diff mbox series

[v4,2/2] grep/pcre2: better support invalid UTF-8 haystacks

Message ID 20210124114855.13036-3-avarab@gmail.com (mailing list archive)
State New, archived
Headers show
Series None | expand

Commit Message

Ævar Arnfjörð Bjarmason Jan. 24, 2021, 11:48 a.m. UTC 
Improve the support for invalid UTF-8 haystacks given a non-ASCII
needle when using the PCREv2 backend.

This is a more complete fix for a bug I started to fix in
870eea8166 (grep: do not enter PCRE2_UTF mode on fixed matching,
2019-07-26), now that PCREv2 has the PCRE2_MATCH_INVALID_UTF mode we
can make use of it.

This fixes the sort of case described in 8a5999838e (grep: stess test
PCRE v2 on invalid UTF-8 data, 2019-07-26), i.e.:

    - The subject string is non-ASCII (e.g. "ævar")
    - We're under a is_utf8_locale(), e.g. "en_US.UTF-8", not "C"
    - We are using --ignore-case, or we're a non-fixed pattern

If those conditions were satisfied and we matched found non-valid
UTF-8 data PCREv2 might bark on it, in practice this only happened
under the JIT backend (turned on by default on most platforms).

Ultimately this fixes a "regression" in b65abcafc7 ("grep: use PCRE v2
for optimized fixed-string search", 2019-07-01), I'm putting that in
scare-quotes because before then we wouldn't properly support these
complex case-folding, locale etc. cases either, it just broke in
different ways.

There was a bug related to this the PCRE2_NO_START_OPTIMIZE flag fixed
in PCREv2 10.36. It can be worked around by setting the
PCRE2_NO_START_OPTIMIZE flag. Let's do that in those cases, and add
tests for the bug.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 Makefile                        |  1 +
 grep.c                          |  8 +++++-
 grep.h                          |  4 +++
 t/helper/test-pcre2-config.c    | 12 +++++++++
 t/helper/test-tool.c            |  1 +
 t/helper/test-tool.h            |  1 +
 t/t7812-grep-icase-non-ascii.sh | 46 ++++++++++++++++++++++++++++++++-
 7 files changed, 71 insertions(+), 2 deletions(-)
 create mode 100644 t/helper/test-pcre2-config.c

Comments

Ramsay Jones Jan. 24, 2021, 1:53 p.m. UTC | #1 
On 24/01/2021 11:48, Ævar Arnfjörð Bjarmason wrote:
> Improve the support for invalid UTF-8 haystacks given a non-ASCII
> needle when using the PCREv2 backend.
> 
> This is a more complete fix for a bug I started to fix in
> 870eea8166 (grep: do not enter PCRE2_UTF mode on fixed matching,
> 2019-07-26), now that PCREv2 has the PCRE2_MATCH_INVALID_UTF mode we
> can make use of it.
> 
> This fixes the sort of case described in 8a5999838e (grep: stess test
> PCRE v2 on invalid UTF-8 data, 2019-07-26), i.e.:
> 
>     - The subject string is non-ASCII (e.g. "ævar")
>     - We're under a is_utf8_locale(), e.g. "en_US.UTF-8", not "C"
>     - We are using --ignore-case, or we're a non-fixed pattern
> 
> If those conditions were satisfied and we matched found non-valid
> UTF-8 data PCREv2 might bark on it, in practice this only happened
> under the JIT backend (turned on by default on most platforms).
> 
> Ultimately this fixes a "regression" in b65abcafc7 ("grep: use PCRE v2
> for optimized fixed-string search", 2019-07-01), I'm putting that in
> scare-quotes because before then we wouldn't properly support these
> complex case-folding, locale etc. cases either, it just broke in
> different ways.
> 
> There was a bug related to this the PCRE2_NO_START_OPTIMIZE flag fixed
> in PCREv2 10.36. It can be worked around by setting the
> PCRE2_NO_START_OPTIMIZE flag. Let's do that in those cases, and add
> tests for the bug.
> 
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
>  Makefile                        |  1 +
>  grep.c                          |  8 +++++-
>  grep.h                          |  4 +++
>  t/helper/test-pcre2-config.c    | 12 +++++++++
>  t/helper/test-tool.c            |  1 +
>  t/helper/test-tool.h            |  1 +
>  t/t7812-grep-icase-non-ascii.sh | 46 ++++++++++++++++++++++++++++++++-
>  7 files changed, 71 insertions(+), 2 deletions(-)
>  create mode 100644 t/helper/test-pcre2-config.c
> 
> diff --git a/Makefile b/Makefile
> index 4edfda3e00..42a7ed96e2 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -722,6 +722,7 @@ TEST_BUILTINS_OBJS += test-online-cpus.o
>  TEST_BUILTINS_OBJS += test-parse-options.o
>  TEST_BUILTINS_OBJS += test-parse-pathspec-file.o
>  TEST_BUILTINS_OBJS += test-path-utils.o
> +TEST_BUILTINS_OBJS += test-pcre2-config.o
>  TEST_BUILTINS_OBJS += test-pkt-line.o
>  TEST_BUILTINS_OBJS += test-prio-queue.o
>  TEST_BUILTINS_OBJS += test-proc-receive.o
> diff --git a/grep.c b/grep.c
> index efeb6dc58d..e329f19877 100644
> --- a/grep.c
> +++ b/grep.c
> @@ -492,7 +492,13 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
>  	}
>  	if (!opt->ignore_locale && is_utf8_locale() && has_non_ascii(p->pattern) &&
>  	    !(!opt->ignore_case && (p->fixed || p->is_fixed)))
> -		options |= PCRE2_UTF;
> +		options |= (PCRE2_UTF | PCRE2_MATCH_INVALID_UTF);
> +
> +	if (PCRE2_MATCH_INVALID_UTF &&
> +	    options & (PCRE2_UTF | PCRE2_CASELESS) &&
> +	    !(PCRE2_MAJOR >= 10 && PCRE2_MAJOR >= 36))
                                   ^^^^^^^^^^^^^^^^^^
I assume that this should be s/_MAJOR/_MINOR/. ;-)

> +		/* Work around https://bugs.exim.org/show_bug.cgi?id=2642 fixed in 10.36 */
> +		options |= PCRE2_NO_START_OPTIMIZE;
>  
>  	p->pcre2_pattern = pcre2_compile((PCRE2_SPTR)p->pattern,
>  					 p->patternlen, options, &error, &erroffset,

ATB,
Ramsay Jones
Ramsay Jones Jan. 24, 2021, 2:24 p.m. UTC | #2 
On 24/01/2021 13:53, Ramsay Jones wrote:
[snip]

>> diff --git a/grep.c b/grep.c
>> index efeb6dc58d..e329f19877 100644
>> --- a/grep.c
>> +++ b/grep.c
>> @@ -492,7 +492,13 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
>>  	}
>>  	if (!opt->ignore_locale && is_utf8_locale() && has_non_ascii(p->pattern) &&
>>  	    !(!opt->ignore_case && (p->fixed || p->is_fixed)))
>> -		options |= PCRE2_UTF;
>> +		options |= (PCRE2_UTF | PCRE2_MATCH_INVALID_UTF);
>> +
>> +	if (PCRE2_MATCH_INVALID_UTF &&
>> +	    options & (PCRE2_UTF | PCRE2_CASELESS) &&
>> +	    !(PCRE2_MAJOR >= 10 && PCRE2_MAJOR >= 36))
>                                    ^^^^^^^^^^^^^^^^^^
> I assume that this should be s/_MAJOR/_MINOR/. ;-)
> 

Although, perhaps you want:

            !(((PCRE2_MAJOR * 100) + PCRE2_MINOR) >= 1036)

... or something similar.

ATB,
Ramsay Jones
Ævar Arnfjörð Bjarmason Jan. 24, 2021, 2:49 p.m. UTC | #3 
On Sun, Jan 24 2021, Ramsay Jones wrote:

> On 24/01/2021 13:53, Ramsay Jones wrote:
> [snip]
>
>>> diff --git a/grep.c b/grep.c
>>> index efeb6dc58d..e329f19877 100644
>>> --- a/grep.c
>>> +++ b/grep.c
>>> @@ -492,7 +492,13 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
>>>  	}
>>>  	if (!opt->ignore_locale && is_utf8_locale() && has_non_ascii(p->pattern) &&
>>>  	    !(!opt->ignore_case && (p->fixed || p->is_fixed)))
>>> -		options |= PCRE2_UTF;
>>> +		options |= (PCRE2_UTF | PCRE2_MATCH_INVALID_UTF);
>>> +
>>> +	if (PCRE2_MATCH_INVALID_UTF &&
>>> +	    options & (PCRE2_UTF | PCRE2_CASELESS) &&
>>> +	    !(PCRE2_MAJOR >= 10 && PCRE2_MAJOR >= 36))
>>                                    ^^^^^^^^^^^^^^^^^^
>> I assume that this should be s/_MAJOR/_MINOR/. ;-)
>> 

Oops on the s/MAJOR/MINOR/g. Well spotted, I think I'll wait a bit more
for other comments for a re-roll.

Perhaps Junio can be kind and do the s/_MAJOR/_MINOR/ fixup in the
meantime to save be from spamming the list too much...

FWIW I have tested this on a verion without PCRE2_MATCH_INVALID_UTF, but
I think I did that by manually editing the "PCRE2_UTF" line above, and
then wrote this bug.

> Although, perhaps you want:
>
>             !(((PCRE2_MAJOR * 100) + PCRE2_MINOR) >= 1036)
>
> ... or something similar.

Probably better to use pcre2_config(PCRE2_CONFIG_VERSION) at that point
and versioncmp() the string.

FWIW we used this pattern (I added) before with PCRE, see e87de7cab4
(grep: un-break building with PCRE < 8.32, 2017-05-25).

And if you want to be clever ((PCRE2_MAJOR) | ((PCRE2_MINOR) << 16)) is
probably better, then you can get it out with bit operations :)
Ramsay Jones Jan. 24, 2021, 4:10 p.m. UTC | #4 
On 24/01/2021 14:49, Ævar Arnfjörð Bjarmason wrote:
> 
> On Sun, Jan 24 2021, Ramsay Jones wrote:
> 
>> On 24/01/2021 13:53, Ramsay Jones wrote:
>> [snip]
>>
>>>> diff --git a/grep.c b/grep.c
>>>> index efeb6dc58d..e329f19877 100644
>>>> --- a/grep.c
>>>> +++ b/grep.c
>>>> @@ -492,7 +492,13 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
>>>>  	}
>>>>  	if (!opt->ignore_locale && is_utf8_locale() && has_non_ascii(p->pattern) &&
>>>>  	    !(!opt->ignore_case && (p->fixed || p->is_fixed)))
>>>> -		options |= PCRE2_UTF;
>>>> +		options |= (PCRE2_UTF | PCRE2_MATCH_INVALID_UTF);
>>>> +
>>>> +	if (PCRE2_MATCH_INVALID_UTF &&
>>>> +	    options & (PCRE2_UTF | PCRE2_CASELESS) &&
>>>> +	    !(PCRE2_MAJOR >= 10 && PCRE2_MAJOR >= 36))
>>>                                    ^^^^^^^^^^^^^^^^^^
>>> I assume that this should be s/_MAJOR/_MINOR/. ;-)
>>>
> 
> Oops on the s/MAJOR/MINOR/g. Well spotted, I think I'll wait a bit more
> for other comments for a re-roll.
> 
> Perhaps Junio can be kind and do the s/_MAJOR/_MINOR/ fixup in the
> meantime to save be from spamming the list too much...

Umm, sorry for not making myself clear, _just_ changing MAJOR to
MINOR is insufficient.

> 
> FWIW I have tested this on a verion without PCRE2_MATCH_INVALID_UTF, but
> I think I did that by manually editing the "PCRE2_UTF" line above, and
> then wrote this bug.

Yep, I seem to have 10.34 on Linux Mint 20.1 (based on Ubuntu 20.04).

> 
>> Although, perhaps you want:
>>
>>             !(((PCRE2_MAJOR * 100) + PCRE2_MINOR) >= 1036)
>>
>> ... or something similar.
> 
> Probably better to use pcre2_config(PCRE2_CONFIG_VERSION) at that point
> and versioncmp() the string.

OK, but it needs to be 'something similar' (try putting, say, MAJOR 11
and MINOR 0->35 in your expression).

ATB,
Ramsay Jones
Ævar Arnfjörð Bjarmason Jan. 24, 2021, 5:29 p.m. UTC | #5 
On Sun, Jan 24 2021, Ramsay Jones wrote:

> On 24/01/2021 14:49, Ævar Arnfjörð Bjarmason wrote:
>> 
>> On Sun, Jan 24 2021, Ramsay Jones wrote:
>> 
>>> On 24/01/2021 13:53, Ramsay Jones wrote:
>>> [snip]
>>>
>>>>> diff --git a/grep.c b/grep.c
>>>>> index efeb6dc58d..e329f19877 100644
>>>>> --- a/grep.c
>>>>> +++ b/grep.c
>>>>> @@ -492,7 +492,13 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
>>>>>  	}
>>>>>  	if (!opt->ignore_locale && is_utf8_locale() && has_non_ascii(p->pattern) &&
>>>>>  	    !(!opt->ignore_case && (p->fixed || p->is_fixed)))
>>>>> -		options |= PCRE2_UTF;
>>>>> +		options |= (PCRE2_UTF | PCRE2_MATCH_INVALID_UTF);
>>>>> +
>>>>> +	if (PCRE2_MATCH_INVALID_UTF &&
>>>>> +	    options & (PCRE2_UTF | PCRE2_CASELESS) &&
>>>>> +	    !(PCRE2_MAJOR >= 10 && PCRE2_MAJOR >= 36))
>>>>                                    ^^^^^^^^^^^^^^^^^^
>>>> I assume that this should be s/_MAJOR/_MINOR/. ;-)
>>>>
>> 
>> Oops on the s/MAJOR/MINOR/g. Well spotted, I think I'll wait a bit more
>> for other comments for a re-roll.
>> 
>> Perhaps Junio can be kind and do the s/_MAJOR/_MINOR/ fixup in the
>> meantime to save be from spamming the list too much...
>
> Umm, sorry for not making myself clear, _just_ changing MAJOR to
> MINOR is insufficient.
>
>> 
>> FWIW I have tested this on a verion without PCRE2_MATCH_INVALID_UTF, but
>> I think I did that by manually editing the "PCRE2_UTF" line above, and
>> then wrote this bug.
>
> Yep, I seem to have 10.34 on Linux Mint 20.1 (based on Ubuntu 20.04).
>
>> 
>>> Although, perhaps you want:
>>>
>>>             !(((PCRE2_MAJOR * 100) + PCRE2_MINOR) >= 1036)
>>>
>>> ... or something similar.
>> 
>> Probably better to use pcre2_config(PCRE2_CONFIG_VERSION) at that point
>> and versioncmp() the string.
>
> OK, but it needs to be 'something similar' (try putting, say, MAJOR 11
> and MINOR 0->35 in your expression).

Ah yes, of course. I re-rolled a v5 with a fix for that. Thanks.
diff mbox series

Patch

diff --git a/Makefile b/Makefile
index 4edfda3e00..42a7ed96e2 100644
--- a/Makefile
+++ b/Makefile
@@ -722,6 +722,7 @@  TEST_BUILTINS_OBJS += test-online-cpus.o
 TEST_BUILTINS_OBJS += test-parse-options.o
 TEST_BUILTINS_OBJS += test-parse-pathspec-file.o
 TEST_BUILTINS_OBJS += test-path-utils.o
+TEST_BUILTINS_OBJS += test-pcre2-config.o
 TEST_BUILTINS_OBJS += test-pkt-line.o
 TEST_BUILTINS_OBJS += test-prio-queue.o
 TEST_BUILTINS_OBJS += test-proc-receive.o
diff --git a/grep.c b/grep.c
index efeb6dc58d..e329f19877 100644
--- a/grep.c
+++ b/grep.c
@@ -492,7 +492,13 @@  static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
 	}
 	if (!opt->ignore_locale && is_utf8_locale() && has_non_ascii(p->pattern) &&
 	    !(!opt->ignore_case && (p->fixed || p->is_fixed)))
-		options |= PCRE2_UTF;
+		options |= (PCRE2_UTF | PCRE2_MATCH_INVALID_UTF);
+
+	if (PCRE2_MATCH_INVALID_UTF &&
+	    options & (PCRE2_UTF | PCRE2_CASELESS) &&
+	    !(PCRE2_MAJOR >= 10 && PCRE2_MAJOR >= 36))
+		/* Work around https://bugs.exim.org/show_bug.cgi?id=2642 fixed in 10.36 */
+		options |= PCRE2_NO_START_OPTIMIZE;
 
 	p->pcre2_pattern = pcre2_compile((PCRE2_SPTR)p->pattern,
 					 p->patternlen, options, &error, &erroffset,
diff --git a/grep.h b/grep.h
index b5c4e223a8..ade21c8812 100644
--- a/grep.h
+++ b/grep.h
@@ -18,6 +18,10 @@  typedef int pcre2_code;
 typedef int pcre2_match_data;
 typedef int pcre2_compile_context;
 #endif
+#ifndef PCRE2_MATCH_INVALID_UTF
+/* PCRE2_MATCH_* dummy also with !USE_LIBPCRE2, for test-pcre2-config.c */
+#define PCRE2_MATCH_INVALID_UTF 0
+#endif
 #include "thread-utils.h"
 #include "userdiff.h"
 
diff --git a/t/helper/test-pcre2-config.c b/t/helper/test-pcre2-config.c
new file mode 100644
index 0000000000..5258fdddba
--- /dev/null
+++ b/t/helper/test-pcre2-config.c
@@ -0,0 +1,12 @@ 
+#include "test-tool.h"
+#include "cache.h"
+#include "grep.h"
+
+int cmd__pcre2_config(int argc, const char **argv)
+{
+	if (argc == 2 && !strcmp(argv[1], "has-PCRE2_MATCH_INVALID_UTF")) {
+		int value = PCRE2_MATCH_INVALID_UTF;
+		return !value;
+	}
+	return 1;
+}
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 9d6d14d929..f97cd9f48a 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -46,6 +46,7 @@  static struct test_cmd cmds[] = {
 	{ "parse-options", cmd__parse_options },
 	{ "parse-pathspec-file", cmd__parse_pathspec_file },
 	{ "path-utils", cmd__path_utils },
+	{ "pcre2-config", cmd__pcre2_config },
 	{ "pkt-line", cmd__pkt_line },
 	{ "prio-queue", cmd__prio_queue },
 	{ "proc-receive", cmd__proc_receive},
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index a6470ff62c..28072c0ad5 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -35,6 +35,7 @@  int cmd__online_cpus(int argc, const char **argv);
 int cmd__parse_options(int argc, const char **argv);
 int cmd__parse_pathspec_file(int argc, const char** argv);
 int cmd__path_utils(int argc, const char **argv);
+int cmd__pcre2_config(int argc, const char **argv);
 int cmd__pkt_line(int argc, const char **argv);
 int cmd__prio_queue(int argc, const char **argv);
 int cmd__proc_receive(int argc, const char **argv);
diff --git a/t/t7812-grep-icase-non-ascii.sh b/t/t7812-grep-icase-non-ascii.sh
index 38457c2e4f..e5d1e4ea68 100755
--- a/t/t7812-grep-icase-non-ascii.sh
+++ b/t/t7812-grep-icase-non-ascii.sh
@@ -57,7 +57,12 @@  test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: setup invalid UTF-8 data'
 	printf "\\200\\n" >invalid-0x80 &&
 	echo "ævar" >expected &&
 	cat expected >>invalid-0x80 &&
-	git add invalid-0x80
+	git add invalid-0x80 &&
+
+	# Test for PCRE2_MATCH_INVALID_UTF bug
+	# https://bugs.exim.org/show_bug.cgi?id=2642
+	printf "\\345Aæ\\n" >invalid-0xe5 &&
+	git add invalid-0xe5
 '
 
 test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: grep ASCII from invalid UTF-8 data' '
@@ -67,6 +72,13 @@  test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: grep ASCII from invalid UT
 	test_cmp expected actual
 '
 
+test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: grep ASCII from invalid UTF-8 data (PCRE2 bug #2642)' '
+	git grep -h "Aæ" invalid-0xe5 >actual &&
+	test_cmp invalid-0xe5 actual &&
+	git grep -h "(*NO_JIT)Aæ" invalid-0xe5 >actual &&
+	test_cmp invalid-0xe5 actual
+'
+
 test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: grep non-ASCII from invalid UTF-8 data' '
 	git grep -h "æ" invalid-0x80 >actual &&
 	test_cmp expected actual &&
@@ -74,9 +86,41 @@  test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: grep non-ASCII from invali
 	test_cmp expected actual
 '
 
+test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: grep non-ASCII from invalid UTF-8 data (PCRE2 bug #2642)' '
+	git grep -h "Aæ" invalid-0xe5 >actual &&
+	test_cmp invalid-0xe5 actual &&
+	git grep -h "(*NO_JIT)Aæ" invalid-0xe5 >actual &&
+	test_cmp invalid-0xe5 actual
+'
+
+test_lazy_prereq PCRE2_MATCH_INVALID_UTF '
+	test-tool pcre2-config has-PCRE2_MATCH_INVALID_UTF
+'
+
 test_expect_success GETTEXT_LOCALE,LIBPCRE2 'PCRE v2: grep non-ASCII from invalid UTF-8 data with -i' '
 	test_might_fail git grep -hi "Æ" invalid-0x80 >actual &&
 	test_might_fail git grep -hi "(*NO_JIT)Æ" invalid-0x80 >actual
 '
 
+test_expect_success GETTEXT_LOCALE,LIBPCRE2,PCRE2_MATCH_INVALID_UTF 'PCRE v2: grep non-ASCII from invalid UTF-8 data with -i' '
+	git grep -hi "Æ" invalid-0x80 >actual &&
+	test_cmp expected actual &&
+	git grep -hi "(*NO_JIT)Æ" invalid-0x80 >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success GETTEXT_LOCALE,LIBPCRE2,PCRE2_MATCH_INVALID_UTF 'PCRE v2: grep non-ASCII from invalid UTF-8 data with -i (PCRE2 bug #2642)' '
+	git grep -hi "Æ" invalid-0xe5 >actual &&
+	test_cmp invalid-0xe5 actual &&
+	git grep -hi "(*NO_JIT)Æ" invalid-0xe5 >actual &&
+	test_cmp invalid-0xe5 actual &&
+
+	# Only the case of grepping the ASCII part in a way that
+	# relies on -i fails
+	git grep -hi "aÆ" invalid-0xe5 >actual &&
+	test_cmp invalid-0xe5 actual &&
+	git grep -hi "(*NO_JIT)aÆ" invalid-0xe5 >actual &&
+	test_cmp invalid-0xe5 actual
+'
+
 test_done