[PATCH] vboxsf: Replace all non-returning strlcpy with strscpy

[PATCH] vboxsf: Replace all non-returning strlcpy with strscpy

[Azeem Shaikh]

strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
---
 fs/vboxsf/super.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/vboxsf/super.c b/fs/vboxsf/super.c
index d2f6df69f611..1fb8f4df60cb 100644
--- a/fs/vboxsf/super.c
+++ b/fs/vboxsf/super.c
@@ -176,7 +176,7 @@ static int vboxsf_fill_super(struct super_block *sb, struct fs_context *fc)
 	}
 	folder_name->size = size;
 	folder_name->length = size - 1;
-	strlcpy(folder_name->string.utf8, fc->source, size);
+	strscpy(folder_name->string.utf8, fc->source, size);
 	err = vboxsf_map_folder(folder_name, &sbi->root);
 	kfree(folder_name);
 	if (err) {
-- 
2.40.1.521.gf1e218fcd8-goog

Re: [PATCH] vboxsf: Replace all non-returning strlcpy with strscpy

[Hans de Goede]

Hi,

On 5/10/23 23:11, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
> No return values were used, so direct replacement is safe.
> 
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> [2] https://github.com/KSPP/linux/issues/89
> 
> Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Regards,

Hans



> ---
>  fs/vboxsf/super.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/vboxsf/super.c b/fs/vboxsf/super.c
> index d2f6df69f611..1fb8f4df60cb 100644
> --- a/fs/vboxsf/super.c
> +++ b/fs/vboxsf/super.c
> @@ -176,7 +176,7 @@ static int vboxsf_fill_super(struct super_block *sb, struct fs_context *fc)
>  	}
>  	folder_name->size = size;
>  	folder_name->length = size - 1;
> -	strlcpy(folder_name->string.utf8, fc->source, size);
> +	strscpy(folder_name->string.utf8, fc->source, size);
>  	err = vboxsf_map_folder(folder_name, &sbi->root);
>  	kfree(folder_name);
>  	if (err) {

Re: [PATCH] vboxsf: Replace all non-returning strlcpy with strscpy

[Kees Cook]

On Wed, May 10, 2023 at 09:11:46PM +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
> No return values were used, so direct replacement is safe.
> 
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> [2] https://github.com/KSPP/linux/issues/89
> 
> Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>

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

-- 
Kees Cook

Re: [PATCH] vboxsf: Replace all non-returning strlcpy with strscpy

[Kees Cook]

On Wed, 10 May 2023 21:11:46 +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
> No return values were used, so direct replacement is safe.
> 
> [...]

Applied to for-next/hardening, thanks!

[1/1] vboxsf: Replace all non-returning strlcpy with strscpy
      https://git.kernel.org/kees/c/883f8fe87686

-- 
Kees Cook