* [PATCH] io_uring: fix provide_buffers sign extension
@ 2021-03-19 10:21 Pavel Begunkov
2021-03-19 10:31 ` Colin Ian King
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Pavel Begunkov @ 2021-03-19 10:21 UTC (permalink / raw)
To: Jens Axboe, io-uring; +Cc: Colin Ian King
io_provide_buffers_prep()'s "p->len * p->nbufs" to sign extension
problems. Not a huge problem as it's only used for access_ok() and
increases the checked length, but better to keep typing right.
Reported-by: Colin Ian King <[email protected]>
Fixes: efe68c1ca8f49 ("io_uring: validate the full range of provided buffers for access")
Signed-off-by: Pavel Begunkov <[email protected]>
---
fs/io_uring.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index c2489b463eb9..4f1c98502a09 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3978,6 +3978,7 @@ static int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
static int io_provide_buffers_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
+ unsigned long size;
struct io_provide_buf *p = &req->pbuf;
u64 tmp;
@@ -3991,7 +3992,8 @@ static int io_provide_buffers_prep(struct io_kiocb *req,
p->addr = READ_ONCE(sqe->addr);
p->len = READ_ONCE(sqe->len);
- if (!access_ok(u64_to_user_ptr(p->addr), (p->len * p->nbufs)))
+ size = (unsigned long)p->len * p->nbufs;
+ if (!access_ok(u64_to_user_ptr(p->addr), size))
return -EFAULT;
p->bgid = READ_ONCE(sqe->buf_group);
--
2.24.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] io_uring: fix provide_buffers sign extension
2021-03-19 10:21 [PATCH] io_uring: fix provide_buffers sign extension Pavel Begunkov
@ 2021-03-19 10:31 ` Colin Ian King
2021-03-19 10:34 ` Pavel Begunkov
2021-03-22 1:47 ` Pavel Begunkov
2021-03-22 13:41 ` Jens Axboe
2 siblings, 1 reply; 6+ messages in thread
From: Colin Ian King @ 2021-03-19 10:31 UTC (permalink / raw)
To: Pavel Begunkov, Jens Axboe, io-uring
On 19/03/2021 10:21, Pavel Begunkov wrote:
> io_provide_buffers_prep()'s "p->len * p->nbufs" to sign extension
> problems. Not a huge problem as it's only used for access_ok() and
> increases the checked length, but better to keep typing right.
>
> Reported-by: Colin Ian King <[email protected]>
> Fixes: efe68c1ca8f49 ("io_uring: validate the full range of provided buffers for access")
> Signed-off-by: Pavel Begunkov <[email protected]>
> ---
> fs/io_uring.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index c2489b463eb9..4f1c98502a09 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -3978,6 +3978,7 @@ static int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
> static int io_provide_buffers_prep(struct io_kiocb *req,
> const struct io_uring_sqe *sqe)
> {
> + unsigned long size;
> struct io_provide_buf *p = &req->pbuf;
> u64 tmp;
>
> @@ -3991,7 +3992,8 @@ static int io_provide_buffers_prep(struct io_kiocb *req,
> p->addr = READ_ONCE(sqe->addr);
> p->len = READ_ONCE(sqe->len);
>
> - if (!access_ok(u64_to_user_ptr(p->addr), (p->len * p->nbufs)))
> + size = (unsigned long)p->len * p->nbufs;
> + if (!access_ok(u64_to_user_ptr(p->addr), size))
> return -EFAULT;
>
> p->bgid = READ_ONCE(sqe->buf_group);
>
Does it make sense to make size a u64 and cast to a u64 rather than
unsigned long?
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] io_uring: fix provide_buffers sign extension
2021-03-19 10:31 ` Colin Ian King
@ 2021-03-19 10:34 ` Pavel Begunkov
2021-03-19 10:39 ` Colin Ian King
0 siblings, 1 reply; 6+ messages in thread
From: Pavel Begunkov @ 2021-03-19 10:34 UTC (permalink / raw)
To: Colin Ian King, Jens Axboe, io-uring
On 19/03/2021 10:31, Colin Ian King wrote:
> On 19/03/2021 10:21, Pavel Begunkov wrote:
>> io_provide_buffers_prep()'s "p->len * p->nbufs" to sign extension
>> problems. Not a huge problem as it's only used for access_ok() and
>> increases the checked length, but better to keep typing right.
>>
>> Reported-by: Colin Ian King <[email protected]>
>> Fixes: efe68c1ca8f49 ("io_uring: validate the full range of provided buffers for access")
>> Signed-off-by: Pavel Begunkov <[email protected]>
>> ---
>> fs/io_uring.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>> index c2489b463eb9..4f1c98502a09 100644
>> --- a/fs/io_uring.c
>> +++ b/fs/io_uring.c
>> @@ -3978,6 +3978,7 @@ static int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
>> static int io_provide_buffers_prep(struct io_kiocb *req,
>> const struct io_uring_sqe *sqe)
>> {
>> + unsigned long size;
>> struct io_provide_buf *p = &req->pbuf;
>> u64 tmp;
>>
>> @@ -3991,7 +3992,8 @@ static int io_provide_buffers_prep(struct io_kiocb *req,
>> p->addr = READ_ONCE(sqe->addr);
>> p->len = READ_ONCE(sqe->len);
>>
>> - if (!access_ok(u64_to_user_ptr(p->addr), (p->len * p->nbufs)))
>> + size = (unsigned long)p->len * p->nbufs;
>> + if (!access_ok(u64_to_user_ptr(p->addr), size))
>> return -EFAULT;
>>
>> p->bgid = READ_ONCE(sqe->buf_group);
>>
>
> Does it make sense to make size a u64 and cast to a u64 rather than
> unsigned long?
static inline int __access_ok(unsigned long addr, unsigned long size)
{
return 1;
}
Not sure. I was thinking about size_t, but ended up sticking
to access_ok types.
--
Pavel Begunkov
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] io_uring: fix provide_buffers sign extension
2021-03-19 10:34 ` Pavel Begunkov
@ 2021-03-19 10:39 ` Colin Ian King
0 siblings, 0 replies; 6+ messages in thread
From: Colin Ian King @ 2021-03-19 10:39 UTC (permalink / raw)
To: Pavel Begunkov, Jens Axboe, io-uring
On 19/03/2021 10:34, Pavel Begunkov wrote:
> On 19/03/2021 10:31, Colin Ian King wrote:
>> On 19/03/2021 10:21, Pavel Begunkov wrote:
>>> io_provide_buffers_prep()'s "p->len * p->nbufs" to sign extension
>>> problems. Not a huge problem as it's only used for access_ok() and
>>> increases the checked length, but better to keep typing right.
>>>
>>> Reported-by: Colin Ian King <[email protected]>
>>> Fixes: efe68c1ca8f49 ("io_uring: validate the full range of provided buffers for access")
>>> Signed-off-by: Pavel Begunkov <[email protected]>
>>> ---
>>> fs/io_uring.c | 4 +++-
>>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>>> index c2489b463eb9..4f1c98502a09 100644
>>> --- a/fs/io_uring.c
>>> +++ b/fs/io_uring.c
>>> @@ -3978,6 +3978,7 @@ static int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
>>> static int io_provide_buffers_prep(struct io_kiocb *req,
>>> const struct io_uring_sqe *sqe)
>>> {
>>> + unsigned long size;
>>> struct io_provide_buf *p = &req->pbuf;
>>> u64 tmp;
>>>
>>> @@ -3991,7 +3992,8 @@ static int io_provide_buffers_prep(struct io_kiocb *req,
>>> p->addr = READ_ONCE(sqe->addr);
>>> p->len = READ_ONCE(sqe->len);
>>>
>>> - if (!access_ok(u64_to_user_ptr(p->addr), (p->len * p->nbufs)))
>>> + size = (unsigned long)p->len * p->nbufs;
>>> + if (!access_ok(u64_to_user_ptr(p->addr), size))
>>> return -EFAULT;
>>>
>>> p->bgid = READ_ONCE(sqe->buf_group);
>>>
>>
>> Does it make sense to make size a u64 and cast to a u64 rather than
>> unsigned long?
>
> static inline int __access_ok(unsigned long addr, unsigned long size)
> {
> return 1;
> }
>
> Not sure. I was thinking about size_t, but ended up sticking
> to access_ok types.
>
Ah, yep. OK.
Reviewed-by: Colin Ian King <[email protected]>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] io_uring: fix provide_buffers sign extension
2021-03-19 10:21 [PATCH] io_uring: fix provide_buffers sign extension Pavel Begunkov
2021-03-19 10:31 ` Colin Ian King
@ 2021-03-22 1:47 ` Pavel Begunkov
2021-03-22 13:41 ` Jens Axboe
2 siblings, 0 replies; 6+ messages in thread
From: Pavel Begunkov @ 2021-03-22 1:47 UTC (permalink / raw)
To: Jens Axboe, io-uring; +Cc: Colin Ian King
On 19/03/2021 10:21, Pavel Begunkov wrote:
> io_provide_buffers_prep()'s "p->len * p->nbufs" to sign extension
> problems. Not a huge problem as it's only used for access_ok() and
> increases the checked length, but better to keep typing right.
Forgot to mention, I suggest it for 5.12, simple enough and
may be a problem for userspace in some rare cases.
> Reported-by: Colin Ian King <[email protected]>
> Fixes: efe68c1ca8f49 ("io_uring: validate the full range of provided buffers for access")
> Signed-off-by: Pavel Begunkov <[email protected]>
> ---
> fs/io_uring.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index c2489b463eb9..4f1c98502a09 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -3978,6 +3978,7 @@ static int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
> static int io_provide_buffers_prep(struct io_kiocb *req,
> const struct io_uring_sqe *sqe)
> {
> + unsigned long size;
> struct io_provide_buf *p = &req->pbuf;
> u64 tmp;
>
> @@ -3991,7 +3992,8 @@ static int io_provide_buffers_prep(struct io_kiocb *req,
> p->addr = READ_ONCE(sqe->addr);
> p->len = READ_ONCE(sqe->len);
>
> - if (!access_ok(u64_to_user_ptr(p->addr), (p->len * p->nbufs)))
> + size = (unsigned long)p->len * p->nbufs;
> + if (!access_ok(u64_to_user_ptr(p->addr), size))
> return -EFAULT;
>
> p->bgid = READ_ONCE(sqe->buf_group);
>
--
Pavel Begunkov
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] io_uring: fix provide_buffers sign extension
2021-03-19 10:21 [PATCH] io_uring: fix provide_buffers sign extension Pavel Begunkov
2021-03-19 10:31 ` Colin Ian King
2021-03-22 1:47 ` Pavel Begunkov
@ 2021-03-22 13:41 ` Jens Axboe
2 siblings, 0 replies; 6+ messages in thread
From: Jens Axboe @ 2021-03-22 13:41 UTC (permalink / raw)
To: Pavel Begunkov, io-uring; +Cc: Colin Ian King
On 3/19/21 4:21 AM, Pavel Begunkov wrote:
> io_provide_buffers_prep()'s "p->len * p->nbufs" to sign extension
> problems. Not a huge problem as it's only used for access_ok() and
> increases the checked length, but better to keep typing right.
Applied, thanks.
--
Jens Axboe
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-03-22 13:42 UTC | newest]
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2021-03-19 10:21 [PATCH] io_uring: fix provide_buffers sign extension Pavel Begunkov
2021-03-19 10:31 ` Colin Ian King
2021-03-19 10:34 ` Pavel Begunkov
2021-03-19 10:39 ` Colin Ian King
2021-03-22 1:47 ` Pavel Begunkov
2021-03-22 13:41 ` Jens Axboe
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