From b3051cd82d92dda7e247c116b953bcdc0779e4e4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Sat, 2 Nov 2019 12:09:37 +0100 Subject: [PATCH] libbpf: Fix error handling in bpf_map__reuse_fd() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ 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 Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/157269297769.394725.12634985106772698611.stgit@toke.dk Signed-off-by: Sasha Levin --- tools/lib/bpf/libbpf.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index a62be78fc07b..249fa8d7376e 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -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 @@ err_close_new_fd: close(new_fd); err_free_new_name: free(new_name); - return -errno; + return err; } static int