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authorCong Wang <xiyou.wangcong@gmail.com>2020-06-02 21:49:10 -0700
committerDavid S. Miller <davem@davemloft.net>2020-06-04 15:33:45 -0700
commitc36f05559104b66bcd7f617e931e38c680227b74 (patch)
tree7d9c4ae3f77f7888b614b79562f9b6f3c558bf3b /fs/utimes.c
parentef1c75593e770aff8749e902aa0deb6855a3f485 (diff)
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genetlink: fix memory leaks in genl_family_rcv_msg_dumpit()
There are two kinds of memory leaks in genl_family_rcv_msg_dumpit(): 1. Before we call ops->start(), whenever an error happens, we forget to free the memory allocated in genl_family_rcv_msg_dumpit(). 2. When ops->start() fails, the 'info' has been already installed on the per socket control block, so we should not free it here. More importantly, nlk->cb_running is still false at this point, so netlink_sock_destruct() cannot free it either. The first kind of memory leaks is easier to resolve, but the second one requires some deeper thoughts. After reviewing how netfilter handles this, the most elegant solution I find is just to use a similar way to allocate the memory, that is, moving memory allocations from caller into ops->start(). With this, we can solve both kinds of memory leaks: for 1), no memory allocation happens before ops->start(); for 2), ops->start() handles its own failures and 'info' is installed to the socket control block only when success. The only ugliness here is we have to pass all local variables on stack via a struct, but this is not hard to understand. Alternatively, we can introduce a ops->free() to solve this too, but it is overkill as only genetlink has this problem so far. Fixes: 1927f41a22a0 ("net: genetlink: introduce dump info struct to be available during dumpit op") Reported-by: syzbot+21f04f481f449c8db840@syzkaller.appspotmail.com Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Cc: Florian Westphal <fw@strlen.de> Cc: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Jiri Pirko <jiri@mellanox.com> Cc: YueHaibing <yuehaibing@huawei.com> Cc: Shaochun Chen <cscnull@gmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'fs/utimes.c')
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