Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Daniel Borkmann says:

====================
pull-request: bpf 2021-01-29

1) Fix two copy_{from,to}_user() warn_on_once splats for BPF cgroup getsockopt
   infra when user space is trying to race against optlen, from Loris Reiff.

2) Fix a missing fput() in BPF inode storage map update helper, from Pan Bian.

3) Fix a build error on unresolved symbols on disabled networking / keys LSM
   hooks, from Mikko Ylinen.

4) Fix preload BPF prog build when the output directory from make points to a
   relative path, from Quentin Monnet.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  bpf, preload: Fix build when $(O) points to a relative path
  bpf: Drop disabled LSM hooks from the sleepable set
  bpf, inode_storage: Put file handler if no storage was found
  bpf, cgroup: Fix problematic bounds check
  bpf, cgroup: Fix optlen WARN_ON_ONCE toctou
====================

Link: https://lore.kernel.org/r/20210129001556.6648-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

4 files changed, 27 insertions, 3 deletions

diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c
index 2f0597320b6d..6639640523c0 100644
--- a/kernel/bpf/bpf_inode_storage.c
+++ b/kernel/bpf/bpf_inode_storage.c
@@ -125,8 +125,12 @@ static int bpf_fd_inode_storage_update_elem(struct bpf_map *map, void *key,
 
 	fd = *(int *)key;
 	f = fget_raw(fd);
-	if (!f || !inode_storage_ptr(f->f_inode))
+	if (!f)
+		return -EBADF;
+	if (!inode_storage_ptr(f->f_inode)) {
+		fput(f);
 		return -EBADF;
+	}
 
 	sdata = bpf_local_storage_update(f->f_inode,
 					 (struct bpf_local_storage_map *)map,
diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c
index 70e5e0b6d69d..1622a44d1617 100644
--- a/kernel/bpf/bpf_lsm.c
+++ b/kernel/bpf/bpf_lsm.c
@@ -149,7 +149,11 @@ BTF_ID(func, bpf_lsm_file_ioctl)
 BTF_ID(func, bpf_lsm_file_lock)
 BTF_ID(func, bpf_lsm_file_open)
 BTF_ID(func, bpf_lsm_file_receive)
+
+#ifdef CONFIG_SECURITY_NETWORK
 BTF_ID(func, bpf_lsm_inet_conn_established)
+#endif /* CONFIG_SECURITY_NETWORK */
+
 BTF_ID(func, bpf_lsm_inode_create)
 BTF_ID(func, bpf_lsm_inode_free_security)
 BTF_ID(func, bpf_lsm_inode_getattr)
@@ -166,7 +170,11 @@ BTF_ID(func, bpf_lsm_inode_symlink)
 BTF_ID(func, bpf_lsm_inode_unlink)
 BTF_ID(func, bpf_lsm_kernel_module_request)
 BTF_ID(func, bpf_lsm_kernfs_init_security)
+
+#ifdef CONFIG_KEYS
 BTF_ID(func, bpf_lsm_key_free)
+#endif /* CONFIG_KEYS */
+
 BTF_ID(func, bpf_lsm_mmap_file)
 BTF_ID(func, bpf_lsm_netlink_send)
 BTF_ID(func, bpf_lsm_path_notify)
@@ -181,6 +189,8 @@ BTF_ID(func, bpf_lsm_sb_show_options)
 BTF_ID(func, bpf_lsm_sb_statfs)
 BTF_ID(func, bpf_lsm_sb_umount)
 BTF_ID(func, bpf_lsm_settime)
+
+#ifdef CONFIG_SECURITY_NETWORK
 BTF_ID(func, bpf_lsm_socket_accept)
 BTF_ID(func, bpf_lsm_socket_bind)
 BTF_ID(func, bpf_lsm_socket_connect)
@@ -195,6 +205,8 @@ BTF_ID(func, bpf_lsm_socket_recvmsg)
 BTF_ID(func, bpf_lsm_socket_sendmsg)
 BTF_ID(func, bpf_lsm_socket_shutdown)
 BTF_ID(func, bpf_lsm_socket_socketpair)
+#endif /* CONFIG_SECURITY_NETWORK */
+
 BTF_ID(func, bpf_lsm_syslog)
 BTF_ID(func, bpf_lsm_task_alloc)
 BTF_ID(func, bpf_lsm_task_getsecid)
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 96555a8a2c54..6aa9e10c6335 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -1442,6 +1442,11 @@ int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level,
 			goto out;
 		}
 
+		if (ctx.optlen < 0) {
+			ret = -EFAULT;
+			goto out;
+		}
+
 		if (copy_from_user(ctx.optval, optval,
 				   min(ctx.optlen, max_optlen)) != 0) {
 			ret = -EFAULT;
@@ -1459,7 +1464,7 @@ int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level,
 		goto out;
 	}
 
-	if (ctx.optlen > max_optlen) {
+	if (ctx.optlen > max_optlen || ctx.optlen < 0) {
 		ret = -EFAULT;
 		goto out;
 	}
diff --git a/kernel/bpf/preload/Makefile b/kernel/bpf/preload/Makefile
index 23ee310b6eb4..1951332dd15f 100644
--- a/kernel/bpf/preload/Makefile
+++ b/kernel/bpf/preload/Makefile
@@ -4,8 +4,11 @@ LIBBPF_SRCS = $(srctree)/tools/lib/bpf/
 LIBBPF_A = $(obj)/libbpf.a
 LIBBPF_OUT = $(abspath $(obj))
 
+# Although not in use by libbpf's Makefile, set $(O) so that the "dummy" test
+# in tools/scripts/Makefile.include always succeeds when building the kernel
+# with $(O) pointing to a relative path, as in "make O=build bindeb-pkg".
 $(LIBBPF_A):
-	$(Q)$(MAKE) -C $(LIBBPF_SRCS) OUTPUT=$(LIBBPF_OUT)/ $(LIBBPF_OUT)/libbpf.a
+	$(Q)$(MAKE) -C $(LIBBPF_SRCS) O=$(LIBBPF_OUT)/ OUTPUT=$(LIBBPF_OUT)/ $(LIBBPF_OUT)/libbpf.a
 
 userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi \
 	-I $(srctree)/tools/lib/ -Wno-unused-result