2019-05-27 05:55:35

by Xiubo Li

[permalink] [raw]
Subject: [PATCH] nbd: fix crash when the blksize is zero

From: Xiubo Li <[email protected]>

This will allow the blksize to be set zero and then use 1024 as
default.

Signed-off-by: Xiubo Li <[email protected]>
---
drivers/block/nbd.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 053958a..4c1de1c 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -135,6 +135,8 @@ struct nbd_cmd {

#define NBD_MAGIC 0x68797548

+#define NBD_DEF_BLKSIZE 1024
+
static unsigned int nbds_max = 16;
static int max_part = 16;
static struct workqueue_struct *recv_workqueue;
@@ -1237,6 +1239,14 @@ static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
nbd_config_put(nbd);
}

+static bool nbd_is_valid_blksize(unsigned long blksize)
+{
+ if (!blksize || !is_power_of_2(blksize) || blksize < 512 ||
+ blksize > PAGE_SIZE)
+ return false;
+ return true;
+}
+
/* Must be called with config_lock held */
static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
unsigned int cmd, unsigned long arg)
@@ -1252,8 +1262,9 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
case NBD_SET_SOCK:
return nbd_add_socket(nbd, arg, false);
case NBD_SET_BLKSIZE:
- if (!arg || !is_power_of_2(arg) || arg < 512 ||
- arg > PAGE_SIZE)
+ if (!arg)
+ arg = NBD_DEF_BLKSIZE;
+ if (!nbd_is_valid_blksize(arg))
return -EINVAL;
nbd_size_set(nbd, arg,
div_s64(config->bytesize, arg));
@@ -1333,7 +1344,7 @@ static struct nbd_config *nbd_alloc_config(void)
atomic_set(&config->recv_threads, 0);
init_waitqueue_head(&config->recv_wq);
init_waitqueue_head(&config->conn_wait);
- config->blksize = 1024;
+ config->blksize = NBD_DEF_BLKSIZE;
atomic_set(&config->live_connections, 0);
try_module_get(THIS_MODULE);
return config;
@@ -1769,6 +1780,10 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
u64 bsize =
nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
+ if (!bsize)
+ bsize = NBD_DEF_BLKSIZE;
+ if (!nbd_is_valid_blksize(bsize))
+ return -EINVAL;
nbd_size_set(nbd, bsize, div64_u64(config->bytesize, bsize));
}
if (info->attrs[NBD_ATTR_TIMEOUT]) {
--
1.8.3.1


2019-05-29 13:52:00

by Josef Bacik

[permalink] [raw]
Subject: Re: [PATCH] nbd: fix crash when the blksize is zero

On Mon, May 27, 2019 at 01:44:38PM +0800, [email protected] wrote:
> From: Xiubo Li <[email protected]>
>
> This will allow the blksize to be set zero and then use 1024 as
> default.
>
> Signed-off-by: Xiubo Li <[email protected]>

Hmm sorry I missed this somehow

Reviewed-by: Josef Bacik <[email protected]>

Thanks,

Josef

2019-05-29 18:56:48

by Mike Christie

[permalink] [raw]
Subject: Re: [PATCH] nbd: fix crash when the blksize is zero

On 05/27/2019 12:44 AM, [email protected] wrote:
> From: Xiubo Li <[email protected]>
>
> This will allow the blksize to be set zero and then use 1024 as
> default.
>
> Signed-off-by: Xiubo Li <[email protected]>
> ---
> drivers/block/nbd.c | 21 ++++++++++++++++++---
> 1 file changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 053958a..4c1de1c 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -135,6 +135,8 @@ struct nbd_cmd {
>
> #define NBD_MAGIC 0x68797548
>
> +#define NBD_DEF_BLKSIZE 1024
> +
> static unsigned int nbds_max = 16;
> static int max_part = 16;
> static struct workqueue_struct *recv_workqueue;
> @@ -1237,6 +1239,14 @@ static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
> nbd_config_put(nbd);
> }
>
> +static bool nbd_is_valid_blksize(unsigned long blksize)
> +{
> + if (!blksize || !is_power_of_2(blksize) || blksize < 512 ||
> + blksize > PAGE_SIZE)
> + return false;
> + return true;
> +}
> +
> /* Must be called with config_lock held */
> static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
> unsigned int cmd, unsigned long arg)
> @@ -1252,8 +1262,9 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
> case NBD_SET_SOCK:
> return nbd_add_socket(nbd, arg, false);
> case NBD_SET_BLKSIZE:
> - if (!arg || !is_power_of_2(arg) || arg < 512 ||
> - arg > PAGE_SIZE)
> + if (!arg)
> + arg = NBD_DEF_BLKSIZE;
> + if (!nbd_is_valid_blksize(arg))
> return -EINVAL;
> nbd_size_set(nbd, arg,
> div_s64(config->bytesize, arg));
> @@ -1333,7 +1344,7 @@ static struct nbd_config *nbd_alloc_config(void)
> atomic_set(&config->recv_threads, 0);
> init_waitqueue_head(&config->recv_wq);
> init_waitqueue_head(&config->conn_wait);
> - config->blksize = 1024;
> + config->blksize = NBD_DEF_BLKSIZE;
> atomic_set(&config->live_connections, 0);
> try_module_get(THIS_MODULE);
> return config;
> @@ -1769,6 +1780,10 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
> if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
> u64 bsize =
> nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
> + if (!bsize)
> + bsize = NBD_DEF_BLKSIZE;
> + if (!nbd_is_valid_blksize(bsize))
> + return -EINVAL;

You can't only return here. You need to also drop the mutex, do
nbd_put, and drop config_refs reference.

Maybe you want to move this check to the beginning of the function with
the NBD_ATTR_SIZE_BYTES sanity check since the error handling is easier
there.


> nbd_size_set(nbd, bsize, div64_u64(config->bytesize, bsize));
> }
> if (info->attrs[NBD_ATTR_TIMEOUT]) {
>

2019-05-30 01:29:33

by Xiubo Li

[permalink] [raw]
Subject: Re: [PATCH] nbd: fix crash when the blksize is zero

On 2019/5/30 2:55, Mike Christie wrote:
> On 05/27/2019 12:44 AM, [email protected] wrote:
>> From: Xiubo Li <[email protected]>
>>
>> This will allow the blksize to be set zero and then use 1024 as
>> default.
>>
>> Signed-off-by: Xiubo Li <[email protected]>
>> ---
>> drivers/block/nbd.c | 21 ++++++++++++++++++---
>> 1 file changed, 18 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
>> index 053958a..4c1de1c 100644
>> --- a/drivers/block/nbd.c
>> +++ b/drivers/block/nbd.c
>> @@ -135,6 +135,8 @@ struct nbd_cmd {
>>
>> #define NBD_MAGIC 0x68797548
>>
>> +#define NBD_DEF_BLKSIZE 1024
>> +
>> static unsigned int nbds_max = 16;
>> static int max_part = 16;
>> static struct workqueue_struct *recv_workqueue;
>> @@ -1237,6 +1239,14 @@ static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
>> nbd_config_put(nbd);
>> }
>>
>> +static bool nbd_is_valid_blksize(unsigned long blksize)
>> +{
>> + if (!blksize || !is_power_of_2(blksize) || blksize < 512 ||
>> + blksize > PAGE_SIZE)
>> + return false;
>> + return true;
>> +}
>> +
>> /* Must be called with config_lock held */
>> static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
>> unsigned int cmd, unsigned long arg)
>> @@ -1252,8 +1262,9 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
>> case NBD_SET_SOCK:
>> return nbd_add_socket(nbd, arg, false);
>> case NBD_SET_BLKSIZE:
>> - if (!arg || !is_power_of_2(arg) || arg < 512 ||
>> - arg > PAGE_SIZE)
>> + if (!arg)
>> + arg = NBD_DEF_BLKSIZE;
>> + if (!nbd_is_valid_blksize(arg))
>> return -EINVAL;
>> nbd_size_set(nbd, arg,
>> div_s64(config->bytesize, arg));
>> @@ -1333,7 +1344,7 @@ static struct nbd_config *nbd_alloc_config(void)
>> atomic_set(&config->recv_threads, 0);
>> init_waitqueue_head(&config->recv_wq);
>> init_waitqueue_head(&config->conn_wait);
>> - config->blksize = 1024;
>> + config->blksize = NBD_DEF_BLKSIZE;
>> atomic_set(&config->live_connections, 0);
>> try_module_get(THIS_MODULE);
>> return config;
>> @@ -1769,6 +1780,10 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
>> if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
>> u64 bsize =
>> nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
>> + if (!bsize)
>> + bsize = NBD_DEF_BLKSIZE;
>> + if (!nbd_is_valid_blksize(bsize))
>> + return -EINVAL;
> You can't only return here. You need to also drop the mutex, do
> nbd_put, and drop config_refs reference.
>
> Maybe you want to move this check to the beginning of the function with
> the NBD_ATTR_SIZE_BYTES sanity check since the error handling is easier
> there.

Yeah, right.

I saw your resend patch of this and that looks good to me.

Thanks
BRs
Xiubo


>
>> nbd_size_set(nbd, bsize, div64_u64(config->bytesize, bsize));
>> }
>> if (info->attrs[NBD_ATTR_TIMEOUT]) {
>>