From 7f677633379b4abb3281cdbe7e7006f049305c03 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Fri, 10 Feb 2017 20:28:24 -0800 Subject: bpf: introduce BPF_F_ALLOW_OVERRIDE flag If BPF_F_ALLOW_OVERRIDE flag is used in BPF_PROG_ATTACH command to the given cgroup the descendent cgroup will be able to override effective bpf program that was inherited from this cgroup. By default it's not passed, therefore override is disallowed. Examples: 1. prog X attached to /A with default prog Y fails to attach to /A/B and /A/B/C Everything under /A runs prog X 2. prog X attached to /A with allow_override. prog Y fails to attach to /A/B with default (non-override) prog M attached to /A/B with allow_override. Everything under /A/B runs prog M only. 3. prog X attached to /A with allow_override. prog Y fails to attach to /A with default. The user has to detach first to switch the mode. In the future this behavior may be extended with a chain of non-overridable programs. Also fix the bug where detach from cgroup where nothing is attached was not throwing error. Return ENOENT in such case. Add several testcases and adjust libbpf. Fixes: 3007098494be ("cgroup: add support for eBPF programs") Signed-off-by: Alexei Starovoitov Acked-by: Daniel Borkmann Acked-by: Tejun Heo Acked-by: Daniel Mack Signed-off-by: David S. Miller --- tools/lib/bpf/bpf.c | 4 +++- tools/lib/bpf/bpf.h | 3 ++- 2 files changed, 5 insertions(+), 2 deletions(-) (limited to 'tools') diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 3ddb58a36d3c..ae752fa4eaa7 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -168,7 +168,8 @@ int bpf_obj_get(const char *pathname) return sys_bpf(BPF_OBJ_GET, &attr, sizeof(attr)); } -int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type) +int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type, + unsigned int flags) { union bpf_attr attr; @@ -176,6 +177,7 @@ int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type) attr.target_fd = target_fd; attr.attach_bpf_fd = prog_fd; attr.attach_type = type; + attr.attach_flags = flags; return sys_bpf(BPF_PROG_ATTACH, &attr, sizeof(attr)); } diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index a2f9853dd882..4ac6c4b84100 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -41,7 +41,8 @@ int bpf_map_delete_elem(int fd, void *key); int bpf_map_get_next_key(int fd, void *key, void *next_key); int bpf_obj_pin(int fd, const char *pathname); int bpf_obj_get(const char *pathname); -int bpf_prog_attach(int prog_fd, int attachable_fd, enum bpf_attach_type type); +int bpf_prog_attach(int prog_fd, int attachable_fd, enum bpf_attach_type type, + unsigned int flags); int bpf_prog_detach(int attachable_fd, enum bpf_attach_type type); -- cgit v1.2.3-59-g8ed1b From 5463b3d043826ff8ef487edbd1ef1bfffb677437 Mon Sep 17 00:00:00 2001 From: Stephen Rothwell Date: Tue, 14 Feb 2017 08:22:20 +1100 Subject: bpf: kernel header files need to be copied into the tools directory Signed-off-by: Stephen Rothwell Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- tools/include/uapi/linux/bpf.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'tools') diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 0eb0e87dbe9f..d2b0ac799d03 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -116,6 +116,12 @@ enum bpf_attach_type { #define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE +/* If BPF_F_ALLOW_OVERRIDE flag is used in BPF_PROG_ATTACH command + * to the given target_fd cgroup the descendent cgroup will be able to + * override effective bpf program that was inherited from this cgroup + */ +#define BPF_F_ALLOW_OVERRIDE (1U << 0) + #define BPF_PSEUDO_MAP_FD 1 /* flags for BPF_MAP_UPDATE_ELEM command */ @@ -171,6 +177,7 @@ union bpf_attr { __u32 target_fd; /* container object to attach to */ __u32 attach_bpf_fd; /* eBPF program to attach */ __u32 attach_type; + __u32 attach_flags; }; } __attribute__((aligned(8))); -- cgit v1.2.3-59-g8ed1b