2024-05-07 20:15:09

by Thorsten Blum

Subject: [PATCH] misc: fastrpc: Use memdup_user()

Switching to memdup_user() overwrites the allocated memory only once,
whereas kzalloc() followed by copy_from_user() initializes the allocated
memory to zero and then immediately overwrites it.

Fixes the following Coccinelle/coccicheck warning reported by
memdup_user.cocci:

WARNING opportunity for memdup_user

Signed-off-by: Thorsten Blum <[email protected]>
---
drivers/misc/fastrpc.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 4c67e2c5a82e..2857cddaf812 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -1259,17 +1259,12 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
goto err;
}

- name = kzalloc(init.namelen, GFP_KERNEL);
- if (!name) {
- err = -ENOMEM;
+ name = memdup_user((void __user *)(uintptr_t)init.name, init.namelen);
+ if (IS_ERR(name)) {
+ err = PTR_ERR(name);
goto err;
}

- if (copy_from_user(name, (void __user *)(uintptr_t)init.name, init.namelen)) {
- err = -EFAULT;
- goto err_name;
- }
-
if (!fl->cctx->remote_heap) {
err = fastrpc_remote_heap_alloc(fl, fl->sctx->dev, init.memlen,
&fl->cctx->remote_heap);
--
2.45.0

2024-05-07 21:00:16

by Arnd Bergmann

Subject: Re: [PATCH] misc: fastrpc: Use memdup_user()

On Tue, May 7, 2024, at 22:12, Thorsten Blum wrote:
> Switching to memdup_user() overwrites the allocated memory only once,
> whereas kzalloc() followed by copy_from_user() initializes the allocated
> memory to zero and then immediately overwrites it.
>
> Fixes the following Coccinelle/coccicheck warning reported by
> memdup_user.cocci:
>
> WARNING opportunity for memdup_user
>
> Signed-off-by: Thorsten Blum <[email protected]>

The patch looks correct to me.

> ---
> drivers/misc/fastrpc.c | 11 +++--------
> 1 file changed, 3 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index 4c67e2c5a82e..2857cddaf812 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -1259,17 +1259,12 @@ static int
> fastrpc_init_create_static_process(struct fastrpc_user *fl,
> goto err;
> }
>
> - name = kzalloc(init.namelen, GFP_KERNEL);
> - if (!name) {
> - err = -ENOMEM;
> + name = memdup_user((void __user *)(uintptr_t)init.name, init.namelen);
> + if (IS_ERR(name)) {
> + err = PTR_ERR(name);
> goto err;
> }

There is also a chance to simplify this further using u64_to_user_ptr()
instead of the double cast if you want.

Acked-by: Arnd Bergmann <[email protected]>

Arnd

2024-05-07 22:24:38

by Thorsten Blum

Subject: [PATCH v2] misc: fastrpc: Use memdup_user()

Switching to memdup_user() overwrites the allocated memory only once,
whereas kzalloc() followed by copy_from_user() initializes the allocated
memory to zero and then immediately overwrites it.

Fixes the following Coccinelle/coccicheck warning reported by
memdup_user.cocci:

WARNING opportunity for memdup_user

Signed-off-by: Thorsten Blum <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
---
Changes in v2:
- Use u64_to_user_ptr() as suggested by Arnd Bergmann (thanks!)
- Preserve Acked-by: tag
---
drivers/misc/fastrpc.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 4c67e2c5a82e..694fc083b1bd 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -1259,17 +1259,12 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
goto err;
}

- name = kzalloc(init.namelen, GFP_KERNEL);
- if (!name) {
- err = -ENOMEM;
+ name = memdup_user(u64_to_user_ptr(init.name), init.namelen);
+ if (IS_ERR(name)) {
+ err = PTR_ERR(name);
goto err;
}

- if (copy_from_user(name, (void __user *)(uintptr_t)init.name, init.namelen)) {
- err = -EFAULT;
- goto err_name;
- }
-
if (!fl->cctx->remote_heap) {
err = fastrpc_remote_heap_alloc(fl, fl->sctx->dev, init.memlen,
&fl->cctx->remote_heap);
--
2.45.0

2024-05-27 09:21:38

by Thorsten Blum

Subject: [RESEND PATCH v2] misc: fastrpc: Use memdup_user()

Switching to memdup_user() overwrites the allocated memory only once,
whereas kzalloc() followed by copy_from_user() initializes the allocated
memory to zero and then immediately overwrites it.

Fixes the following Coccinelle/coccicheck warning reported by
memdup_user.cocci:

WARNING opportunity for memdup_user

Signed-off-by: Thorsten Blum <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
---
Changes in v2:
- Use u64_to_user_ptr() as suggested by Arnd Bergmann (thanks!)
- Preserve Acked-by: tag
---
drivers/misc/fastrpc.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 4c67e2c5a82e..694fc083b1bd 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -1259,17 +1259,12 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
goto err;
}

- name = kzalloc(init.namelen, GFP_KERNEL);
- if (!name) {
- err = -ENOMEM;
+ name = memdup_user(u64_to_user_ptr(init.name), init.namelen);
+ if (IS_ERR(name)) {
+ err = PTR_ERR(name);
goto err;
}

- if (copy_from_user(name, (void __user *)(uintptr_t)init.name, init.namelen)) {
- err = -EFAULT;
- goto err_name;
- }
-
if (!fl->cctx->remote_heap) {
err = fastrpc_remote_heap_alloc(fl, fl->sctx->dev, init.memlen,
&fl->cctx->remote_heap);
--
2.45.1

2024-05-28 11:47:53

by Srinivas Kandagatla

Subject: Re: [PATCH v2] misc: fastrpc: Use memdup_user()

On Wed, 08 May 2024 00:22:27 +0200, Thorsten Blum wrote:
> Switching to memdup_user() overwrites the allocated memory only once,
> whereas kzalloc() followed by copy_from_user() initializes the allocated
> memory to zero and then immediately overwrites it.
>
> Fixes the following Coccinelle/coccicheck warning reported by
> memdup_user.cocci:
>
> [...]

Applied, thanks!

[1/1] misc: fastrpc: Use memdup_user()
commit: a16833330e2fa60912af6abebde711bf2c672cf9

Best regards,
--
Srinivas Kandagatla <[email protected]>

2024-05-28 12:05:54

by Srinivas Kandagatla

Subject: Re: [RESEND PATCH v2] misc: fastrpc: Use memdup_user()

On Mon, 27 May 2024 10:44:30 +0200, Thorsten Blum wrote:
> Switching to memdup_user() overwrites the allocated memory only once,
> whereas kzalloc() followed by copy_from_user() initializes the allocated
> memory to zero and then immediately overwrites it.
>
> Fixes the following Coccinelle/coccicheck warning reported by
> memdup_user.cocci:
>
> [...]

Applied, thanks!

[1/1] misc: fastrpc: Use memdup_user()
commit: a16833330e2fa60912af6abebde711bf2c672cf9

Best regards,
--
Srinivas Kandagatla <[email protected]>