From: Noam Postavsky Date: Mon, 11 Dec 2017 23:53:34 +0000 (-0500) Subject: Raise limit of regexp repetition (Bug#24914) X-Git-Tag: emacs-27.0.90~5801 X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=559f1606166822394df3988c18c0ad02984ac675;p=emacs.git Raise limit of regexp repetition (Bug#24914) * src/regex.h (RE_DUP_MAX): Raise limit to 2^16-1. * etc/NEWS: Announce it. * doc/lispref/searching.texi (Regexp Backslash): Document it. * test/src/regex-tests.el (regex-repeat-limit): Test it. * src/regex.h (reg_errcode_t): Add REG_ESIZEBR code. * src/regex.c (re_error_msgid): Add corresponding entry. (GET_INTERVAL_COUNT): Return it instead of the more generic REG_EBADBR when encountering a repetition greater than RE_DUP_MAX. * lisp/isearch.el (isearch-search): Don't convert errors starting with "Invalid" into "incomplete". Such errors are not incomplete, in the sense that they cannot be corrected by appending more characters to the end of the regexp. The affected error messages are: - REG_BADPAT "Invalid regular expression" - \\(?X:\\) where X is not a legal group number - \\_X where X is not < or > - REG_ECOLLATE "Invalid collation character" - There is no code to throw this. - REG_ECTYPE "Invalid character class name" - [[:foo:] where foo is not a valid class name - REG_ESUBREG "Invalid back reference" - \N where N is referenced before matching group N - REG_BADBR "Invalid content of \\{\\}" - \\{N,M\\} where N < 0, M < N, M or N larger than max - \\{NX where X is not a digit or backslash - \\{N\\X where X is not a } - REG_ERANGE "Invalid range end" - There is no code to throw this. - REG_BADRPT "Invalid preceding regular expression" - We never throw this. It would usually indicate a "*" with no preceding regexp text, but Emacs allows that to match a literal "*". --- diff --git a/doc/lispref/searching.texi b/doc/lispref/searching.texi index e759967aa8a..26985b5d267 100644 --- a/doc/lispref/searching.texi +++ b/doc/lispref/searching.texi @@ -642,10 +642,10 @@ is omitted, the minimum is 0; if @var{n} is omitted, there is no maximum. For both forms, @var{m} and @var{n}, if specified, may be no larger than @ifnottex -2**15 @minus{} 1 +2**16 @minus{} 1 @end ifnottex @tex -@math{2^{15}-1} +@math{2^{16}-1} @end tex . diff --git a/etc/NEWS b/etc/NEWS index ad315536034..27bde2d147c 100644 --- a/etc/NEWS +++ b/etc/NEWS @@ -80,6 +80,13 @@ indirectly, e.g., by checking that functions like It blocks line breaking after a one-letter word, also in the case when this word is preceded by a non-space, but non-alphanumeric character. ++++ +** The limit on repetitions in regexps has been raised to 2^16-1. +It was previously limited to 2^15-1. For example, the following +regular expression was previously invalid, but is now accepted: + + x\{32768\} + * Editing Changes in Emacs 27.1 diff --git a/lisp/isearch.el b/lisp/isearch.el index 23dd9afccdb..9297c0f95ba 100644 --- a/lisp/isearch.el +++ b/lisp/isearch.el @@ -2858,7 +2858,7 @@ Optional third argument, if t, means if fail just return nil (no error). (setq isearch-error (car (cdr lossage))) (cond ((string-match - "\\`Premature \\|\\`Unmatched \\|\\`Invalid " + "\\`Premature \\|\\`Unmatched " isearch-error) (setq isearch-error "incomplete input")) ((and (not isearch-regexp) diff --git a/src/regex.c b/src/regex.c index 2185fc97d3b..122cf712422 100644 --- a/src/regex.c +++ b/src/regex.c @@ -1194,7 +1194,8 @@ static const char *re_error_msgid[] = gettext_noop ("Premature end of regular expression"), /* REG_EEND */ gettext_noop ("Regular expression too big"), /* REG_ESIZE */ gettext_noop ("Unmatched ) or \\)"), /* REG_ERPAREN */ - gettext_noop ("Range striding over charsets") /* REG_ERANGEX */ + gettext_noop ("Range striding over charsets"), /* REG_ERANGEX */ + gettext_noop ("Invalid content of \\{\\}, repetitions too big") /* REG_ESIZEBR */ }; /* Whether to allocate memory during matching. */ @@ -1915,7 +1916,7 @@ struct range_table_work_area if (num < 0) \ num = 0; \ if (RE_DUP_MAX / 10 - (RE_DUP_MAX % 10 < c - '0') < num) \ - FREE_STACK_RETURN (REG_BADBR); \ + FREE_STACK_RETURN (REG_ESIZEBR); \ num = num * 10 + c - '0'; \ if (p == pend) \ FREE_STACK_RETURN (REG_EBRACE); \ diff --git a/src/regex.h b/src/regex.h index b4aad6daac9..6974951f575 100644 --- a/src/regex.h +++ b/src/regex.h @@ -270,8 +270,10 @@ extern ptrdiff_t emacs_re_safe_alloca; #ifdef RE_DUP_MAX # undef RE_DUP_MAX #endif -/* If sizeof(int) == 2, then ((1 << 15) - 1) overflows. */ -#define RE_DUP_MAX (0x7fff) +/* Repeat counts are stored in opcodes as 2 byte integers. This was + previously limited to 7fff because the parsing code uses signed + ints. But Emacs only runs on 32 bit platforms anyway. */ +#define RE_DUP_MAX (0xffff) /* POSIX `cflags' bits (i.e., information for `regcomp'). */ @@ -337,7 +339,8 @@ typedef enum REG_EEND, /* Premature end. */ REG_ESIZE, /* Compiled pattern bigger than 2^16 bytes. */ REG_ERPAREN, /* Unmatched ) or \); not returned from regcomp. */ - REG_ERANGEX /* Range striding over charsets. */ + REG_ERANGEX, /* Range striding over charsets. */ + REG_ESIZEBR /* n or m too big in \{n,m\} */ } reg_errcode_t; /* This data structure represents a compiled pattern. Before calling diff --git a/test/src/regex-tests.el b/test/src/regex-tests.el index 86aa7d26350..083ed5c4c8c 100644 --- a/test/src/regex-tests.el +++ b/test/src/regex-tests.el @@ -677,4 +677,10 @@ This evaluates the PTESTS test cases from glibc." This evaluates the TESTS test cases from glibc." (should-not (regex-tests-TESTS))) +(ert-deftest regex-repeat-limit () + "Test the #xFFFF repeat limit." + (should (string-match "\\`x\\{65535\\}" (make-string 65535 ?x))) + (should-not (string-match "\\`x\\{65535\\}" (make-string 65534 ?x))) + (should-error (string-match "\\`x\\{65536\\}" "X") :type 'invalid-regexp)) + ;;; regex-tests.el ends here