diff options
| author |  Andrii Nakryiko <andrii@kernel.org>
| 2023-05-25 15:13:11 -0700 |
|---|---|---|
| committer |  Daniel Borkmann <daniel@iogearbox.net>
| 2023-05-26 12:05:52 +0200 |
| commit | 4aadd2920b81b3d7e5c8ac63c7d5d673f3c8aaeb (patch) | |
| tree | 4a1d54f6f718825b19120ab68b73447f570321e0 | |
| parent | libbpf: Ensure libbpf always opens files with O_CLOEXEC (diff) | |
| download | linux-4aadd2920b81b3d7e5c8ac63c7d5d673f3c8aaeb.tar.gz linux-4aadd2920b81b3d7e5c8ac63c7d5d673f3c8aaeb.tar.bz2 linux-4aadd2920b81b3d7e5c8ac63c7d5d673f3c8aaeb.zip | |
libbpf: Ensure FD >= 3 during bpf_map__reuse_fd()
Improve bpf_map__reuse_fd() logic and ensure that dup'ed map FD is
"good" (>= 3) and has O_CLOEXEC flags. Use fcntl(F_DUPFD_CLOEXEC) for
that, similarly to ensure_good_fd() helper we already use in low-level
APIs that work with bpf() syscall.
Suggested-by: Lennart Poettering <lennart@poettering.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230525221311.2136408-2-andrii@kernel.org
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 60ef4c5e3bee..47632606b06d 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4414,18 +4414,17 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd) if (!new_name) return libbpf_err(-errno); - new_fd = open("/", O_RDONLY | O_CLOEXEC); + /* + * Like dup(), but make sure new FD is >= 3 and has O_CLOEXEC set. + * This is similar to what we do in ensure_good_fd(), but without + * closing original FD. + */ + new_fd = fcntl(fd, F_DUPFD_CLOEXEC, 3); if (new_fd < 0) { err = -errno; goto err_free_new_name; } - new_fd = dup3(fd, new_fd, O_CLOEXEC); - if (new_fd < 0) { - err = -errno; - goto err_close_new_fd; - } - err = zclose(map->fd); if (err) { err = -errno; |