292 lines
9.5 KiB
C
292 lines
9.5 KiB
C
|
{
|
||
|
|
"variable-offset ctx access",
|
||
|
|
.insns = {
|
||
|
|
/* Get an unknown value */
|
||
|
|
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||
|
|
/* Make it small and 4-byte aligned */
|
||
|
|
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
|
||
|
|
/* add it to skb. We now have either &skb->len or
|
||
|
|
* &skb->pkt_type, but we don't know which
|
||
|
|
*/
|
||
|
|
BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_2),
|
||
|
|
/* dereference it */
|
||
|
|
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, 0),
|
||
|
|
BPF_EXIT_INSN(),
|
||
|
|
},
|
||
|
|
.errstr = "variable ctx access var_off=(0x0; 0x4)",
|
||
|
|
.result = REJECT,
|
||
|
|
.prog_type = BPF_PROG_TYPE_LWT_IN,
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"variable-offset stack read, priv vs unpriv",
|
||
|
|
.insns = {
|
||
|
|
/* Fill the top 8 bytes of the stack */
|
||
|
|
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
|
||
|
|
/* Get an unknown value */
|
||
|
|
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||
|
|
/* Make it small and 4-byte aligned */
|
||
|
|
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
|
||
|
|
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 8),
|
||
|
|
/* add it to fp. We now have either fp-4 or fp-8, but
|
||
|
|
* we don't know which
|
||
|
|
*/
|
||
|
|
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||
|
|
/* dereference it for a stack read */
|
||
|
|
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 0),
|
||
|
|
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||
|
|
BPF_EXIT_INSN(),
|
||
|
|
},
|
||
|
|
.result = ACCEPT,
|
||
|
|
.result_unpriv = REJECT,
|
||
|
|
.errstr_unpriv = "R2 variable stack access prohibited for !root",
|
||
|
|
.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"variable-offset stack read, uninitialized",
|
||
|
|
.insns = {
|
||
|
|
/* Get an unknown value */
|
||
|
|
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||
|
|
/* Make it small and 4-byte aligned */
|
||
|
|
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
|
||
|
|
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 8),
|
||
|
|
/* add it to fp. We now have either fp-4 or fp-8, but
|
||
|
|
* we don't know which
|
||
|
|
*/
|
||
|
|
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||
|
|
/* dereference it for a stack read */
|
||
|
|
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 0),
|
||
|
|
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||
|
|
BPF_EXIT_INSN(),
|
||
|
|
},
|
||
|
|
.result = REJECT,
|
||
|
|
.errstr = "invalid variable-offset read from stack R2",
|
||
|
|
.prog_type = BPF_PROG_TYPE_LWT_IN,
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"variable-offset stack write, priv vs unpriv",
|
||
|
|
.insns = {
|
||
|
|
/* Get an unknown value */
|
||
|
|
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||
|
|
/* Make it small and 8-byte aligned */
|
||
|
|
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 8),
|
||
|
|
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 16),
|
||
|
|
/* Add it to fp. We now have either fp-8 or fp-16, but
|
||
|
|
* we don't know which
|
||
|
|
*/
|
||
|
|
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||
|
|
/* Dereference it for a stack write */
|
||
|
|
BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
|
||
|
|
/* Now read from the address we just wrote. This shows
|
||
|
|
* that, after a variable-offset write, a priviledged
|
||
|
|
* program can read the slots that were in the range of
|
||
|
|
* that write (even if the verifier doesn't actually know
|
||
|
|
* if the slot being read was really written to or not.
|
||
|
|
*/
|
||
|
|
BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_2, 0),
|
||
|
|
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||
|
|
BPF_EXIT_INSN(),
|
||
|
|
},
|
||
|
|
/* Variable stack access is rejected for unprivileged.
|
||
|
|
*/
|
||
|
|
.errstr_unpriv = "R2 variable stack access prohibited for !root",
|
||
|
|
.result_unpriv = REJECT,
|
||
|
|
.result = ACCEPT,
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"variable-offset stack write clobbers spilled regs",
|
||
|
|
.insns = {
|
||
|
|
/* Dummy instruction; needed because we need to patch the next one
|
||
|
|
* and we can't patch the first instruction.
|
||
|
|
*/
|
||
|
|
BPF_MOV64_IMM(BPF_REG_6, 0),
|
||
|
|
/* Make R0 a map ptr */
|
||
|
|
BPF_LD_MAP_FD(BPF_REG_0, 0),
|
||
|
|
/* Get an unknown value */
|
||
|
|
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||
|
|
/* Make it small and 8-byte aligned */
|
||
|
|
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 8),
|
||
|
|
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 16),
|
||
|
|
/* Add it to fp. We now have either fp-8 or fp-16, but
|
||
|
|
* we don't know which.
|
||
|
|
*/
|
||
|
|
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||
|
|
/* Spill R0(map ptr) into stack */
|
||
|
|
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
|
||
|
|
/* Dereference the unknown value for a stack write */
|
||
|
|
BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
|
||
|
|
/* Fill the register back into R2 */
|
||
|
|
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -8),
|
||
|
|
/* Try to dereference R2 for a memory load */
|
||
|
|
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 8),
|
||
|
|
BPF_EXIT_INSN(),
|
||
|
|
},
|
||
|
|
.fixup_map_hash_8b = { 1 },
|
||
|
|
/* The unprivileged case is not too interesting; variable
|
||
|
|
* stack access is rejected.
|
||
|
|
*/
|
||
|
|
.errstr_unpriv = "R2 variable stack access prohibited for !root",
|
||
|
|
.result_unpriv = REJECT,
|
||
|
|
/* In the priviledged case, dereferencing a spilled-and-then-filled
|
||
|
|
* register is rejected because the previous variable offset stack
|
||
|
|
* write might have overwritten the spilled pointer (i.e. we lose track
|
||
|
|
* of the spilled register when we analyze the write).
|
||
|
|
*/
|
||
|
|
.errstr = "R2 invalid mem access 'scalar'",
|
||
|
|
.result = REJECT,
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"indirect variable-offset stack access, unbounded",
|
||
|
|
.insns = {
|
||
|
|
BPF_MOV64_IMM(BPF_REG_2, 6),
|
||
|
|
BPF_MOV64_IMM(BPF_REG_3, 28),
|
||
|
|
/* Fill the top 16 bytes of the stack. */
|
||
|
|
BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, 0),
|
||
|
|
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
|
||
|
|
/* Get an unknown value. */
|
||
|
|
BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_1, offsetof(struct bpf_sock_ops,
|
||
|
|
bytes_received)),
|
||
|
|
/* Check the lower bound but don't check the upper one. */
|
||
|
|
BPF_JMP_IMM(BPF_JSLT, BPF_REG_4, 0, 4),
|
||
|
|
/* Point the lower bound to initialized stack. Offset is now in range
|
||
|
|
* from fp-16 to fp+0x7fffffffffffffef, i.e. max value is unbounded.
|
||
|
|
*/
|
||
|
|
BPF_ALU64_IMM(BPF_SUB, BPF_REG_4, 16),
|
||
|
|
BPF_ALU64_REG(BPF_ADD, BPF_REG_4, BPF_REG_10),
|
||
|
|
BPF_MOV64_IMM(BPF_REG_5, 8),
|
||
|
|
/* Dereference it indirectly. */
|
||
|
|
BPF_EMIT_CALL(BPF_FUNC_getsockopt),
|
||
|
|
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||
|
|
BPF_EXIT_INSN(),
|
||
|
|
},
|
||
|
|
.errstr = "invalid unbounded variable-offset indirect access to stack R4",
|
||
|
|
.result = REJECT,
|
||
|
|
.prog_type = BPF_PROG_TYPE_SOCK_OPS,
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"indirect variable-offset stack access, max out of bound",
|
||
|
|
.insns = {
|
||
|
|
/* Fill the top 8 bytes of the stack */
|
||
|
|
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
|
||
|
|
/* Get an unknown value */
|
||
|
|
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||
|
|
/* Make it small and 4-byte aligned */
|
||
|
|
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
|
||
|
|
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 8),
|
||
|
|
/* add it to fp. We now have either fp-4 or fp-8, but
|
||
|
|
* we don't know which
|
||
|
|
*/
|
||
|
|
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||
|
|
/* dereference it indirectly */
|
||
|
|
BPF_LD_MAP_FD(BPF_REG_1, 0),
|
||
|
|
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
|
||
|
|
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||
|
|
BPF_EXIT_INSN(),
|
||
|
|
},
|
||
|
|
.fixup_map_hash_8b = { 5 },
|
||
|
|
.errstr = "invalid variable-offset indirect access to stack R2",
|
||
|
|
.result = REJECT,
|
||
|
|
.prog_type = BPF_PROG_TYPE_LWT_IN,
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"indirect variable-offset stack access, min out of bound",
|
||
|
|
.insns = {
|
||
|
|
/* Fill the top 8 bytes of the stack */
|
||
|
|
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
|
||
|
|
/* Get an unknown value */
|
||
|
|
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||
|
|
/* Make it small and 4-byte aligned */
|
||
|
|
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
|
||
|
|
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 516),
|
||
|
|
/* add it to fp. We now have either fp-516 or fp-512, but
|
||
|
|
* we don't know which
|
||
|
|
*/
|
||
|
|
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||
|
|
/* dereference it indirectly */
|
||
|
|
BPF_LD_MAP_FD(BPF_REG_1, 0),
|
||
|
|
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
|
||
|
|
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||
|
|
BPF_EXIT_INSN(),
|
||
|
|
},
|
||
|
|
.fixup_map_hash_8b = { 5 },
|
||
|
|
.errstr = "invalid variable-offset indirect access to stack R2",
|
||
|
|
.result = REJECT,
|
||
|
|
.prog_type = BPF_PROG_TYPE_LWT_IN,
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"indirect variable-offset stack access, min_off < min_initialized",
|
||
|
|
.insns = {
|
||
|
|
/* Fill only the top 8 bytes of the stack. */
|
||
|
|
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
|
||
|
|
/* Get an unknown value */
|
||
|
|
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||
|
|
/* Make it small and 4-byte aligned. */
|
||
|
|
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
|
||
|
|
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 16),
|
||
|
|
/* Add it to fp. We now have either fp-12 or fp-16, but we don't know
|
||
|
|
* which. fp-16 size 8 is partially uninitialized stack.
|
||
|
|
*/
|
||
|
|
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||
|
|
/* Dereference it indirectly. */
|
||
|
|
BPF_LD_MAP_FD(BPF_REG_1, 0),
|
||
|
|
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
|
||
|
|
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||
|
|
BPF_EXIT_INSN(),
|
||
|
|
},
|
||
|
|
.fixup_map_hash_8b = { 5 },
|
||
|
|
.errstr = "invalid indirect read from stack R2 var_off",
|
||
|
|
.result = REJECT,
|
||
|
|
.prog_type = BPF_PROG_TYPE_LWT_IN,
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"indirect variable-offset stack access, priv vs unpriv",
|
||
|
|
.insns = {
|
||
|
|
/* Fill the top 16 bytes of the stack. */
|
||
|
|
BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, 0),
|
||
|
|
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
|
||
|
|
/* Get an unknown value. */
|
||
|
|
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||
|
|
/* Make it small and 4-byte aligned. */
|
||
|
|
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
|
||
|
|
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 16),
|
||
|
|
/* Add it to fp. We now have either fp-12 or fp-16, we don't know
|
||
|
|
* which, but either way it points to initialized stack.
|
||
|
|
*/
|
||
|
|
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||
|
|
/* Dereference it indirectly. */
|
||
|
|
BPF_LD_MAP_FD(BPF_REG_1, 0),
|
||
|
|
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
|
||
|
|
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||
|
|
BPF_EXIT_INSN(),
|
||
|
|
},
|
||
|
|
.fixup_map_hash_8b = { 6 },
|
||
|
|
.errstr_unpriv = "R2 variable stack access prohibited for !root",
|
||
|
|
.result_unpriv = REJECT,
|
||
|
|
.result = ACCEPT,
|
||
|
|
.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"indirect variable-offset stack access, ok",
|
||
|
|
.insns = {
|
||
|
|
/* Fill the top 16 bytes of the stack. */
|
||
|
|
BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, 0),
|
||
|
|
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
|
||
|
|
/* Get an unknown value. */
|
||
|
|
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||
|
|
/* Make it small and 4-byte aligned. */
|
||
|
|
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
|
||
|
|
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 16),
|
||
|
|
/* Add it to fp. We now have either fp-12 or fp-16, we don't know
|
||
|
|
* which, but either way it points to initialized stack.
|
||
|
|
*/
|
||
|
|
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||
|
|
/* Dereference it indirectly. */
|
||
|
|
BPF_LD_MAP_FD(BPF_REG_1, 0),
|
||
|
|
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
|
||
|
|
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||
|
|
BPF_EXIT_INSN(),
|
||
|
|
},
|
||
|
|
.fixup_map_hash_8b = { 6 },
|
||
|
|
.result = ACCEPT,
|
||
|
|
.prog_type = BPF_PROG_TYPE_LWT_IN,
|
||
|
|
},
|