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Fix parsing of POSIX bracket expressions.

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The docs are misleading. [[:alpha:]] is actually a character class
*containing* a POSIX bracket expression, and that means you can have
expressions like [[:alpha:][:digit:]_?!]
This commit is contained in:
Nick Rolfe
2021-07-28 15:02:13 +01:00
parent 5d336d8e1d
commit 3abe047cac
3 changed files with 220 additions and 110 deletions
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33
ql/src/codeql_ruby/regexp/ParseRegExp.qll
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@@ -205,26 +205,24 @@ class RegExp extends AST::RegExpLiteral {
this.namedCharacterProperty(start, end, result)
}
/** Matches a POSIX bracket expression such as `[[:alnum:]]` */
/** Matches a POSIX bracket expression such as `[:alnum:]` within a character class. */
private predicate posixStyleNamedCharacterProperty(int start, int end, string name) {
this.getChar(start) = "[" and
this.getChar(start + 1) = "[" and
this.getChar(start + 2) = ":" and
this.getChar(start + 1) = ":" and
end =
min(int e |
e > start and
this.getChar(e - 3) = ":" and
this.getChar(e - 2) = "]" and
this.getChar(e - 2) = ":" and
this.getChar(e - 1) = "]"
|
e
) and
exists(int nameStart |
this.getChar(start + 3) = "^" and nameStart = start + 4
this.getChar(start + 2) = "^" and nameStart = start + 3
or
not this.getChar(start + 3) = "^" and nameStart = start + 3
not this.getChar(start + 2) = "^" and nameStart = start + 2
|
name = this.getText().substring(nameStart, end - 3)
name = this.getText().substring(nameStart, end - 2)
)
}
@@ -233,6 +231,8 @@ class RegExp extends AST::RegExpLiteral {
* - `\p{Space}`
* - `\P{Digit}` upper-case P means inverted
* - `\p{^Word}` caret also means inverted
*
* These can occur both inside and outside of character classes.
*/
private predicate pStyleNamedCharacterProperty(int start, int end, string name) {
this.escapingChar(start) and
@@ -297,11 +297,22 @@ class RegExp extends AST::RegExpLiteral {
exists(int x, int y | this.charSet(x, y) and index in [x + 1 .. y - 2])
}
predicate inPosixBracket(int index) {
exists(int x, int y |
this.posixStyleNamedCharacterProperty(x, y, _) and index in [x + 1 .. y - 2]
)
}
/** 'Simple' characters are any that don't alter the parsing of the regex. */
private predicate simpleCharacter(int start, int end) {
end = start + 1 and
not this.charSet(start, _) and
not this.charSet(_, start + 1) and
not exists(int x, int y |
this.posixStyleNamedCharacterProperty(x, y, _) and
start >= x and
end <= y
) and
exists(string c | c = this.getChar(start) |
exists(int x, int y, int z |
this.charSet(x, z) and
@@ -332,7 +343,9 @@ class RegExp extends AST::RegExpLiteral {
) and
not exists(int x, int y | this.groupStart(x, y) and x <= start and y >= end) and
not exists(int x, int y | this.backreference(x, y) and x <= start and y >= end) and
not exists(int x, int y | this.namedCharacterProperty(x, y, _) and x <= start and y >= end)
not exists(int x, int y |
this.pStyleNamedCharacterProperty(x, y, _) and x <= start and y >= end
)
}
predicate normalCharacter(int start, int end) {
@@ -595,7 +608,7 @@ class RegExp extends AST::RegExpLiteral {
or
this.backreference(start, end)
or
this.namedCharacterProperty(start, end, _)
this.pStyleNamedCharacterProperty(start, end, _)
}
private predicate qualifier(int start, int end, boolean maybeEmpty, boolean mayRepeatForever) {