fast-import: check committer name more strictly

The documentation declares following identity format:
(<name> SP)? LT <email> GT
where name is any string without LF and LT characters.
But fast-import just accepts any string up to first GT
instead of checking the whole format, and moreover just
writes it as is to the commit object.

git-fsck checks for [^<\n]* <[^<>\n]*> format. Note that the
space is mandatory. And the space quirk is already handled via
extending the string to the left when needed.

Modify fast-import input identity format to a slightly stricter
one - deny LF, LT and GT in both <name> and <email>. And check
for it.

This is stricter then git-fsck as fsck accepts "Name> <email>"
currently, but soon fsck check will be adjusted likewise.

Signed-off-by: Dmitry Ivankov <divanorama@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-fast-import.txt

@@ -413,8 +413,8 @@ Here `<name>` is the person's display name (for example
 (``cm@example.com'').  `LT` and `GT` are the literal less-than (\x3c)
 and greater-than (\x3e) symbols.  These are required to delimit
 the email address from the other fields in the line.  Note that
-`<name>` is free-form and may contain any sequence of bytes, except
-`LT` and `LF`.  It is typically UTF-8 encoded.
+`<name>` and `<email>` are free-form and may contain any sequence
+of bytes, except `LT`, `GT` and `LF`.  `<name>` is typically UTF-8 encoded.
 
 The time of the change is specified by `<when>` using the date format
 that was selected by the \--date-format=<fmt> command line option.

fast-import.c

@@ -1967,7 +1967,7 @@ static int validate_raw_date(const char *src, char *result, int maxlen)
 
 static char *parse_ident(const char *buf)
 {
-	const char *gt;
+	const char *ltgt;
 	size_t name_len;
 	char *ident;
 
@@ -1975,28 +1975,33 @@ static char *parse_ident(const char *buf)
 	if (*buf == '<')
 		--buf;
 
-	gt = strrchr(buf, '>');
-	if (!gt)
+	ltgt = buf + strcspn(buf, "<>");
+	if (*ltgt != '<')
+		die("Missing < in ident string: %s", buf);
+	if (ltgt != buf && ltgt[-1] != ' ')
+		die("Missing space before < in ident string: %s", buf);
+	ltgt = ltgt + 1 + strcspn(ltgt + 1, "<>");
+	if (*ltgt != '>')
 		die("Missing > in ident string: %s", buf);
-	gt++;
-	if (*gt != ' ')
+	ltgt++;
+	if (*ltgt != ' ')
 		die("Missing space after > in ident string: %s", buf);
-	gt++;
-	name_len = gt - buf;
+	ltgt++;
+	name_len = ltgt - buf;
 	ident = xmalloc(name_len + 24);
 	strncpy(ident, buf, name_len);
 
 	switch (whenspec) {
 	case WHENSPEC_RAW:
-		if (validate_raw_date(gt, ident + name_len, 24) < 0)
-			die("Invalid raw date \"%s\" in ident: %s", gt, buf);
+		if (validate_raw_date(ltgt, ident + name_len, 24) < 0)
+			die("Invalid raw date \"%s\" in ident: %s", ltgt, buf);
 		break;
 	case WHENSPEC_RFC2822:
-		if (parse_date(gt, ident + name_len, 24) < 0)
-			die("Invalid rfc2822 date \"%s\" in ident: %s", gt, buf);
+		if (parse_date(ltgt, ident + name_len, 24) < 0)
+			die("Invalid rfc2822 date \"%s\" in ident: %s", ltgt, buf);
 		break;
 	case WHENSPEC_NOW:
-		if (strcmp("now", gt))
+		if (strcmp("now", ltgt))
 			die("Date in ident must be 'now': %s", buf);
 		datestamp(ident + name_len, 24);
 		break;

t/t9300-fast-import.sh

@@ -370,7 +370,7 @@ data <<COMMIT
 empty commit
 COMMIT
 INPUT_END
-test_expect_failure 'B: fail on invalid committer (1)' '
+test_expect_success 'B: fail on invalid committer (1)' '
 	test_must_fail git fast-import <input
 '
 git update-ref -d refs/heads/invalid-committer || true
@@ -382,7 +382,7 @@ data <<COMMIT
 empty commit
 COMMIT
 INPUT_END
-test_expect_failure 'B: fail on invalid committer (2)' '
+test_expect_success 'B: fail on invalid committer (2)' '
 	test_must_fail git fast-import <input
 '
 git update-ref -d refs/heads/invalid-committer || true
@@ -394,7 +394,7 @@ data <<COMMIT
 empty commit
 COMMIT
 INPUT_END
-test_expect_failure 'B: fail on invalid committer (3)' '
+test_expect_success 'B: fail on invalid committer (3)' '
 	test_must_fail git fast-import <input
 '
 git update-ref -d refs/heads/invalid-committer || true
@@ -406,7 +406,7 @@ data <<COMMIT
 empty commit
 COMMIT
 INPUT_END
-test_expect_failure 'B: fail on invalid committer (4)' '
+test_expect_success 'B: fail on invalid committer (4)' '
 	test_must_fail git fast-import <input
 '
 git update-ref -d refs/heads/invalid-committer || true
@@ -418,7 +418,7 @@ data <<COMMIT
 empty commit
 COMMIT
 INPUT_END
-test_expect_failure 'B: fail on invalid committer (5)' '
+test_expect_success 'B: fail on invalid committer (5)' '
 	test_must_fail git fast-import <input
 '
 git update-ref -d refs/heads/invalid-committer || true