We tested and found an alarm caused by nbd_ioctl arg without verification.
The UBSAN warning calltrace like below:
UBSAN: Undefined behaviour in fs/buffer.c:1709:35
signed integer overflow:
-9223372036854775808 - 1 cannot be represented in type 'long long int'
CPU: 3 PID: 2523 Comm: syz-executor.0 Not tainted 4.19.90 #1
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace+0x0/0x3f0 arch/arm64/kernel/time.c:78
show_stack+0x28/0x38 arch/arm64/kernel/traps.c:158
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x170/0x1dc lib/dump_stack.c:118
ubsan_epilogue+0x18/0xb4 lib/ubsan.c:161
handle_overflow+0x188/0x1dc lib/ubsan.c:192
__ubsan_handle_sub_overflow+0x34/0x44 lib/ubsan.c:206
__block_write_full_page+0x94c/0xa20 fs/buffer.c:1709
block_write_full_page+0x1f0/0x280 fs/buffer.c:2934
blkdev_writepage+0x34/0x40 fs/block_dev.c:607
__writepage+0x68/0xe8 mm/page-writeback.c:2305
write_cache_pages+0x44c/0xc70 mm/page-writeback.c:2240
generic_writepages+0xdc/0x148 mm/page-writeback.c:2329
blkdev_writepages+0x2c/0x38 fs/block_dev.c:2114
do_writepages+0xd4/0x250 mm/page-writeback.c:2344
The reason for triggering this warning is __block_write_full_page()
-> i_size_read(inode) - 1 overflow.
inode->i_size is assigned in __nbd_ioctl() -> nbd_set_size() -> bytesize.
We think it is necessary to limit the size of arg to prevent errors.
Moreover, __nbd_ioctl() -> nbd_add_socket(), arg will be cast to int.
Assuming the value of arg is 0x80000000000000001) (on a 64-bit machine),
it will become 1 after the coercion, which will return unexpected results.
Fix it by adding checks to prevent passing in too large numbers.
Signed-off-by: Zhong Jinghua <[email protected]>
---
drivers/block/nbd.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 592cfa8b765a..e1c954094b6c 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -325,6 +325,9 @@ static int nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
if (blk_validate_block_size(blksize))
return -EINVAL;
+ if (bytesize < 0)
+ return -EINVAL;
+
nbd->config->bytesize = bytesize;
nbd->config->blksize_bits = __ffs(blksize);
@@ -1111,6 +1114,9 @@ static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
struct nbd_sock *nsock;
int err;
+ /* Arg will be cast to int, check it to avoid overflow */
+ if (arg > INT_MAX)
+ return -EINVAL;
sock = nbd_get_socket(nbd, arg, &err);
if (!sock)
return err;
--
2.31.1
ping...
Hello，
Anyone looking this？
在 2023/2/6 22:58, Zhong Jinghua 写道:
> We tested and found an alarm caused by nbd_ioctl arg without verification.
> The UBSAN warning calltrace like below:
>
> UBSAN: Undefined behaviour in fs/buffer.c:1709:35
> signed integer overflow:
> -9223372036854775808 - 1 cannot be represented in type 'long long int'
> CPU: 3 PID: 2523 Comm: syz-executor.0 Not tainted 4.19.90 #1
> Hardware name: linux,dummy-virt (DT)
> Call trace:
> dump_backtrace+0x0/0x3f0 arch/arm64/kernel/time.c:78
> show_stack+0x28/0x38 arch/arm64/kernel/traps.c:158
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x170/0x1dc lib/dump_stack.c:118
> ubsan_epilogue+0x18/0xb4 lib/ubsan.c:161
> handle_overflow+0x188/0x1dc lib/ubsan.c:192
> __ubsan_handle_sub_overflow+0x34/0x44 lib/ubsan.c:206
> __block_write_full_page+0x94c/0xa20 fs/buffer.c:1709
> block_write_full_page+0x1f0/0x280 fs/buffer.c:2934
> blkdev_writepage+0x34/0x40 fs/block_dev.c:607
> __writepage+0x68/0xe8 mm/page-writeback.c:2305
> write_cache_pages+0x44c/0xc70 mm/page-writeback.c:2240
> generic_writepages+0xdc/0x148 mm/page-writeback.c:2329
> blkdev_writepages+0x2c/0x38 fs/block_dev.c:2114
> do_writepages+0xd4/0x250 mm/page-writeback.c:2344
>
> The reason for triggering this warning is __block_write_full_page()
> -> i_size_read(inode) - 1 overflow.
> inode->i_size is assigned in __nbd_ioctl() -> nbd_set_size() -> bytesize.
> We think it is necessary to limit the size of arg to prevent errors.
>
> Moreover, __nbd_ioctl() -> nbd_add_socket(), arg will be cast to int.
> Assuming the value of arg is 0x80000000000000001) (on a 64-bit machine),
> it will become 1 after the coercion, which will return unexpected results.
>
> Fix it by adding checks to prevent passing in too large numbers.
>
> Signed-off-by: Zhong Jinghua <[email protected]>
> ---
> drivers/block/nbd.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 592cfa8b765a..e1c954094b6c 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -325,6 +325,9 @@ static int nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
> if (blk_validate_block_size(blksize))
> return -EINVAL;
>
> + if (bytesize < 0)
> + return -EINVAL;
> +
> nbd->config->bytesize = bytesize;
> nbd->config->blksize_bits = __ffs(blksize);
>
> @@ -1111,6 +1114,9 @@ static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
> struct nbd_sock *nsock;
> int err;
>
> + /* Arg will be cast to int, check it to avoid overflow */
> + if (arg > INT_MAX)
> + return -EINVAL;
> sock = nbd_get_socket(nbd, arg, &err);
> if (!sock)
> return err;
ping...
Hello
Anyone looking this？
在 2023/2/6 22:58, Zhong Jinghua 写道:
> We tested and found an alarm caused by nbd_ioctl arg without verification.
> The UBSAN warning calltrace like below:
>
> UBSAN: Undefined behaviour in fs/buffer.c:1709:35
> signed integer overflow:
> -9223372036854775808 - 1 cannot be represented in type 'long long int'
> CPU: 3 PID: 2523 Comm: syz-executor.0 Not tainted 4.19.90 #1
> Hardware name: linux,dummy-virt (DT)
> Call trace:
> dump_backtrace+0x0/0x3f0 arch/arm64/kernel/time.c:78
> show_stack+0x28/0x38 arch/arm64/kernel/traps.c:158
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x170/0x1dc lib/dump_stack.c:118
> ubsan_epilogue+0x18/0xb4 lib/ubsan.c:161
> handle_overflow+0x188/0x1dc lib/ubsan.c:192
> __ubsan_handle_sub_overflow+0x34/0x44 lib/ubsan.c:206
> __block_write_full_page+0x94c/0xa20 fs/buffer.c:1709
> block_write_full_page+0x1f0/0x280 fs/buffer.c:2934
> blkdev_writepage+0x34/0x40 fs/block_dev.c:607
> __writepage+0x68/0xe8 mm/page-writeback.c:2305
> write_cache_pages+0x44c/0xc70 mm/page-writeback.c:2240
> generic_writepages+0xdc/0x148 mm/page-writeback.c:2329
> blkdev_writepages+0x2c/0x38 fs/block_dev.c:2114
> do_writepages+0xd4/0x250 mm/page-writeback.c:2344
>
> The reason for triggering this warning is __block_write_full_page()
> -> i_size_read(inode) - 1 overflow.
> inode->i_size is assigned in __nbd_ioctl() -> nbd_set_size() -> bytesize.
> We think it is necessary to limit the size of arg to prevent errors.
>
> Moreover, __nbd_ioctl() -> nbd_add_socket(), arg will be cast to int.
> Assuming the value of arg is 0x80000000000000001) (on a 64-bit machine),
> it will become 1 after the coercion, which will return unexpected results.
>
> Fix it by adding checks to prevent passing in too large numbers.
>
> Signed-off-by: Zhong Jinghua <[email protected]>
> ---
> drivers/block/nbd.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 592cfa8b765a..e1c954094b6c 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -325,6 +325,9 @@ static int nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
> if (blk_validate_block_size(blksize))
> return -EINVAL;
>
> + if (bytesize < 0)
> + return -EINVAL;
> +
> nbd->config->bytesize = bytesize;
> nbd->config->blksize_bits = __ffs(blksize);
>
> @@ -1111,6 +1114,9 @@ static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
> struct nbd_sock *nsock;
> int err;
>
> + /* Arg will be cast to int, check it to avoid overflow */
> + if (arg > INT_MAX)
> + return -EINVAL;
> sock = nbd_get_socket(nbd, arg, &err);
> if (!sock)
> return err;
ping...
Hello
Anyone looking this？
在 2023/3/14 15:10, zhongjinghua 写道:
> ping...
>
> Hello
>
> Anyone looking this？
>
> 在 2023/2/6 22:58, Zhong Jinghua 写道:
>> We tested and found an alarm caused by nbd_ioctl arg without
>> verification.
>> The UBSAN warning calltrace like below:
>>
>> UBSAN: Undefined behaviour in fs/buffer.c:1709:35
>> signed integer overflow:
>> -9223372036854775808 - 1 cannot be represented in type 'long long int'
>> CPU: 3 PID: 2523 Comm: syz-executor.0 Not tainted 4.19.90 #1
>> Hardware name: linux,dummy-virt (DT)
>> Call trace:
>> dump_backtrace+0x0/0x3f0 arch/arm64/kernel/time.c:78
>> show_stack+0x28/0x38 arch/arm64/kernel/traps.c:158
>> __dump_stack lib/dump_stack.c:77 [inline]
>> dump_stack+0x170/0x1dc lib/dump_stack.c:118
>> ubsan_epilogue+0x18/0xb4 lib/ubsan.c:161
>> handle_overflow+0x188/0x1dc lib/ubsan.c:192
>> __ubsan_handle_sub_overflow+0x34/0x44 lib/ubsan.c:206
>> __block_write_full_page+0x94c/0xa20 fs/buffer.c:1709
>> block_write_full_page+0x1f0/0x280 fs/buffer.c:2934
>> blkdev_writepage+0x34/0x40 fs/block_dev.c:607
>> __writepage+0x68/0xe8 mm/page-writeback.c:2305
>> write_cache_pages+0x44c/0xc70 mm/page-writeback.c:2240
>> generic_writepages+0xdc/0x148 mm/page-writeback.c:2329
>> blkdev_writepages+0x2c/0x38 fs/block_dev.c:2114
>> do_writepages+0xd4/0x250 mm/page-writeback.c:2344
>>
>> The reason for triggering this warning is __block_write_full_page()
>> -> i_size_read(inode) - 1 overflow.
>> inode->i_size is assigned in __nbd_ioctl() -> nbd_set_size() ->
>> bytesize.
>> We think it is necessary to limit the size of arg to prevent errors.
>>
>> Moreover, __nbd_ioctl() -> nbd_add_socket(), arg will be cast to int.
>> Assuming the value of arg is 0x80000000000000001) (on a 64-bit machine),
>> it will become 1 after the coercion, which will return unexpected
>> results.
>>
>> Fix it by adding checks to prevent passing in too large numbers.
>>
>> Signed-off-by: Zhong Jinghua <[email protected]>
>> ---
>> drivers/block/nbd.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
>> index 592cfa8b765a..e1c954094b6c 100644
>> --- a/drivers/block/nbd.c
>> +++ b/drivers/block/nbd.c
>> @@ -325,6 +325,9 @@ static int nbd_set_size(struct nbd_device *nbd,
>> loff_t bytesize,
>> if (blk_validate_block_size(blksize))
>> return -EINVAL;
>> + if (bytesize < 0)
>> + return -EINVAL;
>> +
>> nbd->config->bytesize = bytesize;
>> nbd->config->blksize_bits = __ffs(blksize);
>> @@ -1111,6 +1114,9 @@ static int nbd_add_socket(struct nbd_device
>> *nbd, unsigned long arg,
>> struct nbd_sock *nsock;
>> int err;
>> + /* Arg will be cast to int, check it to avoid overflow */
>> + if (arg > INT_MAX)
>> + return -EINVAL;
>> sock = nbd_get_socket(nbd, arg, &err);
>> if (!sock)
>> return err;
?? 2023/02/06 22:58, Zhong Jinghua д??:
> We tested and found an alarm caused by nbd_ioctl arg without verification.
> The UBSAN warning calltrace like below:
>
> UBSAN: Undefined behaviour in fs/buffer.c:1709:35
> signed integer overflow:
> -9223372036854775808 - 1 cannot be represented in type 'long long int'
> CPU: 3 PID: 2523 Comm: syz-executor.0 Not tainted 4.19.90 #1
> Hardware name: linux,dummy-virt (DT)
> Call trace:
> dump_backtrace+0x0/0x3f0 arch/arm64/kernel/time.c:78
> show_stack+0x28/0x38 arch/arm64/kernel/traps.c:158
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x170/0x1dc lib/dump_stack.c:118
> ubsan_epilogue+0x18/0xb4 lib/ubsan.c:161
> handle_overflow+0x188/0x1dc lib/ubsan.c:192
> __ubsan_handle_sub_overflow+0x34/0x44 lib/ubsan.c:206
> __block_write_full_page+0x94c/0xa20 fs/buffer.c:1709
> block_write_full_page+0x1f0/0x280 fs/buffer.c:2934
> blkdev_writepage+0x34/0x40 fs/block_dev.c:607
> __writepage+0x68/0xe8 mm/page-writeback.c:2305
> write_cache_pages+0x44c/0xc70 mm/page-writeback.c:2240
> generic_writepages+0xdc/0x148 mm/page-writeback.c:2329
> blkdev_writepages+0x2c/0x38 fs/block_dev.c:2114
> do_writepages+0xd4/0x250 mm/page-writeback.c:2344
>
> The reason for triggering this warning is __block_write_full_page()
> -> i_size_read(inode) - 1 overflow.
> inode->i_size is assigned in __nbd_ioctl() -> nbd_set_size() -> bytesize.
> We think it is necessary to limit the size of arg to prevent errors.
>
> Moreover, __nbd_ioctl() -> nbd_add_socket(), arg will be cast to int.
> Assuming the value of arg is 0x80000000000000001) (on a 64-bit machine),
> it will become 1 after the coercion, which will return unexpected results.
>
> Fix it by adding checks to prevent passing in too large numbers.
Looks good to me, feel free to add:
Reviewed-by: Yu Kuai <[email protected]>
>
> Signed-off-by: Zhong Jinghua <[email protected]>
> ---
> drivers/block/nbd.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 592cfa8b765a..e1c954094b6c 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -325,6 +325,9 @@ static int nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
> if (blk_validate_block_size(blksize))
> return -EINVAL;
>
> + if (bytesize < 0)
> + return -EINVAL;
> +
> nbd->config->bytesize = bytesize;
> nbd->config->blksize_bits = __ffs(blksize);
>
> @@ -1111,6 +1114,9 @@ static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
> struct nbd_sock *nsock;
> int err;
>
> + /* Arg will be cast to int, check it to avoid overflow */
> + if (arg > INT_MAX)
> + return -EINVAL;
> sock = nbd_get_socket(nbd, arg, &err);
> if (!sock)
> return err;
>
On Mon, Feb 06, 2023 at 10:58:05PM +0800, Zhong Jinghua wrote:
> We tested and found an alarm caused by nbd_ioctl arg without verification.
> The UBSAN warning calltrace like below:
>
> UBSAN: Undefined behaviour in fs/buffer.c:1709:35
> signed integer overflow:
> -9223372036854775808 - 1 cannot be represented in type 'long long int'
> CPU: 3 PID: 2523 Comm: syz-executor.0 Not tainted 4.19.90 #1
> Hardware name: linux,dummy-virt (DT)
> Call trace:
> dump_backtrace+0x0/0x3f0 arch/arm64/kernel/time.c:78
> show_stack+0x28/0x38 arch/arm64/kernel/traps.c:158
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x170/0x1dc lib/dump_stack.c:118
> ubsan_epilogue+0x18/0xb4 lib/ubsan.c:161
> handle_overflow+0x188/0x1dc lib/ubsan.c:192
> __ubsan_handle_sub_overflow+0x34/0x44 lib/ubsan.c:206
> __block_write_full_page+0x94c/0xa20 fs/buffer.c:1709
> block_write_full_page+0x1f0/0x280 fs/buffer.c:2934
> blkdev_writepage+0x34/0x40 fs/block_dev.c:607
> __writepage+0x68/0xe8 mm/page-writeback.c:2305
> write_cache_pages+0x44c/0xc70 mm/page-writeback.c:2240
> generic_writepages+0xdc/0x148 mm/page-writeback.c:2329
> blkdev_writepages+0x2c/0x38 fs/block_dev.c:2114
> do_writepages+0xd4/0x250 mm/page-writeback.c:2344
>
> The reason for triggering this warning is __block_write_full_page()
> -> i_size_read(inode) - 1 overflow.
> inode->i_size is assigned in __nbd_ioctl() -> nbd_set_size() -> bytesize.
> We think it is necessary to limit the size of arg to prevent errors.
>
> Moreover, __nbd_ioctl() -> nbd_add_socket(), arg will be cast to int.
> Assuming the value of arg is 0x80000000000000001) (on a 64-bit machine),
> it will become 1 after the coercion, which will return unexpected results.
>
> Fix it by adding checks to prevent passing in too large numbers.
>
> Signed-off-by: Zhong Jinghua <[email protected]>
Reviewed-by: Josef Bacik <[email protected]>
Thanks,
Josef
On Mon, 06 Feb 2023 22:58:05 +0800, Zhong Jinghua wrote:
> We tested and found an alarm caused by nbd_ioctl arg without verification.
> The UBSAN warning calltrace like below:
>
> UBSAN: Undefined behaviour in fs/buffer.c:1709:35
> signed integer overflow:
> -9223372036854775808 - 1 cannot be represented in type 'long long int'
> CPU: 3 PID: 2523 Comm: syz-executor.0 Not tainted 4.19.90 #1
> Hardware name: linux,dummy-virt (DT)
> Call trace:
> dump_backtrace+0x0/0x3f0 arch/arm64/kernel/time.c:78
> show_stack+0x28/0x38 arch/arm64/kernel/traps.c:158
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x170/0x1dc lib/dump_stack.c:118
> ubsan_epilogue+0x18/0xb4 lib/ubsan.c:161
> handle_overflow+0x188/0x1dc lib/ubsan.c:192
> __ubsan_handle_sub_overflow+0x34/0x44 lib/ubsan.c:206
> __block_write_full_page+0x94c/0xa20 fs/buffer.c:1709
> block_write_full_page+0x1f0/0x280 fs/buffer.c:2934
> blkdev_writepage+0x34/0x40 fs/block_dev.c:607
> __writepage+0x68/0xe8 mm/page-writeback.c:2305
> write_cache_pages+0x44c/0xc70 mm/page-writeback.c:2240
> generic_writepages+0xdc/0x148 mm/page-writeback.c:2329
> blkdev_writepages+0x2c/0x38 fs/block_dev.c:2114
> do_writepages+0xd4/0x250 mm/page-writeback.c:2344
>
> [...]
Applied, thanks!
[1/1] nbd: fix incomplete validation of ioctl arg
commit: 55793ea54d77719a071b1ccc05a05056e3b5e009
Best regards,
--
Jens Axboe