[edk2-libc Patch] StdLib/LibC: Fix corner case in use of StrnCpyS() and AsciiStrnCpyS()

[edk2-libc Patch] StdLib/LibC: Fix corner case in use of StrnCpyS() and AsciiStrnCpyS()

[Michael D Kinney]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3361

DestMax must be > Length or StrnCpyS() and AsciiStrnCpyS()
return an error.  Set DestMax to n + 1 for these LibC APIs.

Cc: Rebecca Cran <rebecca@nuviainc.com>
Cc: Jayaprakash Nevara <n.jayaprakash@intel.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
---
 StdLib/LibC/String/Copying.c | 2 +-
 StdLib/LibC/Wchar/Copying.c  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/StdLib/LibC/String/Copying.c b/StdLib/LibC/String/Copying.c
index c296714..a50331b 100644
--- a/StdLib/LibC/String/Copying.c
+++ b/StdLib/LibC/String/Copying.c
@@ -90,7 +90,7 @@ strcpy(char * __restrict s1, const char * __restrict s2)
 **/
 char     *strncpy(char * __restrict s1, const char * __restrict s2, size_t n)
 {
-  AsciiStrnCpyS (s1, n, s2, n);
+  AsciiStrnCpyS (s1, n + 1, s2, n);
   return s1;
   //char *dest = s1;
 
diff --git a/StdLib/LibC/Wchar/Copying.c b/StdLib/LibC/Wchar/Copying.c
index 45ceda7..d5a1149 100644
--- a/StdLib/LibC/Wchar/Copying.c
+++ b/StdLib/LibC/Wchar/Copying.c
@@ -44,7 +44,7 @@ wchar_t *wcscpy(wchar_t * __restrict s1, const wchar_t * __restrict s2)
 **/
 wchar_t *wcsncpy(wchar_t * __restrict s1, const wchar_t * __restrict s2, size_t n)
 {
-  return (wchar_t *)StrnCpyS ((CHAR16 *)s1, (UINTN)n, (CONST CHAR16 *)s2, (UINTN)n);
+  return (wchar_t *)StrnCpyS ((CHAR16 *)s1, (UINTN)n + 1, (CONST CHAR16 *)s2, (UINTN)n);
 }
 
 /** The wmemcpy function copies n wide characters from the object pointed to by
-- 
2.32.0.windows.1

Re: [edk2-libc Patch] StdLib/LibC: Fix corner case in use of StrnCpyS() and AsciiStrnCpyS()

[Rebecca Cran]

Reviewed-by: Rebecca Cran <rebecca@nuviainc.com>


-- 

Rebecca Cran


On 9/1/21 1:18 AM, Michael D Kinney wrote:
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3361
>
> DestMax must be > Length or StrnCpyS() and AsciiStrnCpyS()
> return an error.  Set DestMax to n + 1 for these LibC APIs.
>
> Cc: Rebecca Cran <rebecca@nuviainc.com>
> Cc: Jayaprakash Nevara <n.jayaprakash@intel.com>
> Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
> ---
>   StdLib/LibC/String/Copying.c | 2 +-
>   StdLib/LibC/Wchar/Copying.c  | 2 +-
>   2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/StdLib/LibC/String/Copying.c b/StdLib/LibC/String/Copying.c
> index c296714..a50331b 100644
> --- a/StdLib/LibC/String/Copying.c
> +++ b/StdLib/LibC/String/Copying.c
> @@ -90,7 +90,7 @@ strcpy(char * __restrict s1, const char * __restrict s2)
>   **/
>   char     *strncpy(char * __restrict s1, const char * __restrict s2, size_t n)
>   {
> -  AsciiStrnCpyS (s1, n, s2, n);
> +  AsciiStrnCpyS (s1, n + 1, s2, n);
>     return s1;
>     //char *dest = s1;
>   
> diff --git a/StdLib/LibC/Wchar/Copying.c b/StdLib/LibC/Wchar/Copying.c
> index 45ceda7..d5a1149 100644
> --- a/StdLib/LibC/Wchar/Copying.c
> +++ b/StdLib/LibC/Wchar/Copying.c
> @@ -44,7 +44,7 @@ wchar_t *wcscpy(wchar_t * __restrict s1, const wchar_t * __restrict s2)
>   **/
>   wchar_t *wcsncpy(wchar_t * __restrict s1, const wchar_t * __restrict s2, size_t n)
>   {
> -  return (wchar_t *)StrnCpyS ((CHAR16 *)s1, (UINTN)n, (CONST CHAR16 *)s2, (UINTN)n);
> +  return (wchar_t *)StrnCpyS ((CHAR16 *)s1, (UINTN)n + 1, (CONST CHAR16 *)s2, (UINTN)n);
>   }
>   
>   /** The wmemcpy function copies n wide characters from the object pointed to by