libbpf: Use O_CLOEXEC uniformly when opening fds

There are some instances where we don't use O_CLOEXEC when opening an
fd, fix these up. Otherwise, it is possible that a parallel fork causes
these fds to leak into a child process on execve.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211028063501.2239335-6-memxor@gmail.com

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 0c628c3..7e4c558 100644 (file)
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -897,7 +897,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf,
                return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
        }
 
-       fd = open(path, O_RDONLY);
+       fd = open(path, O_RDONLY | O_CLOEXEC);
        if (fd < 0) {
                err = -errno;
                pr_warn("failed to open %s: %s\n", path, strerror(errno));

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 73e1e70..742d1a3 100644 (file)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1232,7 +1232,7 @@ static int bpf_object__elf_init(struct bpf_object *obj)
                 */
                elf = elf_memory((char *)obj->efile.obj_buf, obj->efile.obj_buf_sz);
        } else {
-               obj->efile.fd = open(obj->path, O_RDONLY);
+               obj->efile.fd = open(obj->path, O_RDONLY | O_CLOEXEC);
                if (obj->efile.fd < 0) {
                        char errmsg[STRERR_BUFSIZE], *cp;
 
@@ -9615,7 +9615,7 @@ static int append_to_file(const char *file, const char *fmt, ...)
        int fd, n, err = 0;
        va_list ap;
 
-       fd = open(file, O_WRONLY | O_APPEND, 0);
+       fd = open(file, O_WRONLY | O_APPEND | O_CLOEXEC, 0);
        if (fd < 0)
                return -errno;
 
@@ -11260,7 +11260,7 @@ int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz)
        int fd, err = 0, len;
        char buf[128];
 
-       fd = open(fcpu, O_RDONLY);
+       fd = open(fcpu, O_RDONLY | O_CLOEXEC);
        if (fd < 0) {
                err = -errno;
                pr_warn("Failed to open cpu mask file %s: %d\n", fcpu, err);

diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c
index cd8c703..68f2dbf 100644 (file)
--- a/tools/lib/bpf/libbpf_probes.c
+++ b/tools/lib/bpf/libbpf_probes.c
@@ -33,7 +33,7 @@ static int get_vendor_id(int ifindex)
 
        snprintf(path, sizeof(path), "/sys/class/net/%s/device/vendor", ifname);
 
-       fd = open(path, O_RDONLY);
+       fd = open(path, O_RDONLY | O_CLOEXEC);
        if (fd < 0)
                return -1;
 

diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c
index ce0800e..f677dcc 100644 (file)
--- a/tools/lib/bpf/linker.c
+++ b/tools/lib/bpf/linker.c
@@ -301,7 +301,7 @@ static int init_output_elf(struct bpf_linker *linker, const char *file)
        if (!linker->filename)
                return -ENOMEM;
 
-       linker->fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+       linker->fd = open(file, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0644);
        if (linker->fd < 0) {
                err = -errno;
                pr_warn("failed to create '%s': %d\n", file, err);
@@ -556,7 +556,7 @@ static int linker_load_obj_file(struct bpf_linker *linker, const char *filename,
 
        obj->filename = filename;
 
-       obj->fd = open(filename, O_RDONLY);
+       obj->fd = open(filename, O_RDONLY | O_CLOEXEC);
        if (obj->fd < 0) {
                err = -errno;
                pr_warn("failed to open file '%s': %d\n", filename, err);

diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
index a211169..81f8fbc 100644 (file)
--- a/tools/lib/bpf/xsk.c
+++ b/tools/lib/bpf/xsk.c
@@ -300,7 +300,7 @@ int xsk_umem__create_v0_0_4(struct xsk_umem **umem_ptr, void *umem_area,
        if (!umem)
                return -ENOMEM;
 
-       umem->fd = socket(AF_XDP, SOCK_RAW, 0);
+       umem->fd = socket(AF_XDP, SOCK_RAW | SOCK_CLOEXEC, 0);
        if (umem->fd < 0) {
                err = -errno;
                goto out_umem_alloc;
@@ -549,7 +549,7 @@ static int xsk_get_max_queues(struct xsk_socket *xsk)
        struct ifreq ifr = {};
        int fd, err, ret;
 
-       fd = socket(AF_LOCAL, SOCK_DGRAM, 0);
+       fd = socket(AF_LOCAL, SOCK_DGRAM | SOCK_CLOEXEC, 0);
        if (fd < 0)
                return -errno;
 
@@ -1046,7 +1046,7 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr,
        }
 
        if (umem->refcount++ > 0) {
-               xsk->fd = socket(AF_XDP, SOCK_RAW, 0);
+               xsk->fd = socket(AF_XDP, SOCK_RAW | SOCK_CLOEXEC, 0);
                if (xsk->fd < 0) {
                        err = -errno;
                        goto out_xsk_alloc;