security: bpf: Add LSM hooks for bpf object related syscall

Introduce several LSM hooks for the syscalls that will allow the
userspace to access to eBPF object such as eBPF programs and eBPF maps.
The security check is aimed to enforce a per object security protection
for eBPF object so only processes with the right priviliges can
read/write to a specific map or use a specific eBPF program. Besides
that, a general security hook is added before the multiplexer of bpf
syscall to check the cmd and the attribute used for the command. The
actual security module can decide which command need to be checked and
how the cmd should be checked.

Signed-off-by: Chenbo Feng <fengc@google.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 32 insertions, 0 deletions

diff --git a/security/security.c b/security/security.c
index 4bf0f57..1cd8526 100644
--- a/security/security.c
+++ b/security/security.c
@@ -12,6 +12,7 @@
  *	(at your option) any later version.
  */
 
+#include <linux/bpf.h>
 #include <linux/capability.h>
 #include <linux/dcache.h>
 #include <linux/module.h>
@@ -1703,3 +1704,34 @@ int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule,
 				actx);
 }
 #endif /* CONFIG_AUDIT */
+
+#ifdef CONFIG_BPF_SYSCALL
+int security_bpf(int cmd, union bpf_attr *attr, unsigned int size)
+{
+	return call_int_hook(bpf, 0, cmd, attr, size);
+}
+int security_bpf_map(struct bpf_map *map, fmode_t fmode)
+{
+	return call_int_hook(bpf_map, 0, map, fmode);
+}
+int security_bpf_prog(struct bpf_prog *prog)
+{
+	return call_int_hook(bpf_prog, 0, prog);
+}
+int security_bpf_map_alloc(struct bpf_map *map)
+{
+	return call_int_hook(bpf_map_alloc_security, 0, map);
+}
+int security_bpf_prog_alloc(struct bpf_prog_aux *aux)
+{
+	return call_int_hook(bpf_prog_alloc_security, 0, aux);
+}
+void security_bpf_map_free(struct bpf_map *map)
+{
+	call_void_hook(bpf_map_free_security, map);
+}
+void security_bpf_prog_free(struct bpf_prog_aux *aux)
+{
+	call_void_hook(bpf_prog_free_security, aux);
+}
+#endif /* CONFIG_BPF_SYSCALL */