From: Zheng Bin <zhengbin13@huawei.com> stable inclusion from linux-4.19.133 commit 306290bad932950adccfbf99c27b70c105c2c183 -------------------------------- [ Upstream commit 579dd91ab3a5446b148e7f179b6596b270dace46 ] When adding first socket to nbd, if nsock's allocation failed, the data structure member "config->socks" was reallocated, but the data structure member "config->num_connections" was not updated. A memory leak will occur then because the function "nbd_config_put" will free "config->socks" only when "config->num_connections" is not zero. Fixes: 03bf73c315ed ("nbd: prevent memory leak") Reported-by: syzbot+934037347002901b8d2a@syzkaller.appspotmail.com Signed-off-by: Zheng Bin <zhengbin13@huawei.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/block/nbd.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 49f98b9b2777..97fcb040056c 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -993,25 +993,26 @@ static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg, test_bit(NBD_RT_BOUND, &config->runtime_flags))) { dev_err(disk_to_dev(nbd->disk), "Device being setup by another task"); - sockfd_put(sock); - return -EBUSY; + err = -EBUSY; + goto put_socket; + } + + nsock = kzalloc(sizeof(*nsock), GFP_KERNEL); + if (!nsock) { + err = -ENOMEM; + goto put_socket; } socks = krealloc(config->socks, (config->num_connections + 1) * sizeof(struct nbd_sock *), GFP_KERNEL); if (!socks) { - sockfd_put(sock); - return -ENOMEM; + kfree(nsock); + err = -ENOMEM; + goto put_socket; } config->socks = socks; - nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL); - if (!nsock) { - sockfd_put(sock); - return -ENOMEM; - } - nsock->fallback_index = -1; nsock->dead = false; mutex_init(&nsock->tx_lock); @@ -1023,6 +1024,10 @@ static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg, atomic_inc(&config->live_connections); return 0; + +put_socket: + sockfd_put(sock); + return err; } static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg) -- 2.25.1