From 486f13bbec488424037a24e7d58a9e1c2f91d19f Mon Sep 17 00:00:00 2001
From: Elijah Newren <newren@gmail.com>
Date: Wed, 27 Nov 2024 09:24:17 -0800
Subject: [PATCH] fast-import: disallow more path components

Instead of just disallowing '.' and '..', make use of verify_path() to
ensure that fast-import will disallow anything we wouldn't allow into
the index, such as anything under .git/, .gitmodules as a symlink, or
a dos drive prefix on Windows.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 builtin/fast-import.c  |  5 +--
 t/t9300-fast-import.sh | 82 +++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 84 insertions(+), 3 deletions(-)

diff --git a/builtin/fast-import.c b/builtin/fast-import.c
index 995ef76f9d6c6a..1e7452dd64d0ab 100644
--- a/builtin/fast-import.c
+++ b/builtin/fast-import.c
@@ -13,6 +13,7 @@
 #include "delta.h"
 #include "pack.h"
 #include "path.h"
+#include "read-cache-ll.h"
 #include "refs.h"
 #include "csum-file.h"
 #include "quote.h"
@@ -1411,6 +1412,8 @@ static int tree_content_set(
 		die("Empty path component found in input");
 	if (!*slash1 && !S_ISDIR(mode) && subtree)
 		die("Non-directories cannot have subtrees");
+	if (!verify_path(p, mode))
+		die("invalid path '%s'", p);
 
 	if (!root->tree)
 		load_tree(root);
@@ -1466,8 +1469,6 @@ static int tree_content_set(
 		root->tree = t = grow_tree_content(t, t->entry_count);
 	e = new_tree_entry();
 	e->name = to_atom(p, n);
-	if (is_dot_or_dotdot(e->name->str_dat))
-		die("path %s contains invalid component", p);
 	e->versions[0].mode = 0;
 	oidclr(&e->versions[0].oid, the_repository->hash_algo);
 	t->entries[t->entry_count++] = e;
diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index caf3dc003a028b..e8e8a191d9dcd6 100755
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -522,7 +522,7 @@ test_expect_success 'B: fail on invalid committer (5)' '
 	test_must_fail git fast-import <input
 '
 
-test_expect_success 'B: fail on invalid file path' '
+test_expect_success 'B: fail on invalid file path of ..' '
 	cat >input <<-INPUT_END &&
 	blob
 	mark :1
@@ -542,6 +542,86 @@ test_expect_success 'B: fail on invalid file path' '
 	test_must_fail git fast-import <input
 '
 
+test_expect_success 'B: fail on invalid file path of .' '
+	cat >input <<-INPUT_END &&
+	blob
+	mark :1
+	data <<EOF
+	File contents
+	EOF
+
+	commit refs/heads/badpath
+	committer Name <email> $GIT_COMMITTER_DATE
+	data <<COMMIT
+	Commit Message
+	COMMIT
+	M 100644 :1 ./invalid-path
+	INPUT_END
+
+	test_when_finished "git update-ref -d refs/heads/badpath" &&
+	test_must_fail git fast-import <input
+'
+
+test_expect_success WINDOWS 'B: fail on invalid file path of C:' '
+	cat >input <<-INPUT_END &&
+	blob
+	mark :1
+	data <<EOF
+	File contents
+	EOF
+
+	commit refs/heads/badpath
+	committer Name <email> $GIT_COMMITTER_DATE
+	data <<COMMIT
+	Commit Message
+	COMMIT
+	M 100644 :1 C:/invalid-path
+	INPUT_END
+
+	test_when_finished "git update-ref -d refs/heads/badpath" &&
+	test_must_fail git fast-import <input
+'
+
+test_expect_success 'B: fail on invalid file path of .git' '
+	cat >input <<-INPUT_END &&
+	blob
+	mark :1
+	data <<EOF
+	File contents
+	EOF
+
+	commit refs/heads/badpath
+	committer Name <email> $GIT_COMMITTER_DATE
+	data <<COMMIT
+	Commit Message
+	COMMIT
+	M 100644 :1 .git/invalid-path
+	INPUT_END
+
+	test_when_finished "git update-ref -d refs/heads/badpath" &&
+	test_must_fail git fast-import <input
+'
+
+test_expect_success 'B: fail on invalid file path of .gitmodules' '
+	cat >input <<-INPUT_END &&
+	blob
+	mark :1
+	data <<EOF
+	File contents
+	EOF
+
+	commit refs/heads/badpath
+	committer Name <email> $GIT_COMMITTER_DATE
+	data <<COMMIT
+	Commit Message
+	COMMIT
+	M 120000 :1 .gitmodules
+	INPUT_END
+
+	test_when_finished "git update-ref -d refs/heads/badpath" &&
+	test_must_fail git fast-import <input
+'
+
 ###
 ### series C
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