Kernel/libc - Fixed memory clobbering when vsnprintf output is bigger than buffer

diff --git a/KernelLand/Kernel/libc.c b/KernelLand/Kernel/libc.c
index b0c083b..2950782 100644 (file)
--- a/KernelLand/Kernel/libc.c
+++ b/KernelLand/Kernel/libc.c
@@ -187,8 +187,8 @@ void itoa(char *buf, Uint64 num, int base, int minLength, char pad)
  * \brief Append a character the the vsnprintf output
  */
 #define PUTCH(ch)      do { \
-               if(pos < __maxlen) { \
-                       if(__s) __s[pos] = ch; \
+               if(pos < __maxlen && __s) { \
+                       __s[pos] = ch; \
                } else { \
                        (void)ch;\
                } \
@@ -201,7 +201,7 @@ void itoa(char *buf, Uint64 num, int base, int minLength, char pad)
 /**
  * \brief VArg String Number Print Formatted
  */
-int vsnprintf(char *__s, size_t __maxlen, const char *__format, va_list args)
+int vsnprintf(char *__s, const size_t __maxlen, const char *__format, va_list args)
 {
        char    c, pad = ' ';
         int    minSize = 0, precision = -1, len;
@@ -404,7 +404,7 @@ int vsnprintf(char *__s, size_t __maxlen, const char *__format, va_list args)
                }
        }
        
-       if(__s && pos != __maxlen)
+       if(__s && pos < __maxlen)
                __s[pos] = '\0';
        
        return pos;