Commit b3051cd8 authored Nov 02, 2019 by Toke Høiland-Jørgensen Committed by Greg Kroah-Hartman Dec 31, 2019

libbpf: Fix error handling in bpf_map__reuse_fd()



[ Upstream commit d1b4574a4b86565325ef2e545eda8dfc9aa07c60 ]

bpf_map__reuse_fd() was calling close() in the error path before returning
an error value based on errno. However, close can change errno, so that can
lead to potentially misleading error messages. Instead, explicitly store
errno in the err variable before each goto.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157269297769.394725.12634985106772698611.stgit@toke.dk


Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 77a6a265

tools/lib/bpf/libbpf.c

+10 −4

Original line number	Diff line number	Diff line
		@@ -1073,16 +1073,22 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd)
		return -errno;

		new_fd = open("/", O_RDONLY \| O_CLOEXEC);
		if (new_fd < 0)
		if (new_fd < 0) {
		err = -errno;
		goto err_free_new_name;
		}

		new_fd = dup3(fd, new_fd, O_CLOEXEC);
		if (new_fd < 0)
		if (new_fd < 0) {
		err = -errno;
		goto err_close_new_fd;
		}

		err = zclose(map->fd);
		if (err)
		if (err) {
		err = -errno;
		goto err_close_new_fd;
		}
		free(map->name);

		map->fd = new_fd;
		@@ -1101,7 +1107,7 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd)
		close(new_fd);
		err_free_new_name:
		free(new_name);
		return -errno;
		return err;
		}

		static int