| From 0abf1e8d89aecd32dbdabda5da4d52a2d57a7cff Mon Sep 17 00:00:00 2001 |
| From: Karl Williamson <khw@cpan.org> |
| Date: Tue, 6 Feb 2018 14:50:48 -0700 |
| Subject: [PATCH] [perl #132063]: Heap buffer overflow |
| |
| The proximal cause is several instances in regexec.c of the code |
| assuming that the input was valid UTF-8, whereas the input was too short |
| for what the start byte claimed it would be. |
| |
| I grepped through the core for any other similar uses, and did not find |
| any. |
| |
| (cherry picked from commit fe7d8ba0a1bf567af8fa8fea128e2b9f4c553e84) |
| |
| CVE: CVE-2018-6798 |
| Upstream-Status: Backport [https://perl5.git.perl.org/perl.git/patch/0abf1e8d89aecd32dbdabda5da4d52a2d57a7cff] |
| |
| Signed-off-by: Jagadeesh Krishnanjanappa <jkrishnanjanappa@mvista.com> |
| --- |
| regexec.c | 29 ++++++++++++++++------------- |
| t/lib/warnings/regexec | 7 +++++++ |
| 2 files changed, 23 insertions(+), 13 deletions(-) |
| |
| diff --git a/regexec.c b/regexec.c |
| index 5735b997fd..ea432c39d3 100644 |
| --- a/regexec.c |
| +++ b/regexec.c |
| @@ -1466,7 +1466,9 @@ Perl_re_intuit_start(pTHX_ |
| ? trie_utf8_fold \ |
| : trie_latin_utf8_fold))) |
| |
| -#define REXEC_TRIE_READ_CHAR(trie_type, trie, widecharmap, uc, uscan, len, uvc, charid, foldlen, foldbuf, uniflags) \ |
| +/* 'uscan' is set to foldbuf, and incremented, so below the end of uscan is |
| + * 'foldbuf+sizeof(foldbuf)' */ |
| +#define REXEC_TRIE_READ_CHAR(trie_type, trie, widecharmap, uc, uc_end, uscan, len, uvc, charid, foldlen, foldbuf, uniflags) \ |
| STMT_START { \ |
| STRLEN skiplen; \ |
| U8 flags = FOLD_FLAGS_FULL; \ |
| @@ -1474,7 +1476,7 @@ STMT_START { |
| case trie_flu8: \ |
| _CHECK_AND_WARN_PROBLEMATIC_LOCALE; \ |
| if (utf8_target && UTF8_IS_ABOVE_LATIN1(*uc)) { \ |
| - _CHECK_AND_OUTPUT_WIDE_LOCALE_UTF8_MSG(uc, uc + UTF8SKIP(uc)); \ |
| + _CHECK_AND_OUTPUT_WIDE_LOCALE_UTF8_MSG(uc, uc_end - uc); \ |
| } \ |
| goto do_trie_utf8_fold; \ |
| case trie_utf8_exactfa_fold: \ |
| @@ -1483,7 +1485,7 @@ STMT_START { |
| case trie_utf8_fold: \ |
| do_trie_utf8_fold: \ |
| if ( foldlen>0 ) { \ |
| - uvc = utf8n_to_uvchr( (const U8*) uscan, UTF8_MAXLEN, &len, uniflags ); \ |
| + uvc = utf8n_to_uvchr( (const U8*) uscan, foldlen, &len, uniflags ); \ |
| foldlen -= len; \ |
| uscan += len; \ |
| len=0; \ |
| @@ -1500,7 +1502,7 @@ STMT_START { |
| /* FALLTHROUGH */ \ |
| case trie_latin_utf8_fold: \ |
| if ( foldlen>0 ) { \ |
| - uvc = utf8n_to_uvchr( (const U8*) uscan, UTF8_MAXLEN, &len, uniflags ); \ |
| + uvc = utf8n_to_uvchr( (const U8*) uscan, foldlen, &len, uniflags ); \ |
| foldlen -= len; \ |
| uscan += len; \ |
| len=0; \ |
| @@ -1519,7 +1521,7 @@ STMT_START { |
| } \ |
| /* FALLTHROUGH */ \ |
| case trie_utf8: \ |
| - uvc = utf8n_to_uvchr( (const U8*) uc, UTF8_MAXLEN, &len, uniflags ); \ |
| + uvc = utf8n_to_uvchr( (const U8*) uc, uc_end - uc, &len, uniflags ); \ |
| break; \ |
| case trie_plain: \ |
| uvc = (UV)*uc; \ |
| @@ -2599,10 +2601,10 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, |
| } |
| points[pointpos++ % maxlen]= uc; |
| if (foldlen || uc < (U8*)strend) { |
| - REXEC_TRIE_READ_CHAR(trie_type, trie, |
| - widecharmap, uc, |
| - uscan, len, uvc, charid, foldlen, |
| - foldbuf, uniflags); |
| + REXEC_TRIE_READ_CHAR(trie_type, trie, widecharmap, uc, |
| + (U8 *) strend, uscan, len, uvc, |
| + charid, foldlen, foldbuf, |
| + uniflags); |
| DEBUG_TRIE_EXECUTE_r({ |
| dump_exec_pos( (char *)uc, c, strend, |
| real_start, s, utf8_target, 0); |
| @@ -5511,8 +5513,9 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog) |
| if ( base && (foldlen || uc < (U8*)(reginfo->strend))) { |
| I32 offset; |
| REXEC_TRIE_READ_CHAR(trie_type, trie, widecharmap, uc, |
| - uscan, len, uvc, charid, foldlen, |
| - foldbuf, uniflags); |
| + (U8 *) reginfo->strend, uscan, |
| + len, uvc, charid, foldlen, |
| + foldbuf, uniflags); |
| charcount++; |
| if (foldlen>0) |
| ST.longfold = TRUE; |
| @@ -5642,8 +5645,8 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog) |
| while (foldlen) { |
| if (!--chars) |
| break; |
| - uvc = utf8n_to_uvchr(uscan, UTF8_MAXLEN, &len, |
| - uniflags); |
| + uvc = utf8n_to_uvchr(uscan, foldlen, &len, |
| + uniflags); |
| uscan += len; |
| foldlen -= len; |
| } |
| diff --git a/t/lib/warnings/regexec b/t/lib/warnings/regexec |
| index 900dd6ee7f..6635142dea 100644 |
| --- a/t/lib/warnings/regexec |
| +++ b/t/lib/warnings/regexec |
| @@ -260,3 +260,10 @@ setlocale(&POSIX::LC_CTYPE, $utf8_locale); |
| "k" =~ /(?[ \N{KELVIN SIGN} ])/i; |
| ":" =~ /(?[ \: ])/; |
| EXPECT |
| +######## |
| +# NAME perl #132063, read beyond buffer end |
| +# OPTION fatal |
| +"\xff" =~ /(?il)\x{100}|\x{100}/; |
| +EXPECT |
| +Malformed UTF-8 character: \xff (too short; 1 byte available, need 13) in pattern match (m//) at - line 2. |
| +Malformed UTF-8 character (fatal) at - line 2. |
| -- |
| 2.15.1-424-g9478a660812 |
| |