[v9] Rust support

[PATCH v9 01/27] kallsyms: use `sizeof` instead of hardcoded size

Posted by Miguel Ojeda 3 years, 8 months ago

From: Boqun Feng <boqun.feng@gmail.com>

This removes one place where the `500` constant is hardcoded.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Co-developed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 scripts/kallsyms.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index f18e6dfc68c5..52f5488c61bc 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -206,7 +206,7 @@ static struct sym_entry *read_symbol(FILE *in)
 
 	rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name);
 	if (rc != 3) {
-		if (rc != EOF && fgets(name, 500, in) == NULL)
+		if (rc != EOF && fgets(name, sizeof(name), in) == NULL)
 			fprintf(stderr, "Read error or end of file.\n");
 		return NULL;
 	}
-- 
2.37.1

Re: [PATCH v9 01/27] kallsyms: use `sizeof` instead of hardcoded size

Posted by Konstantin Shelekhin 3 years, 8 months ago

> diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
> index f18e6dfc68c5..52f5488c61bc 100644
> --- a/scripts/kallsyms.c
> +++ b/scripts/kallsyms.c
> @@ -206,7 +206,7 @@ static struct sym_entry *read_symbol(FILE *in)
>  
>  	rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name);
>  	if (rc != 3) {
> -		if (rc != EOF && fgets(name, 500, in) == NULL)
> +		if (rc != EOF && fgets(name, sizeof(name), in) == NULL)
>  			fprintf(stderr, "Read error or end of file.\n");
>  		return NULL;
>  	}

Might be another nit, but IMO it's better to use ARRAY_SIZE() here.

Re: [PATCH v9 01/27] kallsyms: use `sizeof` instead of hardcoded size

Posted by Kees Cook 3 years, 7 months ago

On Sat, Aug 06, 2022 at 01:40:33AM +0300, Konstantin Shelekhin wrote:
> > diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
> > index f18e6dfc68c5..52f5488c61bc 100644
> > --- a/scripts/kallsyms.c
> > +++ b/scripts/kallsyms.c
> > @@ -206,7 +206,7 @@ static struct sym_entry *read_symbol(FILE *in)
> >  
> >  	rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name);
> >  	if (rc != 3) {
> > -		if (rc != EOF && fgets(name, 500, in) == NULL)
> > +		if (rc != EOF && fgets(name, sizeof(name), in) == NULL)
> >  			fprintf(stderr, "Read error or end of file.\n");
> >  		return NULL;
> >  	}
> 
> Might be another nit, but IMO it's better to use ARRAY_SIZE() here.

I'm not sure I see a benefit for char arrays. It'll produce the same
result, and the tradition for string functions is to use sizeof().
*shrug*

Either way:

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

Re: [PATCH v9 01/27] kallsyms: use `sizeof` instead of hardcoded size

Posted by Konstantin Shelekhin 3 years, 7 months ago

On Wed, Aug 17, 2022 at 12:36:33PM -0700, Kees Cook wrote:
> On Sat, Aug 06, 2022 at 01:40:33AM +0300, Konstantin Shelekhin wrote:
> > > diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
> > > index f18e6dfc68c5..52f5488c61bc 100644
> > > --- a/scripts/kallsyms.c
> > > +++ b/scripts/kallsyms.c
> > > @@ -206,7 +206,7 @@ static struct sym_entry *read_symbol(FILE *in)
> > >
> > >     rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name);
> > >     if (rc != 3) {
> > > -           if (rc != EOF && fgets(name, 500, in) == NULL)
> > > +           if (rc != EOF && fgets(name, sizeof(name), in) == NULL)
> > >                     fprintf(stderr, "Read error or end of file.\n");
> > >             return NULL;
> > >     }
> >
> > Might be another nit, but IMO it's better to use ARRAY_SIZE() here.
> 
> I'm not sure I see a benefit for char arrays. It'll produce the same
> result, and the tradition for string functions is to use sizeof().
> *shrug*

ARRAY_SIZE() (though not this one) can catch this:

  - char array[16];
  + char *array;

Saves me some.

Re: [PATCH v9 01/27] kallsyms: use `sizeof` instead of hardcoded size

Posted by Kees Cook 3 years, 7 months ago

On Thu, Aug 18, 2022 at 12:03:37PM +0300, Konstantin Shelekhin wrote:
> On Wed, Aug 17, 2022 at 12:36:33PM -0700, Kees Cook wrote:
> > On Sat, Aug 06, 2022 at 01:40:33AM +0300, Konstantin Shelekhin wrote:
> > > > diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
> > > > index f18e6dfc68c5..52f5488c61bc 100644
> > > > --- a/scripts/kallsyms.c
> > > > +++ b/scripts/kallsyms.c
> > > > @@ -206,7 +206,7 @@ static struct sym_entry *read_symbol(FILE *in)
> > > >
> > > >     rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name);
> > > >     if (rc != 3) {
> > > > -           if (rc != EOF && fgets(name, 500, in) == NULL)
> > > > +           if (rc != EOF && fgets(name, sizeof(name), in) == NULL)
> > > >                     fprintf(stderr, "Read error or end of file.\n");
> > > >             return NULL;
> > > >     }
> > >
> > > Might be another nit, but IMO it's better to use ARRAY_SIZE() here.
> > 
> > I'm not sure I see a benefit for char arrays. It'll produce the same
> > result, and the tradition for string functions is to use sizeof().
> > *shrug*
> 
> ARRAY_SIZE() (though not this one) can catch this:
> 
>   - char array[16];
>   + char *array;
> 
> Saves me some.

Oh, that's an excellent point; I forgot it'll actually compile-time
error if the var is a pointer. +1

-- 
Kees Cook

Re: [PATCH v9 01/27] kallsyms: use `sizeof` instead of hardcoded size

Posted by Miguel Ojeda 3 years, 6 months ago

On Thu, Aug 18, 2022 at 6:03 PM Kees Cook <keescook@chromium.org> wrote:
>
> Oh, that's an excellent point; I forgot it'll actually compile-time
> error if the var is a pointer. +1

In this case it doesn't, because `scripts/kallsyms.c` defines its own
`ARRAY_SIZE` that doesn't have the `__must_be_array`.

I have changed it for v10 anyway, since that way we may benefit in the
future if the `ARRAY_SIZE` here gains the check.

Cheers,
Miguel

Re: [PATCH v9 01/27] kallsyms: use `sizeof` instead of hardcoded size

Posted by Geert Stappers 3 years, 8 months ago

On Fri, Aug 05, 2022 at 05:41:46PM +0200, Miguel Ojeda wrote:
> From: Boqun Feng <boqun.feng@gmail.com>
> 
> This removes one place where the `500` constant is hardcoded.
> 
> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> Co-developed-by: Miguel Ojeda <ojeda@kernel.org>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
>  scripts/kallsyms.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
> index f18e6dfc68c5..52f5488c61bc 100644
> --- a/scripts/kallsyms.c
> +++ b/scripts/kallsyms.c
> @@ -206,7 +206,7 @@ static struct sym_entry *read_symbol(FILE *in)
>  
>  	rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name);
>  	if (rc != 3) {
> -		if (rc != EOF && fgets(name, 500, in) == NULL)
> +		if (rc != EOF && fgets(name, sizeof(name), in) == NULL)
>  			fprintf(stderr, "Read error or end of file.\n");
>  		return NULL;
>  	}
> -- 
> 2.37.1
> 


Signed-off-by: Geert Stappers <stappers@stappers.nl>


And I think that this patch and all other "rust" kallsyms patches
allready should have been accepted in the v3 or v5 series.





Regards
Geert Stappers
-- 
Silence is hard to parse

Re: [PATCH v9 01/27] kallsyms: use `sizeof` instead of hardcoded size

Posted by Miguel Ojeda 3 years, 8 months ago

On Fri, Aug 5, 2022 at 6:48 PM Geert Stappers <stappers@stappers.nl> wrote:
>
> Signed-off-by: Geert Stappers <stappers@stappers.nl>

Thanks for the message and the support, but please note that since you
are not in the path of the patch, you cannot use this tag; instead
look into Reviewed-by etc. See
https://www.kernel.org/doc/html/v5.19/process/submitting-patches.html#when-to-use-acked-by-cc-and-co-developed-by
and the following section for details.

> And I think that this patch and all other "rust" kallsyms patches
> allready should have been accepted in the v3 or v5 series.

Yeah, it could be a good idea to get the prerequisites in first. Let's
see if the patches get some Reviewed-bys (e.g. I had to remove Kees'
one because I had to split the patch).

Cheers,
Miguel