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bpf: Prepare bpf syscall to be used from kernel and user space.

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With the help from bpfptr_t prepare relevant bpf syscall commands
to be used from kernel and user space.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210514003623.28033-4-alexei.starovoitov@gmail.com
This commit is contained in:
Alexei Starovoitov 2021-05-13 17:36:05 -07:00 committed by Daniel Borkmann
parent cdf7fb0a9f
commit af2ac3e13e
5 changed files with 104 additions and 66 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
include/linux/bpf.h
View File

@ -22,6 +22,7 @@
#include <linux/sched/mm.h>
#include <linux/slab.h>
#include <linux/percpu-refcount.h>
#include <linux/bpfptr.h>
struct bpf_verifier_env;
struct bpf_verifier_log;
@ -1428,7 +1429,7 @@ struct bpf_iter__bpf_map_elem {
int bpf_iter_reg_target(const struct bpf_iter_reg *reg_info);
void bpf_iter_unreg_target(const struct bpf_iter_reg *reg_info);
bool bpf_iter_prog_supported(struct bpf_prog *prog);
int bpf_iter_link_attach(const union bpf_attr *attr, struct bpf_prog *prog);
int bpf_iter_link_attach(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_prog *prog);
int bpf_iter_new_fd(struct bpf_link *link);
bool bpf_link_is_iter(struct bpf_link *link);
struct bpf_prog *bpf_iter_get_info(struct bpf_iter_meta *meta, bool in_stop);
@ -1459,7 +1460,7 @@ int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value);
int bpf_get_file_flag(int flags);
int bpf_check_uarg_tail_zero(void __user *uaddr, size_t expected_size,
int bpf_check_uarg_tail_zero(bpfptr_t uaddr, size_t expected_size,
size_t actual_size);
/* memcpy that is used with 8-byte aligned pointers, power-of-8 size and
@ -1479,8 +1480,7 @@ static inline void bpf_long_memcpy(void *dst, const void *src, u32 size)
}
/* verify correctness of eBPF program */
int bpf_check(struct bpf_prog **fp, union bpf_attr *attr,
union bpf_attr __user *uattr);
int bpf_check(struct bpf_prog **fp, union bpf_attr *attr, bpfptr_t uattr);
#ifndef CONFIG_BPF_JIT_ALWAYS_ON
void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth);

13
kernel/bpf/bpf_iter.c
View File

@ -473,15 +473,16 @@ bool bpf_link_is_iter(struct bpf_link *link)
return link->ops == &bpf_iter_link_lops;
}
int bpf_iter_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
int bpf_iter_link_attach(const union bpf_attr *attr, bpfptr_t uattr,
struct bpf_prog *prog)
{
union bpf_iter_link_info __user *ulinfo;
struct bpf_link_primer link_primer;
struct bpf_iter_target_info *tinfo;
union bpf_iter_link_info linfo;
struct bpf_iter_link *link;
u32 prog_btf_id, linfo_len;
bool existed = false;
bpfptr_t ulinfo;
int err;
if (attr->link_create.target_fd || attr->link_create.flags)
@ -489,18 +490,18 @@ int bpf_iter_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
memset(&linfo, 0, sizeof(union bpf_iter_link_info));
ulinfo = u64_to_user_ptr(attr->link_create.iter_info);
ulinfo = make_bpfptr(attr->link_create.iter_info, uattr.is_kernel);
linfo_len = attr->link_create.iter_info_len;
if (!ulinfo ^ !linfo_len)
if (bpfptr_is_null(ulinfo) ^ !linfo_len)
return -EINVAL;
if (ulinfo) {
if (!bpfptr_is_null(ulinfo)) {
err = bpf_check_uarg_tail_zero(ulinfo, sizeof(linfo),
linfo_len);
if (err)
return err;
linfo_len = min_t(u32, linfo_len, sizeof(linfo));
if (copy_from_user(&linfo, ulinfo, linfo_len))
if (copy_from_bpfptr(&linfo, ulinfo, linfo_len))
return -EFAULT;
}

107
kernel/bpf/syscall.c
View File

@ -72,11 +72,10 @@ static const struct bpf_map_ops * const bpf_map_types[] = {
* copy_from_user() call. However, this is not a concern since this function is
* meant to be a future-proofing of bits.
*/
int bpf_check_uarg_tail_zero(void __user *uaddr,
int bpf_check_uarg_tail_zero(bpfptr_t uaddr,
size_t expected_size,
size_t actual_size)
{
unsigned char __user *addr = uaddr + expected_size;
int res;
if (unlikely(actual_size > PAGE_SIZE)) /* silly large */
@ -85,7 +84,12 @@ int bpf_check_uarg_tail_zero(void __user *uaddr,
if (actual_size <= expected_size)
return 0;
res = check_zeroed_user(addr, actual_size - expected_size);
if (uaddr.is_kernel)
res = memchr_inv(uaddr.kernel + expected_size, 0,
actual_size - expected_size) == NULL;
else
res = check_zeroed_user(uaddr.user + expected_size,
actual_size - expected_size);
if (res < 0)
return res;
return res ? 0 : -E2BIG;
@ -1004,6 +1008,17 @@ static void *__bpf_copy_key(void __user *ukey, u64 key_size)
return NULL;
}
static void *___bpf_copy_key(bpfptr_t ukey, u64 key_size)
{
if (key_size)
return memdup_bpfptr(ukey, key_size);
if (!bpfptr_is_null(ukey))
return ERR_PTR(-EINVAL);
return NULL;
}
/* last field in 'union bpf_attr' used by this command */
#define BPF_MAP_LOOKUP_ELEM_LAST_FIELD flags
@ -1074,10 +1089,10 @@ err_put:
#define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags
static int map_update_elem(union bpf_attr *attr)
static int map_update_elem(union bpf_attr *attr, bpfptr_t uattr)
{
void __user *ukey = u64_to_user_ptr(attr->key);
void __user *uvalue = u64_to_user_ptr(attr->value);
bpfptr_t ukey = make_bpfptr(attr->key, uattr.is_kernel);
bpfptr_t uvalue = make_bpfptr(attr->value, uattr.is_kernel);
int ufd = attr->map_fd;
struct bpf_map *map;
void *key, *value;
@ -1103,7 +1118,7 @@ static int map_update_elem(union bpf_attr *attr)
goto err_put;
}
key = __bpf_copy_key(ukey, map->key_size);
key = ___bpf_copy_key(ukey, map->key_size);
if (IS_ERR(key)) {
err = PTR_ERR(key);
goto err_put;
@ -1123,7 +1138,7 @@ static int map_update_elem(union bpf_attr *attr)
goto free_key;
err = -EFAULT;
if (copy_from_user(value, uvalue, value_size) != 0)
if (copy_from_bpfptr(value, uvalue, value_size) != 0)
goto free_value;
err = bpf_map_update_value(map, f, key, value, attr->flags);
@ -2076,7 +2091,7 @@ 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 attach_prog_fd
static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr)
{
enum bpf_prog_type type = attr->prog_type;
struct bpf_prog *prog, *dst_prog = NULL;
@ -2101,7 +2116,8 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
return -EPERM;
/* copy eBPF program license from user space */
if (strncpy_from_user(license, u64_to_user_ptr(attr->license),
if (strncpy_from_bpfptr(license,
make_bpfptr(attr->license, uattr.is_kernel),
sizeof(license) - 1) < 0)
return -EFAULT;
license[sizeof(license) - 1] = 0;
@ -2186,7 +2202,8 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
prog->len = attr->insn_cnt;
err = -EFAULT;
if (copy_from_user(prog->insns, u64_to_user_ptr(attr->insns),
if (copy_from_bpfptr(prog->insns,
make_bpfptr(attr->insns, uattr.is_kernel),
bpf_prog_insn_size(prog)) != 0)
goto free_prog_sec;
@ -3423,7 +3440,7 @@ static int bpf_prog_get_info_by_fd(struct file *file,
u32 ulen;
int err;
err = bpf_check_uarg_tail_zero(uinfo, sizeof(info), info_len);
err = bpf_check_uarg_tail_zero(USER_BPFPTR(uinfo), sizeof(info), info_len);
if (err)
return err;
info_len = min_t(u32, sizeof(info), info_len);
@ -3702,7 +3719,7 @@ static int bpf_map_get_info_by_fd(struct file *file,
u32 info_len = attr->info.info_len;
int err;
err = bpf_check_uarg_tail_zero(uinfo, sizeof(info), info_len);
err = bpf_check_uarg_tail_zero(USER_BPFPTR(uinfo), sizeof(info), info_len);
if (err)
return err;
info_len = min_t(u32, sizeof(info), info_len);
@ -3745,7 +3762,7 @@ static int bpf_btf_get_info_by_fd(struct file *file,
u32 info_len = attr->info.info_len;
int err;
err = bpf_check_uarg_tail_zero(uinfo, sizeof(*uinfo), info_len);
err = bpf_check_uarg_tail_zero(USER_BPFPTR(uinfo), sizeof(*uinfo), info_len);
if (err)
return err;
@ -3762,7 +3779,7 @@ static int bpf_link_get_info_by_fd(struct file *file,
u32 info_len = attr->info.info_len;
int err;
err = bpf_check_uarg_tail_zero(uinfo, sizeof(info), info_len);
err = bpf_check_uarg_tail_zero(USER_BPFPTR(uinfo), sizeof(info), info_len);
if (err)
return err;
info_len = min_t(u32, sizeof(info), info_len);
@ -4023,13 +4040,14 @@ err_put:
return err;
}
static int tracing_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
static int tracing_bpf_link_attach(const union bpf_attr *attr, bpfptr_t uattr,
struct bpf_prog *prog)
{
if (attr->link_create.attach_type != prog->expected_attach_type)
return -EINVAL;
if (prog->expected_attach_type == BPF_TRACE_ITER)
return bpf_iter_link_attach(attr, prog);
return bpf_iter_link_attach(attr, uattr, prog);
else if (prog->type == BPF_PROG_TYPE_EXT)
return bpf_tracing_prog_attach(prog,
attr->link_create.target_fd,
@ -4038,7 +4056,7 @@ static int tracing_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *
}
#define BPF_LINK_CREATE_LAST_FIELD link_create.iter_info_len
static int link_create(union bpf_attr *attr)
static int link_create(union bpf_attr *attr, bpfptr_t uattr)
{
enum bpf_prog_type ptype;
struct bpf_prog *prog;
@ -4057,7 +4075,7 @@ static int link_create(union bpf_attr *attr)
goto out;
if (prog->type == BPF_PROG_TYPE_EXT) {
ret = tracing_bpf_link_attach(attr, prog);
ret = tracing_bpf_link_attach(attr, uattr, prog);
goto out;
}
@ -4078,7 +4096,7 @@ static int link_create(union bpf_attr *attr)
ret = cgroup_bpf_link_attach(attr, prog);
break;
case BPF_PROG_TYPE_TRACING:
ret = tracing_bpf_link_attach(attr, prog);
ret = tracing_bpf_link_attach(attr, uattr, prog);
break;
case BPF_PROG_TYPE_FLOW_DISSECTOR:
case BPF_PROG_TYPE_SK_LOOKUP:
@ -4366,7 +4384,7 @@ out_prog_put:
return ret;
}
SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size)
static int __sys_bpf(int cmd, bpfptr_t uattr, unsigned int size)
{
union bpf_attr attr;
int err;
@ -4381,7 +4399,7 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
/* copy attributes from user space, may be less than sizeof(bpf_attr) */
memset(&attr, 0, sizeof(attr));
if (copy_from_user(&attr, uattr, size) != 0)
if (copy_from_bpfptr(&attr, uattr, size) != 0)
return -EFAULT;
err = security_bpf(cmd, &attr, size);
@ -4396,7 +4414,7 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
err = map_lookup_elem(&attr);
break;
case BPF_MAP_UPDATE_ELEM:
err = map_update_elem(&attr);
err = map_update_elem(&attr, uattr);
break;
case BPF_MAP_DELETE_ELEM:
err = map_delete_elem(&attr);
@ -4423,21 +4441,21 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
err = bpf_prog_detach(&attr);
break;
case BPF_PROG_QUERY:
err = bpf_prog_query(&attr, uattr);
err = bpf_prog_query(&attr, uattr.user);
break;
case BPF_PROG_TEST_RUN:
err = bpf_prog_test_run(&attr, uattr);
err = bpf_prog_test_run(&attr, uattr.user);
break;
case BPF_PROG_GET_NEXT_ID:
err = bpf_obj_get_next_id(&attr, uattr,
err = bpf_obj_get_next_id(&attr, uattr.user,
&prog_idr, &prog_idr_lock);
break;
case BPF_MAP_GET_NEXT_ID:
err = bpf_obj_get_next_id(&attr, uattr,
err = bpf_obj_get_next_id(&attr, uattr.user,
&map_idr, &map_idr_lock);
break;
case BPF_BTF_GET_NEXT_ID:
err = bpf_obj_get_next_id(&attr, uattr,
err = bpf_obj_get_next_id(&attr, uattr.user,
&btf_idr, &btf_idr_lock);
break;
case BPF_PROG_GET_FD_BY_ID:
@ -4447,7 +4465,7 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
err = bpf_map_get_fd_by_id(&attr);
break;
case BPF_OBJ_GET_INFO_BY_FD:
err = bpf_obj_get_info_by_fd(&attr, uattr);
err = bpf_obj_get_info_by_fd(&attr, uattr.user);
break;
case BPF_RAW_TRACEPOINT_OPEN:
err = bpf_raw_tracepoint_open(&attr);
@ -4459,26 +4477,26 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
err = bpf_btf_get_fd_by_id(&attr);
break;
case BPF_TASK_FD_QUERY:
err = bpf_task_fd_query(&attr, uattr);
err = bpf_task_fd_query(&attr, uattr.user);
break;
case BPF_MAP_LOOKUP_AND_DELETE_ELEM:
err = map_lookup_and_delete_elem(&attr);
break;
case BPF_MAP_LOOKUP_BATCH:
err = bpf_map_do_batch(&attr, uattr, BPF_MAP_LOOKUP_BATCH);
err = bpf_map_do_batch(&attr, uattr.user, BPF_MAP_LOOKUP_BATCH);
break;
case BPF_MAP_LOOKUP_AND_DELETE_BATCH:
err = bpf_map_do_batch(&attr, uattr,
err = bpf_map_do_batch(&attr, uattr.user,
BPF_MAP_LOOKUP_AND_DELETE_BATCH);
break;
case BPF_MAP_UPDATE_BATCH:
err = bpf_map_do_batch(&attr, uattr, BPF_MAP_UPDATE_BATCH);
err = bpf_map_do_batch(&attr, uattr.user, BPF_MAP_UPDATE_BATCH);
break;
case BPF_MAP_DELETE_BATCH:
err = bpf_map_do_batch(&attr, uattr, BPF_MAP_DELETE_BATCH);
err = bpf_map_do_batch(&attr, uattr.user, BPF_MAP_DELETE_BATCH);
break;
case BPF_LINK_CREATE:
err = link_create(&attr);
err = link_create(&attr, uattr);
break;
case BPF_LINK_UPDATE:
err = link_update(&attr);
@ -4487,7 +4505,7 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
err = bpf_link_get_fd_by_id(&attr);
break;
case BPF_LINK_GET_NEXT_ID:
err = bpf_obj_get_next_id(&attr, uattr,
err = bpf_obj_get_next_id(&attr, uattr.user,
&link_idr, &link_idr_lock);
break;
case BPF_ENABLE_STATS:
@ -4510,6 +4528,11 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
return err;
}
SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size)
{
return __sys_bpf(cmd, USER_BPFPTR(uattr), size);
}
static bool syscall_prog_is_valid_access(int off, int size,
enum bpf_access_type type,
const struct bpf_prog *prog,
@ -4524,8 +4547,20 @@ static bool syscall_prog_is_valid_access(int off, int size,
BPF_CALL_3(bpf_sys_bpf, int, cmd, void *, attr, u32, attr_size)
{
switch (cmd) {
case BPF_MAP_CREATE:
case BPF_MAP_UPDATE_ELEM:
case BPF_MAP_FREEZE:
case BPF_PROG_LOAD:
break;
/* case BPF_PROG_TEST_RUN:
* is not part of this list to prevent recursive test_run
*/
default:
return -EINVAL;
}
return __sys_bpf(cmd, KERNEL_BPFPTR(attr), attr_size);
}
const struct bpf_func_proto bpf_sys_bpf_proto = {
.func = bpf_sys_bpf,

34
kernel/bpf/verifier.c
View File

@ -9436,7 +9436,7 @@ static int check_abnormal_return(struct bpf_verifier_env *env)
static int check_btf_func(struct bpf_verifier_env *env,
const union bpf_attr *attr,
union bpf_attr __user *uattr)
bpfptr_t uattr)
{
const struct btf_type *type, *func_proto, *ret_type;
u32 i, nfuncs, urec_size, min_size;
@ -9445,7 +9445,7 @@ static int check_btf_func(struct bpf_verifier_env *env,
struct bpf_func_info_aux *info_aux = NULL;
struct bpf_prog *prog;
const struct btf *btf;
void __user *urecord;
bpfptr_t urecord;
u32 prev_offset = 0;
bool scalar_return;
int ret = -ENOMEM;
@ -9473,7 +9473,7 @@ static int check_btf_func(struct bpf_verifier_env *env,
prog = env->prog;
btf = prog->aux->btf;
urecord = u64_to_user_ptr(attr->func_info);
urecord = make_bpfptr(attr->func_info, uattr.is_kernel);
min_size = min_t(u32, krec_size, urec_size);
krecord = kvcalloc(nfuncs, krec_size, GFP_KERNEL | __GFP_NOWARN);
@ -9491,13 +9491,15 @@ static int check_btf_func(struct bpf_verifier_env *env,
/* set the size kernel expects so loader can zero
* out the rest of the record.
*/
if (put_user(min_size, &uattr->func_info_rec_size))
if (copy_to_bpfptr_offset(uattr,
offsetof(union bpf_attr, func_info_rec_size),
&min_size, sizeof(min_size)))
ret = -EFAULT;
}
goto err_free;
}
if (copy_from_user(&krecord[i], urecord, min_size)) {
if (copy_from_bpfptr(&krecord[i], urecord, min_size)) {
ret = -EFAULT;
goto err_free;
}
@ -9549,7 +9551,7 @@ static int check_btf_func(struct bpf_verifier_env *env,
}
prev_offset = krecord[i].insn_off;
urecord += urec_size;
bpfptr_add(&urecord, urec_size);
}
prog->aux->func_info = krecord;
@ -9581,14 +9583,14 @@ static void adjust_btf_func(struct bpf_verifier_env *env)
static int check_btf_line(struct bpf_verifier_env *env,
const union bpf_attr *attr,
union bpf_attr __user *uattr)
bpfptr_t uattr)
{
u32 i, s, nr_linfo, ncopy, expected_size, rec_size, prev_offset = 0;
struct bpf_subprog_info *sub;
struct bpf_line_info *linfo;
struct bpf_prog *prog;
const struct btf *btf;
void __user *ulinfo;
bpfptr_t ulinfo;
int err;
nr_linfo = attr->line_info_cnt;
@ -9614,7 +9616,7 @@ static int check_btf_line(struct bpf_verifier_env *env,
s = 0;
sub = env->subprog_info;
ulinfo = u64_to_user_ptr(attr->line_info);
ulinfo = make_bpfptr(attr->line_info, uattr.is_kernel);
expected_size = sizeof(struct bpf_line_info);
ncopy = min_t(u32, expected_size, rec_size);
for (i = 0; i < nr_linfo; i++) {
@ -9622,14 +9624,15 @@ static int check_btf_line(struct bpf_verifier_env *env,
if (err) {
if (err == -E2BIG) {
verbose(env, "nonzero tailing record in line_info");
if (put_user(expected_size,
&uattr->line_info_rec_size))
if (copy_to_bpfptr_offset(uattr,
offsetof(union bpf_attr, line_info_rec_size),
&expected_size, sizeof(expected_size)))
err = -EFAULT;
}
goto err_free;
}
if (copy_from_user(&linfo[i], ulinfo, ncopy)) {
if (copy_from_bpfptr(&linfo[i], ulinfo, ncopy)) {
err = -EFAULT;
goto err_free;
}
@ -9681,7 +9684,7 @@ static int check_btf_line(struct bpf_verifier_env *env,
}
prev_offset = linfo[i].insn_off;
ulinfo += rec_size;
bpfptr_add(&ulinfo, rec_size);
}
if (s != env->subprog_cnt) {
@ -9703,7 +9706,7 @@ err_free:
static int check_btf_info(struct bpf_verifier_env *env,
const union bpf_attr *attr,
union bpf_attr __user *uattr)
bpfptr_t uattr)
{
struct btf *btf;
int err;
@ -13275,8 +13278,7 @@ struct btf *bpf_get_btf_vmlinux(void)
return btf_vmlinux;
}
int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
union bpf_attr __user *uattr)
int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr)
{
u64 start_time = ktime_get_ns();
struct bpf_verifier_env *env;

2
net/bpf/test_run.c
View File

@ -409,7 +409,7 @@ static void *bpf_ctx_init(const union bpf_attr *kattr, u32 max_size)
return ERR_PTR(-ENOMEM);
if (data_in) {
err = bpf_check_uarg_tail_zero(data_in, max_size, size);
err = bpf_check_uarg_tail_zero(USER_BPFPTR(data_in), max_size, size);
if (err) {
kfree(data);
return ERR_PTR(err);