Centos-kernel-stream-9/include/linux/bpf_lsm.h

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2020 Google LLC.
*/
#ifndef _LINUX_BPF_LSM_H
#define _LINUX_BPF_LSM_H
#include <linux/sched.h>
#include <linux/bpf.h>
#include <linux/bpf_verifier.h>
#include <linux/lsm_hooks.h>
#ifdef CONFIG_BPF_LSM
#define LSM_HOOK(RET, DEFAULT, NAME, ...) \
RET bpf_lsm_##NAME(__VA_ARGS__);
#include <linux/lsm_hook_defs.h>
#undef LSM_HOOK
struct bpf_storage_blob {
struct bpf_local_storage __rcu *storage;
};
extern struct lsm_blob_sizes bpf_lsm_blob_sizes;
int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
const struct bpf_prog *prog);
bool bpf_lsm_is_sleepable_hook(u32 btf_id);
bpf: Do not mark certain LSM hook arguments as trusted Bugzilla: https://bugzilla.redhat.com/2177177 Conflicts: Context change due to missing commit 401e64b3a4af ("bpf-lsm: Make bpf_lsm_userns_create() sleepable") commit c0c852dd1876dc1db4600ce951a92aadd3073b1c Author: Yonghong Song <yhs@fb.com> Date: Sat Dec 3 12:49:54 2022 -0800 bpf: Do not mark certain LSM hook arguments as trusted Martin mentioned that the verifier cannot assume arguments from LSM hook sk_alloc_security being trusted since after the hook is called, the sk ref_count is set to 1. This will overwrite the ref_count changed by the bpf program and may cause ref_count underflow later on. I then further checked some other hooks. For example, for bpf_lsm_file_alloc() hook in fs/file_table.c, f->f_cred = get_cred(cred); error = security_file_alloc(f); if (unlikely(error)) { file_free_rcu(&f->f_rcuhead); return ERR_PTR(error); } atomic_long_set(&f->f_count, 1); The input parameter 'f' to security_file_alloc() cannot be trusted as well. Specifically, I investiaged bpf_map/bpf_prog/file/sk/task alloc/free lsm hooks. Except bpf_map_alloc and task_alloc, arguments for all other hooks should not be considered as trusted. This may not be a complete list, but it covers common usage for sk and task. Fixes: 3f00c5239344 ("bpf: Allow trusted pointers to be passed to KF_TRUSTED_ARGS kfuncs") Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20221203204954.2043348-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
2023-03-21 10:11:40 +00:00
bool bpf_lsm_is_trusted(const struct bpf_prog *prog);
static inline struct bpf_storage_blob *bpf_inode(
const struct inode *inode)
{
if (unlikely(!inode->i_security))
return NULL;
return inode->i_security + bpf_lsm_blob_sizes.lbs_inode;
}
extern const struct bpf_func_proto bpf_inode_storage_get_proto;
extern const struct bpf_func_proto bpf_inode_storage_delete_proto;
void bpf_inode_storage_free(struct inode *inode);
bpf: per-cgroup lsm flavor Bugzilla: https://bugzilla.redhat.com/2137876 Conflicts: already applied 65d9ecfe0ca73 "bpf: Fix ref_obj_id for dynptr data slices in verifier" commit 69fd337a975c7e690dfe49d9cb4fe5ba1e6db44e Author: Stanislav Fomichev <sdf@google.com> Date: Tue Jun 28 10:43:06 2022 -0700 bpf: per-cgroup lsm flavor Allow attaching to lsm hooks in the cgroup context. Attaching to per-cgroup LSM works exactly like attaching to other per-cgroup hooks. New BPF_LSM_CGROUP is added to trigger new mode; the actual lsm hook we attach to is signaled via existing attach_btf_id. For the hooks that have 'struct socket' or 'struct sock' as its first argument, we use the cgroup associated with that socket. For the rest, we use 'current' cgroup (this is all on default hierarchy == v2 only). Note that for some hooks that work on 'struct sock' we still take the cgroup from 'current' because some of them work on the socket that hasn't been properly initialized yet. Behind the scenes, we allocate a shim program that is attached to the trampoline and runs cgroup effective BPF programs array. This shim has some rudimentary ref counting and can be shared between several programs attaching to the same lsm hook from different cgroups. Note that this patch bloats cgroup size because we add 211 cgroup_bpf_attach_type(s) for simplicity sake. This will be addressed in the subsequent patch. Also note that we only add non-sleepable flavor for now. To enable sleepable use-cases, bpf_prog_run_array_cg has to grab trace rcu, shim programs have to be freed via trace rcu, cgroup_bpf.effective should be also trace-rcu-managed + maybe some other changes that I'm not aware of. Reviewed-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20220628174314.1216643-4-sdf@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Artem Savkov <asavkov@redhat.com>
2022-10-31 10:08:09 +00:00
void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog, bpf_func_t *bpf_func);
int bpf_lsm_get_retval_range(const struct bpf_prog *prog,
struct bpf_retval_range *range);
#else /* !CONFIG_BPF_LSM */
static inline bool bpf_lsm_is_sleepable_hook(u32 btf_id)
{
return false;
}
bpf: Do not mark certain LSM hook arguments as trusted Bugzilla: https://bugzilla.redhat.com/2177177 Conflicts: Context change due to missing commit 401e64b3a4af ("bpf-lsm: Make bpf_lsm_userns_create() sleepable") commit c0c852dd1876dc1db4600ce951a92aadd3073b1c Author: Yonghong Song <yhs@fb.com> Date: Sat Dec 3 12:49:54 2022 -0800 bpf: Do not mark certain LSM hook arguments as trusted Martin mentioned that the verifier cannot assume arguments from LSM hook sk_alloc_security being trusted since after the hook is called, the sk ref_count is set to 1. This will overwrite the ref_count changed by the bpf program and may cause ref_count underflow later on. I then further checked some other hooks. For example, for bpf_lsm_file_alloc() hook in fs/file_table.c, f->f_cred = get_cred(cred); error = security_file_alloc(f); if (unlikely(error)) { file_free_rcu(&f->f_rcuhead); return ERR_PTR(error); } atomic_long_set(&f->f_count, 1); The input parameter 'f' to security_file_alloc() cannot be trusted as well. Specifically, I investiaged bpf_map/bpf_prog/file/sk/task alloc/free lsm hooks. Except bpf_map_alloc and task_alloc, arguments for all other hooks should not be considered as trusted. This may not be a complete list, but it covers common usage for sk and task. Fixes: 3f00c5239344 ("bpf: Allow trusted pointers to be passed to KF_TRUSTED_ARGS kfuncs") Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20221203204954.2043348-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
2023-03-21 10:11:40 +00:00
static inline bool bpf_lsm_is_trusted(const struct bpf_prog *prog)
{
return false;
}
static inline int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
const struct bpf_prog *prog)
{
return -EOPNOTSUPP;
}
static inline struct bpf_storage_blob *bpf_inode(
const struct inode *inode)
{
return NULL;
}
static inline void bpf_inode_storage_free(struct inode *inode)
{
}
bpf: per-cgroup lsm flavor Bugzilla: https://bugzilla.redhat.com/2137876 Conflicts: already applied 65d9ecfe0ca73 "bpf: Fix ref_obj_id for dynptr data slices in verifier" commit 69fd337a975c7e690dfe49d9cb4fe5ba1e6db44e Author: Stanislav Fomichev <sdf@google.com> Date: Tue Jun 28 10:43:06 2022 -0700 bpf: per-cgroup lsm flavor Allow attaching to lsm hooks in the cgroup context. Attaching to per-cgroup LSM works exactly like attaching to other per-cgroup hooks. New BPF_LSM_CGROUP is added to trigger new mode; the actual lsm hook we attach to is signaled via existing attach_btf_id. For the hooks that have 'struct socket' or 'struct sock' as its first argument, we use the cgroup associated with that socket. For the rest, we use 'current' cgroup (this is all on default hierarchy == v2 only). Note that for some hooks that work on 'struct sock' we still take the cgroup from 'current' because some of them work on the socket that hasn't been properly initialized yet. Behind the scenes, we allocate a shim program that is attached to the trampoline and runs cgroup effective BPF programs array. This shim has some rudimentary ref counting and can be shared between several programs attaching to the same lsm hook from different cgroups. Note that this patch bloats cgroup size because we add 211 cgroup_bpf_attach_type(s) for simplicity sake. This will be addressed in the subsequent patch. Also note that we only add non-sleepable flavor for now. To enable sleepable use-cases, bpf_prog_run_array_cg has to grab trace rcu, shim programs have to be freed via trace rcu, cgroup_bpf.effective should be also trace-rcu-managed + maybe some other changes that I'm not aware of. Reviewed-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20220628174314.1216643-4-sdf@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Artem Savkov <asavkov@redhat.com>
2022-10-31 10:08:09 +00:00
static inline void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog,
bpf_func_t *bpf_func)
{
}
static inline int bpf_lsm_get_retval_range(const struct bpf_prog *prog,
struct bpf_retval_range *range)
{
return -EOPNOTSUPP;
}
#endif /* CONFIG_BPF_LSM */
#endif /* _LINUX_BPF_LSM_H */