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[PATCH] misc: fastrpc: Use memdup_user()

Thorsten Blum posted 1 patch 1 year, 7 months ago
There is a newer version of this series
drivers/misc/fastrpc.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
[PATCH] misc: fastrpc: Use memdup_user()
Posted by Thorsten Blum 1 year, 7 months ago 
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 <thorsten.blum@toblux.com>
---
 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
Re: [PATCH] misc: fastrpc: Use memdup_user()
Posted by Arnd Bergmann 1 year, 7 months ago 
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 <thorsten.blum@toblux.com>

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 <arnd@arndb.de>

      Arnd
[PATCH v2] misc: fastrpc: Use memdup_user()
Posted by Thorsten Blum 1 year, 7 months ago 
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 <thorsten.blum@toblux.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
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
Re: [PATCH v2] misc: fastrpc: Use memdup_user()
Posted by Srinivas Kandagatla 1 year, 6 months ago 
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 <srinivas.kandagatla@linaro.org>
[RESEND PATCH v2] misc: fastrpc: Use memdup_user()
Posted by Thorsten Blum 1 year, 6 months ago 
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 <thorsten.blum@toblux.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
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
Re: [RESEND PATCH v2] misc: fastrpc: Use memdup_user()
Posted by Srinivas Kandagatla 1 year, 6 months ago 
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 <srinivas.kandagatla@linaro.org>

Patchew 2.1-devel-b67e4c2

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