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[PATCH v2] grep: work around UTF-8 related JIT bug in PCRE2 <= 10.34

From
Mathias Krause <minipli@grsecurity.net>
Date
Mar 23, 2023, 17:25 UTC
Message-ID
<20230323172539.25230-1-minipli@grsecurity.net>
In-Reply-To
<20230323144000.21146-1-minipli@grsecurity.net>

Stephane is reporting[1] a regression introduced in git v2.40.0 that leads to 'git grep' segfaulting in his CI pipeline. It turns out, he's using an older version of libpcre2 that triggers a wild pointer dereference in the generated JIT code that was fixed in PCRE2 10.35.

Instead of completely disabling the JIT compiler for the buggy version, just mask out the Unicode property handling as we used to do prior to commit acabd2048ee0 ("grep: correctly identify utf-8 characters with \{b,w} in -P").

[1] https://lore.kernel.org/git/7E83DAA1-F9A9-4151-8D07-D80EA6D59EEA@clumio.com/
Reported-by: Stephane Odul <stephane@clumio.com>
Signed-off-by: Mathias Krause <minipli@grsecurity.net>
---
v2:
- make PCRE2_UCP masking depend only on the PCRE2 version, as
  suggested by Junio
 grep.c | 9 +++++++++
 grep.h | 3 +++
 2 files changed, 12 insertions(+)
diff --git a/grep.c b/grep.c
index cee44a78d044..dcfa7a27bf88 100644
--- a/grep.c
+++ b/grep.c
@@ -320,6 +320,15 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
 	if (!opt->ignore_locale && is_utf8_locale() && !literal)
 		options |= (PCRE2_UTF | PCRE2_UCP | PCRE2_MATCH_INVALID_UTF);
 
+#ifndef GIT_PCRE2_VERSION_10_35_OR_HIGHER
+	/*
+	 * Work around a JIT bug related to invalid Unicode character handling
+	 * fixed in 10.35:
+	 * https://github.com/PCRE2Project/pcre2/commit/c21bd977547d
+	 */
+	options &= ~PCRE2_UCP;
+#endif
+
 #ifndef GIT_PCRE2_VERSION_10_36_OR_HIGHER
 	/* Work around https://bugs.exim.org/show_bug.cgi?id=2642 fixed in 10.36 */
 	if (PCRE2_MATCH_INVALID_UTF && options & (PCRE2_UTF | PCRE2_CASELESS))
diff --git a/grep.h b/grep.h
index 6075f997e68f..c59592e3bdba 100644
--- a/grep.h
+++ b/grep.h
@@ -7,6 +7,9 @@
 #if (PCRE2_MAJOR >= 10 && PCRE2_MINOR >= 36) || PCRE2_MAJOR >= 11
 #define GIT_PCRE2_VERSION_10_36_OR_HIGHER
 #endif
+#if (PCRE2_MAJOR >= 10 && PCRE2_MINOR >= 35) || PCRE2_MAJOR >= 11
+#define GIT_PCRE2_VERSION_10_35_OR_HIGHER
+#endif
 #if (PCRE2_MAJOR >= 10 && PCRE2_MINOR >= 34) || PCRE2_MAJOR >= 11
 #define GIT_PCRE2_VERSION_10_34_OR_HIGHER
 #endif
-- 
2.39.2
Previous: Mathias Krause
Message 11 of 11 in “Suspected git grep regression in git 2.40.0”
  1. Stephane OdulMar 21, 2023
  2. Bagas SanjayaMar 21, 2023
  3. Junio C HamanoMar 21, 2023
  4. Mathias KrauseMar 21, 2023
  5. Stephane OdulMar 21, 2023
  6. Mathias KrauseMar 22, 2023
  7. Stephane OdulMar 22, 2023
  8. Mathias KrauseMar 23, 2023
  9. Junio C HamanoMar 23, 2023
  10. Mathias KrauseMar 23, 2023
  11. grep: work around UTF-8 related JIT bug in PCRE2 <= 10.34Mathias Krause, Mar 23, 2023

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