[patch v2] usb: f_fs: off by one bug in _ffs_func_bind()

[patch v2] usb: f_fs: off by one bug in _ffs_func_bind()

[Dan Carpenter]

This loop is supposed to set all the .num[] values to -1 but it's off by
one so it skips the first element and sets one element past the end of
the array.

I've cleaned up the loop a little as well.

Fixes: ddf8abd25994 ('USB: f_fs: the FunctionFS driver')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2: move the eps_ptr assignment outside the loop.

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 73515d5..d26eb64 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -2729,6 +2729,7 @@ static int _ffs_func_bind(struct usb_configuration *c,
 		func->ffs->ss_descs_count;
 
 	int fs_len, hs_len, ss_len, ret, i;
+	struct ffs_ep *eps_ptr;
 
 	/* Make it a single chunk, less management later on */
 	vla_group(d);
@@ -2777,12 +2778,9 @@ static int _ffs_func_bind(struct usb_configuration *c,
 	       ffs->raw_descs_length);
 
 	memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
-	for (ret = ffs->eps_count; ret; --ret) {
-		struct ffs_ep *ptr;
-
-		ptr = vla_ptr(vlabuf, d, eps);
-		ptr[ret].num = -1;
-	}
+	eps_ptr = vla_ptr(vlabuf, d, eps);
+	for (i = 0; i < ffs->eps_count; i++)
+		eps_ptr[i].num = -1;
 
 	/* Save pointers
 	 * d_eps == vlabuf, func->eps used to kfree vlabuf later

Re: [patch v2] usb: f_fs: off by one bug in _ffs_func_bind()

[walter harms]

much better readable than the original.
nice work

re,
 wh

Am 28.05.2016 06:48, schrieb Dan Carpenter:
> This loop is supposed to set all the .num[] values to -1 but it's off by
> one so it skips the first element and sets one element past the end of
> the array.
> 
> I've cleaned up the loop a little as well.
> 
> Fixes: ddf8abd25994 ('USB: f_fs: the FunctionFS driver')
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> v2: move the eps_ptr assignment outside the loop.
> 
> diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
> index 73515d5..d26eb64 100644
> --- a/drivers/usb/gadget/function/f_fs.c
> +++ b/drivers/usb/gadget/function/f_fs.c
> @@ -2729,6 +2729,7 @@ static int _ffs_func_bind(struct usb_configuration *c,
>  		func->ffs->ss_descs_count;
>  
>  	int fs_len, hs_len, ss_len, ret, i;
> +	struct ffs_ep *eps_ptr;
>  
>  	/* Make it a single chunk, less management later on */
>  	vla_group(d);
> @@ -2777,12 +2778,9 @@ static int _ffs_func_bind(struct usb_configuration *c,
>  	       ffs->raw_descs_length);
>  
>  	memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
> -	for (ret = ffs->eps_count; ret; --ret) {
> -		struct ffs_ep *ptr;
> -
> -		ptr = vla_ptr(vlabuf, d, eps);
> -		ptr[ret].num = -1;
> -	}
> +	eps_ptr = vla_ptr(vlabuf, d, eps);
> +	for (i = 0; i < ffs->eps_count; i++)
> +		eps_ptr[i].num = -1;
>  
>  	/* Save pointers
>  	 * d_eps == vlabuf, func->eps used to kfree vlabuf later
> --
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> 

Re: [patch v2] usb: f_fs: off by one bug in _ffs_func_bind()

[Michal Nazarewicz]

On Sat, May 28 2016, Dan Carpenter wrote:
> This loop is supposed to set all the .num[] values to -1 but it's off by
> one so it skips the first element and sets one element past the end of
> the array.
>
> I've cleaned up the loop a little as well.
>
> Fixes: ddf8abd25994 ('USB: f_fs: the FunctionFS driver')
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Acked-by: Michal Nazarewicz <mina86@mina86.com>

> ---
> v2: move the eps_ptr assignment outside the loop.
>
> diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
> index 73515d5..d26eb64 100644
> --- a/drivers/usb/gadget/function/f_fs.c
> +++ b/drivers/usb/gadget/function/f_fs.c
> @@ -2729,6 +2729,7 @@ static int _ffs_func_bind(struct usb_configuration *c,
>  		func->ffs->ss_descs_count;
>  
>  	int fs_len, hs_len, ss_len, ret, i;
> +	struct ffs_ep *eps_ptr;
>  
>  	/* Make it a single chunk, less management later on */
>  	vla_group(d);
> @@ -2777,12 +2778,9 @@ static int _ffs_func_bind(struct usb_configuration *c,
>  	       ffs->raw_descs_length);
>  
>  	memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
> -	for (ret = ffs->eps_count; ret; --ret) {
> -		struct ffs_ep *ptr;
> -
> -		ptr = vla_ptr(vlabuf, d, eps);
> -		ptr[ret].num = -1;
> -	}
> +	eps_ptr = vla_ptr(vlabuf, d, eps);
> +	for (i = 0; i < ffs->eps_count; i++)
> +		eps_ptr[i].num = -1;
>  
>  	/* Save pointers
>  	 * d_eps == vlabuf, func->eps used to kfree vlabuf later

-- 
Best regards
ミハウ “𝓶𝓲𝓷𝓪86” ナザレヴイツ
«If at first you don’t succeed, give up skydiving»