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Merged
merged 11 commits into from
Nov 22, 2024
Merged

SECO-94 completion part 1 #12

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753521e
bpf: Introduce composable reg, ret and arg types.
bmastbergen Nov 18, 2024
dd6c760
bpf: Replace ARG_XXX_OR_NULL with ARG_XXX | PTR_MAYBE_NULL
bmastbergen Nov 18, 2024
a85fa58
bpf: Replace RET_XXX_OR_NULL with RET_XXX | PTR_MAYBE_NULL
bmastbergen Nov 18, 2024
82ce598
bpf: Replace PTR_TO_XXX_OR_NULL with PTR_TO_XXX | PTR_MAYBE_NULL
bmastbergen Nov 18, 2024
5e05f02
bpf: Introduce MEM_RDONLY flag
bmastbergen Nov 18, 2024
ae76ec7
bpf: Convert PTR_TO_MEM_OR_NULL to composable types.
bmastbergen Nov 18, 2024
58415d5
bpf: Make per_cpu_ptr return rdonly PTR_TO_MEM.
bmastbergen Nov 18, 2024
2d1b5f7
bpf: Add MEM_RDONLY for helper args that are pointers to rdonly mem.
bmastbergen Nov 20, 2024
a5b2c2d
bpf/selftests: Test PTR_TO_RDONLY_MEM
bmastbergen Nov 20, 2024
fd26b64
bpf: Fix crash due to out of bounds access into reg2btf_ids.
bmastbergen Nov 20, 2024
a1b347e
bpf: Check PTR_TO_MEM | MEM_RDONLY in check_helper_mem_access
bmastbergen Nov 20, 2024
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19 changes: 12 additions & 7 deletions include/linux/bpf.h
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Original file line number Diff line number Diff line change
Expand Up @@ -363,17 +363,22 @@ enum bpf_return_type {
RET_INTEGER, /* function returns integer */
RET_VOID, /* function doesn't return anything */
RET_PTR_TO_MAP_VALUE, /* returns a pointer to map elem value */
RET_PTR_TO_MAP_VALUE_OR_NULL, /* returns a pointer to map elem value or NULL */
RET_PTR_TO_SOCKET_OR_NULL, /* returns a pointer to a socket or NULL */
RET_PTR_TO_TCP_SOCK_OR_NULL, /* returns a pointer to a tcp_sock or NULL */
RET_PTR_TO_SOCK_COMMON_OR_NULL, /* returns a pointer to a sock_common or NULL */
RET_PTR_TO_ALLOC_MEM_OR_NULL, /* returns a pointer to dynamically allocated memory or NULL */
RET_PTR_TO_BTF_ID_OR_NULL, /* returns a pointer to a btf_id or NULL */
RET_PTR_TO_MEM_OR_BTF_ID_OR_NULL, /* returns a pointer to a valid memory or a btf_id or NULL */
RET_PTR_TO_SOCKET, /* returns a pointer to a socket */
RET_PTR_TO_TCP_SOCK, /* returns a pointer to a tcp_sock */
RET_PTR_TO_SOCK_COMMON, /* returns a pointer to a sock_common */
RET_PTR_TO_ALLOC_MEM, /* returns a pointer to dynamically allocated memory */
RET_PTR_TO_MEM_OR_BTF_ID, /* returns a pointer to a valid memory or a btf_id */
RET_PTR_TO_BTF_ID, /* returns a pointer to a btf_id */
__BPF_RET_TYPE_MAX,

/* Extended ret_types. */
RET_PTR_TO_MAP_VALUE_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_MAP_VALUE,
RET_PTR_TO_SOCKET_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_SOCKET,
RET_PTR_TO_TCP_SOCK_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_TCP_SOCK,
RET_PTR_TO_SOCK_COMMON_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_SOCK_COMMON,
RET_PTR_TO_ALLOC_MEM_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_ALLOC_MEM,
RET_PTR_TO_BTF_ID_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_BTF_ID,

/* This must be the last entry. Its purpose is to ensure the enum is
* wide enough to hold the higher bits reserved for bpf_type_flag.
*/
Expand Down
2 changes: 1 addition & 1 deletion kernel/bpf/helpers.c
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Original file line number Diff line number Diff line change
Expand Up @@ -670,7 +670,7 @@ BPF_CALL_2(bpf_per_cpu_ptr, const void *, ptr, u32, cpu)
const struct bpf_func_proto bpf_per_cpu_ptr_proto = {
.func = bpf_per_cpu_ptr,
.gpl_only = false,
.ret_type = RET_PTR_TO_MEM_OR_BTF_ID_OR_NULL,
.ret_type = RET_PTR_TO_MEM_OR_BTF_ID | PTR_MAYBE_NULL,
.arg1_type = ARG_PTR_TO_PERCPU_BTF_ID,
.arg2_type = ARG_ANYTHING,
};
Expand Down
52 changes: 26 additions & 26 deletions kernel/bpf/verifier.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5931,6 +5931,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
int *insn_idx_p)
{
const struct bpf_func_proto *fn = NULL;
enum bpf_return_type ret_type;
struct bpf_reg_state *regs;
struct bpf_call_arg_meta meta;
int insn_idx = *insn_idx_p;
Expand Down Expand Up @@ -6057,13 +6058,13 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;

/* update return register (already marked as written above) */
if (fn->ret_type == RET_INTEGER) {
ret_type = fn->ret_type;
if (ret_type == RET_INTEGER) {
/* sets type to SCALAR_VALUE */
mark_reg_unknown(env, regs, BPF_REG_0);
} else if (fn->ret_type == RET_VOID) {
} else if (ret_type == RET_VOID) {
regs[BPF_REG_0].type = NOT_INIT;
} else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL ||
fn->ret_type == RET_PTR_TO_MAP_VALUE) {
} else if (base_type(ret_type) == RET_PTR_TO_MAP_VALUE) {
/* There is no offset yet applied, variable or fixed */
mark_reg_known_zero(env, regs, BPF_REG_0);
/* remember map_ptr, so that check_map_access()
Expand All @@ -6076,28 +6077,27 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
return -EINVAL;
}
regs[BPF_REG_0].map_ptr = meta.map_ptr;
if (fn->ret_type == RET_PTR_TO_MAP_VALUE) {
if (type_may_be_null(ret_type)) {
regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
} else {
regs[BPF_REG_0].type = PTR_TO_MAP_VALUE;
if (map_value_has_spin_lock(meta.map_ptr))
regs[BPF_REG_0].id = ++env->id_gen;
} else {
regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
}
} else if (fn->ret_type == RET_PTR_TO_SOCKET_OR_NULL) {
} else if (base_type(ret_type) == RET_PTR_TO_SOCKET) {
mark_reg_known_zero(env, regs, BPF_REG_0);
regs[BPF_REG_0].type = PTR_TO_SOCKET_OR_NULL;
} else if (fn->ret_type == RET_PTR_TO_SOCK_COMMON_OR_NULL) {
} else if (base_type(ret_type) == RET_PTR_TO_SOCK_COMMON) {
mark_reg_known_zero(env, regs, BPF_REG_0);
regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON_OR_NULL;
} else if (fn->ret_type == RET_PTR_TO_TCP_SOCK_OR_NULL) {
} else if (base_type(ret_type) == RET_PTR_TO_TCP_SOCK) {
mark_reg_known_zero(env, regs, BPF_REG_0);
regs[BPF_REG_0].type = PTR_TO_TCP_SOCK_OR_NULL;
} else if (fn->ret_type == RET_PTR_TO_ALLOC_MEM_OR_NULL) {
} else if (base_type(ret_type) == RET_PTR_TO_ALLOC_MEM) {
mark_reg_known_zero(env, regs, BPF_REG_0);
regs[BPF_REG_0].type = PTR_TO_MEM_OR_NULL;
regs[BPF_REG_0].mem_size = meta.mem_size;
} else if (fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID_OR_NULL ||
fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID) {
} else if (base_type(ret_type) == RET_PTR_TO_MEM_OR_BTF_ID) {
const struct btf_type *t;

mark_reg_known_zero(env, regs, BPF_REG_0);
Expand All @@ -6116,28 +6116,28 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
return -EINVAL;
}
regs[BPF_REG_0].type =
fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID ?
PTR_TO_MEM : PTR_TO_MEM_OR_NULL;
(ret_type & PTR_MAYBE_NULL) ?
PTR_TO_MEM_OR_NULL : PTR_TO_MEM;
regs[BPF_REG_0].mem_size = tsize;
} else {
regs[BPF_REG_0].type =
fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID ?
PTR_TO_BTF_ID : PTR_TO_BTF_ID_OR_NULL;
(ret_type & PTR_MAYBE_NULL) ?
PTR_TO_BTF_ID_OR_NULL : PTR_TO_BTF_ID;
regs[BPF_REG_0].btf = meta.ret_btf;
regs[BPF_REG_0].btf_id = meta.ret_btf_id;
}
} else if (fn->ret_type == RET_PTR_TO_BTF_ID_OR_NULL ||
fn->ret_type == RET_PTR_TO_BTF_ID) {
} else if (base_type(ret_type) == RET_PTR_TO_BTF_ID) {
int ret_btf_id;

mark_reg_known_zero(env, regs, BPF_REG_0);
regs[BPF_REG_0].type = fn->ret_type == RET_PTR_TO_BTF_ID ?
PTR_TO_BTF_ID :
PTR_TO_BTF_ID_OR_NULL;
regs[BPF_REG_0].type = (ret_type & PTR_MAYBE_NULL) ?
PTR_TO_BTF_ID_OR_NULL :
PTR_TO_BTF_ID;
ret_btf_id = *fn->ret_btf_id;
if (ret_btf_id == 0) {
verbose(env, "invalid return type %d of func %s#%d\n",
fn->ret_type, func_id_name(func_id), func_id);
verbose(env, "invalid return type %u of func %s#%d\n",
base_type(ret_type), func_id_name(func_id),
func_id);
return -EINVAL;
}
/* current BPF helper definitions are only coming from
Expand All @@ -6146,8 +6146,8 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
regs[BPF_REG_0].btf = btf_vmlinux;
regs[BPF_REG_0].btf_id = ret_btf_id;
} else {
verbose(env, "unknown return type %d of func %s#%d\n",
fn->ret_type, func_id_name(func_id), func_id);
verbose(env, "unknown return type %u of func %s#%d\n",
base_type(ret_type), func_id_name(func_id), func_id);
return -EINVAL;
}

Expand Down