From 6503226743a2fa24c7330d4541560a5b8fa821d6 Mon Sep 17 00:00:00 2001 From: Magne Mahre Date: Thu, 17 Feb 2011 12:43:53 +0100 Subject: Bug#48053 String::c_ptr has a race and/or does an invalid memory reference There are two issues present here. 1) There is a possibility that we test a byte beyond the allocated buffer 2) We compare a byte that might never have been initalized to see if it's 0. The first issue is not triggered by existing code, but an ASSERT has been added to safe-guard against introducing new code that triggers it. The second issue is what triggers the Valgrind warnings reported in the bug report. A buffer is allocated in class String to hold the value. This buffer is populated by the character data constituting the string, but is not zero-terminated in most cases. Testing if it is indeed zero-terminated means that we check a byte that has never been explicitly set, thus causing Valgrind to trigger. Note that issue 2 is not a serious problem. The variable is read, and if it's not zero, we will set it to zero. There are no further consequences. Note that this patch does not fix the underlying problems with issue 1, as it is deemed too risky to fix at this point (as noted in the bug report). As discussed in the report, the c_ptr() method should probably be replaced, but this requires a thorough analysis of the ~200 calls to the method. sql/set_var.cc: These two cases have been reported to fail with Valgrind. --- mysql-test/r/ctype_cp1251.result | 2 ++ 1 file changed, 2 insertions(+) (limited to 'mysql-test/r/ctype_cp1251.result') diff --git a/mysql-test/r/ctype_cp1251.result b/mysql-test/r/ctype_cp1251.result index dc12f9ceb03..2e91ecb7bc0 100644 --- a/mysql-test/r/ctype_cp1251.result +++ b/mysql-test/r/ctype_cp1251.result @@ -375,6 +375,8 @@ FD FD FD D18D FD FE FE FE D18E FE FF FF FF D18F FF DROP TABLE t1; +set global LC_TIME_NAMES=convert((-8388608) using cp1251); +ERROR HY000: Unknown locale: '-8388608' # # End of 5.1 tests # -- cgit v1.2.1