[PATCH v2 1/2] commit: reject invalid UTF-8 codepoints
- From
brian m. carlson <sandals@crustytoothpaste.net>
- Date
- Jul 4, 2013, 17:19 UTC
- Message-ID
- <20130704171943.GA267700@vauxhall.crustytoothpaste.net>
- In-Reply-To
- <cover.1372957719.git.sandals@crustytoothpaste.net>
The commit code already contains code for validating UTF-8, but it does not check for invalid values, such as guaranteed non-characters and surrogates. Fix this by explicitly checking for and rejecting such characters.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> --- commit.c | 27 ++++++++++++++++++++++----- t/t3900-i18n-commit.sh | 12 ++++++++++++ 2 files changed, 34 insertions(+), 5 deletions(-)
diff --git a/commit.c b/commit.c index 888e02a..2264106 100644 --- a/commit.c +++ b/commit.c @@ -1244,6 +1244,7 @@ static int find_invalid_utf8(const char *buf, int len) while (len) { unsigned char c = *buf++; int bytes, bad_offset; + unsigned int codepoint; len--; offset++; @@ -1264,24 +1265,40 @@ static int find_invalid_utf8(const char *buf, int len) bytes++; } - /* Must be between 1 and 5 more bytes */ - if (bytes < 1 || bytes > 5) + /* + * Must be between 1 and 3 more bytes. Longer sequences result in + * codepoints beyond U+10FFFF, which are guaranteed never to exist. + */ + if (bytes < 1 || bytes > 3) return bad_offset; /* Do we *have* that many bytes? */ if (len < bytes) return bad_offset; + /* Place the encoded bits at the bottom of the value. */ + codepoint = (c & 0x7f) >> bytes; + offset += bytes; len -= bytes; /* And verify that they are good continuation bytes */ do { + codepoint <<= 6; + codepoint |= *buf & 0x3f; if ((*buf++ & 0xc0) != 0x80) return bad_offset; } while (--bytes); - /* We could/should check the value and length here too */ + /* No codepoints can ever be allocated beyond U+10FFFF. */ + if (codepoint > 0x10ffff) + return bad_offset; + /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */ + if ((codepoint & 0x1ff800) == 0xd800) + return bad_offset; + /* U+FFFE and U+FFFF are guaranteed non-characters. */ + if ((codepoint & 0x1ffffe) == 0xfffe) + return bad_offset; } return -1; } @@ -1292,8 +1309,8 @@ static int find_invalid_utf8(const char *buf, int len) * If it isn't, it assumes any non-utf8 characters are Latin1, * and does the conversion. * - * Fixme: we should probably also disallow overlong forms and - * invalid characters. But we don't do that currently. + * Fixme: we should probably also disallow overlong forms. + * But we don't do that currently. */ static int verify_utf8(struct strbuf *buf) { diff --git a/t/t3900-i18n-commit.sh b/t/t3900-i18n-commit.sh index 37ddabb..ee8ba6c 100755 --- a/t/t3900-i18n-commit.sh +++ b/t/t3900-i18n-commit.sh @@ -39,6 +39,18 @@ test_expect_failure 'UTF-16 refused because of NULs' ' git commit -a -F "$TEST_DIRECTORY"/t3900/UTF-16.txt ' +test_expect_success 'UTF-8 invalid characters refused' ' + test_when_finished "rm -f $HOME/stderr $HOME/invalid" && + rm -f "$HOME/stderr" && + echo "UTF-8 characters" >F && + printf "Commit message\n\nInvalid surrogate:\355\240\200\n" \ + >"$HOME/invalid" && + git commit -a -F "$HOME/invalid" \ + 2>"$HOME"/stderr && + grep "did not conform" "$HOME"/stderr +' + +rm -f "$HOME/stderr" for H in ISO8859-1 eucJP ISO-2022-JP do
-- 1.8.3.1