From ba7a44da68adfa4f0d8285de4cdc16e3754929a8 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 25 May 2023 15:13:10 -0700 Subject: [PATCH] libbpf: Ensure libbpf always opens files with O_CLOEXEC Make sure that libbpf code always gets FD with O_CLOEXEC flag set, regardless if file is open through open() or fopen(). For the latter this means to add "e" to mode string, which is supported since pretty ancient glibc v2.7. Also drop the outdated TODO comment in usdt.c, which was already completed. Suggested-by: Lennart Poettering Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20230525221311.2136408-1-andrii@kernel.org --- src/btf.c | 2 +- src/libbpf.c | 6 +++--- src/libbpf_probes.c | 2 +- src/usdt.c | 5 ++--- 4 files changed, 7 insertions(+), 8 deletions(-) diff --git a/src/btf.c b/src/btf.c index 0a2c079..8484b56 100644 --- a/src/btf.c +++ b/src/btf.c @@ -1064,7 +1064,7 @@ static struct btf *btf_parse_raw(const char *path, struct btf *base_btf) int err = 0; long sz; - f = fopen(path, "rb"); + f = fopen(path, "rbe"); if (!f) { err = -errno; goto err_out; diff --git a/src/libbpf.c b/src/libbpf.c index 1ceb3a9..60ef4c5 100644 --- a/src/libbpf.c +++ b/src/libbpf.c @@ -4351,7 +4351,7 @@ static int bpf_get_map_info_from_fdinfo(int fd, struct bpf_map_info *info) snprintf(file, sizeof(file), "/proc/%d/fdinfo/%d", getpid(), fd); memset(info, 0, sizeof(*info)); - fp = fopen(file, "r"); + fp = fopen(file, "re"); if (!fp) { err = -errno; pr_warn("failed to open %s: %d. No procfs support?\n", file, @@ -7455,7 +7455,7 @@ int libbpf_kallsyms_parse(kallsyms_cb_t cb, void *ctx) int ret, err = 0; FILE *f; - f = fopen("/proc/kallsyms", "r"); + f = fopen("/proc/kallsyms", "re"); if (!f) { err = -errno; pr_warn("failed to open /proc/kallsyms: %d\n", err); @@ -10075,7 +10075,7 @@ static int parse_uint_from_file(const char *file, const char *fmt) int err, ret; FILE *f; - f = fopen(file, "r"); + f = fopen(file, "re"); if (!f) { err = -errno; pr_debug("failed to open '%s': %s\n", file, diff --git a/src/libbpf_probes.c b/src/libbpf_probes.c index 6065f40..5f78a02 100644 --- a/src/libbpf_probes.c +++ b/src/libbpf_probes.c @@ -38,7 +38,7 @@ static __u32 get_ubuntu_kernel_version(void) if (faccessat(AT_FDCWD, ubuntu_kver_file, R_OK, AT_EACCESS) != 0) return 0; - f = fopen(ubuntu_kver_file, "r"); + f = fopen(ubuntu_kver_file, "re"); if (!f) return 0; diff --git a/src/usdt.c b/src/usdt.c index 086eef3..f1a1415 100644 --- a/src/usdt.c +++ b/src/usdt.c @@ -466,7 +466,7 @@ static int parse_vma_segs(int pid, const char *lib_path, struct elf_seg **segs, proceed: sprintf(line, "/proc/%d/maps", pid); - f = fopen(line, "r"); + f = fopen(line, "re"); if (!f) { err = -errno; pr_warn("usdt: failed to open '%s' to get base addr of '%s': %d\n", @@ -954,8 +954,7 @@ struct bpf_link *usdt_manager_attach_usdt(struct usdt_manager *man, const struct spec_map_fd = bpf_map__fd(man->specs_map); ip_map_fd = bpf_map__fd(man->ip_to_spec_id_map); - /* TODO: perform path resolution similar to uprobe's */ - fd = open(path, O_RDONLY); + fd = open(path, O_RDONLY | O_CLOEXEC); if (fd < 0) { err = -errno; pr_warn("usdt: failed to open ELF binary '%s': %d\n", path, err);