mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-08-27 22:57:30 +02:00
Reduce an unnecessary O(N^3) loop in lexer.
The lexer's handling of operators contained an O(N^3) hazard when dealing with long strings of + or - characters; it seems hard to prevent this case from being O(N^2), but the additional N multiplier was not needed. Backpatch all the way since this has been there since 7.x, and it presents at least a mild hazard in that trying to do Bind, PREPARE or EXPLAIN on a hostile query could take excessive time (without honouring cancels or timeouts) even if the query was never executed.
This commit is contained in:
parent
90b0f30aea
commit
4854ead60a
@ -881,20 +881,33 @@ other .
|
||||
* to forbid operator names like '?-' that could not be
|
||||
* sequences of SQL operators.
|
||||
*/
|
||||
while (nchars > 1 &&
|
||||
(yytext[nchars - 1] == '+' ||
|
||||
yytext[nchars - 1] == '-'))
|
||||
if (nchars > 1 &&
|
||||
(yytext[nchars - 1] == '+' ||
|
||||
yytext[nchars - 1] == '-'))
|
||||
{
|
||||
int ic;
|
||||
|
||||
for (ic = nchars - 2; ic >= 0; ic--)
|
||||
{
|
||||
if (strchr("~!@#^&|`?%", yytext[ic]))
|
||||
char c = yytext[ic];
|
||||
if (c == '~' || c == '!' || c == '@' ||
|
||||
c == '#' || c == '^' || c == '&' ||
|
||||
c == '|' || c == '`' || c == '?' ||
|
||||
c == '%')
|
||||
break;
|
||||
}
|
||||
if (ic >= 0)
|
||||
break; /* found a char that makes it OK */
|
||||
nchars--; /* else remove the +/-, and check again */
|
||||
if (ic < 0)
|
||||
{
|
||||
/*
|
||||
* didn't find a qualifying character, so remove
|
||||
* all trailing [+-]
|
||||
*/
|
||||
do {
|
||||
nchars--;
|
||||
} while (nchars > 1 &&
|
||||
(yytext[nchars - 1] == '+' ||
|
||||
yytext[nchars - 1] == '-'));
|
||||
}
|
||||
}
|
||||
|
||||
SET_YYLLOC();
|
||||
|
@ -798,20 +798,33 @@ other .
|
||||
* to forbid operator names like '?-' that could not be
|
||||
* sequences of SQL operators.
|
||||
*/
|
||||
while (nchars > 1 &&
|
||||
(yytext[nchars - 1] == '+' ||
|
||||
yytext[nchars - 1] == '-'))
|
||||
if (nchars > 1 &&
|
||||
(yytext[nchars - 1] == '+' ||
|
||||
yytext[nchars - 1] == '-'))
|
||||
{
|
||||
int ic;
|
||||
|
||||
for (ic = nchars - 2; ic >= 0; ic--)
|
||||
{
|
||||
if (strchr("~!@#^&|`?%", yytext[ic]))
|
||||
char c = yytext[ic];
|
||||
if (c == '~' || c == '!' || c == '@' ||
|
||||
c == '#' || c == '^' || c == '&' ||
|
||||
c == '|' || c == '`' || c == '?' ||
|
||||
c == '%')
|
||||
break;
|
||||
}
|
||||
if (ic >= 0)
|
||||
break; /* found a char that makes it OK */
|
||||
nchars--; /* else remove the +/-, and check again */
|
||||
if (ic < 0)
|
||||
{
|
||||
/*
|
||||
* didn't find a qualifying character, so remove
|
||||
* all trailing [+-]
|
||||
*/
|
||||
do {
|
||||
nchars--;
|
||||
} while (nchars > 1 &&
|
||||
(yytext[nchars - 1] == '+' ||
|
||||
yytext[nchars - 1] == '-'));
|
||||
}
|
||||
}
|
||||
|
||||
if (nchars < yyleng)
|
||||
|
@ -687,20 +687,33 @@ cppline {space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})((\/\*[^*/]*\*+
|
||||
* to forbid operator names like '?-' that could not be
|
||||
* sequences of SQL operators.
|
||||
*/
|
||||
while (nchars > 1 &&
|
||||
(yytext[nchars-1] == '+' ||
|
||||
yytext[nchars-1] == '-'))
|
||||
if (nchars > 1 &&
|
||||
(yytext[nchars - 1] == '+' ||
|
||||
yytext[nchars - 1] == '-'))
|
||||
{
|
||||
int ic;
|
||||
|
||||
for (ic = nchars-2; ic >= 0; ic--)
|
||||
for (ic = nchars - 2; ic >= 0; ic--)
|
||||
{
|
||||
if (strchr("~!@#^&|`?%", yytext[ic]))
|
||||
char c = yytext[ic];
|
||||
if (c == '~' || c == '!' || c == '@' ||
|
||||
c == '#' || c == '^' || c == '&' ||
|
||||
c == '|' || c == '`' || c == '?' ||
|
||||
c == '%')
|
||||
break;
|
||||
}
|
||||
if (ic >= 0)
|
||||
break; /* found a char that makes it OK */
|
||||
nchars--; /* else remove the +/-, and check again */
|
||||
if (ic < 0)
|
||||
{
|
||||
/*
|
||||
* didn't find a qualifying character, so remove
|
||||
* all trailing [+-]
|
||||
*/
|
||||
do {
|
||||
nchars--;
|
||||
} while (nchars > 1 &&
|
||||
(yytext[nchars - 1] == '+' ||
|
||||
yytext[nchars - 1] == '-'));
|
||||
}
|
||||
}
|
||||
|
||||
if (nchars < yyleng)
|
||||
|
Loading…
Reference in New Issue
Block a user