diff mbox series

[05/20] Fix invalid pointer dereference in wcscpy_chk

Message ID 8a778b8eecc1ad9d782884291965864ea5c20ef7.1666877952.git.szabolcs.nagy@arm.com
State Committed
Commit e5ece9de1417ac33c755226f3dd962fc2c7d97aa
Headers
Series patches from the morello port |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent

Commit Message

Szabolcs Nagy Oct. 27, 2022, 3:32 p.m. UTC 
  The src pointer is const and points to a different object, so accessing
dest via src is invalid.
---
 debug/wcscpy_chk.c | 34 +++++++---------------------------
 1 file changed, 7 insertions(+), 27 deletions(-)

Comments

Florian Weimer Oct. 28, 2022, 5:34 a.m. UTC | #1 
* Szabolcs Nagy via Libc-alpha:

> The src pointer is const and points to a different object, so accessing
> dest via src is invalid.
> ---
>  debug/wcscpy_chk.c | 34 +++++++---------------------------
>  1 file changed, 7 insertions(+), 27 deletions(-)
>
> diff --git a/debug/wcscpy_chk.c b/debug/wcscpy_chk.c
> index 8ef03f81e4..d2dc769181 100644
> --- a/debug/wcscpy_chk.c
> +++ b/debug/wcscpy_chk.c
> @@ -24,36 +24,16 @@ wchar_t *
>  __wcscpy_chk (wchar_t *dest, const wchar_t *src, size_t n)
>  {
>    wint_t c;
> +  wchar_t *wcp = dest;
>  
> +  do
>      {
> +      if (__glibc_unlikely (n-- == 0))
> +        __chk_fail ();
> +      c = *src++;
> +      *wcp++ = c;
>      }
> +  while (c != L'\0');
>  
>    return dest;
>  }

Seems fine.

Reviewed-by: Florian Weimer <fweimer@redhat.com>

Thanks,
Florian
diff mbox series

Patch

diff --git a/debug/wcscpy_chk.c b/debug/wcscpy_chk.c
index 8ef03f81e4..d2dc769181 100644
--- a/debug/wcscpy_chk.c
+++ b/debug/wcscpy_chk.c
@@ -24,36 +24,16 @@  wchar_t *
 __wcscpy_chk (wchar_t *dest, const wchar_t *src, size_t n)
 {
   wint_t c;
-  wchar_t *wcp;
+  wchar_t *wcp = dest;
 
-  if (__alignof__ (wchar_t) >= sizeof (wchar_t))
+  do
     {
-      const ptrdiff_t off = dest - src - 1;
-
-      wcp = (wchar_t *) src;
-
-      do
-	{
-	  if (__glibc_unlikely (n-- == 0))
-	    __chk_fail ();
-	  c = *wcp++;
-	  wcp[off] = c;
-	}
-      while (c != L'\0');
-    }
-  else
-    {
-      wcp = dest;
-
-      do
-	{
-	  if (__glibc_unlikely (n-- == 0))
-	    __chk_fail ();
-	  c = *src++;
-	  *wcp++ = c;
-	}
-      while (c != L'\0');
+      if (__glibc_unlikely (n-- == 0))
+        __chk_fail ();
+      c = *src++;
+      *wcp++ = c;
     }
+  while (c != L'\0');
 
   return dest;
 }