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bpf: allow helpers access to variable memory

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Currently, helpers that read and write from/to the stack can do so using
a pair of arguments of type ARG_PTR_TO_STACK and ARG_CONST_STACK_SIZE.
ARG_CONST_STACK_SIZE accepts a constant register of type CONST_IMM, so
that the verifier can safely check the memory access. However, requiring
the argument to be a constant can be limiting in some circumstances.

Since the current logic keeps track of the minimum and maximum value of
a register throughout the simulated execution, ARG_CONST_STACK_SIZE can
be changed to also accept an UNKNOWN_VALUE register in case its
boundaries have been set and the range doesn't cause invalid memory
accesses.

One common situation when this is useful:

int len;
char buf[BUFSIZE]; /* BUFSIZE is 128 */

if (some_condition)
	len = 42;
else
	len = 84;

some_helper(..., buf, len & (BUFSIZE - 1));

The compiler can often decide to assign the constant values 42 or 48
into a variable on the stack, instead of keeping it in a register. When
the variable is then read back from stack into the register in order to
be passed to the helper, the verifier will not be able to recognize the
register as constant (the verifier is not currently tracking all
constant writes into memory), and the program won't be valid.

However, by allowing the helper to accept an UNKNOWN_VALUE register,
this program will work because the bitwise AND operation will set the
range of possible values for the UNKNOWN_VALUE register to [0, BUFSIZE),
so the verifier can guarantee the helper call will be safe (assuming the
argument is of type ARG_CONST_STACK_SIZE_OR_ZERO, otherwise one more
check against 0 would be needed). Custom ranges can be set not only with
ALU operations, but also by explicitly comparing the UNKNOWN_VALUE
register with constants.

Another very common example happens when intercepting system call
arguments and accessing user-provided data of variable size using
bpf_probe_read(). One can load at runtime the user-provided length in an
UNKNOWN_VALUE register, and then read that exact amount of data up to a
compile-time determined limit in order to fit into the proper local
storage allocated on the stack, without having to guess a suboptimal
access size at compile time.

Also, in case the helpers accepting the UNKNOWN_VALUE register operate
in raw mode, disable the raw mode so that the program is required to
initialize all memory, since there is no guarantee the helper will fill
it completely, leaving possibilities for data leak (just relevant when
the memory used by the helper is the stack, not when using a pointer to
map element value or packet). In other words, ARG_PTR_TO_RAW_STACK will
be treated as ARG_PTR_TO_STACK.

Signed-off-by: Gianluca Borello <g.borello@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Gianluca Borello 2017-01-09 10:19:49 -08:00 committed by David S. Miller
parent f0318d01b6
commit 06c1c04972
2 changed files with 474 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

74
kernel/bpf/verifier.c
View File

@ -980,6 +980,25 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
return 0; return 0;
} }
static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
int access_size, bool zero_size_allowed,
struct bpf_call_arg_meta *meta)
{
struct bpf_reg_state *regs = env->cur_state.regs;
switch (regs[regno].type) {
case PTR_TO_PACKET:
return check_packet_access(env, regno, 0, access_size);
case PTR_TO_MAP_VALUE:
return check_map_access(env, regno, 0, access_size);
case PTR_TO_MAP_VALUE_ADJ:
return check_map_access_adj(env, regno, 0, access_size);
default: /* const_imm|ptr_to_stack or invalid ptr */
return check_stack_boundary(env, regno, access_size,
zero_size_allowed, meta);
}
}
static int check_func_arg(struct bpf_verifier_env *env, u32 regno, static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
enum bpf_arg_type arg_type, enum bpf_arg_type arg_type,
struct bpf_call_arg_meta *meta) struct bpf_call_arg_meta *meta)
@ -1018,7 +1037,10 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
} else if (arg_type == ARG_CONST_STACK_SIZE || } else if (arg_type == ARG_CONST_STACK_SIZE ||
arg_type == ARG_CONST_STACK_SIZE_OR_ZERO) { arg_type == ARG_CONST_STACK_SIZE_OR_ZERO) {
expected_type = CONST_IMM; expected_type = CONST_IMM;
if (type != expected_type) /* One exception. Allow UNKNOWN_VALUE registers when the
* boundaries are known and don't cause unsafe memory accesses
*/
if (type != UNKNOWN_VALUE && type != expected_type)
goto err_type; goto err_type;
} else if (arg_type == ARG_CONST_MAP_PTR) { } else if (arg_type == ARG_CONST_MAP_PTR) {
expected_type = CONST_PTR_TO_MAP; expected_type = CONST_PTR_TO_MAP;
@ -1099,15 +1121,47 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
verbose("ARG_CONST_STACK_SIZE cannot be first argument\n"); verbose("ARG_CONST_STACK_SIZE cannot be first argument\n");
return -EACCES; return -EACCES;
} }
if (regs[regno - 1].type == PTR_TO_PACKET)
err = check_packet_access(env, regno - 1, 0, reg->imm); /* If the register is UNKNOWN_VALUE, the access check happens
else if (regs[regno - 1].type == PTR_TO_MAP_VALUE) * using its boundaries. Otherwise, just use its imm
err = check_map_access(env, regno - 1, 0, reg->imm); */
else if (regs[regno - 1].type == PTR_TO_MAP_VALUE_ADJ) if (type == UNKNOWN_VALUE) {
err = check_map_access_adj(env, regno - 1, 0, reg->imm); /* For unprivileged variable accesses, disable raw
else * mode so that the program is required to
err = check_stack_boundary(env, regno - 1, reg->imm, * initialize all the memory that the helper could
zero_size_allowed, meta); * just partially fill up.
*/
meta = NULL;
if (reg->min_value < 0) {
verbose("R%d min value is negative, either use unsigned or 'var &= const'\n",
regno);
return -EACCES;
}
if (reg->min_value == 0) {
err = check_helper_mem_access(env, regno - 1, 0,
zero_size_allowed,
meta);
if (err)
return err;
}
if (reg->max_value == BPF_REGISTER_MAX_RANGE) {
verbose("R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n",
regno);
return -EACCES;
}
err = check_helper_mem_access(env, regno - 1,
reg->max_value,
zero_size_allowed, meta);
if (err)
return err;
} else {
/* register is CONST_IMM */
err = check_helper_mem_access(env, regno - 1, reg->imm,
zero_size_allowed, meta);
}
} }
return err; return err;

410
tools/testing/selftests/bpf/test_verifier.c
View File

@ -3442,6 +3442,416 @@ static struct bpf_test tests[] = {
.result = ACCEPT, .result = ACCEPT,
.result_unpriv = REJECT, .result_unpriv = REJECT,
}, },
{
"helper access to variable memory: stack, bitwise AND + JMP, correct bounds",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -64),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -56),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -48),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -40),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -32),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -24),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
BPF_MOV64_IMM(BPF_REG_2, 16),
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 64),
BPF_MOV64_IMM(BPF_REG_4, 0),
BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: stack, bitwise AND, zero included",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
BPF_MOV64_IMM(BPF_REG_2, 16),
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 64),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_EXIT_INSN(),
},
.errstr = "invalid stack type R1 off=-64 access_size=0",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: stack, bitwise AND + JMP, wrong max",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
BPF_MOV64_IMM(BPF_REG_2, 16),
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 65),
BPF_MOV64_IMM(BPF_REG_4, 0),
BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "invalid stack type R1 off=-64 access_size=65",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: stack, JMP, correct bounds",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -64),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -56),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -48),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -40),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -32),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -24),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
BPF_MOV64_IMM(BPF_REG_2, 16),
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 64, 4),
BPF_MOV64_IMM(BPF_REG_4, 0),
BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: stack, JMP (signed), correct bounds",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -64),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -56),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -48),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -40),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -32),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -24),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
BPF_MOV64_IMM(BPF_REG_2, 16),
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
BPF_JMP_IMM(BPF_JSGT, BPF_REG_2, 64, 4),
BPF_MOV64_IMM(BPF_REG_4, 0),
BPF_JMP_REG(BPF_JSGE, BPF_REG_4, BPF_REG_2, 2),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: stack, JMP, bounds + offset",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
BPF_MOV64_IMM(BPF_REG_2, 16),
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 64, 5),
BPF_MOV64_IMM(BPF_REG_4, 0),
BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 3),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 1),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "invalid stack type R1 off=-64 access_size=65",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: stack, JMP, wrong max",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
BPF_MOV64_IMM(BPF_REG_2, 16),
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 65, 4),
BPF_MOV64_IMM(BPF_REG_4, 0),
BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "invalid stack type R1 off=-64 access_size=65",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: stack, JMP, no max check",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
BPF_MOV64_IMM(BPF_REG_2, 16),
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
BPF_MOV64_IMM(BPF_REG_4, 0),
BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R2 unbounded memory access",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: stack, JMP, no min check",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
BPF_MOV64_IMM(BPF_REG_2, 16),
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 64, 3),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "invalid stack type R1 off=-64 access_size=0",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: stack, JMP (signed), no min check",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
BPF_MOV64_IMM(BPF_REG_2, 16),
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
BPF_JMP_IMM(BPF_JSGT, BPF_REG_2, 64, 3),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R2 min value is negative",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: map, JMP, correct bounds",
.insns = {
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 10),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_MOV64_IMM(BPF_REG_2, sizeof(struct test_val)),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -128),
BPF_JMP_IMM(BPF_JSGT, BPF_REG_2,
sizeof(struct test_val), 4),
BPF_MOV64_IMM(BPF_REG_4, 0),
BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.fixup_map2 = { 3 },
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: map, JMP, wrong max",
.insns = {
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 10),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_MOV64_IMM(BPF_REG_2, sizeof(struct test_val)),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -128),
BPF_JMP_IMM(BPF_JSGT, BPF_REG_2,
sizeof(struct test_val) + 1, 4),
BPF_MOV64_IMM(BPF_REG_4, 0),
BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.fixup_map2 = { 3 },
.errstr = "invalid access to map value, value_size=48 off=0 size=49",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: map adjusted, JMP, correct bounds",
.insns = {
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 11),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 20),
BPF_MOV64_IMM(BPF_REG_2, sizeof(struct test_val)),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -128),
BPF_JMP_IMM(BPF_JSGT, BPF_REG_2,
sizeof(struct test_val) - 20, 4),
BPF_MOV64_IMM(BPF_REG_4, 0),
BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.fixup_map2 = { 3 },
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: map adjusted, JMP, wrong max",
.insns = {
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 11),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 20),
BPF_MOV64_IMM(BPF_REG_2, sizeof(struct test_val)),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -128),
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -128),
BPF_JMP_IMM(BPF_JSGT, BPF_REG_2,
sizeof(struct test_val) - 19, 4),
BPF_MOV64_IMM(BPF_REG_4, 0),
BPF_JMP_REG(BPF_JGE, BPF_REG_4, BPF_REG_2, 2),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.fixup_map2 = { 3 },
.errstr = "R1 min value is outside of the array range",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: size > 0 not allowed on NULL",
.insns = {
BPF_MOV64_IMM(BPF_REG_1, 0),
BPF_MOV64_IMM(BPF_REG_2, 0),
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 64),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_MOV64_IMM(BPF_REG_4, 0),
BPF_MOV64_IMM(BPF_REG_5, 0),
BPF_EMIT_CALL(BPF_FUNC_csum_diff),
BPF_EXIT_INSN(),
},
.errstr = "R1 type=imm expected=fp",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
"helper access to variable memory: size = 0 not allowed on != NULL",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_2, 0),
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, 0),
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 8),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_MOV64_IMM(BPF_REG_4, 0),
BPF_MOV64_IMM(BPF_REG_5, 0),
BPF_EMIT_CALL(BPF_FUNC_csum_diff),
BPF_EXIT_INSN(),
},
.errstr = "invalid stack type R1 off=-8 access_size=0",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
"helper access to variable memory: 8 bytes leak",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -64),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -56),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -48),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -40),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -24),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
BPF_MOV64_IMM(BPF_REG_2, 0),
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 63),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 1),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
BPF_EXIT_INSN(),
},
.errstr = "invalid indirect read from stack off -64+32 size 64",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
"helper access to variable memory: 8 bytes no leak (init memory)",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -64),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -56),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -48),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -40),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -32),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -24),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
BPF_MOV64_IMM(BPF_REG_2, 0),
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 32),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 32),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_EMIT_CALL(BPF_FUNC_probe_read),
BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
}; };
static int probe_filter_length(const struct bpf_insn *fp) static int probe_filter_length(const struct bpf_insn *fp)