[PATCH 0/2] string: Add stracpy and stracpy_pad

[PATCH 0/2] string: Add stracpy and stracpy_pad

[Joe Perches]

Add more string copy mechanisms to help avoid defects

Joe Perches (2):
  string: Add stracpy and stracpy_pad mechanisms
  kernel-doc: core-api: Include string.h into core-api

 Documentation/core-api/kernel-api.rst |  3 +++
 include/linux/string.h                | 46 +++++++++++++++++++++++++++++++++--
 lib/string.c                          | 10 +++++---
 3 files changed, 53 insertions(+), 6 deletions(-)

-- 
2.15.0

[PATCH 2/2] kernel-doc: core-api: Include string.h into core-api

[Joe Perches]

core-api should show all the various string functions including the
newly added stracpy and stracpy_pad.

Miscellanea:

o Update the Returns: value for strscpy
o fix a defect with %NUL)

Signed-off-by: Joe Perches <joe@perches.com>
---
 Documentation/core-api/kernel-api.rst |  3 +++
 include/linux/string.h                |  5 +++--
 lib/string.c                          | 10 ++++++----
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/Documentation/core-api/kernel-api.rst b/Documentation/core-api/kernel-api.rst
index 08af5caf036d..f77de49b1d51 100644
--- a/Documentation/core-api/kernel-api.rst
+++ b/Documentation/core-api/kernel-api.rst
@@ -42,6 +42,9 @@ String Manipulation
 .. kernel-doc:: lib/string.c
    :export:
 
+.. kernel-doc:: include/linux/string.h
+   :internal:
+
 .. kernel-doc:: mm/util.c
    :functions: kstrdup kstrdup_const kstrndup kmemdup kmemdup_nul memdup_user
                vmemdup_user strndup_user memdup_user_nul
diff --git a/include/linux/string.h b/include/linux/string.h
index f80b0973f0e5..329188fffc11 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -515,8 +515,9 @@ static inline void memcpy_and_pad(void *dest, size_t dest_len,
  * But this can lead to bugs due to typos, or if prefix is a pointer
  * and not a constant. Instead use str_has_prefix().
  *
- * Returns: 0 if @str does not start with @prefix
-         strlen(@prefix) if @str does start with @prefix
+ * Returns:
+ * * strlen(@prefix) if @str starts with @prefix
+ * * 0 if @str does not start with @prefix
  */
 static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
 {
diff --git a/lib/string.c b/lib/string.c
index 461fb620f85f..53582b6dce2a 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -173,8 +173,9 @@ EXPORT_SYMBOL(strlcpy);
  * doesn't unnecessarily force the tail of the destination buffer to be
  * zeroed.  If zeroing is desired please use strscpy_pad().
  *
- * Return: The number of characters copied (not including the trailing
- *         %NUL) or -E2BIG if the destination buffer wasn't big enough.
+ * Returns:
+ * * The number of characters copied (not including the trailing %NUL)
+ * * -E2BIG if count is 0.
  */
 ssize_t strscpy(char *dest, const char *src, size_t count)
 {
@@ -253,8 +254,9 @@ EXPORT_SYMBOL(strscpy);
  * For full explanation of why you may want to consider using the
  * 'strscpy' functions please see the function docstring for strscpy().
  *
- * Return: The number of characters copied (not including the trailing
- *         %NUL) or -E2BIG if the destination buffer wasn't big enough.
+ * Returns:
+ * * The number of characters copied (not including the trailing %NUL)
+ * * -E2BIG if count is 0.
  */
 ssize_t strscpy_pad(char *dest, const char *src, size_t count)
 {
-- 
2.15.0

Re: [PATCH 2/2] kernel-doc: core-api: Include string.h into core-api

[Kees Cook]

On Mon, Jul 22, 2019 at 05:38:16PM -0700, Joe Perches wrote:
> core-api should show all the various string functions including the
> newly added stracpy and stracpy_pad.
> 
> Miscellanea:
> 
> o Update the Returns: value for strscpy
> o fix a defect with %NUL)
> 
> Signed-off-by: Joe Perches <joe@perches.com>

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

-Kees

> ---
>  Documentation/core-api/kernel-api.rst |  3 +++
>  include/linux/string.h                |  5 +++--
>  lib/string.c                          | 10 ++++++----
>  3 files changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/Documentation/core-api/kernel-api.rst b/Documentation/core-api/kernel-api.rst
> index 08af5caf036d..f77de49b1d51 100644
> --- a/Documentation/core-api/kernel-api.rst
> +++ b/Documentation/core-api/kernel-api.rst
> @@ -42,6 +42,9 @@ String Manipulation
>  .. kernel-doc:: lib/string.c
>     :export:
>  
> +.. kernel-doc:: include/linux/string.h
> +   :internal:
> +
>  .. kernel-doc:: mm/util.c
>     :functions: kstrdup kstrdup_const kstrndup kmemdup kmemdup_nul memdup_user
>                 vmemdup_user strndup_user memdup_user_nul
> diff --git a/include/linux/string.h b/include/linux/string.h
> index f80b0973f0e5..329188fffc11 100644
> --- a/include/linux/string.h
> +++ b/include/linux/string.h
> @@ -515,8 +515,9 @@ static inline void memcpy_and_pad(void *dest, size_t dest_len,
>   * But this can lead to bugs due to typos, or if prefix is a pointer
>   * and not a constant. Instead use str_has_prefix().
>   *
> - * Returns: 0 if @str does not start with @prefix
> -         strlen(@prefix) if @str does start with @prefix
> + * Returns:
> + * * strlen(@prefix) if @str starts with @prefix
> + * * 0 if @str does not start with @prefix
>   */
>  static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
>  {
> diff --git a/lib/string.c b/lib/string.c
> index 461fb620f85f..53582b6dce2a 100644
> --- a/lib/string.c
> +++ b/lib/string.c
> @@ -173,8 +173,9 @@ EXPORT_SYMBOL(strlcpy);
>   * doesn't unnecessarily force the tail of the destination buffer to be
>   * zeroed.  If zeroing is desired please use strscpy_pad().
>   *
> - * Return: The number of characters copied (not including the trailing
> - *         %NUL) or -E2BIG if the destination buffer wasn't big enough.
> + * Returns:
> + * * The number of characters copied (not including the trailing %NUL)
> + * * -E2BIG if count is 0.
>   */
>  ssize_t strscpy(char *dest, const char *src, size_t count)
>  {
> @@ -253,8 +254,9 @@ EXPORT_SYMBOL(strscpy);
>   * For full explanation of why you may want to consider using the
>   * 'strscpy' functions please see the function docstring for strscpy().
>   *
> - * Return: The number of characters copied (not including the trailing
> - *         %NUL) or -E2BIG if the destination buffer wasn't big enough.
> + * Returns:
> + * * The number of characters copied (not including the trailing %NUL)
> + * * -E2BIG if count is 0.
>   */
>  ssize_t strscpy_pad(char *dest, const char *src, size_t count)
>  {
> -- 
> 2.15.0
> 

-- 
Kees Cook