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

[PATCH] dlm: 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/dlm/config.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/dlm/config.c b/fs/dlm/config.c
index d31319d08581..2beceff024e3 100644
--- a/fs/dlm/config.c
+++ b/fs/dlm/config.c
@@ -116,9 +116,9 @@ static ssize_t cluster_cluster_name_store(struct config_item *item,
 {
 	struct dlm_cluster *cl = config_item_to_cluster(item);
 
-	strlcpy(dlm_config.ci_cluster_name, buf,
+	strscpy(dlm_config.ci_cluster_name, buf,
 				sizeof(dlm_config.ci_cluster_name));
-	strlcpy(cl->cl_cluster_name, buf, sizeof(cl->cl_cluster_name));
+	strscpy(cl->cl_cluster_name, buf, sizeof(cl->cl_cluster_name));
 	return len;
 }
 

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

[Kees Cook]

On Wed, May 10, 2023 at 10:12:37PM +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] dlm: Replace all non-returning strlcpy with strscpy

[Azeem Shaikh]

On Thu, May 11, 2023 at 12:26 PM Kees Cook <keescook@chromium.org> wrote:
>
> On Wed, May 10, 2023 at 10:12:37PM +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

Friendly ping on this.

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

[Kees Cook]

On Wed, 10 May 2023 22:12:37 +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] dlm: Replace all non-returning strlcpy with strscpy
      https://git.kernel.org/kees/c/30ad0627f169

-- 
Kees Cook