path: root/src/regex
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2019-08-07fix failure of glob to match broken symlinks under some conditionsRich Felker-5/+12
when the pattern ended with one or more literal path components, or when the GLOB_MARK flag was passed to request that glob flag directory results and the type obtained by readdir was unknown or inconclusive (symlink), the stat function was called to evaluate existence and/or determine type. however, stat fails with ENOENT for broken symlinks, and this caused the match to be omitted from the results. instead, use stat only for the unknown/inconclusive cases with GLOB_MARK, and otherwise, or if stat fails, use lstat existence still needs to be determined. this minimizes the number of costly syscalls, performing both only in the case where GLOB_MARK is in use and there is a final literal path component which is a broken symlink. based on/simplified from patch by James Y Knight.
2019-08-06glob: implement GLOB_TILDE and GLOB_TILDE_CHECKIsmael Luceno-1/+41
2018-10-13allow escaped path-separator slashes in globRich Felker-11/+22
previously (before and after rewrite), spurious escaping of path separators as \/ was not treated the same as /, but rather got split as an unpaired \ at the end of the fnmatch pattern and an unescaped /, resulting in a mismatch/error. for the case of \/ as part of the maximal literal prefix, remove the explicit rejection of it and move the handling of / below escape processing. for the case of \/ after a proper glob pattern, it's hard to parse the pattern, so don't. instead cheat and count repetitions of \ prior to the already-found / character. if there are an odd number, the last is escaping the /, so back up the split position by one. now the char clobbered by null termination is variable, so save it and restore as needed.
2018-10-12rewrite core of the glob implementation for correctness & optimizationRich Felker-105/+112
this code has been long overdue for a rewrite, but the immediate cause that necessitated it was total failure to see past unreadable path components. for example, A/B/* would fail to match anything, even though it should succeed, when both A and A/B are searchable but only A/B is readable. this problem both was caught in conformance testing, and impacted users. the old glob implementation insisted on searching the listing of each path component for a match, even if the next component was a literal. it also used considerable stack space, up to length of the pattern, per recursion level, and relied on an artificial bound of the pattern length by PATH_MAX, which was incorrect because a pattern can be much longer than PATH_MAX while having matches shorter (for example, with necessarily long bracket expressions, or with redundancy). in the new implementation, each level of recursion starts by consuming the maximal literal (possibly escaped-literal) path prefix remaining in the pattern, and only opening a directory to read when there is a proper glob pattern in the next path component. it then recurses into each matching entry. the top-level glob function provided automatic storage (up to PATH_MAX) for construction of candidate/result strings, and allocates a duplicate of the pattern that can be modified in-place with temporary null-termination to pass to fnmatch. this allocation is not a big deal since glob already has to perform allocation, and has to link free to clean up if it experiences an allocation failure or other error after some results have already been allocated. care is taken to use the d_type field from iterated dirents when possible; stat is called only when there are literal path components past the last proper-glob component, or when needed to disambiguate symlinks for the purpose of GLOB_MARK. one peculiarity with the new implementation is the manner in which the error handling callback will be called. if attempting to match */B/C/D where a directory A exists that is inaccessible, the error reported will be a stat error for A/B/C/D rather than (previous and wrong implementation) an opendir error for A, or (likely on other implementations) a stat error for A/B. such behavior does not seem to be non-conforming, but if it turns out to be undesirable for any reason, backtracking could be done on error to report the first component producing it. also, redundant slashes are no longer normalized, but preserved as they appear in the pattern; this is probably more correct, and falls out naturally from the algorithm used. since trailing slashes (which force all matches to be directories) are preserved as well, the behavior of GLOB_MARK has been adjusted not to append an additional slash to results that already end in slash.
2018-10-11fix redundant computations of strlen in glob append functionRich Felker-2/+5
len was already passed as an argument, so don't use strcat, and use memcpy instead of strcpy.
2018-10-11fix invalid substitute of [1] for flexible array member in globRich Felker-2/+2
2018-09-12remove spurious inclusion of libc.h for LFS64 ABI aliasesRich Felker-3/+2
the LFS64 macro was not self-documenting and barely saved any characters. simply use weak_alias directly so that it's clear what's being done, and doesn't depend on a header to provide a strange macro.
2018-09-12apply hidden visibility to various remaining internal interfacesRich Felker-4/+4
2017-10-21fix regression in glob with literal . or .. path componentRich Felker-3/+5
commit 8c4be3e2209d2a1d3874b8bc2b474668fcbbbac6 was written to preclude the GLOB_PERIOD extension from matching these directory entries, but also precluded literal matches. adjust the check that excludes . and .. to check whether the GLOB_PERIOD flag is in effect, so that it cannot alter behavior in cases governed by the standard, and also don't exclude . or .. in any case where normal glob behavior (fnmatch's FNM_PERIOD flag) would have included one or both of them (patterns such as ".*"). it's still not clear whether this is the preferred behavior for GLOB_PERIOD, but at least it's clear that it can no longer break applications which are not relying on quirks of a nonstandard feature.
2017-09-06fix glob descent into . and .. with GLOB_PERIODRich Felker-0/+4
GLOB_PERIOD is a gnu extension, and GNU glob does not seem to honor it except in the last path component. it's not clear whether this a bug or intentional, but it seems reasonable that it should exclude the special entries . and .. when walking. changes based on report and analysis by Julien Ramseier.
2017-06-08fix glob failure to match plain "/" to root directoryRich Felker-1/+1
the check to prevent matching empty string wrongly blocked matching of "/" due to checking emptiness after stripping leading slashes rather than checking the full original argument string. simplified from patch by Julien Ramseier.
2017-03-21regex: fix newline matching with negated bracketsJulien Ramseier-0/+14
With REG_NEWLINE, POSIX says: "A <newline> in string shall not be matched by a period outside a bracket expression or by any form of a non-matching list"
2017-03-14fix free of uninitialized buffer pointer on error in regexecRich Felker-3/+3
the fix in commit c3edc06d1e1360f3570db9155d6b318ae0d0f0f7 for CVE-2016-8859 used gotos to exit on overflow conditions, but the code in that error path assumed the buffer pointer was valid or null. thus, the conditions which previously led to under-allocation and buffer overflow could instead lead to an invalid pointer being passed to free.
2017-01-02make globfree safe after failed glob from over-length argumentRich Felker-2/+2
commit 0dc99ac413d8bc054a2e95578475c7122455eee8 added input length checking to avoid unsafe VLA allocation, but put it in the wrong place, before the glob_t structure was zeroed out. while POSIX isn't clear on whether it's permitted to call globfree after glob failed with GLOB_NOSPACE, making it safe is clearly better than letting uninitialized pointers get passed to free in non-conforming callers. while we're fixing this, change strlen check to the idiomatic strnlen version to avoid unbounded input scanning before returning an error.
2016-12-16handle ^ and $ in BRE subexpression start and end as anchorsSzabolcs Nagy-9/+12
In BRE, ^ is an anchor at the beginning of an expression, optionally it may be an anchor at the beginning of a subexpression and must be treated as a literal otherwise. Previously musl treated ^ in subexpressions as literal, but at least glibc and gnu sed treats it as an anchor and that's the more useful behaviour: it can always be escaped to get back the literal meaning. Same for $ at the end of a subexpression. Portable BRE should not rely on this, but there are sed commands in build scripts which do. This changes the meaning of the BREs: \(^a\) \(a\|^b\) \(a$\) \(a$\|b\)
2016-10-06fix regexec with haystack strings longer than INT_MAXRich Felker-26/+28
we inherited from TRE regexec code that's utterly wrong with respect to the integer types it's using. while it doesn't appear that compilers are producing unsafe output, signed integer overflows seem to happen, and regexec fails to find matches past offset INT_MAX. this patch fixes the type of all variables/fields used to store offsets in the string from int to regoff_t. after the changes, basic testing showed that regexec can now find matches past 2GB (INT_MAX) and past 4GB on x86_64, and code generation is unchanged on i386.
2016-10-06fix missing integer overflow checks in regexec buffer size computationsRich Felker-5/+18
most of the possible overflows were already ruled out in practice by regcomp having already succeeded performing larger allocations. however at least the num_states*num_tags multiplication can clearly overflow in practice. for safety, check them all, and use the proper type, size_t, rather than int. also improve comments, use calloc in place of malloc+memset, and remove bogus casts.
2016-05-22fix the use of uninitialized value in regcompSzabolcs Nagy-0/+2
the num_submatches field of some ast nodes was not initialized in tre_add_tag_{left,right}, but was accessed later. this was a benign bug since the uninitialized values were never used (these values are created during tre_add_tags and copied around during tre_expand_ast where they are also used in computations, but nothing in the final tnfa depends on them).
2016-03-02fix ^* at the start of a complete BRESzabolcs Nagy-0/+4
This is a workaround to treat * as literal * at the start of a BRE. Ideally ^ would be treated as an anchor at the start of any BRE subexpression and similarly $ would be an anchor at the end of any subexpression. This is not required by the standard and hard to do with the current code, but it's the existing practice. If it is changed, * should be treated as literal after such anchor as well.
2016-03-02fix * at the start of a BRE subexpressionSzabolcs Nagy-4/+0
commit 7eaa76fc2e7993582989d3838b1ac32dd8abac09 made * invalid at the start of a BRE subexpression, but it should be accepted as literal * there according to the standard. This patch does not fix subexpressions starting with ^*.
2016-01-31regex: increase the stack tre uses for tnfa creationSzabolcs Nagy-1/+1
10k elements stack is increased to 1000k, otherwise tnfa creation fails for reasonable sized patterns: a single literal char can add 7 elements to this stack, so regcomp of an 1500 char long pattern (with only litral chars) fails with REG_ESPACE. (the new limit allows about < 150k chars, this arbitrary limit allows most command line regex usage.) ideally there would be no upper bound: regcomp dynamically reallocates this buffer, every reallocation checks for allocation failure and at the end this stack is freed so there is no reason for special bound. however that may have unwanted effect on regcomp and regexec runtime so this is a conservative change.
2016-01-30regex: simplify the {,} repetition parsing logicSzabolcs Nagy-20/+19
2016-01-30regex: treat \+, \? as repetitions in BRESzabolcs Nagy-1/+5
These are undefined escape sequences by the standard, but often used in sed scripts.
2016-01-30regex: rewrite the repetition parsing codeSzabolcs Nagy-30/+29
The goto logic was hard to follow and modify. This is in preparation for the BRE \+ and \? support.
2016-01-30regex: treat \| in BRE as alternationSzabolcs Nagy-2/+17
The standard does not define semantics for \| in BRE, but some code depends on it meaning alternation. Empty alternative expression is allowed to be consistent with ERE. Based on a patch by Rob Landley.
2016-01-30regex: reject repetitions in some cases with REG_BADRPTSzabolcs Nagy-3/+12
Previously repetitions were accepted after empty expressions like in (*|?)|{2}, but in BRE the handling of * and \{\} were not consistent: they were accepted as literals in some cases and repetitions in others. It is better to treat repetitions after an empty expression as an error (this is allowed by the standard, and glibc mostly does the same). This is hard to do consistently with the current logic so the new rule is: Reject repetitions after empty expressions, except after assertions ^*, $? and empty groups ()+ and never treat them as literals. Empty alternation (|a) is undefined by the standard, but it can be useful so that should be accepted.
2016-01-30regex: clean up position accounting for literal nodesSzabolcs Nagy-4/+2
This should not change the meaning of the code, just make the intent clearer: advancing position is tied to adding a new literal.
2015-09-24regcomp: propagate allocation failuresSzabolcs Nagy-1/+2
The error code of an allocating function was not checked in tre_add_tag.
2015-06-16byte-based C locale, phase 1: multibyte character handling functionsRich Felker-1/+2
this patch makes the functions which work directly on multibyte characters treat the high bytes as individual abstract code units rather than as multibyte sequences when MB_CUR_MAX is 1. since MB_CUR_MAX is presently defined as a constant 4, all of the new code added is dead code, and optimizing compilers' code generation should not be affected at all. a future commit will activate the new code. as abstract code units, bytes 0x80 to 0xff are represented by wchar_t values 0xdf80 to 0xdfff, at the end of the surrogates range. this ensures that they will never be misinterpreted as Unicode characters, and that all wctype functions return false for these "characters" without needing locale-specific logic. a high range outside of Unicode such as 0x7fffff80 to 0x7fffffff was also considered, but since C11's char16_t also needs to be able to represent conversions of these bytes, the surrogate range was the natural choice.
2015-03-27regex: fix character class repetitionsSzabolcs Nagy-0/+5
Internally regcomp needs to copy some iteration nodes before translating the AST into TNFA representation. Literal nodes were not copied correctly: the class type and list of negated class types were not copied so classes were ignored (in the non-negated case an ignored char class caused the literal to match everything). This affects iterations when the upper bound is finite, larger than one or the lower bound is larger than one. So eg. the EREs [[:digit:]]{2} [^[:space:]ab]{1,4} were treated as .{2} [^ab]{1,4} The fix is done with minimal source modification to copy the necessary fields, but the AST preparation and node handling code of tre will need to be cleaned up for clarity.
2015-03-23do not treat \0 as a backref in BRESzabolcs Nagy-1/+1
The valid BRE backref tokens are \1 .. \9, and 0 is not a special character either so \0 is undefined by the standard. Such undefined escaped characters are treated as literal characters currently, following existing practice, so \0 is the same as 0.
2015-03-20suppress backref processing in ERE regcompRich Felker-1/+1
one of the features of ERE is that it's actually a regular language and does not admit expressions which cannot be matched in linear time. introduction of \n backref support into regcomp's ERE parsing was unintentional.
2015-03-20fix memory-corruption in regcomp with backslash followed by high byteRich Felker-1/+1
the regex parser handles the (undefined) case of an unexpected byte following a backslash as a literal. however, instead of correctly decoding a character, it was treating the byte value itself as a character. this was not only semantically unjustified, but turned out to be dangerous on archs where plain char is signed: bytes in the range 252-255 alias the internal codes -4 through -1 used for special types of literal nodes in the AST.
2014-12-17implement FNM_CASEFOLD extension to fnmatch functionNagy Szabolcs-11/+25
2014-09-13rewrite the regex pattern parser in regcompSzabolcs Nagy-1081/+634
The new code is a bit simpler and the generated code is about 1KB smaller (on i386). The basic design was kept including internal interfaces, TNFA generation was not touched. The old tre parser had various issues: [^aa-z] negated overlapping ranges in a bracket expression were handled incorrectly (eg [^aa-z] was handled as [^a] instead of [^a-z]) a{,2} missing lower bound in a counted repetition should be an error, but it was accepted with broken semantics: a{,2} was treated as a{0,3}, the new parser rejects it a{999,} large min count was not rejected (a{5000,} failed with REG_ESPACE due to reaching a stack limit), the new parser enforces the RE_DUP_MAX limit \xff regcomp used to accept a pattern with illegal sequences in it (treated them as empty expression so p\xffq matched pq) the new parser rejects such patterns with REG_BADPAT or REG_ERANGE [^b-fD-H] with REG_ICASE old parser turned this into [^b-fB-F] because of the negated overlapping range issue (see above), the new parser treats it as [^b-hB-H], POSIX seems to require [^d-fD-F], but practical implementations do case-folding first and negate the character set later instead of the other way around. (Supporting the posix way efficiently would require significant changes so it was left as is, it is unclear if any application actually expects the posix behaviour, this issue is raised on the austingroup tracker: ). another case-insensitive matching issue is that unicode case folding rules can group more than two characters together while towupper and towlower can only work for a pair of upper and lower case characters, this is a limitation of POSIX so it is not fixed. invalid bracket and brace expressions may return different error codes now (REG_ERANGE instead of REG_EBRACK or REG_BADBR instead of REG_EBRACE) otherwise the new parser should be compatible with the old one. regcomp should be able to handle arbitrary pattern input if the pattern length is limited, the only exception is the use of large repetition counts (eg. (a{255}){255}) which require exp amount of memory and there is no easy workaround.
2014-09-05fix memory leak in regexec when input contains illegal sequenceSzabolcs Nagy-5/+6
2014-07-26add support for LC_TIME and LC_MESSAGES translationsRich Felker-0/+2
for LC_MESSAGES, translation of strerror and similar literal message functions is supported. for messages in other places (particularly the dynamic linker) that use format strings, translation is not yet supported. in order to make it possible and safe, such messages will need to be refactored to separate the textual content from the format. for LC_TIME, the day and month names and strftime-style format strings provided by nl_langinfo are supported for translation. however there may be limitations, as some of the original C-locale nl_langinfo strings are non-unique and thus perhaps non-suitable as keys. overall, the locale support activated by this commit should not be seen as complete and polished but as a basis for beginning to test locale functionality and implement locales.
2014-07-17fix crash in regexec for nonzero nmatch argument with REG_NOSUBRich Felker-0/+1
per POSIX, the nmatch and pmatch arguments are ignored when the regex was compiled with REG_NOSUB.
2013-12-12include cleanups: remove unused headers and add feature test macrosSzabolcs Nagy-3/+0
2013-12-02implement FNM_LEADING_DIR extension flag in fnmatchRich Felker-2/+9
previously this flag was defined and accepted as a no-op, possibly breaking some software that uses it. given the choice to remove the definition and possibly break applications that were already working, or simply implement the feature, the latter turned out to be easy enough to make the decision easy. in the case where the FNM_PATHNAME flag is also set, this implementation is clean and essentially optimal. otherwise, it's an inefficient "brute force" implementation. at some point, when cleaning up and refactoring this code, I may add a more direct code path for handling FNM_LEADING_DIR in the non-FNM_PATHNAME case, but at this point my main interest is avoiding introducing new bugs in the code that implements the standard fnmatch features specified by POSIX.
2013-12-01fix fnmatch corner cases related to escapingRich Felker-4/+4
the FNM_PATHNAME logic for advancing by /-delimited components was incorrect when the / character was escaped (i.e. \/), and a final \ at the end of pattern was not handled correctly.
2013-12-01fix the end of string matching in fnmatch with FNM_PATHNAMESzabolcs Nagy-2/+2
a '/' in the pattern could be incorrectly matched against the terminating null byte in the string causing arbitrarily long sequence of out-of-bounds access in fnmatch("/","",FNM_PATHNAME)
2013-10-07fix allocation sizes in regcompSzabolcs Nagy-4/+4
sizeof had incorrect argument in a few places, the size was always large enough so the issue was not critical.
2013-02-01revert regex "cleanup" that seems unjustified and may break backtrackingRich Felker-0/+3
it's not clear to me at the moment whether the code that was removed (and which is now being re-added) is needed, but it's far from being a no-op, and i don't want to risk breaking regex in this release.
2013-01-15remove unused "params" related code from regexSzabolcs Nagy-21/+11
some structs and functions had reference to the params feature of tre that is not used by the code anymore
2013-01-14regex: remove an unused local variable from regexecSzabolcs Nagy-3/+0
pos_start local variable is not used in tre_tnfa_run_backtrack
2012-09-06use restrict everywhere it's required by c99 and/or posix 2008Rich Felker-5/+5
to deal with the fact that the public headers may be used with pre-c99 compilers, __restrict is used in place of restrict, and defined appropriately for any supported compiler. we also avoid the form [restrict] since older versions of gcc rejected it due to a bug in the original c99 standard, and instead use the form *restrict.
2012-05-25fix regex on armRich Felker-1/+1
TRE has a broken assumption that wchar_t is signed, which is a sane expectation, but not required by the standard, and false on ARM's ABI. i leave tre_char_t as wchar_t for now, since a pointer to it is directly passed to functions that need pointer to wchar_t. it does not seem to break anything. and since the maximum unicode scalar value is 0x10ffff, just use that explicitly rather than using the max value of any particular C type.
2012-05-13remove some no-op end of string tests from regex parserRich Felker-4/+0
these are cruft from the original code which used an explicit string length rather than null termination. i blindly converted all the checks to null terminator checks, without noticing that in several cases, the subsequent switch statement would automatically handle the null byte correctly.
2012-05-13another BRE fix: in ^*, * is literalRich Felker-0/+2
i don't understand why this has to be conditional on being in BRE mode, but enabling this code unconditionally breaks a huge number of ERE test cases.