prot);
+ if (alloc_slab) {
+ req_prot_cleanup(prot->rsk_prot);

- kmem_cache_destroy(prot->slab);
- prot->slab = NULL;
+ kmem_cache_destroy(prot->slab);
+ prot->slab = NULL;
+ }
out:
- return -ENOBUFS;
+ return ret;
}
EXPORT_SYMBOL(proto_register);

--
2.17.1
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