Merge patch series "coredump: further cleanups"

Christian Brauner <brauner@kernel.org> says:

Continue reworking the coredump code so it's easier to follow and modify
in the future.

* Each method is moved into a separate helper.
* The cleanup code is simplified and unified.
* Entangle the dependency between the pipe coredump rate limiting and
  the common exit path.

It's likely that there'll be more.

* patches from https://lore.kernel.org/20250612-work-coredump-massage-v1-0-315c0c34ba94@kernel.org: (24 commits)
  coredump: add coredump_skip() helper
  coredump: avoid pointless variable
  coredump: order auto cleanup variables at the top
  coredump: add coredump_cleanup()
  coredump: auto cleanup prepare_creds()
  cred: add auto cleanup method
  coredump: directly return
  coredump: auto cleanup argv
  coredump: add coredump_write()
  coredump: use a single helper for the socket
  coredump: move pipe specific file check into coredump_pipe()
  coredump: split pipe coredumping into coredump_pipe()
  coredump: move core_pipe_count to global variable
  coredump: prepare to simplify exit paths
  coredump: split file coredumping into coredump_file()
  coredump: rename do_coredump() to vfs_coredump()
  selftests/coredump: make sure invalid paths are rejected
  coredump: validate socket path in coredump_parse()
  coredump: don't allow ".." in coredump socket path
  fs: move name_contains_dotdot() to header
  ...

Link: https://lore.kernel.org/20250612-work-coredump-massage-v1-0-315c0c34ba94@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

1 files changed, 26 insertions, 6 deletions

diff --git a/tools/testing/selftests/coredump/stackdump_test.c b/tools/testing/selftests/coredump/stackdump_test.c
index 9a789156f27e..a4ac80bb1003 100644
--- a/tools/testing/selftests/coredump/stackdump_test.c
+++ b/tools/testing/selftests/coredump/stackdump_test.c
@@ -241,16 +241,19 @@ out:
 
 static bool set_core_pattern(const char *pattern)
 {
-	FILE *file;
-	int ret;
+	int fd;
+	ssize_t ret;
 
-	file = fopen("/proc/sys/kernel/core_pattern", "w");
-	if (!file)
+	fd = open("/proc/sys/kernel/core_pattern", O_WRONLY | O_CLOEXEC);
+	if (fd < 0)
 		return false;
 
-	ret = fprintf(file, "%s", pattern);
-	fclose(file);
+	ret = write(fd, pattern, strlen(pattern));
+	close(fd);
+	if (ret < 0)
+		return false;
 
+	fprintf(stderr, "Set core_pattern to '%s' | %zu == %zu\n", pattern, ret, strlen(pattern));
 	return ret == strlen(pattern);
 }
 
@@ -1804,4 +1807,21 @@ out:
 	wait_and_check_coredump_server(pid_coredump_server, _metadata, self);
 }
 
+TEST_F(coredump, socket_invalid_paths)
+{
+	ASSERT_FALSE(set_core_pattern("@ /tmp/coredump.socket"));
+	ASSERT_FALSE(set_core_pattern("@/tmp/../coredump.socket"));
+	ASSERT_FALSE(set_core_pattern("@../coredump.socket"));
+	ASSERT_FALSE(set_core_pattern("@/tmp/coredump.socket/.."));
+	ASSERT_FALSE(set_core_pattern("@.."));
+
+	ASSERT_FALSE(set_core_pattern("@@ /tmp/coredump.socket"));
+	ASSERT_FALSE(set_core_pattern("@@/tmp/../coredump.socket"));
+	ASSERT_FALSE(set_core_pattern("@@../coredump.socket"));
+	ASSERT_FALSE(set_core_pattern("@@/tmp/coredump.socket/.."));
+	ASSERT_FALSE(set_core_pattern("@@.."));
+
+	ASSERT_FALSE(set_core_pattern("@@@/tmp/coredump.socket"));
+}
+
 TEST_HARNESS_MAIN