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Message-ID: <20190904184335.360074-2-ast@kernel.org>
Date: Wed, 4 Sep 2019 11:43:34 -0700
From: Alexei Starovoitov <ast@...nel.org>
To: <davem@...emloft.net>
CC: <daniel@...earbox.net>, <peterz@...radead.org>,
<luto@...capital.net>, <netdev@...r.kernel.org>,
<bpf@...r.kernel.org>, <kernel-team@...com>,
<linux-api@...r.kernel.org>
Subject: [PATCH v3 bpf-next 2/3] bpf: implement CAP_BPF
Implement permissions as stated in uapi/linux/capability.h
Signed-off-by: Alexei Starovoitov <ast@...nel.org>
---
kernel/bpf/arraymap.c | 2 +-
kernel/bpf/cgroup.c | 2 +-
kernel/bpf/core.c | 4 +-
kernel/bpf/hashtab.c | 4 +-
kernel/bpf/lpm_trie.c | 2 +-
kernel/bpf/queue_stack_maps.c | 2 +-
kernel/bpf/reuseport_array.c | 2 +-
kernel/bpf/stackmap.c | 2 +-
kernel/bpf/syscall.c | 32 ++++++++------
kernel/bpf/verifier.c | 4 +-
kernel/trace/bpf_trace.c | 2 +-
net/core/bpf_sk_storage.c | 2 +-
net/core/filter.c | 10 +++--
tools/testing/selftests/bpf/test_verifier.c | 46 +++++++++++++++++----
14 files changed, 77 insertions(+), 39 deletions(-)
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 1c65ce0098a9..149f868a02dc 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -73,7 +73,7 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr)
bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
int ret, numa_node = bpf_map_attr_numa_node(attr);
u32 elem_size, index_mask, max_entries;
- bool unpriv = !capable(CAP_SYS_ADMIN);
+ bool unpriv = !capable_bpf();
u64 cost, array_size, mask64;
struct bpf_map_memory mem;
struct bpf_array *array;
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 6a6a154cfa7b..9c659ba5c146 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -795,7 +795,7 @@ cgroup_base_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
case BPF_FUNC_get_current_cgroup_id:
return &bpf_get_current_cgroup_id_proto;
case BPF_FUNC_trace_printk:
- if (capable(CAP_SYS_ADMIN))
+ if (capable_bpf_tracing())
return bpf_get_trace_printk_proto();
/* fall through */
default:
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 8191a7db2777..6b53c064e8e6 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))
+ !capable_bpf())
return;
spin_lock_bh(&bpf_lock);
@@ -768,7 +768,7 @@ static int bpf_jit_charge_modmem(u32 pages)
{
if (atomic_long_add_return(pages, &bpf_jit_current) >
(bpf_jit_limit >> PAGE_SHIFT)) {
- if (!capable(CAP_SYS_ADMIN)) {
+ if (!capable_bpf()) {
atomic_long_sub(pages, &bpf_jit_current);
return -EPERM;
}
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 22066a62c8c9..0fae5c45f425 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -244,9 +244,9 @@ static int htab_map_alloc_check(union bpf_attr *attr)
BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) !=
offsetof(struct htab_elem, hash_node.pprev));
- if (lru && !capable(CAP_SYS_ADMIN))
+ if (lru && !capable_bpf())
/* LRU implementation is much complicated than other
- * maps. Hence, limit to CAP_SYS_ADMIN for now.
+ * maps. Hence, limit to CAP_BPF.
*/
return -EPERM;
diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c
index 56e6c75d354d..11da3be8a4e5 100644
--- a/kernel/bpf/lpm_trie.c
+++ b/kernel/bpf/lpm_trie.c
@@ -543,7 +543,7 @@ static struct bpf_map *trie_alloc(union bpf_attr *attr)
u64 cost = sizeof(*trie), cost_per_node;
int ret;
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf())
return ERR_PTR(-EPERM);
/* check sanity of attributes */
diff --git a/kernel/bpf/queue_stack_maps.c b/kernel/bpf/queue_stack_maps.c
index f697647ceb54..d83afac32863 100644
--- a/kernel/bpf/queue_stack_maps.c
+++ b/kernel/bpf/queue_stack_maps.c
@@ -45,7 +45,7 @@ static bool queue_stack_map_is_full(struct bpf_queue_stack *qs)
/* Called from syscall */
static int queue_stack_map_alloc_check(union bpf_attr *attr)
{
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf())
return -EPERM;
/* check sanity of attributes */
diff --git a/kernel/bpf/reuseport_array.c b/kernel/bpf/reuseport_array.c
index 50c083ba978c..b268fe4b2972 100644
--- a/kernel/bpf/reuseport_array.c
+++ b/kernel/bpf/reuseport_array.c
@@ -154,7 +154,7 @@ static struct bpf_map *reuseport_array_alloc(union bpf_attr *attr)
struct bpf_map_memory mem;
u64 array_size;
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf())
return ERR_PTR(-EPERM);
array_size = sizeof(*array);
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index 052580c33d26..477063c63b27 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -90,7 +90,7 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
u64 cost, n_buckets;
int err;
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_tracing())
return ERR_PTR(-EPERM);
if (attr->map_flags & ~STACK_CREATE_FLAG_MASK)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index ca60eafa6922..2b832eeafda9 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1176,7 +1176,7 @@ static int map_freeze(const union bpf_attr *attr)
err = -EBUSY;
goto err_put;
}
- if (!capable(CAP_SYS_ADMIN)) {
+ if (!capable_bpf()) {
err = -EPERM;
goto err_put;
}
@@ -1635,7 +1635,7 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) &&
(attr->prog_flags & BPF_F_ANY_ALIGNMENT) &&
- !capable(CAP_SYS_ADMIN))
+ !capable_bpf())
return -EPERM;
/* copy eBPF program license from user space */
@@ -1648,11 +1648,11 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
is_gpl = license_is_gpl_compatible(license);
if (attr->insn_cnt == 0 ||
- attr->insn_cnt > (capable(CAP_SYS_ADMIN) ? BPF_COMPLEXITY_LIMIT_INSNS : BPF_MAXINSNS))
+ attr->insn_cnt > (capable_bpf() ? BPF_COMPLEXITY_LIMIT_INSNS : BPF_MAXINSNS))
return -E2BIG;
if (type != BPF_PROG_TYPE_SOCKET_FILTER &&
type != BPF_PROG_TYPE_CGROUP_SKB &&
- !capable(CAP_SYS_ADMIN))
+ !capable_bpf())
return -EPERM;
bpf_prog_load_fixup_attach_type(attr);
@@ -1803,6 +1803,9 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
char tp_name[128];
int tp_fd, err;
+ if (!capable_bpf_tracing())
+ return -EPERM;
+
if (strncpy_from_user(tp_name, u64_to_user_ptr(attr->raw_tracepoint.name),
sizeof(tp_name) - 1) < 0)
return -EFAULT;
@@ -2081,7 +2084,10 @@ static int bpf_prog_test_run(const union bpf_attr *attr,
struct bpf_prog *prog;
int ret = -ENOTSUPP;
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf_net_admin)
+ /* test_run callback is available for networking progs only.
+ * Add capable_bpf_tracing() above when tracing progs become runable.
+ */
return -EPERM;
if (CHECK_ATTR(BPF_PROG_TEST_RUN))
return -EINVAL;
@@ -2118,7 +2124,7 @@ static int bpf_obj_get_next_id(const union bpf_attr *attr,
if (CHECK_ATTR(BPF_OBJ_GET_NEXT_ID) || next_id >= INT_MAX)
return -EINVAL;
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf())
return -EPERM;
next_id++;
@@ -2144,7 +2150,7 @@ static int bpf_prog_get_fd_by_id(const union bpf_attr *attr)
if (CHECK_ATTR(BPF_PROG_GET_FD_BY_ID))
return -EINVAL;
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf())
return -EPERM;
spin_lock_bh(&prog_idr_lock);
@@ -2178,7 +2184,7 @@ static int bpf_map_get_fd_by_id(const union bpf_attr *attr)
attr->open_flags & ~BPF_OBJ_FLAG_MASK)
return -EINVAL;
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf())
return -EPERM;
f_flags = bpf_get_file_flag(attr->open_flags);
@@ -2353,7 +2359,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
info.run_time_ns = stats.nsecs;
info.run_cnt = stats.cnt;
- if (!capable(CAP_SYS_ADMIN)) {
+ if (!capable_bpf()) {
info.jited_prog_len = 0;
info.xlated_prog_len = 0;
info.nr_jited_ksyms = 0;
@@ -2671,7 +2677,7 @@ static int bpf_btf_load(const union bpf_attr *attr)
if (CHECK_ATTR(BPF_BTF_LOAD))
return -EINVAL;
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf())
return -EPERM;
return btf_new_fd(attr);
@@ -2684,7 +2690,7 @@ static int bpf_btf_get_fd_by_id(const union bpf_attr *attr)
if (CHECK_ATTR(BPF_BTF_GET_FD_BY_ID))
return -EINVAL;
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf())
return -EPERM;
return btf_get_fd_by_id(attr->btf_id);
@@ -2753,7 +2759,7 @@ static int bpf_task_fd_query(const union bpf_attr *attr,
if (CHECK_ATTR(BPF_TASK_FD_QUERY))
return -EINVAL;
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf_tracing())
return -EPERM;
if (attr->task_fd_query.flags != 0)
@@ -2821,7 +2827,7 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
union bpf_attr attr = {};
int err;
- if (sysctl_unprivileged_bpf_disabled && !capable(CAP_SYS_ADMIN))
+ if (sysctl_unprivileged_bpf_disabled && !capable_bpf())
return -EPERM;
err = bpf_check_uarg_tail_zero(uattr, sizeof(attr), size);
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f340cfe53c6e..b2a229557602 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -987,7 +987,7 @@ static void __mark_reg_unbounded(struct bpf_reg_state *reg)
reg->umax_value = U64_MAX;
/* constant backtracking is enabled for root only for now */
- reg->precise = capable(CAP_SYS_ADMIN) ? false : true;
+ reg->precise = capable_bpf() ? false : true;
}
/* Mark a register as having a completely unknown (scalar) value. */
@@ -9233,7 +9233,7 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
env->insn_aux_data[i].orig_idx = i;
env->prog = *prog;
env->ops = bpf_verifier_ops[env->prog->type];
- is_priv = capable(CAP_SYS_ADMIN);
+ is_priv = capable_bpf();
/* grab the mutex to protect few globals used by verifier */
if (!is_priv)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index ca1255d14576..cdf8d6c8a430 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1246,7 +1246,7 @@ int perf_event_query_prog_array(struct perf_event *event, void __user *info)
u32 *ids, prog_cnt, ids_len;
int ret;
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf_tracing())
return -EPERM;
if (event->attr.type != PERF_TYPE_TRACEPOINT)
return -EINVAL;
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index da5639a5bd3b..aa74be21f5b6 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -616,7 +616,7 @@ static int bpf_sk_storage_map_alloc_check(union bpf_attr *attr)
!attr->btf_key_type_id || !attr->btf_value_type_id)
return -EINVAL;
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf())
return -EPERM;
if (attr->value_size >= KMALLOC_MAX_SIZE -
diff --git a/net/core/filter.c b/net/core/filter.c
index 17bc9af8f156..fae09b4d4da4 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5990,7 +5990,7 @@ bpf_base_func_proto(enum bpf_func_id func_id)
break;
}
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf())
return NULL;
switch (func_id) {
@@ -5999,7 +5999,9 @@ bpf_base_func_proto(enum bpf_func_id func_id)
case BPF_FUNC_spin_unlock:
return &bpf_spin_unlock_proto;
case BPF_FUNC_trace_printk:
- return bpf_get_trace_printk_proto();
+ if (capable_bpf_tracing())
+ return bpf_get_trace_printk_proto();
+ /* fall through */
default:
return NULL;
}
@@ -6563,7 +6565,7 @@ static bool cg_skb_is_valid_access(int off, int size,
return false;
case bpf_ctx_range(struct __sk_buff, data):
case bpf_ctx_range(struct __sk_buff, data_end):
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf())
return false;
break;
}
@@ -6575,7 +6577,7 @@ static bool cg_skb_is_valid_access(int off, int size,
case bpf_ctx_range_till(struct __sk_buff, cb[0], cb[4]):
break;
case bpf_ctx_range(struct __sk_buff, tstamp):
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable_bpf())
return false;
break;
default:
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index d27fd929abb9..0d5567962c4e 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -807,10 +807,20 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
}
}
+struct libcap {
+ struct __user_cap_header_struct hdr;
+ struct __user_cap_data_struct data[2];
+};
+
static int set_admin(bool admin)
{
cap_t caps;
- const cap_value_t cap_val = CAP_SYS_ADMIN;
+ /* need CAP_BPF to load progs and CAP_NET_ADMIN to run networking progs,
+ * and CAP_TRACING to create stackmap
+ */
+ const cap_value_t cap_net_admin = CAP_NET_ADMIN;
+ const cap_value_t cap_sys_admin = CAP_SYS_ADMIN;
+ struct libcap *cap;
int ret = -1;
caps = cap_get_proc();
@@ -818,11 +828,26 @@ static int set_admin(bool admin)
perror("cap_get_proc");
return -1;
}
- if (cap_set_flag(caps, CAP_EFFECTIVE, 1, &cap_val,
+ cap = (struct libcap *)caps;
+ if (cap_set_flag(caps, CAP_EFFECTIVE, 1, &cap_sys_admin, CAP_CLEAR)) {
+ perror("cap_set_flag clear admin");
+ goto out;
+ }
+ if (cap_set_flag(caps, CAP_EFFECTIVE, 1, &cap_net_admin,
admin ? CAP_SET : CAP_CLEAR)) {
- perror("cap_set_flag");
+ perror("cap_set_flag set_or_clear net");
goto out;
}
+ /* libcap is likely old and simply ignores CAP_BPF and CAP_TRACING,
+ * so update effective bits manually
+ */
+ if (admin) {
+ cap->data[1].effective |= 1 << (38 /* CAP_BPF */ - 32);
+ cap->data[1].effective |= 1 << (39 /* CAP_TRACING */ - 32);
+ } else {
+ cap->data[1].effective &= ~(1 << (38 - 32));
+ cap->data[1].effective &= ~(1 << (39 - 32));
+ }
if (cap_set_proc(caps)) {
perror("cap_set_proc");
goto out;
@@ -1051,9 +1076,11 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
static bool is_admin(void)
{
+ cap_flag_value_t net_priv = CAP_CLEAR;
+ bool tracing_priv = false;
+ bool bpf_priv = false;
+ struct libcap *cap;
cap_t caps;
- cap_flag_value_t sysadmin = CAP_CLEAR;
- const cap_value_t cap_val = CAP_SYS_ADMIN;
#ifdef CAP_IS_SUPPORTED
if (!CAP_IS_SUPPORTED(CAP_SETFCAP)) {
@@ -1066,11 +1093,14 @@ static bool is_admin(void)
perror("cap_get_proc");
return false;
}
- if (cap_get_flag(caps, cap_val, CAP_EFFECTIVE, &sysadmin))
- perror("cap_get_flag");
+ cap = (struct libcap *)caps;
+ bpf_priv = cap->data[1].effective & (1 << (38/* CAP_BPF */ - 32));
+ tracing_priv = cap->data[1].effective & (1 << (39/* CAP_TRACING */ - 32));
+ if (cap_get_flag(caps, CAP_NET_ADMIN, CAP_EFFECTIVE, &net_priv))
+ perror("cap_get_flag NET");
if (cap_free(caps))
perror("cap_free");
- return (sysadmin == CAP_SET);
+ return bpf_priv && tracing_priv && net_priv == CAP_SET;
}
static void get_unpriv_disabled()
--
2.20.0
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