renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-16 01:04:08 +08:00
Code

bpf: Add bpf_bprm_opts_set helper

Browse Source 
The helper allows modification of certain bits on the linux_binprm
struct starting with the secureexec bit which can be updated using the
BPF_F_BPRM_SECUREEXEC flag.

secureexec can be set by the LSM for privilege gaining executions to set
the AT_SECURE auxv for glibc.  When set, the dynamic linker disables the
use of certain environment variables (like LD_PRELOAD).

Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20201117232929.2156341-1-kpsingh@chromium.org
This commit is contained in:
KP Singh 2020-11-17 23:29:28 +00:00 committed by Daniel Borkmann
parent cbf398d765
commit 3f6719c7b6
4 changed files with 60 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
include/uapi/linux/bpf.h
View File

@ -3787,6 +3787,16 @@ union bpf_attr {
* *ARG_PTR_TO_BTF_ID* of type *task_struct*.
* Return
* Pointer to the current task.
*
* long bpf_bprm_opts_set(struct linux_binprm *bprm, u64 flags)
* Description
* Set or clear certain options on *bprm*:
*
* **BPF_F_BPRM_SECUREEXEC** Set the secureexec bit
* which sets the **AT_SECURE** auxv for glibc. The bit
* is cleared if the flag is not specified.
* Return
* **-EINVAL** if invalid *flags* are passed, zero otherwise.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@ -3948,6 +3958,7 @@ union bpf_attr {
FN(task_storage_get), \
FN(task_storage_delete), \
FN(get_current_task_btf), \
FN(bprm_opts_set), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
@ -4119,6 +4130,11 @@ enum bpf_lwt_encap_mode {
BPF_LWT_ENCAP_IP,
};
/* Flags for bpf_bprm_opts_set helper */
enum {
BPF_F_BPRM_SECUREEXEC = (1ULL << 0),
};
#define __bpf_md_ptr(type, name) \
union { \
type name; \

26
kernel/bpf/bpf_lsm.c
View File

@ -7,6 +7,7 @@
#include <linux/filter.h>
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/binfmts.h>
#include <linux/lsm_hooks.h>
#include <linux/bpf_lsm.h>
#include <linux/kallsyms.h>
@ -51,6 +52,29 @@ int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
return 0;
}
/* Mask for all the currently supported BPRM option flags */
#define BPF_F_BRPM_OPTS_MASK BPF_F_BPRM_SECUREEXEC
BPF_CALL_2(bpf_bprm_opts_set, struct linux_binprm *, bprm, u64, flags)
{
if (flags & ~BPF_F_BRPM_OPTS_MASK)
return -EINVAL;
bprm->secureexec = (flags & BPF_F_BPRM_SECUREEXEC);
return 0;
}
BTF_ID_LIST_SINGLE(bpf_bprm_opts_set_btf_ids, struct, linux_binprm)
const static struct bpf_func_proto bpf_bprm_opts_set_proto = {
.func = bpf_bprm_opts_set,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_BTF_ID,
.arg1_btf_id = &bpf_bprm_opts_set_btf_ids[0],
.arg2_type = ARG_ANYTHING,
};
static const struct bpf_func_proto *
bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
{
@ -71,6 +95,8 @@ bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_task_storage_get_proto;
case BPF_FUNC_task_storage_delete:
return &bpf_task_storage_delete_proto;
case BPF_FUNC_bprm_opts_set:
return &bpf_bprm_opts_set_proto;
default:
return tracing_prog_func_proto(func_id, prog);
}

2
scripts/bpf_helpers_doc.py
View File

@ -418,6 +418,7 @@ class PrinterHelpers(Printer):
'struct bpf_tcp_sock',
'struct bpf_tunnel_key',
'struct bpf_xfrm_state',
'struct linux_binprm',
'struct pt_regs',
'struct sk_reuseport_md',
'struct sockaddr',
@ -465,6 +466,7 @@ class PrinterHelpers(Printer):
'struct bpf_tcp_sock',
'struct bpf_tunnel_key',
'struct bpf_xfrm_state',
'struct linux_binprm',
'struct pt_regs',
'struct sk_reuseport_md',
'struct sockaddr',

16
tools/include/uapi/linux/bpf.h
View File

@ -3787,6 +3787,16 @@ union bpf_attr {
* *ARG_PTR_TO_BTF_ID* of type *task_struct*.
* Return
* Pointer to the current task.
*
* long bpf_bprm_opts_set(struct linux_binprm *bprm, u64 flags)
* Description
* Set or clear certain options on *bprm*:
*
* **BPF_F_BPRM_SECUREEXEC** Set the secureexec bit
* which sets the **AT_SECURE** auxv for glibc. The bit
* is cleared if the flag is not specified.
* Return
* **-EINVAL** if invalid *flags* are passed, zero otherwise.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@ -3948,6 +3958,7 @@ union bpf_attr {
FN(task_storage_get), \
FN(task_storage_delete), \
FN(get_current_task_btf), \
FN(bprm_opts_set), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
@ -4119,6 +4130,11 @@ enum bpf_lwt_encap_mode {
BPF_LWT_ENCAP_IP,
};
/* Flags for bpf_bprm_opts_set helper */
enum {
BPF_F_BPRM_SECUREEXEC = (1ULL << 0),
};
#define __bpf_md_ptr(type, name) \
union { \
type name; \