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MDEV-33843: Server crashes by stack-overflow with UPDATEXML #5440

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MDEV-33843: Server crashes by stack-overflow with UPDATEXML #5440

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17 changes: 11 additions & 6 deletions mysql-test/main/xml.result
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Original file line number Diff line number Diff line change
Expand Up @@ -1320,13 +1320,10 @@ f
foo
<b></b>
#
# Start of 10.5 tests
#
# End of 10.5 tests
#
# Start of 10.6 tests
#
#
# MDEV-39210 ExtractValue/UpdateXML crash
# ExtractValue/UpdateXML crash
#
SELECT ExtractValue('<!a/><!b/>', '/a');
ExtractValue('<!a/><!b/>', '/a')
Expand Down Expand Up @@ -1421,4 +1418,12 @@ SELECT ExtractValue('<a/>', REPEAT('(', 100000));
ERROR HY000: Thread stack overrun: 'used bytes' used of a 'available' byte stack, and 'X' bytes needed. Consider increasing the thread_stack system variable.
SELECT ExtractValue('<a/>', REPEAT('/n', 100000));
ERROR HY000: Thread stack overrun: 'used bytes' used of a 'available' byte stack, and 'X' bytes needed. Consider increasing the thread_stack system variable.
# End of 10.6 tests
#
# Start of 10.6 tests
#
#
# MDEV-33843: Server crashes by stack-overflow with UPDATEXML
#
SELECT UPDATEXML(NULL, REPEAT('(', 100000), 1);
ERROR HY000: Thread stack overrun: 'used bytes' used of a 'available' byte stack, and 'X' bytes needed. Consider increasing the thread_stack system variable.
# End of 10.6 test
21 changes: 14 additions & 7 deletions mysql-test/main/xml.test
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Expand Up @@ -822,15 +822,11 @@ DROP TABLE t1;
SELECT 'foo' AS f UNION SELECT BINARY( UpdateXML('<a></a>', '/a', '<b></b>')) AS f;

--echo #
--echo # Start of 10.5 tests
--echo # End of 10.5 tests
--echo #

--echo #
--echo # Start of 10.6 tests
--echo #

--echo #
--echo # MDEV-39210 ExtractValue/UpdateXML crash
--echo # ExtractValue/UpdateXML crash
--echo #

#view protocol generates additional warning
Expand Down Expand Up @@ -911,5 +907,16 @@ SELECT ExtractValue('<a/>', REPEAT('(', 100000));
--error ER_STACK_OVERRUN_NEED_MORE
SELECT ExtractValue('<a/>', REPEAT('/n', 100000));

--echo # End of 10.6 tests
--echo #
--echo # Start of 10.6 tests
--echo #

--echo #
--echo # MDEV-33843: Server crashes by stack-overflow with UPDATEXML
--echo #

--replace_regex /overrun: [0-9]* bytes used of a [0-9]* byte stack, and [0-9]* bytes needed/overrun: 'used bytes' used of a 'available' byte stack, and 'X' bytes needed/
--error ER_STACK_OVERRUN_NEED_MORE
SELECT UPDATEXML(NULL, REPEAT('(', 100000), 1);

--echo # End of 10.6 test
13 changes: 12 additions & 1 deletion sql/item_xmlfunc.cc
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Expand Up @@ -25,7 +25,8 @@
#include "set_var.h"
#include "my_xml.h"
#include "sp_pcontext.h"
#include "sql_parse.h" // THD
#include "sql_class.h" // THD
#include "sql_parse.h" // for check_stack_overrun

/*
TODO: future development directions:
Expand Down Expand Up @@ -2210,9 +2211,19 @@ static int my_xpath_parse_FilterExpr(MY_XPATH *xpath)
RETURN
1 - success
0 - failure

Please note: There is non-standard returning here to
simplify processing in the parser.
*/
static int my_xpath_parse_OrExpr(MY_XPATH *xpath)
{
/*
Check for stack ovver run because it might call itself and
result in stack overflow. Return error if thats the case.
*/
if (check_stack_overrun(current_thd, STACK_MIN_SIZE , NULL))
return 0;

if (!my_xpath_parse_AndExpr(xpath))
return 0;

Expand Down