* [PATCH bpf-next] bpf: add BPF_F_TOKEN_FD flag to pass with BPF token FD
@ 2023-12-19 5:31 Andrii Nakryiko
2023-12-20 12:10 ` Christian Brauner
0 siblings, 1 reply; 2+ messages in thread
From: Andrii Nakryiko @ 2023-12-19 5:31 UTC (permalink / raw)
To: bpf, netdev, brauner, torvalds, ast, daniel; +Cc: linux-fsdevel, kernel-team
Add BPF_F_TOKEN_FD flag to be used across bpf() syscall commands
that accept BPF token FD: BPF_PROG_LOAD, BPF_MAP_CREATE, and
BPF_BTF_LOAD. This flag has to be set whenever token FD is provided.
BPF_BTF_LOAD command didn't have a flags field, so add it as well.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
include/uapi/linux/bpf.h | 10 +++++++---
kernel/bpf/syscall.c | 19 +++++++++++++++----
tools/include/uapi/linux/bpf.h | 10 +++++++---
3 files changed, 29 insertions(+), 10 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index e0545201b55f..539dc19d8d11 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1364,6 +1364,9 @@ enum {
/* Get path from provided FD in BPF_OBJ_PIN/BPF_OBJ_GET commands */
BPF_F_PATH_FD = (1U << 14),
+
+/* BPF token FD is passed in a corresponding command's token_fd field */
+ BPF_F_TOKEN_FD = (1U << 15),
};
/* Flags for BPF_PROG_QUERY. */
@@ -1437,7 +1440,7 @@ union bpf_attr {
* to using 5 hash functions).
*/
__u64 map_extra;
- __u32 map_token_fd;
+ __s32 map_token_fd;
};
struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
@@ -1507,7 +1510,7 @@ union bpf_attr {
* truncated), or smaller (if log buffer wasn't filled completely).
*/
__u32 log_true_size;
- __u32 prog_token_fd;
+ __s32 prog_token_fd;
};
struct { /* anonymous struct used by BPF_OBJ_* commands */
@@ -1620,7 +1623,8 @@ union bpf_attr {
* truncated), or smaller (if log buffer wasn't filled completely).
*/
__u32 btf_log_true_size;
- __u32 btf_token_fd;
+ __u32 btf_flags;
+ __s32 btf_token_fd;
};
struct {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 8faa1a20edf8..d6337842006d 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1137,6 +1137,7 @@ static int map_create(union bpf_attr *attr)
int numa_node = bpf_map_attr_numa_node(attr);
u32 map_type = attr->map_type;
struct bpf_map *map;
+ bool token_flag;
int f_flags;
int err;
@@ -1144,6 +1145,12 @@ static int map_create(union bpf_attr *attr)
if (err)
return -EINVAL;
+ /* check BPF_F_TOKEN_FD flag, remember if it's set, and then clear it
+ * to avoid per-map type checks tripping on unknown flag
+ */
+ token_flag = attr->map_flags & BPF_F_TOKEN_FD;
+ attr->map_flags &= ~BPF_F_TOKEN_FD;
+
if (attr->btf_vmlinux_value_type_id) {
if (attr->map_type != BPF_MAP_TYPE_STRUCT_OPS ||
attr->btf_key_type_id || attr->btf_value_type_id)
@@ -1184,7 +1191,7 @@ static int map_create(union bpf_attr *attr)
if (!ops->map_mem_usage)
return -EINVAL;
- if (attr->map_token_fd) {
+ if (token_flag) {
token = bpf_token_get_from_fd(attr->map_token_fd);
if (IS_ERR(token))
return PTR_ERR(token);
@@ -2641,12 +2648,13 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
BPF_F_TEST_RND_HI32 |
BPF_F_XDP_HAS_FRAGS |
BPF_F_XDP_DEV_BOUND_ONLY |
- BPF_F_TEST_REG_INVARIANTS))
+ BPF_F_TEST_REG_INVARIANTS |
+ BPF_F_TOKEN_FD))
return -EINVAL;
bpf_prog_load_fixup_attach_type(attr);
- if (attr->prog_token_fd) {
+ if (attr->prog_flags & BPF_F_TOKEN_FD) {
token = bpf_token_get_from_fd(attr->prog_token_fd);
if (IS_ERR(token))
return PTR_ERR(token);
@@ -4837,7 +4845,10 @@ static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_
if (CHECK_ATTR(BPF_BTF_LOAD))
return -EINVAL;
- if (attr->btf_token_fd) {
+ if (attr->btf_flags & ~BPF_F_TOKEN_FD)
+ return -EINVAL;
+
+ if (attr->btf_flags & BPF_F_TOKEN_FD) {
token = bpf_token_get_from_fd(attr->btf_token_fd);
if (IS_ERR(token))
return PTR_ERR(token);
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index e0545201b55f..539dc19d8d11 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1364,6 +1364,9 @@ enum {
/* Get path from provided FD in BPF_OBJ_PIN/BPF_OBJ_GET commands */
BPF_F_PATH_FD = (1U << 14),
+
+/* BPF token FD is passed in a corresponding command's token_fd field */
+ BPF_F_TOKEN_FD = (1U << 15),
};
/* Flags for BPF_PROG_QUERY. */
@@ -1437,7 +1440,7 @@ union bpf_attr {
* to using 5 hash functions).
*/
__u64 map_extra;
- __u32 map_token_fd;
+ __s32 map_token_fd;
};
struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
@@ -1507,7 +1510,7 @@ union bpf_attr {
* truncated), or smaller (if log buffer wasn't filled completely).
*/
__u32 log_true_size;
- __u32 prog_token_fd;
+ __s32 prog_token_fd;
};
struct { /* anonymous struct used by BPF_OBJ_* commands */
@@ -1620,7 +1623,8 @@ union bpf_attr {
* truncated), or smaller (if log buffer wasn't filled completely).
*/
__u32 btf_log_true_size;
- __u32 btf_token_fd;
+ __u32 btf_flags;
+ __s32 btf_token_fd;
};
struct {
--
2.34.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH bpf-next] bpf: add BPF_F_TOKEN_FD flag to pass with BPF token FD
2023-12-19 5:31 [PATCH bpf-next] bpf: add BPF_F_TOKEN_FD flag to pass with BPF token FD Andrii Nakryiko
@ 2023-12-20 12:10 ` Christian Brauner
0 siblings, 0 replies; 2+ messages in thread
From: Christian Brauner @ 2023-12-20 12:10 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: bpf, netdev, torvalds, ast, daniel, linux-fsdevel, kernel-team
On Mon, Dec 18, 2023 at 09:31:50PM -0800, Andrii Nakryiko wrote:
> Add BPF_F_TOKEN_FD flag to be used across bpf() syscall commands
> that accept BPF token FD: BPF_PROG_LOAD, BPF_MAP_CREATE, and
> BPF_BTF_LOAD. This flag has to be set whenever token FD is provided.
>
> BPF_BTF_LOAD command didn't have a flags field, so add it as well.
>
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
> ---
Reviewed-by: Christian Brauner <brauner@kernel.org>
> /* Get path from provided FD in BPF_OBJ_PIN/BPF_OBJ_GET commands */
> BPF_F_PATH_FD = (1U << 14),
> +
> +/* BPF token FD is passed in a corresponding command's token_fd field */
> + BPF_F_TOKEN_FD = (1U << 15),
The placement of the new flag right after the BPF_F_PATH_FD flag alone
does tell us everything about the "we didn't know" claims wrt to the
token fd stuff. Literally the same review and the same solution I
requested back then.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2023-12-20 12:10 ` Christian Brauner
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