verbose(env, "w");
}
+static struct bpf_func_state *func(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg)
+{
+ struct bpf_verifier_state *cur = env->cur_state;
+
+ return cur->frame[reg->frameno];
+}
+
static void print_verifier_state(struct bpf_verifier_env *env,
- struct bpf_verifier_state *state)
+ const struct bpf_func_state *state)
{
- struct bpf_reg_state *reg;
+ const struct bpf_reg_state *reg;
enum bpf_reg_type t;
int i;
+ if (state->frameno)
+ verbose(env, " frame%d:", state->frameno);
for (i = 0; i < MAX_BPF_REG; i++) {
reg = &state->regs[i];
t = reg->type;
tnum_is_const(reg->var_off)) {
/* reg->off should be 0 for SCALAR_VALUE */
verbose(env, "%lld", reg->var_off.value + reg->off);
+ if (t == PTR_TO_STACK)
+ verbose(env, ",call_%d", func(env, reg)->callsite);
} else {
verbose(env, "(id=%d", reg->id);
if (t != SCALAR_VALUE)
verbose(env, "\n");
}
-static int copy_stack_state(struct bpf_verifier_state *dst,
- const struct bpf_verifier_state *src)
+static int copy_stack_state(struct bpf_func_state *dst,
+ const struct bpf_func_state *src)
{
if (!src->stack)
return 0;
/* do_check() starts with zero-sized stack in struct bpf_verifier_state to
* make it consume minimal amount of memory. check_stack_write() access from
- * the program calls into realloc_verifier_state() to grow the stack size.
+ * the program calls into realloc_func_state() to grow the stack size.
* Note there is a non-zero 'parent' pointer inside bpf_verifier_state
* which this function copies over. It points to previous bpf_verifier_state
* which is never reallocated
*/
-static int realloc_verifier_state(struct bpf_verifier_state *state, int size,
- bool copy_old)
+static int realloc_func_state(struct bpf_func_state *state, int size,
+ bool copy_old)
{
u32 old_size = state->allocated_stack;
struct bpf_stack_state *new_stack;
return 0;
}
+static void free_func_state(struct bpf_func_state *state)
+{
+ kfree(state->stack);
+ kfree(state);
+}
+
static void free_verifier_state(struct bpf_verifier_state *state,
bool free_self)
{
- kfree(state->stack);
+ int i;
+
+ for (i = 0; i <= state->curframe; i++) {
+ free_func_state(state->frame[i]);
+ state->frame[i] = NULL;
+ }
if (free_self)
kfree(state);
}
/* copy verifier state from src to dst growing dst stack space
* when necessary to accommodate larger src stack
*/
-static int copy_verifier_state(struct bpf_verifier_state *dst,
- const struct bpf_verifier_state *src)
+static int copy_func_state(struct bpf_func_state *dst,
+ const struct bpf_func_state *src)
{
int err;
- err = realloc_verifier_state(dst, src->allocated_stack, false);
+ err = realloc_func_state(dst, src->allocated_stack, false);
if (err)
return err;
- memcpy(dst, src, offsetof(struct bpf_verifier_state, allocated_stack));
+ memcpy(dst, src, offsetof(struct bpf_func_state, allocated_stack));
return copy_stack_state(dst, src);
}
+static int copy_verifier_state(struct bpf_verifier_state *dst_state,
+ const struct bpf_verifier_state *src)
+{
+ struct bpf_func_state *dst;
+ int i, err;
+
+ /* if dst has more stack frames then src frame, free them */
+ for (i = src->curframe + 1; i <= dst_state->curframe; i++) {
+ free_func_state(dst_state->frame[i]);
+ dst_state->frame[i] = NULL;
+ }
+ dst_state->curframe = src->curframe;
+ dst_state->parent = src->parent;
+ for (i = 0; i <= src->curframe; i++) {
+ dst = dst_state->frame[i];
+ if (!dst) {
+ dst = kzalloc(sizeof(*dst), GFP_KERNEL);
+ if (!dst)
+ return -ENOMEM;
+ dst_state->frame[i] = dst;
+ }
+ err = copy_func_state(dst, src->frame[i]);
+ if (err)
+ return err;
+ }
+ return 0;
+}
+
static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx,
int *insn_idx)
{
static const int caller_saved[CALLER_SAVED_REGS] = {
BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5
};
+#define CALLEE_SAVED_REGS 5
+static const int callee_saved[CALLEE_SAVED_REGS] = {
+ BPF_REG_6, BPF_REG_7, BPF_REG_8, BPF_REG_9
+};
static void __mark_reg_not_init(struct bpf_reg_state *reg);
reg->id = 0;
reg->off = 0;
reg->var_off = tnum_unknown;
+ reg->frameno = 0;
__mark_reg_unbounded(reg);
}
}
static void init_reg_state(struct bpf_verifier_env *env,
- struct bpf_reg_state *regs)
+ struct bpf_func_state *state)
{
+ struct bpf_reg_state *regs = state->regs;
int i;
for (i = 0; i < MAX_BPF_REG; i++) {
/* frame pointer */
regs[BPF_REG_FP].type = PTR_TO_STACK;
mark_reg_known_zero(env, regs, BPF_REG_FP);
+ regs[BPF_REG_FP].frameno = state->frameno;
/* 1st arg to a function */
regs[BPF_REG_1].type = PTR_TO_CTX;
mark_reg_known_zero(env, regs, BPF_REG_1);
}
+#define BPF_MAIN_FUNC (-1)
+static void init_func_state(struct bpf_verifier_env *env,
+ struct bpf_func_state *state,
+ int callsite, int frameno, int subprogno)
+{
+ state->callsite = callsite;
+ state->frameno = frameno;
+ state->subprogno = subprogno;
+ init_reg_state(env, state);
+}
+
enum reg_arg_type {
SRC_OP, /* register is used as source operand */
DST_OP, /* register is used as destination operand */
return 0;
}
-static void mark_reg_read(const struct bpf_verifier_state *state, u32 regno)
+struct bpf_verifier_state *skip_callee(struct bpf_verifier_env *env,
+ const struct bpf_verifier_state *state,
+ struct bpf_verifier_state *parent,
+ u32 regno)
{
- struct bpf_verifier_state *parent = state->parent;
+ struct bpf_verifier_state *tmp = NULL;
+
+ /* 'parent' could be a state of caller and
+ * 'state' could be a state of callee. In such case
+ * parent->curframe < state->curframe
+ * and it's ok for r1 - r5 registers
+ *
+ * 'parent' could be a callee's state after it bpf_exit-ed.
+ * In such case parent->curframe > state->curframe
+ * and it's ok for r0 only
+ */
+ if (parent->curframe == state->curframe ||
+ (parent->curframe < state->curframe &&
+ regno >= BPF_REG_1 && regno <= BPF_REG_5) ||
+ (parent->curframe > state->curframe &&
+ regno == BPF_REG_0))
+ return parent;
+
+ if (parent->curframe > state->curframe &&
+ regno >= BPF_REG_6) {
+ /* for callee saved regs we have to skip the whole chain
+ * of states that belong to callee and mark as LIVE_READ
+ * the registers before the call
+ */
+ tmp = parent;
+ while (tmp && tmp->curframe != state->curframe) {
+ tmp = tmp->parent;
+ }
+ if (!tmp)
+ goto bug;
+ parent = tmp;
+ } else {
+ goto bug;
+ }
+ return parent;
+bug:
+ verbose(env, "verifier bug regno %d tmp %p\n", regno, tmp);
+ verbose(env, "regno %d parent frame %d current frame %d\n",
+ regno, parent->curframe, state->curframe);
+ return 0;
+}
+
+static int mark_reg_read(struct bpf_verifier_env *env,
+ const struct bpf_verifier_state *state,
+ struct bpf_verifier_state *parent,
+ u32 regno)
+{
+ bool writes = parent == state->parent; /* Observe write marks */
if (regno == BPF_REG_FP)
/* We don't need to worry about FP liveness because it's read-only */
- return;
+ return 0;
while (parent) {
/* if read wasn't screened by an earlier write ... */
- if (state->regs[regno].live & REG_LIVE_WRITTEN)
+ if (writes && state->frame[state->curframe]->regs[regno].live & REG_LIVE_WRITTEN)
break;
+ parent = skip_callee(env, state, parent, regno);
+ if (!parent)
+ return -EFAULT;
/* ... then we depend on parent's value */
- parent->regs[regno].live |= REG_LIVE_READ;
+ parent->frame[parent->curframe]->regs[regno].live |= REG_LIVE_READ;
state = parent;
parent = state->parent;
+ writes = true;
}
+ return 0;
}
static int check_reg_arg(struct bpf_verifier_env *env, u32 regno,
enum reg_arg_type t)
{
- struct bpf_reg_state *regs = env->cur_state->regs;
+ struct bpf_verifier_state *vstate = env->cur_state;
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
+ struct bpf_reg_state *regs = state->regs;
if (regno >= MAX_BPF_REG) {
verbose(env, "R%d is invalid\n", regno);
verbose(env, "R%d !read_ok\n", regno);
return -EACCES;
}
- mark_reg_read(env->cur_state, regno);
+ return mark_reg_read(env, vstate, vstate->parent, regno);
} else {
/* check whether register used as dest operand can be written to */
if (regno == BPF_REG_FP) {
* stack boundary and alignment are checked in check_mem_access()
*/
static int check_stack_write(struct bpf_verifier_env *env,
- struct bpf_verifier_state *state, int off,
- int size, int value_regno)
+ struct bpf_func_state *state, /* func where register points to */
+ int off, int size, int value_regno)
{
+ struct bpf_func_state *cur; /* state of the current function */
int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err;
+ enum bpf_reg_type type;
- err = realloc_verifier_state(state, round_up(slot + 1, BPF_REG_SIZE),
- true);
+ err = realloc_func_state(state, round_up(slot + 1, BPF_REG_SIZE),
+ true);
if (err)
return err;
/* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0,
return -EACCES;
}
+ cur = env->cur_state->frame[env->cur_state->curframe];
if (value_regno >= 0 &&
- is_spillable_regtype(state->regs[value_regno].type)) {
+ is_spillable_regtype((type = cur->regs[value_regno].type))) {
/* register containing pointer is being spilled into stack */
if (size != BPF_REG_SIZE) {
return -EACCES;
}
+ if (state != cur && type == PTR_TO_STACK) {
+ verbose(env, "cannot spill pointers to stack into stack frame of the caller\n");
+ return -EINVAL;
+ }
+
/* save register state */
- state->stack[spi].spilled_ptr = state->regs[value_regno];
+ state->stack[spi].spilled_ptr = cur->regs[value_regno];
state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
for (i = 0; i < BPF_REG_SIZE; i++)
return 0;
}
-static void mark_stack_slot_read(const struct bpf_verifier_state *state, int slot)
+/* registers of every function are unique and mark_reg_read() propagates
+ * the liveness in the following cases:
+ * - from callee into caller for R1 - R5 that were used as arguments
+ * - from caller into callee for R0 that used as result of the call
+ * - from caller to the same caller skipping states of the callee for R6 - R9,
+ * since R6 - R9 are callee saved by implicit function prologue and
+ * caller's R6 != callee's R6, so when we propagate liveness up to
+ * parent states we need to skip callee states for R6 - R9.
+ *
+ * stack slot marking is different, since stacks of caller and callee are
+ * accessible in both (since caller can pass a pointer to caller's stack to
+ * callee which can pass it to another function), hence mark_stack_slot_read()
+ * has to propagate the stack liveness to all parent states at given frame number.
+ * Consider code:
+ * f1() {
+ * ptr = fp - 8;
+ * *ptr = ctx;
+ * call f2 {
+ * .. = *ptr;
+ * }
+ * .. = *ptr;
+ * }
+ * First *ptr is reading from f1's stack and mark_stack_slot_read() has
+ * to mark liveness at the f1's frame and not f2's frame.
+ * Second *ptr is also reading from f1's stack and mark_stack_slot_read() has
+ * to propagate liveness to f2 states at f1's frame level and further into
+ * f1 states at f1's frame level until write into that stack slot
+ */
+static void mark_stack_slot_read(struct bpf_verifier_env *env,
+ const struct bpf_verifier_state *state,
+ struct bpf_verifier_state *parent,
+ int slot, int frameno)
{
- struct bpf_verifier_state *parent = state->parent;
+ bool writes = parent == state->parent; /* Observe write marks */
while (parent) {
/* if read wasn't screened by an earlier write ... */
- if (state->stack[slot].spilled_ptr.live & REG_LIVE_WRITTEN)
+ if (writes && state->frame[frameno]->stack[slot].spilled_ptr.live & REG_LIVE_WRITTEN)
break;
/* ... then we depend on parent's value */
- parent->stack[slot].spilled_ptr.live |= REG_LIVE_READ;
+ parent->frame[frameno]->stack[slot].spilled_ptr.live |= REG_LIVE_READ;
state = parent;
parent = state->parent;
+ writes = true;
}
}
static int check_stack_read(struct bpf_verifier_env *env,
- struct bpf_verifier_state *state, int off, int size,
- int value_regno)
+ struct bpf_func_state *reg_state /* func where register points to */,
+ int off, int size, int value_regno)
{
+ struct bpf_verifier_state *vstate = env->cur_state;
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
int i, slot = -off - 1, spi = slot / BPF_REG_SIZE;
u8 *stype;
- if (state->allocated_stack <= slot) {
+ if (reg_state->allocated_stack <= slot) {
verbose(env, "invalid read from stack off %d+0 size %d\n",
off, size);
return -EACCES;
}
- stype = state->stack[spi].slot_type;
+ stype = reg_state->stack[spi].slot_type;
if (stype[0] == STACK_SPILL) {
if (size != BPF_REG_SIZE) {
if (value_regno >= 0) {
/* restore register state from stack */
- state->regs[value_regno] = state->stack[spi].spilled_ptr;
+ state->regs[value_regno] = reg_state->stack[spi].spilled_ptr;
/* mark reg as written since spilled pointer state likely
* has its liveness marks cleared by is_state_visited()
* which resets stack/reg liveness for state transitions
*/
state->regs[value_regno].live |= REG_LIVE_WRITTEN;
- mark_stack_slot_read(state, spi);
+ mark_stack_slot_read(env, vstate, vstate->parent, spi,
+ reg_state->frameno);
}
return 0;
} else {
static int check_map_access(struct bpf_verifier_env *env, u32 regno,
int off, int size, bool zero_size_allowed)
{
- struct bpf_verifier_state *state = env->cur_state;
+ struct bpf_verifier_state *vstate = env->cur_state;
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
struct bpf_reg_state *reg = &state->regs[regno];
int err;
strict);
}
+static int update_stack_depth(struct bpf_verifier_env *env,
+ const struct bpf_func_state *func,
+ int off)
+{
+ u16 stack = env->subprog_stack_depth[func->subprogno], total = 0;
+ struct bpf_verifier_state *cur = env->cur_state;
+ int i;
+
+ if (stack >= -off)
+ return 0;
+
+ /* update known max for given subprogram */
+ env->subprog_stack_depth[func->subprogno] = -off;
+
+ /* compute the total for current call chain */
+ for (i = 0; i <= cur->curframe; i++) {
+ u32 depth = env->subprog_stack_depth[cur->frame[i]->subprogno];
+
+ /* round up to 32-bytes, since this is granularity
+ * of interpreter stack sizes
+ */
+ depth = round_up(depth, 32);
+ total += depth;
+ }
+
+ if (total > MAX_BPF_STACK) {
+ verbose(env, "combined stack size of %d calls is %d. Too large\n",
+ cur->curframe, total);
+ return -EACCES;
+ }
+ return 0;
+}
+
/* check whether memory at (regno + off) is accessible for t = (read | write)
* if t==write, value_regno is a register which value is stored into memory
* if t==read, value_regno is a register which will receive the value from memory
int bpf_size, enum bpf_access_type t,
int value_regno)
{
- struct bpf_verifier_state *state = env->cur_state;
struct bpf_reg_state *regs = cur_regs(env);
struct bpf_reg_state *reg = regs + regno;
+ struct bpf_func_state *state;
int size, err = 0;
size = bpf_size_to_bytes(bpf_size);
return -EACCES;
}
- if (env->prog->aux->stack_depth < -off)
- env->prog->aux->stack_depth = -off;
+ state = func(env, reg);
+ err = update_stack_depth(env, state, off);
+ if (err)
+ return err;
if (t == BPF_WRITE)
err = check_stack_write(env, state, off, size,
struct bpf_call_arg_meta *meta)
{
struct bpf_reg_state *reg = cur_regs(env) + regno;
- struct bpf_verifier_state *state = env->cur_state;
+ struct bpf_func_state *state = func(env, reg);
int off, i, slot, spi;
if (reg->type != PTR_TO_STACK) {
return -EACCES;
}
- if (env->prog->aux->stack_depth < -off)
- env->prog->aux->stack_depth = -off;
-
if (meta && meta->raw_mode) {
meta->access_size = access_size;
meta->regno = regno;
return -EACCES;
}
}
- return 0;
+ return update_stack_depth(env, state, off);
}
static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
case BPF_FUNC_tail_call:
if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
goto error;
+ if (env->subprog_cnt) {
+ verbose(env, "tail_calls are not allowed in programs with bpf-to-bpf calls\n");
+ return -EINVAL;
+ }
break;
case BPF_FUNC_perf_event_read:
case BPF_FUNC_perf_event_output:
/* Packet data might have moved, any old PTR_TO_PACKET[_META,_END]
* are now invalid, so turn them into unknown SCALAR_VALUE.
*/
-static void clear_all_pkt_pointers(struct bpf_verifier_env *env)
+static void __clear_all_pkt_pointers(struct bpf_verifier_env *env,
+ struct bpf_func_state *state)
{
- struct bpf_verifier_state *state = env->cur_state;
struct bpf_reg_state *regs = state->regs, *reg;
int i;
}
}
-static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx)
+static void clear_all_pkt_pointers(struct bpf_verifier_env *env)
+{
+ struct bpf_verifier_state *vstate = env->cur_state;
+ int i;
+
+ for (i = 0; i <= vstate->curframe; i++)
+ __clear_all_pkt_pointers(env, vstate->frame[i]);
+}
+
+static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+ int *insn_idx)
+{
+ struct bpf_verifier_state *state = env->cur_state;
+ struct bpf_func_state *caller, *callee;
+ int i, subprog, target_insn;
+
+ if (state->curframe >= MAX_CALL_FRAMES) {
+ verbose(env, "the call stack of %d frames is too deep\n",
+ state->curframe);
+ return -E2BIG;
+ }
+
+ target_insn = *insn_idx + insn->imm;
+ subprog = find_subprog(env, target_insn + 1);
+ if (subprog < 0) {
+ verbose(env, "verifier bug. No program starts at insn %d\n",
+ target_insn + 1);
+ return -EFAULT;
+ }
+
+ caller = state->frame[state->curframe];
+ if (state->frame[state->curframe + 1]) {
+ verbose(env, "verifier bug. Frame %d already allocated\n",
+ state->curframe + 1);
+ return -EFAULT;
+ }
+
+ callee = kzalloc(sizeof(*callee), GFP_KERNEL);
+ if (!callee)
+ return -ENOMEM;
+ state->frame[state->curframe + 1] = callee;
+
+ /* callee cannot access r0, r6 - r9 for reading and has to write
+ * into its own stack before reading from it.
+ * callee can read/write into caller's stack
+ */
+ init_func_state(env, callee,
+ /* remember the callsite, it will be used by bpf_exit */
+ *insn_idx /* callsite */,
+ state->curframe + 1 /* frameno within this callchain */,
+ subprog + 1 /* subprog number within this prog */);
+
+ /* copy r1 - r5 args that callee can access */
+ for (i = BPF_REG_1; i <= BPF_REG_5; i++)
+ callee->regs[i] = caller->regs[i];
+
+ /* after the call regsiters r0 - r5 were scratched */
+ for (i = 0; i < CALLER_SAVED_REGS; i++) {
+ mark_reg_not_init(env, caller->regs, caller_saved[i]);
+ check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
+ }
+
+ /* only increment it after check_reg_arg() finished */
+ state->curframe++;
+
+ /* and go analyze first insn of the callee */
+ *insn_idx = target_insn;
+
+ if (env->log.level) {
+ verbose(env, "caller:\n");
+ print_verifier_state(env, caller);
+ verbose(env, "callee:\n");
+ print_verifier_state(env, callee);
+ }
+ return 0;
+}
+
+static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
+{
+ struct bpf_verifier_state *state = env->cur_state;
+ struct bpf_func_state *caller, *callee;
+ struct bpf_reg_state *r0;
+
+ callee = state->frame[state->curframe];
+ r0 = &callee->regs[BPF_REG_0];
+ if (r0->type == PTR_TO_STACK) {
+ /* technically it's ok to return caller's stack pointer
+ * (or caller's caller's pointer) back to the caller,
+ * since these pointers are valid. Only current stack
+ * pointer will be invalid as soon as function exits,
+ * but let's be conservative
+ */
+ verbose(env, "cannot return stack pointer to the caller\n");
+ return -EINVAL;
+ }
+
+ state->curframe--;
+ caller = state->frame[state->curframe];
+ /* return to the caller whatever r0 had in the callee */
+ caller->regs[BPF_REG_0] = *r0;
+
+ *insn_idx = callee->callsite + 1;
+ if (env->log.level) {
+ verbose(env, "returning from callee:\n");
+ print_verifier_state(env, callee);
+ verbose(env, "to caller at %d:\n", *insn_idx);
+ print_verifier_state(env, caller);
+ }
+ /* clear everything in the callee */
+ free_func_state(callee);
+ state->frame[state->curframe + 1] = NULL;
+ return 0;
+}
+
+static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn_idx)
{
const struct bpf_func_proto *fn = NULL;
struct bpf_reg_state *regs;
const struct bpf_reg_state *ptr_reg,
const struct bpf_reg_state *off_reg)
{
- struct bpf_reg_state *regs = cur_regs(env), *dst_reg;
+ struct bpf_verifier_state *vstate = env->cur_state;
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
+ struct bpf_reg_state *regs = state->regs, *dst_reg;
bool known = tnum_is_const(off_reg->var_off);
s64 smin_val = off_reg->smin_value, smax_val = off_reg->smax_value,
smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value;
dst_reg = ®s[dst];
if (WARN_ON_ONCE(known && (smin_val != smax_val))) {
- print_verifier_state(env, env->cur_state);
+ print_verifier_state(env, state);
verbose(env,
"verifier internal error: known but bad sbounds\n");
return -EINVAL;
}
if (WARN_ON_ONCE(known && (umin_val != umax_val))) {
- print_verifier_state(env, env->cur_state);
+ print_verifier_state(env, state);
verbose(env,
"verifier internal error: known but bad ubounds\n");
return -EINVAL;
static int adjust_reg_min_max_vals(struct bpf_verifier_env *env,
struct bpf_insn *insn)
{
- struct bpf_reg_state *regs = cur_regs(env), *dst_reg, *src_reg;
+ struct bpf_verifier_state *vstate = env->cur_state;
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
+ struct bpf_reg_state *regs = state->regs, *dst_reg, *src_reg;
struct bpf_reg_state *ptr_reg = NULL, off_reg = {0};
u8 opcode = BPF_OP(insn->code);
int rc;
/* Got here implies adding two SCALAR_VALUEs */
if (WARN_ON_ONCE(ptr_reg)) {
- print_verifier_state(env, env->cur_state);
+ print_verifier_state(env, state);
verbose(env, "verifier internal error: unexpected ptr_reg\n");
return -EINVAL;
}
if (WARN_ON(!src_reg)) {
- print_verifier_state(env, env->cur_state);
+ print_verifier_state(env, state);
verbose(env, "verifier internal error: no src_reg\n");
return -EINVAL;
}
return 0;
}
-static void find_good_pkt_pointers(struct bpf_verifier_state *state,
+static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
struct bpf_reg_state *dst_reg,
enum bpf_reg_type type,
bool range_right_open)
{
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
struct bpf_reg_state *regs = state->regs, *reg;
u16 new_range;
- int i;
+ int i, j;
if (dst_reg->off < 0 ||
(dst_reg->off == 0 && range_right_open))
/* keep the maximum range already checked */
regs[i].range = max(regs[i].range, new_range);
- for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
- if (state->stack[i].slot_type[0] != STACK_SPILL)
- continue;
- reg = &state->stack[i].spilled_ptr;
- if (reg->type == type && reg->id == dst_reg->id)
- reg->range = max(reg->range, new_range);
+ for (j = 0; j <= vstate->curframe; j++) {
+ state = vstate->frame[j];
+ for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
+ if (state->stack[i].slot_type[0] != STACK_SPILL)
+ continue;
+ reg = &state->stack[i].spilled_ptr;
+ if (reg->type == type && reg->id == dst_reg->id)
+ reg->range = max(reg->range, new_range);
+ }
}
}
/* The logic is similar to find_good_pkt_pointers(), both could eventually
* be folded together at some point.
*/
-static void mark_map_regs(struct bpf_verifier_state *state, u32 regno,
+static void mark_map_regs(struct bpf_verifier_state *vstate, u32 regno,
bool is_null)
{
+ struct bpf_func_state *state = vstate->frame[vstate->curframe];
struct bpf_reg_state *regs = state->regs;
u32 id = regs[regno].id;
- int i;
+ int i, j;
for (i = 0; i < MAX_BPF_REG; i++)
mark_map_reg(regs, i, id, is_null);
- for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
- if (state->stack[i].slot_type[0] != STACK_SPILL)
- continue;
- mark_map_reg(&state->stack[i].spilled_ptr, 0, id, is_null);
+ for (j = 0; j <= vstate->curframe; j++) {
+ state = vstate->frame[j];
+ for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
+ if (state->stack[i].slot_type[0] != STACK_SPILL)
+ continue;
+ mark_map_reg(&state->stack[i].spilled_ptr, 0, id, is_null);
+ }
}
}
static int check_cond_jmp_op(struct bpf_verifier_env *env,
struct bpf_insn *insn, int *insn_idx)
{
- struct bpf_verifier_state *other_branch, *this_branch = env->cur_state;
- struct bpf_reg_state *regs = this_branch->regs, *dst_reg;
+ struct bpf_verifier_state *this_branch = env->cur_state;
+ struct bpf_verifier_state *other_branch;
+ struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs;
+ struct bpf_reg_state *dst_reg, *other_branch_regs;
u8 opcode = BPF_OP(insn->code);
int err;
other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx);
if (!other_branch)
return -EFAULT;
+ other_branch_regs = other_branch->frame[other_branch->curframe]->regs;
/* detect if we are comparing against a constant value so we can adjust
* our min/max values for our dst register.
if (dst_reg->type == SCALAR_VALUE &&
regs[insn->src_reg].type == SCALAR_VALUE) {
if (tnum_is_const(regs[insn->src_reg].var_off))
- reg_set_min_max(&other_branch->regs[insn->dst_reg],
+ reg_set_min_max(&other_branch_regs[insn->dst_reg],
dst_reg, regs[insn->src_reg].var_off.value,
opcode);
else if (tnum_is_const(dst_reg->var_off))
- reg_set_min_max_inv(&other_branch->regs[insn->src_reg],
+ reg_set_min_max_inv(&other_branch_regs[insn->src_reg],
®s[insn->src_reg],
dst_reg->var_off.value, opcode);
else if (opcode == BPF_JEQ || opcode == BPF_JNE)
/* Comparing for equality, we can combine knowledge */
- reg_combine_min_max(&other_branch->regs[insn->src_reg],
- &other_branch->regs[insn->dst_reg],
+ reg_combine_min_max(&other_branch_regs[insn->src_reg],
+ &other_branch_regs[insn->dst_reg],
®s[insn->src_reg],
®s[insn->dst_reg], opcode);
}
} else if (dst_reg->type == SCALAR_VALUE) {
- reg_set_min_max(&other_branch->regs[insn->dst_reg],
+ reg_set_min_max(&other_branch_regs[insn->dst_reg],
dst_reg, insn->imm, opcode);
}
return -EACCES;
}
if (env->log.level)
- print_verifier_state(env, this_branch);
+ print_verifier_state(env, this_branch->frame[this_branch->curframe]);
return 0;
}
return -EINVAL;
}
+ if (env->subprog_cnt) {
+ /* when program has LD_ABS insn JITs and interpreter assume
+ * that r1 == ctx == skb which is not the case for callees
+ * that can have arbitrary arguments. It's problematic
+ * for main prog as well since JITs would need to analyze
+ * all functions in order to make proper register save/restore
+ * decisions in the main prog. Hence disallow LD_ABS with calls
+ */
+ verbose(env, "BPF_LD_[ABS|IND] instructions cannot be mixed with bpf-to-bpf calls\n");
+ return -EINVAL;
+ }
+
if (insn->dst_reg != BPF_REG_0 || insn->off != 0 ||
BPF_SIZE(insn->code) == BPF_DW ||
(mode == BPF_ABS && insn->src_reg != BPF_REG_0)) {
static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur,
struct idpair *idmap)
{
+ bool equal;
+
if (!(rold->live & REG_LIVE_READ))
/* explored state didn't use this */
return true;
- if (memcmp(rold, rcur, offsetof(struct bpf_reg_state, live)) == 0)
+ equal = memcmp(rold, rcur, offsetof(struct bpf_reg_state, frameno)) == 0;
+
+ if (rold->type == PTR_TO_STACK)
+ /* two stack pointers are equal only if they're pointing to
+ * the same stack frame, since fp-8 in foo != fp-8 in bar
+ */
+ return equal && rold->frameno == rcur->frameno;
+
+ if (equal)
return true;
if (rold->type == NOT_INIT)
tnum_in(rold->var_off, rcur->var_off);
case PTR_TO_CTX:
case CONST_PTR_TO_MAP:
- case PTR_TO_STACK:
case PTR_TO_PACKET_END:
/* Only valid matches are exact, which memcmp() above
* would have accepted
return false;
}
-static bool stacksafe(struct bpf_verifier_state *old,
- struct bpf_verifier_state *cur,
+static bool stacksafe(struct bpf_func_state *old,
+ struct bpf_func_state *cur,
struct idpair *idmap)
{
int i, spi;
* whereas register type in current state is meaningful, it means that
* the current state will reach 'bpf_exit' instruction safely
*/
-static bool states_equal(struct bpf_verifier_env *env,
- struct bpf_verifier_state *old,
- struct bpf_verifier_state *cur)
+static bool func_states_equal(struct bpf_func_state *old,
+ struct bpf_func_state *cur)
{
struct idpair *idmap;
bool ret = false;
return ret;
}
+static bool states_equal(struct bpf_verifier_env *env,
+ struct bpf_verifier_state *old,
+ struct bpf_verifier_state *cur)
+{
+ int i;
+
+ if (old->curframe != cur->curframe)
+ return false;
+
+ /* for states to be equal callsites have to be the same
+ * and all frame states need to be equivalent
+ */
+ for (i = 0; i <= old->curframe; i++) {
+ if (old->frame[i]->callsite != cur->frame[i]->callsite)
+ return false;
+ if (!func_states_equal(old->frame[i], cur->frame[i]))
+ return false;
+ }
+ return true;
+}
+
/* A write screens off any subsequent reads; but write marks come from the
- * straight-line code between a state and its parent. When we arrive at a
- * jump target (in the first iteration of the propagate_liveness() loop),
- * we didn't arrive by the straight-line code, so read marks in state must
- * propagate to parent regardless of state's write marks.
+ * straight-line code between a state and its parent. When we arrive at an
+ * equivalent state (jump target or such) we didn't arrive by the straight-line
+ * code, so read marks in the state must propagate to the parent regardless
+ * of the state's write marks. That's what 'parent == state->parent' comparison
+ * in mark_reg_read() and mark_stack_slot_read() is for.
*/
-static bool do_propagate_liveness(const struct bpf_verifier_state *state,
- struct bpf_verifier_state *parent)
+static int propagate_liveness(struct bpf_verifier_env *env,
+ const struct bpf_verifier_state *vstate,
+ struct bpf_verifier_state *vparent)
{
- bool writes = parent == state->parent; /* Observe write marks */
- bool touched = false; /* any changes made? */
- int i;
+ int i, frame, err = 0;
+ struct bpf_func_state *state, *parent;
- if (!parent)
- return touched;
+ if (vparent->curframe != vstate->curframe) {
+ WARN(1, "propagate_live: parent frame %d current frame %d\n",
+ vparent->curframe, vstate->curframe);
+ return -EFAULT;
+ }
/* Propagate read liveness of registers... */
BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
/* We don't need to worry about FP liveness because it's read-only */
for (i = 0; i < BPF_REG_FP; i++) {
- if (parent->regs[i].live & REG_LIVE_READ)
+ if (vparent->frame[vparent->curframe]->regs[i].live & REG_LIVE_READ)
continue;
- if (writes && (state->regs[i].live & REG_LIVE_WRITTEN))
- continue;
- if (state->regs[i].live & REG_LIVE_READ) {
- parent->regs[i].live |= REG_LIVE_READ;
- touched = true;
+ if (vstate->frame[vstate->curframe]->regs[i].live & REG_LIVE_READ) {
+ err = mark_reg_read(env, vstate, vparent, i);
+ if (err)
+ return err;
}
}
+
/* ... and stack slots */
- for (i = 0; i < state->allocated_stack / BPF_REG_SIZE &&
- i < parent->allocated_stack / BPF_REG_SIZE; i++) {
- if (parent->stack[i].slot_type[0] != STACK_SPILL)
- continue;
- if (state->stack[i].slot_type[0] != STACK_SPILL)
- continue;
- if (parent->stack[i].spilled_ptr.live & REG_LIVE_READ)
- continue;
- if (writes &&
- (state->stack[i].spilled_ptr.live & REG_LIVE_WRITTEN))
- continue;
- if (state->stack[i].spilled_ptr.live & REG_LIVE_READ) {
- parent->stack[i].spilled_ptr.live |= REG_LIVE_READ;
- touched = true;
+ for (frame = 0; frame <= vstate->curframe; frame++) {
+ state = vstate->frame[frame];
+ parent = vparent->frame[frame];
+ for (i = 0; i < state->allocated_stack / BPF_REG_SIZE &&
+ i < parent->allocated_stack / BPF_REG_SIZE; i++) {
+ if (parent->stack[i].slot_type[0] != STACK_SPILL)
+ continue;
+ if (state->stack[i].slot_type[0] != STACK_SPILL)
+ continue;
+ if (parent->stack[i].spilled_ptr.live & REG_LIVE_READ)
+ continue;
+ if (state->stack[i].spilled_ptr.live & REG_LIVE_READ)
+ mark_stack_slot_read(env, vstate, vparent, i, frame);
}
}
- return touched;
-}
-
-/* "parent" is "a state from which we reach the current state", but initially
- * it is not the state->parent (i.e. "the state whose straight-line code leads
- * to the current state"), instead it is the state that happened to arrive at
- * a (prunable) equivalent of the current state. See comment above
- * do_propagate_liveness() for consequences of this.
- * This function is just a more efficient way of calling mark_reg_read() or
- * mark_stack_slot_read() on each reg in "parent" that is read in "state",
- * though it requires that parent != state->parent in the call arguments.
- */
-static void propagate_liveness(const struct bpf_verifier_state *state,
- struct bpf_verifier_state *parent)
-{
- while (do_propagate_liveness(state, parent)) {
- /* Something changed, so we need to feed those changes onward */
- state = parent;
- parent = state->parent;
- }
+ return err;
}
static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
struct bpf_verifier_state_list *new_sl;
struct bpf_verifier_state_list *sl;
struct bpf_verifier_state *cur = env->cur_state;
- int i, err;
+ int i, j, err;
sl = env->explored_states[insn_idx];
if (!sl)
* they'll be immediately forgotten as we're pruning
* this state and will pop a new one.
*/
- propagate_liveness(&sl->state, cur);
+ err = propagate_liveness(env, &sl->state, cur);
+ if (err)
+ return err;
return 1;
}
sl = sl->next;
/* there were no equivalent states, remember current one.
* technically the current state is not proven to be safe yet,
- * but it will either reach bpf_exit (which means it's safe) or
- * it will be rejected. Since there are no loops, we won't be
- * seeing this 'insn_idx' instruction again on the way to bpf_exit
+ * but it will either reach outer most bpf_exit (which means it's safe)
+ * or it will be rejected. Since there are no loops, we won't be
+ * seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx)
+ * again on the way to bpf_exit
*/
new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL);
if (!new_sl)
* explored_states can get read marks.)
*/
for (i = 0; i < BPF_REG_FP; i++)
- cur->regs[i].live = REG_LIVE_NONE;
- for (i = 0; i < cur->allocated_stack / BPF_REG_SIZE; i++)
- if (cur->stack[i].slot_type[0] == STACK_SPILL)
- cur->stack[i].spilled_ptr.live = REG_LIVE_NONE;
+ cur->frame[cur->curframe]->regs[i].live = REG_LIVE_NONE;
+
+ /* all stack frames are accessible from callee, clear them all */
+ for (j = 0; j <= cur->curframe; j++) {
+ struct bpf_func_state *frame = cur->frame[j];
+
+ for (i = 0; i < frame->allocated_stack / BPF_REG_SIZE; i++)
+ if (frame->stack[i].slot_type[0] == STACK_SPILL)
+ frame->stack[i].spilled_ptr.live = REG_LIVE_NONE;
+ }
return 0;
}
struct bpf_verifier_state *state;
struct bpf_insn *insns = env->prog->insnsi;
struct bpf_reg_state *regs;
- int insn_cnt = env->prog->len;
+ int insn_cnt = env->prog->len, i;
int insn_idx, prev_insn_idx = 0;
int insn_processed = 0;
bool do_print_state = false;
state = kzalloc(sizeof(struct bpf_verifier_state), GFP_KERNEL);
if (!state)
return -ENOMEM;
- env->cur_state = state;
- init_reg_state(env, state->regs);
+ state->curframe = 0;
state->parent = NULL;
+ state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL);
+ if (!state->frame[0]) {
+ kfree(state);
+ return -ENOMEM;
+ }
+ env->cur_state = state;
+ init_func_state(env, state->frame[0],
+ BPF_MAIN_FUNC /* callsite */,
+ 0 /* frameno */,
+ 0 /* subprogno, zero == main subprog */);
insn_idx = 0;
for (;;) {
struct bpf_insn *insn;
else
verbose(env, "\nfrom %d to %d:",
prev_insn_idx, insn_idx);
- print_verifier_state(env, state);
+ print_verifier_state(env, state->frame[state->curframe]);
do_print_state = false;
}
if (opcode == BPF_CALL) {
if (BPF_SRC(insn->code) != BPF_K ||
insn->off != 0 ||
- insn->src_reg != BPF_REG_0 ||
+ (insn->src_reg != BPF_REG_0 &&
+ insn->src_reg != BPF_PSEUDO_CALL) ||
insn->dst_reg != BPF_REG_0) {
verbose(env, "BPF_CALL uses reserved fields\n");
return -EINVAL;
}
- err = check_call(env, insn->imm, insn_idx);
+ if (insn->src_reg == BPF_PSEUDO_CALL)
+ err = check_func_call(env, insn, &insn_idx);
+ else
+ err = check_helper_call(env, insn->imm, insn_idx);
if (err)
return err;
return -EINVAL;
}
+ if (state->curframe) {
+ /* exit from nested function */
+ prev_insn_idx = insn_idx;
+ err = prepare_func_exit(env, &insn_idx);
+ if (err)
+ return err;
+ do_print_state = true;
+ continue;
+ }
+
/* eBPF calling convetion is such that R0 is used
* to return the value from eBPF program.
* Make sure that it's readable at this time
insn_idx++;
}
- verbose(env, "processed %d insns, stack depth %d\n", insn_processed,
- env->prog->aux->stack_depth);
+ verbose(env, "processed %d insns, stack depth ", insn_processed);
+ for (i = 0; i < env->subprog_cnt + 1; i++) {
+ u32 depth = env->subprog_stack_depth[i];
+
+ verbose(env, "%d", depth);
+ if (i + 1 < env->subprog_cnt + 1)
+ verbose(env, "+");
+ }
+ verbose(env, "\n");
+ env->prog->aux->stack_depth = env->subprog_stack_depth[0];
return 0;
}
projects / users / jedix / linux-maple.git / commitdiff