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bpf: Use bpf_prog_run_array_cg_flags everywhere
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Rename bpf_prog_run_array_cg_flags to bpf_prog_run_array_cg and
use it everywhere. check_return_code already enforces sane
return ranges for all cgroup types. (only egress and bind hooks have
uncanonical return ranges, the rest is using [0, 1])

No functional changes.

v2:
- 'func_ret & 1' under explicit test (Andrii & Martin)

Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220425220448.3669032-1-sdf@google.com
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Stanislav Fomichev authored and Alexei Starovoitov committed Apr 26, 2022
1 parent 246bdfa commit d9d31cf
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Showing 2 changed files with 26 additions and 54 deletions.
8 changes: 2 additions & 6 deletions include/linux/bpf-cgroup.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -225,24 +225,20 @@ static inline bool cgroup_bpf_sock_enabled(struct sock *sk,

#define BPF_CGROUP_RUN_SA_PROG(sk, uaddr, atype) \
({ \
u32 __unused_flags; \
int __ret = 0; \
if (cgroup_bpf_enabled(atype)) \
__ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, atype, \
NULL, \
&__unused_flags); \
NULL, NULL); \
__ret; \
})

#define BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, atype, t_ctx) \
({ \
u32 __unused_flags; \
int __ret = 0; \
if (cgroup_bpf_enabled(atype)) { \
lock_sock(sk); \
__ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, atype, \
t_ctx, \
&__unused_flags); \
t_ctx, NULL); \
release_sock(sk); \
} \
__ret; \
Expand Down
72 changes: 24 additions & 48 deletions kernel/bpf/cgroup.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,50 +25,18 @@ EXPORT_SYMBOL(cgroup_bpf_enabled_key);
/* __always_inline is necessary to prevent indirect call through run_prog
* function pointer.
*/
static __always_inline int
bpf_prog_run_array_cg_flags(const struct cgroup_bpf *cgrp,
enum cgroup_bpf_attach_type atype,
const void *ctx, bpf_prog_run_fn run_prog,
int retval, u32 *ret_flags)
{
const struct bpf_prog_array_item *item;
const struct bpf_prog *prog;
const struct bpf_prog_array *array;
struct bpf_run_ctx *old_run_ctx;
struct bpf_cg_run_ctx run_ctx;
u32 func_ret;

run_ctx.retval = retval;
migrate_disable();
rcu_read_lock();
array = rcu_dereference(cgrp->effective[atype]);
item = &array->items[0];
old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
while ((prog = READ_ONCE(item->prog))) {
run_ctx.prog_item = item;
func_ret = run_prog(prog, ctx);
if (!(func_ret & 1) && !IS_ERR_VALUE((long)run_ctx.retval))
run_ctx.retval = -EPERM;
*(ret_flags) |= (func_ret >> 1);
item++;
}
bpf_reset_run_ctx(old_run_ctx);
rcu_read_unlock();
migrate_enable();
return run_ctx.retval;
}

static __always_inline int
bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
enum cgroup_bpf_attach_type atype,
const void *ctx, bpf_prog_run_fn run_prog,
int retval)
int retval, u32 *ret_flags)
{
const struct bpf_prog_array_item *item;
const struct bpf_prog *prog;
const struct bpf_prog_array *array;
struct bpf_run_ctx *old_run_ctx;
struct bpf_cg_run_ctx run_ctx;
u32 func_ret;

run_ctx.retval = retval;
migrate_disable();
Expand All @@ -78,7 +46,12 @@ bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
while ((prog = READ_ONCE(item->prog))) {
run_ctx.prog_item = item;
if (!run_prog(prog, ctx) && !IS_ERR_VALUE((long)run_ctx.retval))
func_ret = run_prog(prog, ctx);
if (ret_flags) {
*(ret_flags) |= (func_ret >> 1);
func_ret &= 1;
}
if (!func_ret && !IS_ERR_VALUE((long)run_ctx.retval))
run_ctx.retval = -EPERM;
item++;
}
Expand Down Expand Up @@ -1144,9 +1117,8 @@ int __cgroup_bpf_run_filter_skb(struct sock *sk,
u32 flags = 0;
bool cn;

ret = bpf_prog_run_array_cg_flags(
&cgrp->bpf, atype,
skb, __bpf_prog_run_save_cb, 0, &flags);
ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, skb,
__bpf_prog_run_save_cb, 0, &flags);

/* Return values of CGROUP EGRESS BPF programs are:
* 0: drop packet
Expand All @@ -1172,7 +1144,8 @@ int __cgroup_bpf_run_filter_skb(struct sock *sk,
ret = (cn ? NET_XMIT_DROP : ret);
} else {
ret = bpf_prog_run_array_cg(&cgrp->bpf, atype,
skb, __bpf_prog_run_save_cb, 0);
skb, __bpf_prog_run_save_cb, 0,
NULL);
if (ret && !IS_ERR_VALUE((long)ret))
ret = -EFAULT;
}
Expand Down Expand Up @@ -1202,7 +1175,8 @@ int __cgroup_bpf_run_filter_sk(struct sock *sk,
{
struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);

return bpf_prog_run_array_cg(&cgrp->bpf, atype, sk, bpf_prog_run, 0);
return bpf_prog_run_array_cg(&cgrp->bpf, atype, sk, bpf_prog_run, 0,
NULL);
}
EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk);

Expand Down Expand Up @@ -1247,8 +1221,8 @@ int __cgroup_bpf_run_filter_sock_addr(struct sock *sk,
}

cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
return bpf_prog_run_array_cg_flags(&cgrp->bpf, atype,
&ctx, bpf_prog_run, 0, flags);
return bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run,
0, flags);
}
EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_addr);

Expand All @@ -1275,7 +1249,7 @@ int __cgroup_bpf_run_filter_sock_ops(struct sock *sk,
struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);

return bpf_prog_run_array_cg(&cgrp->bpf, atype, sock_ops, bpf_prog_run,
0);
0, NULL);
}
EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_ops);

Expand All @@ -1292,7 +1266,8 @@ int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,

rcu_read_lock();
cgrp = task_dfl_cgroup(current);
ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0);
ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0,
NULL);
rcu_read_unlock();

return ret;
Expand Down Expand Up @@ -1457,7 +1432,8 @@ int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head,

rcu_read_lock();
cgrp = task_dfl_cgroup(current);
ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0);
ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0,
NULL);
rcu_read_unlock();

kfree(ctx.cur_val);
Expand Down Expand Up @@ -1550,7 +1526,7 @@ int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,

lock_sock(sk);
ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_SETSOCKOPT,
&ctx, bpf_prog_run, 0);
&ctx, bpf_prog_run, 0, NULL);
release_sock(sk);

if (ret)
Expand Down Expand Up @@ -1650,7 +1626,7 @@ int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level,

lock_sock(sk);
ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_GETSOCKOPT,
&ctx, bpf_prog_run, retval);
&ctx, bpf_prog_run, retval, NULL);
release_sock(sk);

if (ret < 0)
Expand Down Expand Up @@ -1699,7 +1675,7 @@ int __cgroup_bpf_run_filter_getsockopt_kern(struct sock *sk, int level,
*/

ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_GETSOCKOPT,
&ctx, bpf_prog_run, retval);
&ctx, bpf_prog_run, retval, NULL);
if (ret < 0)
return ret;

Expand Down

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