// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2023 Isovalent */
#include <linux/bpf.h>
#include <linux/bpf_mprog.h>
static int bpf_mprog_link(struct bpf_tuple *tuple,
u32 id_or_fd, u32 flags,
enum bpf_prog_type type)
{
struct bpf_link *link = ERR_PTR(-EINVAL);
bool id = flags & BPF_F_ID;
if (id)
link = bpf_link_by_id(id_or_fd);
else if (id_or_fd)
link = bpf_link_get_from_fd(id_or_fd);
if (IS_ERR(link))
return PTR_ERR(link);
if (type && link->prog->type != type) {
bpf_link_put(link);
return -EINVAL;
}
tuple->link = link;
tuple->prog = link->prog;
return 0;
}
static int bpf_mprog_prog(struct bpf_tuple *tuple,
u32 id_or_fd, u32 flags,
enum bpf_prog_type type)
{
struct bpf_prog *prog = ERR_PTR(-EINVAL);
bool id = flags & BPF_F_ID;
if (id)
prog = bpf_prog_by_id(id_or_fd);
else if (id_or_fd)
prog = bpf_prog_get(id_or_fd);
if (IS_ERR(prog))
return PTR_ERR(prog);
if (type && prog->type != type) {
bpf_prog_put(prog);
return -EINVAL;
}
tuple->link = NULL;
tuple->prog = prog;
return 0;
}
static int bpf_mprog_tuple_relative(struct bpf_tuple *tuple,
u32 id_or_fd, u32 flags,
enum bpf_prog_type type)
{
bool link = flags & BPF_F_LINK;
bool id = flags & BPF_F_ID;
memset(tuple, 0, sizeof(*tuple));
if (link)
return bpf_mprog_link(tuple, id_or_fd, flags, type);
/* If no relevant flag is set and no id_or_fd was passed, then
* tuple link/prog is just NULLed. This is the case when before/
* after selects first/last position without passing fd.
*/
if (!id && !id_or_fd)
return 0;
return bpf_mprog_prog(tuple, id_or_fd, flags, type);
}
static void bpf_mprog_tuple_put(struct bpf_tuple *tuple)
{
if (tuple->link)
bpf_link_put(tuple->link);
else if (tuple->prog)
bpf_prog_put(tuple->prog);
}
/* The bpf_mprog_{replace,delete}() operate on exact idx position with the
* one exception that for deletion we support delete from front/back. In
* case of front idx is -1, in case of back idx is bpf_mprog_total(entry).
* Adjustment to first and last entry is trivial. The bpf_mprog_insert()
* we have to deal with the following cases:
*
* idx + before:
*
* Insert P4 before P3: idx for old array is 1, idx for new array is 2,
* hence we adjust target idx for the new array, so that memmove copies
* P1 and P2 to the new entry, and we insert P4 into idx 2. Inserting
* before P1 would have old idx -1 and new idx 0.
*
* +--+--+--+ +--+--+--+--+ +--+--+--+--+
* |P1|P2|P3| ==> |P1|P2| |P3| ==> |P1|P2|P4|P3|
* +--+--+--+ +--+--+--+--+ +--+--+--+--+
*
* idx + after:
*
* Insert P4 after P2: idx for old array is 2, idx for new array is 2.
* Again, memmove copies P1 and P2 to the new entry, and we insert P4
* into idx 2. Inserting after P3 would have both old/new idx at 4 aka
* bpf_mprog_total(entry).
*
* +--+--+--+ +--+--+--+--+ +--+--+--+--+
* |P1|P2|P3| ==> |P1|P2| |P3| ==> |P1|P2|P4|P3|
* +--+--+--+ +--+--+--+--+ +--+--+--+--+
*/
static int bpf_mprog_replace(struct bpf_mprog_entry *entry,
struct bpf_mprog_entry **entry_new,
struct bpf_tuple *ntuple, int idx)
{
struct bpf_mprog_fp *fp;
struct bpf_mprog_cp *cp;
struct bpf_prog *oprog;
bpf_mprog_read(entry, idx, &fp, &cp);
oprog = READ_ONCE(fp->prog);
bpf_mprog_write(fp, cp, ntuple);
if (!ntuple->link) {
WARN_ON_ONCE(cp->link);
bpf_prog_put(oprog);
}
*entry_new = entry;
return 0;
}
static int bpf_mprog_insert(struct bpf_mprog_entry *entry,
struct bpf_mprog_entry **entry_new,
struct bpf_tuple *ntuple, int idx, u32 flags)
{
int total = bpf_mprog_total(entry);
struct bpf_mprog_entry *peer;
struct bpf_mprog_fp *fp;
struct bpf_mprog_cp *cp;
peer = bpf_mprog_peer(entry);
bpf_mprog_entry_copy(peer, entry);
if (idx == total)
goto insert;
else if (flags & BPF_F_BEFORE)
idx += 1;
bpf_mprog_entry_grow(peer, idx);
insert:
bpf_mprog_read(peer, idx, &fp, &cp);
bpf_mprog_write(fp, cp, ntuple);
bpf_mprog_inc(peer);
*entry_new = peer;
return 0;
}
static int bpf_mprog_delete(struct bpf_mprog_entry *entry,
struct bpf_mprog_entry **entry_new,
struct bpf_tuple *dtuple, int idx)
{
int total = bpf_mprog_total(entry);
struct bpf_mprog_entry *peer;
peer = bpf_mprog_peer(entry);
bpf_mprog_entry_copy(peer, entry);
if (idx == -1)
idx = 0;
else if (idx == total)
idx = total - 1;
bpf_mprog_entry_shrink(peer, idx);
bpf_mprog_dec(peer);
bpf_mprog_mark_for_release(peer, dtuple);
*entry_new = peer;
return 0;
}
/* In bpf_mprog_pos_*() we evaluate the target position for the BPF
* program/link that needs to be replaced, inserted or deleted for
* each "rule" independently. If all rules agree on that position
* or existing element, then enact replacement, addition or deletion.
* If this is not the case, then the request cannot be satisfied and
* we bail out with an error.
*/
static int bpf_mprog_pos_exact(struct bpf_mprog_entry *entry,
struct bpf_tuple *tuple)
{
struct bpf_mprog_fp *fp;
struct bpf_mprog_cp *cp;
int i;
for (i = 0; i < bpf_mprog_total(entry); i++) {
bpf_mprog_read(entry, i, &fp, &cp);
if (tuple->prog == READ_ONCE(fp->prog))
return tuple->link == cp->link ? i : -EBUSY;
}
return -ENOENT;
}
static int bpf_mprog_pos_before(struct bpf_mprog_entry *entry,
struct bpf_tuple *tuple)
{
struct bpf_mprog_fp *fp;
struct bpf_mprog_cp *cp;
int i;
for (i = 0; i < bpf_mprog_total(entry); i++) {
bpf_mprog_read(entry, i, &fp, &cp);
if (tuple->prog == READ_ONCE(fp->prog) &&
(!tuple->link || tuple->link == cp->link))
return i - 1;
}
return tuple->prog ? -ENOENT : -1;
}
static int bpf_mprog_pos_after(struct bpf_mprog_entry *entry,
struct bpf_tuple *tuple)
{
struct bpf_mprog_fp *fp;
struct bpf_mprog_cp *cp;
int i;
for (i = 0; i < bpf_mprog_total(entry); i++) {
bpf_mprog_read(entry, i, &fp, &cp);
if (tuple->prog == READ_ONCE(fp->prog) &&
(!tuple->link || tuple->link == cp->link))
return i + 1;
}
return tuple->prog ? -ENOENT : bpf_mprog_total(entry);
}
int bpf_mprog_attach(struct bpf_mprog_entry *entry,
struct bpf_mprog_entry **entry_new,
struct bpf_prog *prog_new, struct bpf_link *link,
struct bpf_prog *prog_old,
u32 flags, u32 id_or_fd, u64 revision)
{
struct bpf_tuple rtuple, ntuple = {
.prog = prog_new,
.link = link,
}, otuple = {
.prog = prog_old,
.link = link,
};
int ret, idx = -ERANGE, tidx;
if (revision && revision != bpf_mprog_revision(entry))
return -ESTALE;
if (bpf_mprog_exists(entry, prog_new))
return -EEXIST;
ret = bpf_mprog_tuple_relative(&rtuple, id_or_fd,
flags & ~BPF_F_REPLACE,
prog_new->type);
if (ret)
return ret;
if (flags & BPF_F_REPLACE) {
tidx = bpf_mprog_pos_exact(entry, &otuple);
if (tidx < 0) {
ret = tidx;
goto out;
}
idx = tidx;
} else if (bpf_mprog_total(entry) == bpf_mprog_max()) {
ret = -ERANGE;
goto out;
}
if (flags & BPF_F_BEFORE) {
tidx = bpf_mprog_pos_before(entry, &rtuple);
if (tidx < -1 || (idx >= -1 && tidx != idx)) {
ret = tidx < -1 ? tidx : -ERANGE;
goto out;
}
idx = tidx;
}
if (flags & BPF_F_AFTER) {
tidx = bpf_mprog_pos_after(entry, &rtuple);
if (tidx < -1 || (idx >= -1 && tidx != idx)) {
ret = tidx < 0 ? tidx : -ERANGE;
goto out;
}
idx = tidx;
}
if (idx < -1) {
if (rtuple.prog || flags) {
ret = -EINVAL;
goto out;
}
idx = bpf_mprog_total(entry);
flags = BPF_F_AFTER;
}
if (idx >= bpf_mprog_max()) {
ret = -ERANGE;
goto out;
}
if (flags & BPF_F_REPLACE)
ret = bpf_mprog_replace(entry, entry_new, &ntuple, idx);
else
ret = bpf_mprog_insert(entry, entry_new, &ntuple, idx, flags);
out:
bpf_mprog_tuple_put(&rtuple);
return ret;
}
static int bpf_mprog_fetch(struct bpf_mprog_entry *entry,
struct bpf_tuple *tuple, int idx)
{
int total = bpf_mprog_total(entry);
struct bpf_mprog_cp *cp;
struct bpf_mprog_fp *fp;
struct bpf_prog *prog;
struct bpf_link *link;
if (idx == -1)
idx = 0;
else if (idx == total)
idx = total - 1;
bpf_mprog_read(entry, idx, &fp, &cp);
prog = READ_ONCE(fp->prog);
link = cp->link;
/* The deletion request can either be without filled tuple in which
* case it gets populated here based on idx, or with filled tuple
* where the only thing we end up doing is the WARN_ON_ONCE() assert.
* If we hit a BPF link at the given index, it must not be removed
* from opts path.
*/
if (link && !tuple->link)
return -EBUSY;
WARN_ON_ONCE(tuple->prog && tuple->prog != prog);
WARN_ON_ONCE(tuple->link && tuple->link != link);
tuple->prog = prog;
tuple->link = link;
return 0;
}
int bpf_mprog_detach(struct bpf_mprog_entry *entry,
struct bpf_mprog_entry **entry_new,
struct bpf_prog *prog, struct bpf_link *link,
u32 flags, u32 id_or_fd, u64 revision)
{
struct bpf_tuple rtuple, dtuple = {
.prog = prog,
.link = link,
};
int ret, idx = -ERANGE, tidx;
if (flags & BPF_F_REPLACE)
return -EINVAL;
if (revision && revision != bpf_mprog_revision(entry))
return -ESTALE;
if (!bpf_mprog_total(entry))
return -ENOENT;
ret = bpf_mprog_tuple_relative(&rtuple, id_or_fd, flags,
prog ? prog->type :
BPF_PROG_TYPE_UNSPEC);
if (ret)
return ret;
if (dtuple.prog) {
tidx = bpf_mprog_pos_exact(entry, &dtuple);
if (tidx < 0) {
ret = tidx;
goto out;
}
idx = tidx;
}
if (flags & BPF_F_BEFORE) {
tidx = bpf_mprog_pos_before(entry, &rtuple);
if (tidx < -1 || (idx >= -1 && tidx != idx)) {
ret = tidx < -1 ? tidx : -ERANGE;
goto out;
}
idx = tidx;
}
if (flags & BPF_F_AFTER) {
tidx = bpf_mprog_pos_after(entry, &rtuple);
if (tidx < -1 || (idx >= -1 && tidx != idx)) {
ret = tidx < 0 ? tidx : -ERANGE;
goto out;
}
idx = tidx;
}
if (idx < -1) {
if (rtuple.prog || flags) {
ret = -EINVAL;
goto out;
}
idx = bpf_mprog_total(entry);
flags = BPF_F_AFTER;
}
if (idx >= bpf_mprog_max()) {
ret = -ERANGE;
goto out;
}
ret = bpf_mprog_fetch(entry, &dtuple, idx);
if (ret)
goto out;
ret = bpf_mprog_delete(entry, entry_new, &dtuple, idx);
out:
bpf_mprog_tuple_put(&rtuple);
return ret;
}
int bpf_mprog_query(const union bpf_attr *attr, union bpf_attr __user *uattr,
struct bpf_mprog_entry *entry)
{
u32 __user *uprog_flags, *ulink_flags;
u32 __user *uprog_id, *ulink_id;
struct bpf_mprog_fp *fp;
struct bpf_mprog_cp *cp;
struct bpf_prog *prog;
const u32 flags = 0;
u32 id, count = 0;
u64 revision = 1;
int i, ret = 0;
if (attr->query.query_flags || attr->query.attach_flags)
return -EINVAL;
if (entry) {
revision = bpf_mprog_revision(entry);
count = bpf_mprog_total(entry);
}
if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)))
return -EFAULT;
if (copy_to_user(&uattr->query.revision, &revision, sizeof(revision)))
return -EFAULT;
if (copy_to_user(&uattr->query.count, &count, sizeof(count)))
return -EFAULT;
uprog_id = u64_to_user_ptr(attr->query.prog_ids);
uprog_flags = u64_to_user_ptr(attr->query.prog_attach_flags);
ulink_id = u64_to_user_ptr(attr->query.link_ids);
ulink_flags = u64_to_user_ptr(attr->query.link_attach_flags);
if (attr->query.count == 0 || !uprog_id || !count)
return 0;
if (attr->query.count < count) {
count = attr->query.count;
ret = -ENOSPC;
}
for (i = 0; i < bpf_mprog_max(); i++) {
bpf_mprog_read(entry, i, &fp, &cp);
prog = READ_ONCE(fp->prog);
if (!prog)
break;
id = prog->aux->id;
if (copy_to_user(uprog_id + i, &id, sizeof(id)))
return -EFAULT;
if (uprog_flags &&
copy_to_user(uprog_flags + i, &flags, sizeof(flags)))
return -EFAULT;
id = cp->link ? cp->link->id : 0;
if (ulink_id &&
copy_to_user(ulink_id + i, &id, sizeof(id)))
return -EFAULT;
if (ulink_flags &&
copy_to_user(ulink_flags + i, &flags, sizeof(flags)))
return -EFAULT;
if (i + 1 == count)
break;
}
return ret;
}
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