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authorAlexei Starovoitov <ast@kernel.org>2020-05-13 16:03:54 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2020-05-15 17:29:41 +0200
commit2c78ee898d8f10ae6fb2fa23a3fbaec96b1b7366 (patch)
tree6f2c093168b9b2c532127994bd50ff9f8e82401e /kernel/bpf/core.c
parenta17b53c4a4b55ec322c132b6670743612229ee9c (diff)
bpf: Implement CAP_BPF
Implement permissions as stated in uapi/linux/capability.h In order to do that the verifier allow_ptr_leaks flag is split into four flags and they are set as: env->allow_ptr_leaks = bpf_allow_ptr_leaks(); env->bypass_spec_v1 = bpf_bypass_spec_v1(); env->bypass_spec_v4 = bpf_bypass_spec_v4(); env->bpf_capable = bpf_capable(); The first three currently equivalent to perfmon_capable(), since leaking kernel pointers and reading kernel memory via side channel attacks is roughly equivalent to reading kernel memory with cap_perfmon. 'bpf_capable' enables bounded loops, precision tracking, bpf to bpf calls and other verifier features. 'allow_ptr_leaks' enable ptr leaks, ptr conversions, subtraction of pointers. 'bypass_spec_v1' disables speculative analysis in the verifier, run time mitigations in bpf array, and enables indirect variable access in bpf programs. 'bypass_spec_v4' disables emission of sanitation code by the verifier. That means that the networking BPF program loaded with CAP_BPF + CAP_NET_ADMIN will have speculative checks done by the verifier and other spectre mitigation applied. Such networking BPF program will not be able to leak kernel pointers and will not be able to access arbitrary kernel memory. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200513230355.7858-3-alexei.starovoitov@gmail.com
Diffstat (limited to 'kernel/bpf/core.c')
-rw-r--r--kernel/bpf/core.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 6aa11de67315..c40ff4cf9880 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -646,7 +646,7 @@ static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)
void bpf_prog_kallsyms_add(struct bpf_prog *fp)
{
if (!bpf_prog_kallsyms_candidate(fp) ||
- !capable(CAP_SYS_ADMIN))
+ !bpf_capable())
return;
bpf_prog_ksym_set_addr(fp);