| Message ID | 20231012222810.4120312-7-andrii@kernel.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Paul Moore |
| Headers | show |
| Series | BPF token and BPF FS-based delegation | expand |
On Oct 12, 2023 Andrii Nakryiko <andrii@kernel.org> wrote: > > Add basic support of BPF token to BPF_PROG_LOAD. Wire through a set of > allowed BPF program types and attach types, derived from BPF FS at BPF > token creation time. Then make sure we perform bpf_token_capable() > checks everywhere where it's relevant. > > Signed-off-by: Andrii Nakryiko <andrii@kernel.org> > --- > include/linux/bpf.h | 6 ++ > include/uapi/linux/bpf.h | 2 + > kernel/bpf/core.c | 1 + > kernel/bpf/inode.c | 6 +- > kernel/bpf/syscall.c | 87 ++++++++++++++----- > kernel/bpf/token.c | 27 ++++++ > tools/include/uapi/linux/bpf.h | 2 + > .../selftests/bpf/prog_tests/libbpf_probes.c | 2 + > .../selftests/bpf/prog_tests/libbpf_str.c | 3 + > 9 files changed, 110 insertions(+), 26 deletions(-) ... > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index a2c9edcbcd77..c6b00aee3b62 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -2584,13 +2584,15 @@ static bool is_perfmon_prog_type(enum bpf_prog_type prog_type) > } > > /* last field in 'union bpf_attr' used by this command */ > -#define BPF_PROG_LOAD_LAST_FIELD log_true_size > +#define BPF_PROG_LOAD_LAST_FIELD prog_token_fd > > static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) > { > enum bpf_prog_type type = attr->prog_type; > struct bpf_prog *prog, *dst_prog = NULL; > struct btf *attach_btf = NULL; > + struct bpf_token *token = NULL; > + bool bpf_cap; > int err; > char license[128]; > > @@ -2606,10 +2608,31 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) > BPF_F_XDP_DEV_BOUND_ONLY)) > return -EINVAL; > > + bpf_prog_load_fixup_attach_type(attr); > + > + if (attr->prog_token_fd) { > + token = bpf_token_get_from_fd(attr->prog_token_fd); > + if (IS_ERR(token)) > + return PTR_ERR(token); > + /* if current token doesn't grant prog loading permissions, > + * then we can't use this token, so ignore it and rely on > + * system-wide capabilities checks > + */ > + if (!bpf_token_allow_cmd(token, BPF_PROG_LOAD) || > + !bpf_token_allow_prog_type(token, attr->prog_type, > + attr->expected_attach_type)) { > + bpf_token_put(token); > + token = NULL; > + } At the start of this effort I mentioned how we wanted to have LSM control points when the token is created and when it is used. It is for this reason that we still want a hook inside the bpf_token_allow_cmd() function as it allows us to enable/disable use of the token when its use is first attempted. If the LSM decides to disallow use of the token in this particular case then the token is disabled (set to NULL) while the operation is still allowed to move forward, simply without the token. It's a much cleaner and well behaved approach as it allows the normal BPF access controls to do their work. > + } > + > + bpf_cap = bpf_token_capable(token, CAP_BPF); Similar to the above comment, we want to a LSM control point in bpf_token_capable() so that the LSM can control the token's ability to delegate capability privileges when they are used. Having to delay this access control point to security_bpf_prog_load() is not only awkward but it requires either manual synchronization between all of the different LSMs and the the capability checks in the bpf_prog_load() function or a completely different set of LSM permissions for a token-based BPF program load over a normal BPF program load. We really need these hooks Andrii, I wouldn't have suggested them if I didn't believe they were important. > + err = -EPERM; > + > if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && > (attr->prog_flags & BPF_F_ANY_ALIGNMENT) && > - !bpf_capable()) > - return -EPERM; > + !bpf_cap) > + goto put_token; > > /* Intent here is for unprivileged_bpf_disabled to block BPF program > * creation for unprivileged users; other actions depend > @@ -2618,21 +2641,23 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) > * capability checks are still carried out for these > * and other operations. > */ > - if (sysctl_unprivileged_bpf_disabled && !bpf_capable()) > - return -EPERM; > + if (sysctl_unprivileged_bpf_disabled && !bpf_cap) > + goto put_token; > > if (attr->insn_cnt == 0 || > - attr->insn_cnt > (bpf_capable() ? BPF_COMPLEXITY_LIMIT_INSNS : BPF_MAXINSNS)) > - return -E2BIG; > + attr->insn_cnt > (bpf_cap ? BPF_COMPLEXITY_LIMIT_INSNS : BPF_MAXINSNS)) { > + err = -E2BIG; > + goto put_token; > + } > if (type != BPF_PROG_TYPE_SOCKET_FILTER && > type != BPF_PROG_TYPE_CGROUP_SKB && > - !bpf_capable()) > - return -EPERM; > + !bpf_cap) > + goto put_token; > > - if (is_net_admin_prog_type(type) && !bpf_net_capable()) > - return -EPERM; > - if (is_perfmon_prog_type(type) && !perfmon_capable()) > - return -EPERM; > + if (is_net_admin_prog_type(type) && !bpf_token_capable(token, CAP_NET_ADMIN)) > + goto put_token; > + if (is_perfmon_prog_type(type) && !bpf_token_capable(token, CAP_PERFMON)) > + goto put_token; > > /* attach_prog_fd/attach_btf_obj_fd can specify fd of either bpf_prog > * or btf, we need to check which one it is > @@ -2642,27 +2667,33 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) > if (IS_ERR(dst_prog)) { > dst_prog = NULL; > attach_btf = btf_get_by_fd(attr->attach_btf_obj_fd); > - if (IS_ERR(attach_btf)) > - return -EINVAL; > + if (IS_ERR(attach_btf)) { > + err = -EINVAL; > + goto put_token; > + } > if (!btf_is_kernel(attach_btf)) { > /* attaching through specifying bpf_prog's BTF > * objects directly might be supported eventually > */ > btf_put(attach_btf); > - return -ENOTSUPP; > + err = -ENOTSUPP; > + goto put_token; > } > } > } else if (attr->attach_btf_id) { > /* fall back to vmlinux BTF, if BTF type ID is specified */ > attach_btf = bpf_get_btf_vmlinux(); > - if (IS_ERR(attach_btf)) > - return PTR_ERR(attach_btf); > - if (!attach_btf) > - return -EINVAL; > + if (IS_ERR(attach_btf)) { > + err = PTR_ERR(attach_btf); > + goto put_token; > + } > + if (!attach_btf) { > + err = -EINVAL; > + goto put_token; > + } > btf_get(attach_btf); > } > > - bpf_prog_load_fixup_attach_type(attr); > if (bpf_prog_load_check_attach(type, attr->expected_attach_type, > attach_btf, attr->attach_btf_id, > dst_prog)) { > @@ -2670,7 +2701,8 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) > bpf_prog_put(dst_prog); > if (attach_btf) > btf_put(attach_btf); > - return -EINVAL; > + err = -EINVAL; > + goto put_token; > } > > /* plain bpf_prog allocation */ > @@ -2680,7 +2712,8 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) > bpf_prog_put(dst_prog); > if (attach_btf) > btf_put(attach_btf); > - return -ENOMEM; > + err = -EINVAL; > + goto put_token; > } > > prog->expected_attach_type = attr->expected_attach_type; > @@ -2691,6 +2724,10 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) > prog->aux->sleepable = attr->prog_flags & BPF_F_SLEEPABLE; > prog->aux->xdp_has_frags = attr->prog_flags & BPF_F_XDP_HAS_FRAGS; > > + /* move token into prog->aux, reuse taken refcnt */ > + prog->aux->token = token; > + token = NULL; > + > err = security_bpf_prog_alloc(prog->aux); > if (err) > goto free_prog; > @@ -2792,6 +2829,8 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) > if (prog->aux->attach_btf) > btf_put(prog->aux->attach_btf); > bpf_prog_free(prog); > +put_token: > + bpf_token_put(token); > return err; > } -- paul-moore.com
On Fri, Oct 13, 2023 at 2:15 PM Paul Moore <paul@paul-moore.com> wrote: > > On Oct 12, 2023 Andrii Nakryiko <andrii@kernel.org> wrote: > > > > Add basic support of BPF token to BPF_PROG_LOAD. Wire through a set of > > allowed BPF program types and attach types, derived from BPF FS at BPF > > token creation time. Then make sure we perform bpf_token_capable() > > checks everywhere where it's relevant. > > > > Signed-off-by: Andrii Nakryiko <andrii@kernel.org> > > --- > > include/linux/bpf.h | 6 ++ > > include/uapi/linux/bpf.h | 2 + > > kernel/bpf/core.c | 1 + > > kernel/bpf/inode.c | 6 +- > > kernel/bpf/syscall.c | 87 ++++++++++++++----- > > kernel/bpf/token.c | 27 ++++++ > > tools/include/uapi/linux/bpf.h | 2 + > > .../selftests/bpf/prog_tests/libbpf_probes.c | 2 + > > .../selftests/bpf/prog_tests/libbpf_str.c | 3 + > > 9 files changed, 110 insertions(+), 26 deletions(-) > > ... > > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > > index a2c9edcbcd77..c6b00aee3b62 100644 > > --- a/kernel/bpf/syscall.c > > +++ b/kernel/bpf/syscall.c > > @@ -2584,13 +2584,15 @@ static bool is_perfmon_prog_type(enum bpf_prog_type prog_type) > > } > > > > /* last field in 'union bpf_attr' used by this command */ > > -#define BPF_PROG_LOAD_LAST_FIELD log_true_size > > +#define BPF_PROG_LOAD_LAST_FIELD prog_token_fd > > > > static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) > > { > > enum bpf_prog_type type = attr->prog_type; > > struct bpf_prog *prog, *dst_prog = NULL; > > struct btf *attach_btf = NULL; > > + struct bpf_token *token = NULL; > > + bool bpf_cap; > > int err; > > char license[128]; > > > > @@ -2606,10 +2608,31 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) > > BPF_F_XDP_DEV_BOUND_ONLY)) > > return -EINVAL; > > > > + bpf_prog_load_fixup_attach_type(attr); > > + > > + if (attr->prog_token_fd) { > > + token = bpf_token_get_from_fd(attr->prog_token_fd); > > + if (IS_ERR(token)) > > + return PTR_ERR(token); > > + /* if current token doesn't grant prog loading permissions, > > + * then we can't use this token, so ignore it and rely on > > + * system-wide capabilities checks > > + */ > > + if (!bpf_token_allow_cmd(token, BPF_PROG_LOAD) || > > + !bpf_token_allow_prog_type(token, attr->prog_type, > > + attr->expected_attach_type)) { > > + bpf_token_put(token); > > + token = NULL; > > + } > > At the start of this effort I mentioned how we wanted to have LSM > control points when the token is created and when it is used. It is > for this reason that we still want a hook inside the > bpf_token_allow_cmd() function as it allows us to enable/disable use > of the token when its use is first attempted. If the LSM decides to > disallow use of the token in this particular case then the token is > disabled (set to NULL) while the operation is still allowed to move > forward, simply without the token. It's a much cleaner and well > behaved approach as it allows the normal BPF access controls to do > their work. I see, ok, so you want to be able to say "no BPF token for you", but not just error out the entire operation. Makes sense. > > > + } > > + > > + bpf_cap = bpf_token_capable(token, CAP_BPF); > > Similar to the above comment, we want to a LSM control point in > bpf_token_capable() so that the LSM can control the token's > ability to delegate capability privileges when they are used. Having > to delay this access control point to security_bpf_prog_load() is not > only awkward but it requires either manual synchronization between > all of the different LSMs and the the capability checks in the > bpf_prog_load() function or a completely different set of LSM > permissions for a token-based BPF program load over a normal BPF > program load. > > We really need these hooks Andrii, I wouldn't have suggested them if > I didn't believe they were important. No problem, I'll add both of them. I really didn't want to add hooks for allow_{maps,progs,attachs} (which you agreed shouldn't be added, so we are good), but I think allow_cmds and capable checks are fine. Will add in the next revision. > > > + err = -EPERM; > > + > > if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && > > (attr->prog_flags & BPF_F_ANY_ALIGNMENT) && > > - !bpf_capable()) > > - return -EPERM; > > + !bpf_cap) > > + goto put_token; > > [...]
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 35fc0b06365c..d21efa0ca4d3 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1442,6 +1442,7 @@ struct bpf_prog_aux { #ifdef CONFIG_SECURITY void *security; #endif + struct bpf_token *token; struct bpf_prog_offload *offload; struct btf *btf; struct bpf_func_info *func_info; @@ -1582,6 +1583,8 @@ struct bpf_token { struct user_namespace *userns; u64 allowed_cmds; u64 allowed_maps; + u64 allowed_progs; + u64 allowed_attachs; }; struct bpf_struct_ops_value; @@ -2218,6 +2221,9 @@ struct bpf_token *bpf_token_get_from_fd(u32 ufd); bool bpf_token_allow_cmd(const struct bpf_token *token, enum bpf_cmd cmd); bool bpf_token_allow_map_type(const struct bpf_token *token, enum bpf_map_type type); +bool bpf_token_allow_prog_type(const struct bpf_token *token, + enum bpf_prog_type prog_type, + enum bpf_attach_type attach_type); int bpf_obj_pin_user(u32 ufd, int path_fd, const char __user *pathname); int bpf_obj_get_user(int path_fd, const char __user *pathname, int flags); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index e6d35086152b..45ac44f03530 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1029,6 +1029,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_SK_LOOKUP, BPF_PROG_TYPE_SYSCALL, /* a program that can execute syscalls */ BPF_PROG_TYPE_NETFILTER, + __MAX_BPF_PROG_TYPE }; enum bpf_attach_type { @@ -1499,6 +1500,7 @@ union bpf_attr { * truncated), or smaller (if log buffer wasn't filled completely). */ __u32 log_true_size; + __u32 prog_token_fd; }; struct { /* anonymous struct used by BPF_OBJ_* commands */ diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 08626b519ce2..fc8de25b7948 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2747,6 +2747,7 @@ void bpf_prog_free(struct bpf_prog *fp) if (aux->dst_prog) bpf_prog_put(aux->dst_prog); + bpf_token_put(aux->token); INIT_WORK(&aux->work, bpf_prog_free_deferred); schedule_work(&aux->work); } diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c index e30f0821a35e..0dfcc85593ee 100644 --- a/kernel/bpf/inode.c +++ b/kernel/bpf/inode.c @@ -620,12 +620,14 @@ static int bpf_show_options(struct seq_file *m, struct dentry *root) else if (opts->delegate_maps) seq_printf(m, ",delegate_maps=0x%llx", opts->delegate_maps); - if (opts->delegate_progs == ~0ULL) + mask = (1ULL << __MAX_BPF_PROG_TYPE) - 1; + if ((opts->delegate_progs & mask) == mask) seq_printf(m, ",delegate_progs=any"); else if (opts->delegate_progs) seq_printf(m, ",delegate_progs=0x%llx", opts->delegate_progs); - if (opts->delegate_attachs == ~0ULL) + mask = (1ULL << __MAX_BPF_ATTACH_TYPE) - 1; + if ((opts->delegate_attachs & mask) == mask) seq_printf(m, ",delegate_attachs=any"); else if (opts->delegate_attachs) seq_printf(m, ",delegate_attachs=0x%llx", opts->delegate_attachs); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a2c9edcbcd77..c6b00aee3b62 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2584,13 +2584,15 @@ static bool is_perfmon_prog_type(enum bpf_prog_type prog_type) } /* last field in 'union bpf_attr' used by this command */ -#define BPF_PROG_LOAD_LAST_FIELD log_true_size +#define BPF_PROG_LOAD_LAST_FIELD prog_token_fd static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) { enum bpf_prog_type type = attr->prog_type; struct bpf_prog *prog, *dst_prog = NULL; struct btf *attach_btf = NULL; + struct bpf_token *token = NULL; + bool bpf_cap; int err; char license[128]; @@ -2606,10 +2608,31 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) BPF_F_XDP_DEV_BOUND_ONLY)) return -EINVAL; + bpf_prog_load_fixup_attach_type(attr); + + if (attr->prog_token_fd) { + token = bpf_token_get_from_fd(attr->prog_token_fd); + if (IS_ERR(token)) + return PTR_ERR(token); + /* if current token doesn't grant prog loading permissions, + * then we can't use this token, so ignore it and rely on + * system-wide capabilities checks + */ + if (!bpf_token_allow_cmd(token, BPF_PROG_LOAD) || + !bpf_token_allow_prog_type(token, attr->prog_type, + attr->expected_attach_type)) { + bpf_token_put(token); + token = NULL; + } + } + + bpf_cap = bpf_token_capable(token, CAP_BPF); + err = -EPERM; + if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && (attr->prog_flags & BPF_F_ANY_ALIGNMENT) && - !bpf_capable()) - return -EPERM; + !bpf_cap) + goto put_token; /* Intent here is for unprivileged_bpf_disabled to block BPF program * creation for unprivileged users; other actions depend @@ -2618,21 +2641,23 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) * capability checks are still carried out for these * and other operations. */ - if (sysctl_unprivileged_bpf_disabled && !bpf_capable()) - return -EPERM; + if (sysctl_unprivileged_bpf_disabled && !bpf_cap) + goto put_token; if (attr->insn_cnt == 0 || - attr->insn_cnt > (bpf_capable() ? BPF_COMPLEXITY_LIMIT_INSNS : BPF_MAXINSNS)) - return -E2BIG; + attr->insn_cnt > (bpf_cap ? BPF_COMPLEXITY_LIMIT_INSNS : BPF_MAXINSNS)) { + err = -E2BIG; + goto put_token; + } if (type != BPF_PROG_TYPE_SOCKET_FILTER && type != BPF_PROG_TYPE_CGROUP_SKB && - !bpf_capable()) - return -EPERM; + !bpf_cap) + goto put_token; - if (is_net_admin_prog_type(type) && !bpf_net_capable()) - return -EPERM; - if (is_perfmon_prog_type(type) && !perfmon_capable()) - return -EPERM; + if (is_net_admin_prog_type(type) && !bpf_token_capable(token, CAP_NET_ADMIN)) + goto put_token; + if (is_perfmon_prog_type(type) && !bpf_token_capable(token, CAP_PERFMON)) + goto put_token; /* attach_prog_fd/attach_btf_obj_fd can specify fd of either bpf_prog * or btf, we need to check which one it is @@ -2642,27 +2667,33 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) if (IS_ERR(dst_prog)) { dst_prog = NULL; attach_btf = btf_get_by_fd(attr->attach_btf_obj_fd); - if (IS_ERR(attach_btf)) - return -EINVAL; + if (IS_ERR(attach_btf)) { + err = -EINVAL; + goto put_token; + } if (!btf_is_kernel(attach_btf)) { /* attaching through specifying bpf_prog's BTF * objects directly might be supported eventually */ btf_put(attach_btf); - return -ENOTSUPP; + err = -ENOTSUPP; + goto put_token; } } } else if (attr->attach_btf_id) { /* fall back to vmlinux BTF, if BTF type ID is specified */ attach_btf = bpf_get_btf_vmlinux(); - if (IS_ERR(attach_btf)) - return PTR_ERR(attach_btf); - if (!attach_btf) - return -EINVAL; + if (IS_ERR(attach_btf)) { + err = PTR_ERR(attach_btf); + goto put_token; + } + if (!attach_btf) { + err = -EINVAL; + goto put_token; + } btf_get(attach_btf); } - bpf_prog_load_fixup_attach_type(attr); if (bpf_prog_load_check_attach(type, attr->expected_attach_type, attach_btf, attr->attach_btf_id, dst_prog)) { @@ -2670,7 +2701,8 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) bpf_prog_put(dst_prog); if (attach_btf) btf_put(attach_btf); - return -EINVAL; + err = -EINVAL; + goto put_token; } /* plain bpf_prog allocation */ @@ -2680,7 +2712,8 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) bpf_prog_put(dst_prog); if (attach_btf) btf_put(attach_btf); - return -ENOMEM; + err = -EINVAL; + goto put_token; } prog->expected_attach_type = attr->expected_attach_type; @@ -2691,6 +2724,10 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) prog->aux->sleepable = attr->prog_flags & BPF_F_SLEEPABLE; prog->aux->xdp_has_frags = attr->prog_flags & BPF_F_XDP_HAS_FRAGS; + /* move token into prog->aux, reuse taken refcnt */ + prog->aux->token = token; + token = NULL; + err = security_bpf_prog_alloc(prog->aux); if (err) goto free_prog; @@ -2792,6 +2829,8 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) if (prog->aux->attach_btf) btf_put(prog->aux->attach_btf); bpf_prog_free(prog); +put_token: + bpf_token_put(token); return err; } @@ -3779,7 +3818,7 @@ static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog, case BPF_PROG_TYPE_SK_LOOKUP: return attach_type == prog->expected_attach_type ? 0 : -EINVAL; case BPF_PROG_TYPE_CGROUP_SKB: - if (!bpf_net_capable()) + if (!bpf_token_capable(prog->aux->token, CAP_NET_ADMIN)) /* cg-skb progs can be loaded by unpriv user. * check permissions at attach time. */ diff --git a/kernel/bpf/token.c b/kernel/bpf/token.c index 17b66e11a55b..d4e0cc8075d3 100644 --- a/kernel/bpf/token.c +++ b/kernel/bpf/token.c @@ -77,6 +77,20 @@ static void bpf_token_show_fdinfo(struct seq_file *m, struct file *filp) seq_printf(m, "allowed_maps:\tany\n"); else seq_printf(m, "allowed_maps:\t0x%llx\n", token->allowed_maps); + + BUILD_BUG_ON(__MAX_BPF_PROG_TYPE >= 64); + mask = (1ULL << __MAX_BPF_PROG_TYPE) - 1; + if ((token->allowed_progs & mask) == mask) + seq_printf(m, "allowed_progs:\tany\n"); + else + seq_printf(m, "allowed_progs:\t0x%llx\n", token->allowed_progs); + + BUILD_BUG_ON(__MAX_BPF_ATTACH_TYPE >= 64); + mask = (1ULL << __MAX_BPF_ATTACH_TYPE) - 1; + if ((token->allowed_attachs & mask) == mask) + seq_printf(m, "allowed_attachs:\tany\n"); + else + seq_printf(m, "allowed_attachs:\t0x%llx\n", token->allowed_attachs); } static struct bpf_token *bpf_token_alloc(void) @@ -166,6 +180,8 @@ int bpf_token_create(union bpf_attr *attr) mnt_opts = path.dentry->d_sb->s_fs_info; token->allowed_cmds = mnt_opts->delegate_cmds; token->allowed_maps = mnt_opts->delegate_maps; + token->allowed_progs = mnt_opts->delegate_progs; + token->allowed_attachs = mnt_opts->delegate_attachs; fd = get_unused_fd_flags(O_CLOEXEC); if (fd < 0) { @@ -222,3 +238,14 @@ bool bpf_token_allow_map_type(const struct bpf_token *token, enum bpf_map_type t return token->allowed_maps & (1ULL << type); } + +bool bpf_token_allow_prog_type(const struct bpf_token *token, + enum bpf_prog_type prog_type, + enum bpf_attach_type attach_type) +{ + if (!token || prog_type >= __MAX_BPF_PROG_TYPE || attach_type >= __MAX_BPF_ATTACH_TYPE) + return false; + + return (token->allowed_progs & (1ULL << prog_type)) && + (token->allowed_attachs & (1ULL << attach_type)); +} diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index e6d35086152b..45ac44f03530 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1029,6 +1029,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_SK_LOOKUP, BPF_PROG_TYPE_SYSCALL, /* a program that can execute syscalls */ BPF_PROG_TYPE_NETFILTER, + __MAX_BPF_PROG_TYPE }; enum bpf_attach_type { @@ -1499,6 +1500,7 @@ union bpf_attr { * truncated), or smaller (if log buffer wasn't filled completely). */ __u32 log_true_size; + __u32 prog_token_fd; }; struct { /* anonymous struct used by BPF_OBJ_* commands */ diff --git a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c index 573249a2814d..4ed46ed58a7b 100644 --- a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c +++ b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c @@ -30,6 +30,8 @@ void test_libbpf_probe_prog_types(void) if (prog_type == BPF_PROG_TYPE_UNSPEC) continue; + if (strcmp(prog_type_name, "__MAX_BPF_PROG_TYPE") == 0) + continue; if (!test__start_subtest(prog_type_name)) continue; diff --git a/tools/testing/selftests/bpf/prog_tests/libbpf_str.c b/tools/testing/selftests/bpf/prog_tests/libbpf_str.c index 2a0633f43c73..384bc1f7a65e 100644 --- a/tools/testing/selftests/bpf/prog_tests/libbpf_str.c +++ b/tools/testing/selftests/bpf/prog_tests/libbpf_str.c @@ -189,6 +189,9 @@ static void test_libbpf_bpf_prog_type_str(void) const char *prog_type_str; char buf[256]; + if (prog_type == __MAX_BPF_PROG_TYPE) + continue; + prog_type_name = btf__str_by_offset(btf, e->name_off); prog_type_str = libbpf_bpf_prog_type_str(prog_type); ASSERT_OK_PTR(prog_type_str, prog_type_name);
Add basic support of BPF token to BPF_PROG_LOAD. Wire through a set of allowed BPF program types and attach types, derived from BPF FS at BPF token creation time. Then make sure we perform bpf_token_capable() checks everywhere where it's relevant. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> --- include/linux/bpf.h | 6 ++ include/uapi/linux/bpf.h | 2 + kernel/bpf/core.c | 1 + kernel/bpf/inode.c | 6 +- kernel/bpf/syscall.c | 87 ++++++++++++++----- kernel/bpf/token.c | 27 ++++++ tools/include/uapi/linux/bpf.h | 2 + .../selftests/bpf/prog_tests/libbpf_probes.c | 2 + .../selftests/bpf/prog_tests/libbpf_str.c | 3 + 9 files changed, 110 insertions(+), 26 deletions(-)