From: Johannes Schindelin <johannes.schindelin@gmx.de>
To: git@vger.kernel.org
Cc: Junio C Hamano <gitster@pobox.com>, Jeff King <peff@peff.net>
Subject: [PATCH v3 0/3] Fix a segfault caused by regexec() being called on mmap()ed data
Date: Thu, 8 Sep 2016 09:57:27 +0200 (CEST) [thread overview]
Message-ID: <cover.1473321437.git.johannes.schindelin@gmx.de> (raw)
In-Reply-To: <cover.1473319844.git.johannes.schindelin@gmx.de>
This patch series addresses a problem where `git diff` is called using
`-G` or `-S --pickaxe-regex` on new-born files that are configured
without user diff drivers, and that hence get mmap()ed into memory.
The problem with that: mmap()ed memory is *not* NUL-terminated, yet the
pickaxe code calls regexec() on it just the same.
This problem has been reported by my colleague Chris Sidi.
We solve this by introducing a helper, regexec_buf(), that takes a
pointer and a length instead of a NUL-terminated string.
This helper then uses REG_STARTEND where available, and falls back to
allocating and constructing a NUL-terminated string. Given the
wide-spread support for REG_STARTEND (Linux has it, MacOSX has it, Git
for Windows has it because it uses compat/regex/ that has it), I think
this is a fair trade-off.
Changes since v2:
- changed 3/3 to switch the test_expect_failure from 1/3 to a
test_expect_success
Johannes Schindelin (3):
Demonstrate a problem: our pickaxe code assumes NUL-terminated buffers
Introduce a function to run regexec() on non-NUL-terminated buffers
Use the newly-introduced regexec_buf() function
diff.c | 3 ++-
diffcore-pickaxe.c | 18 ++++++++----------
git-compat-util.h | 21 +++++++++++++++++++++
t/t4061-diff-pickaxe.sh | 22 ++++++++++++++++++++++
xdiff-interface.c | 13 ++++---------
5 files changed, 57 insertions(+), 20 deletions(-)
create mode 100755 t/t4061-diff-pickaxe.sh
Published-As: https://github.com/dscho/git/releases/tag/mmap-regexec-v3
Fetch-It-Via: git fetch https://github.com/dscho/git mmap-regexec-v3
Interdiff vs v2:
diff --git a/t/t4061-diff-pickaxe.sh b/t/t4061-diff-pickaxe.sh
index 5929f2e..f0bf50b 100755
--- a/t/t4061-diff-pickaxe.sh
+++ b/t/t4061-diff-pickaxe.sh
@@ -14,7 +14,7 @@ test_expect_success setup '
test_tick &&
git commit -m "A 4k file"
'
-test_expect_failure '-G matches' '
+test_expect_success '-G matches' '
git diff --name-only -G "^0{4096}$" HEAD^ >out &&
test 4096-zeroes.txt = "$(cat out)"
'
--
2.10.0.windows.1.10.g803177d
base-commit: 6ebdac1bab966b720d776aa43ca188fe378b1f4b
next prev parent reply other threads:[~2016-09-08 7:57 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-05 15:44 [PATCH 0/3] Fix a segfault caused by regexec() being called on mmap()ed data Johannes Schindelin
2016-09-05 15:45 ` [PATCH 1/3] Demonstrate a problem: our pickaxe code assumes NUL-terminated buffers Johannes Schindelin
2016-09-06 18:43 ` Jeff King
2016-09-08 7:53 ` Johannes Schindelin
2016-09-05 15:45 ` [PATCH 2/3] diff_populate_filespec: NUL-terminate buffers Johannes Schindelin
2016-09-06 7:06 ` Jeff King
2016-09-06 16:02 ` Johannes Schindelin
2016-09-06 18:41 ` Jeff King
2016-09-07 18:31 ` Junio C Hamano
2016-09-08 7:52 ` Johannes Schindelin
2016-09-08 7:49 ` Johannes Schindelin
2016-09-08 8:22 ` Jeff King
2016-09-08 16:57 ` Junio C Hamano
2016-09-08 18:22 ` Johannes Schindelin
2016-09-08 18:48 ` Jeff King
2016-09-05 15:45 ` [PATCH 3/3] diff_grep: add assertions verifying that the buffers are NUL-terminated Johannes Schindelin
2016-09-06 7:08 ` Jeff King
2016-09-06 16:04 ` Johannes Schindelin
2016-09-05 19:10 ` [PATCH 0/3] Fix a segfault caused by regexec() being called on mmap()ed data Junio C Hamano
2016-09-06 7:12 ` Jeff King
2016-09-06 14:06 ` Johannes Schindelin
2016-09-06 18:29 ` Jeff King
2016-09-08 7:29 ` Johannes Schindelin
2016-09-08 8:00 ` Jeff King
2016-09-09 10:09 ` Johannes Schindelin
2016-09-09 17:46 ` Junio C Hamano
2016-09-06 13:21 ` Johannes Schindelin
2016-09-06 6:58 ` Jeff King
2016-09-06 14:13 ` Johannes Schindelin
2016-09-08 7:31 ` [PATCH v2 " Johannes Schindelin
2016-09-08 7:31 ` [PATCH v2 2/3] Introduce a function to run regexec() on non-NUL-terminated buffers Johannes Schindelin
2016-09-08 8:04 ` Jeff King
2016-09-09 9:45 ` Johannes Schindelin
2016-09-09 9:59 ` Jeff King
2016-09-08 7:31 ` [PATCH v2 1/3] Demonstrate a problem: our pickaxe code assumes NUL-terminated buffers Johannes Schindelin
2016-09-08 7:31 ` [PATCH v2 3/3] Use the newly-introduced regexec_buf() function Johannes Schindelin
2016-09-08 7:54 ` Johannes Schindelin
2016-09-08 8:10 ` Jeff King
2016-09-08 8:14 ` Jeff King
2016-09-08 8:35 ` Jeff King
2016-09-08 19:06 ` Ramsay Jones
2016-09-08 19:53 ` Jeff King
2016-09-08 21:30 ` Junio C Hamano
2016-09-08 7:33 ` [PATCH v2 0/3] Fix a segfault caused by regexec() being called on mmap()ed data Johannes Schindelin
2016-09-08 8:13 ` Jeff King
2016-09-08 7:57 ` Johannes Schindelin [this message]
2016-09-08 7:57 ` [PATCH v3 1/3] Demonstrate a problem: our pickaxe code assumes NUL-terminated buffers Johannes Schindelin
2016-09-08 7:58 ` [PATCH v3 2/3] Introduce a function to run regexec() on non-NUL-terminated buffers Johannes Schindelin
2016-09-08 17:03 ` Junio C Hamano
2016-09-08 7:59 ` [PATCH v3 3/3] Use the newly-introduced regexec_buf() function Johannes Schindelin
2016-09-08 17:09 ` Junio C Hamano
2016-09-09 9:52 ` Johannes Schindelin
2016-09-09 9:57 ` Jeff King
2016-09-09 10:41 ` Johannes Schindelin
2016-09-09 17:49 ` Junio C Hamano
2016-09-21 18:23 ` [PATCH v4 0/3] Fix a segfault caused by regexec() being called on mmap()ed data Johannes Schindelin
2016-09-21 18:23 ` [PATCH v4 1/3] regex: -G<pattern> feeds a non NUL-terminated string to regexec() and fails Johannes Schindelin
2016-09-21 18:24 ` [PATCH v4 2/3] regex: add regexec_buf() that can work on a non NUL-terminated string Johannes Schindelin
2016-09-21 19:17 ` Junio C Hamano
2016-09-22 18:38 ` Johannes Schindelin
2016-09-21 18:24 ` [PATCH v4 3/3] regex: use regexec_buf() Johannes Schindelin
2016-09-21 19:18 ` Junio C Hamano
2016-09-21 20:09 ` Junio C Hamano
2016-09-21 22:03 ` Jeff King
2016-09-25 14:01 ` Johannes Schindelin
2016-09-21 22:04 ` [PATCH v4 0/3] Fix a segfault caused by regexec() being called on mmap()ed data Jeff King
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