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Fix for bug #41868: crash or memory overrun with concat + upper, date_format

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functions
      
String::realloc() did not check whether the existing string data fits in the newly
allocated buffer for cases when reallocating a String object with external buffer
(i.e.alloced == FALSE).  This could lead to memory overruns in some cases.


mysql-test/r/func_str.result:
  Added a test case for bug #41868.
mysql-test/t/func_str.test:
  Added a test case for bug #41868.
sql/sql_class.cc:
  After each call to Item::send() in select_send::send_data() reset buffer to its
  original state to reduce unnecessary malloc() calls. See comments for bug #41868
  for detailed analysis.
sql/sql_string.cc:
  Fixed String::realloc() to check whether the existing string data fits in the newly allocated buffer for cases when reallocating a String object with external buffer.
This commit is contained in:
Alexey Kopytov
2009-02-03 20:19:01 +03:00
parent ecfdc3560c
commit dfbba6e7fd
5 changed files with 40 additions and 20 deletions
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20
client/sql_string.cc
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@ -72,26 +72,26 @@ bool String::realloc(uint32 alloc_length)
if (alloced)
{
if ((new_ptr= (char*) my_realloc(Ptr,len,MYF(MY_WME))))
{
Ptr=new_ptr;
Alloced_length=len;
}
new_ptr[alloc_length]= 0;
else
return TRUE; // Signal error
return TRUE; // Signal error
}
else if ((new_ptr= (char*) my_malloc(len,MYF(MY_WME))))
{
if (str_length > len - 1)
str_length= 0;
if (str_length) // Avoid bugs in memcpy on AIX
memcpy(new_ptr,Ptr,str_length);
new_ptr[str_length]=0;
Ptr=new_ptr;
Alloced_length=len;
memcpy(new_ptr, Ptr, str_length);
new_ptr[str_length]= 0;
alloced=1;
}
else
return TRUE; // Signal error
Ptr= new_ptr;
Alloced_length= len;
}
Ptr[alloc_length]=0; // This make other funcs shorter
else
Ptr[alloc_length]= 0;
return FALSE;
}