bpf: Restrict bpf when kernel lockdown is in confidentiality mode

bpf_read() and bpf_read_str() could potentially be abused to (eg) allow
private keys in kernel memory to be leaked. Disable them if the kernel
has been locked down in confidentiality mode.

Suggested-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Matthew Garrett <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
cc: [email protected]
cc: Chun-Yi Lee <[email protected]>
cc: Alexei Starovoitov <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Signed-off-by: James Morris <[email protected]>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/security.h b/include/linux/security.h
index 0b2529dbf0f4..e604f4c67f03 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -118,6 +118,7 @@ enum lockdown_reason {
 	LOCKDOWN_INTEGRITY_MAX,
 	LOCKDOWN_KCORE,
 	LOCKDOWN_KPROBES,
+	LOCKDOWN_BPF_READ,
 	LOCKDOWN_CONFIDENTIALITY_MAX,
 };