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authorChenbo Feng <fengc@google.com>2018-03-19 17:57:27 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-03-28 18:24:50 +0200
commitb4e02202a0ba47d7ba546ae681f66ed68e69d459 (patch)
parent3e1130970ec38bae0d4dd2a38678e563f092f7b3 (diff)
bpf: skip unnecessary capability check
commit 0fa4fe85f4724fff89b09741c437cbee9cf8b008 upstream. The current check statement in BPF syscall will do a capability check for CAP_SYS_ADMIN before checking sysctl_unprivileged_bpf_disabled. This code path will trigger unnecessary security hooks on capability checking and cause false alarms on unprivileged process trying to get CAP_SYS_ADMIN access. This can be resolved by simply switch the order of the statement and CAP_SYS_ADMIN is not required anyway if unprivileged bpf syscall is allowed. Signed-off-by: Chenbo Feng <fengc@google.com> Acked-by: Lorenzo Colitti <lorenzo@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 25d074920a00..4e933219fec6 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1455,7 +1455,7 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
union bpf_attr attr = {};
int err;
- if (!capable(CAP_SYS_ADMIN) && sysctl_unprivileged_bpf_disabled)
+ if (sysctl_unprivileged_bpf_disabled && !capable(CAP_SYS_ADMIN))
return -EPERM;
err = check_uarg_tail_zero(uattr, sizeof(attr), size);