Update 5.4.x+fslc up to v5.4.116

Makefile

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 VERSION = 5
 PATCHLEVEL = 4
-SUBLEVEL = 115
+SUBLEVEL = 116
 EXTRAVERSION =
 NAME = Kleptomaniac Octopus
 

kernel/bpf/verifier.c

@@ -4263,40 +4263,51 @@ static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env)
  return &env->insn_aux_data[env->insn_idx];
 }
 
+enum {
+ REASON_BOUNDS = -1,
+ REASON_TYPE = -2,
+ REASON_PATHS = -3,
+ REASON_LIMIT = -4,
+ REASON_STACK = -5,
+};
+
 static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg,
- u32 *ptr_limit, u8 opcode, bool off_is_neg)
+ const struct bpf_reg_state *off_reg,
+ u32 *alu_limit, u8 opcode)
 {
+ bool off_is_neg = off_reg->smin_value < 0;
  bool mask_to_left = (opcode == BPF_ADD && off_is_neg) ||
  (opcode == BPF_SUB && !off_is_neg);
- u32 off, max;
+ u32 max = 0, ptr_limit = 0;
+
+ if (!tnum_is_const(off_reg->var_off) &&
+ (off_reg->smin_value < 0) != (off_reg->smax_value < 0))
+ return REASON_BOUNDS;
 
  switch (ptr_reg->type) {
  case PTR_TO_STACK:
  /* Offset 0 is out-of-bounds, but acceptable start for the
- * left direction, see BPF_REG_FP.
+ * left direction, see BPF_REG_FP. Also, unknown scalar
+ * offset where we would need to deal with min/max bounds is
+ * currently prohibited for unprivileged.
  */
  max = MAX_BPF_STACK + mask_to_left;
- /* Indirect variable offset stack access is prohibited in
- * unprivileged mode so it's not handled here.
- */
- off = ptr_reg->off + ptr_reg->var_off.value;
- if (mask_to_left)
- *ptr_limit = MAX_BPF_STACK + off;
- else
- *ptr_limit = -off - 1;
- return *ptr_limit >= max ? -ERANGE : 0;
+ ptr_limit = -(ptr_reg->var_off.value + ptr_reg->off);
+ break;
  case PTR_TO_MAP_VALUE:
  max = ptr_reg->map_ptr->value_size;
- if (mask_to_left) {
- *ptr_limit = ptr_reg->umax_value + ptr_reg->off;
- } else {
- off = ptr_reg->smin_value + ptr_reg->off;
- *ptr_limit = ptr_reg->map_ptr->value_size - off - 1;
- }
- return *ptr_limit >= max ? -ERANGE : 0;
+ ptr_limit = (mask_to_left ?
+ ptr_reg->smin_value :
+ ptr_reg->umax_value) + ptr_reg->off;
+ break;
  default:
- return -EINVAL;
+ return REASON_TYPE;
  }
+
+ if (ptr_limit >= max)
+ return REASON_LIMIT;
+ *alu_limit = ptr_limit;
+ return 0;
 }
 
 static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env,
@@ -4314,7 +4325,7 @@ static int update_alu_sanitation_state(struct bpf_insn_aux_data *aux,
  if (aux->alu_state &&
  (aux->alu_state != alu_state ||
  aux->alu_limit != alu_limit))
- return -EACCES;
+ return REASON_PATHS;
 
  /* Corresponding fixup done in fixup_bpf_calls(). */
  aux->alu_state = alu_state;
@@ -4333,14 +4344,22 @@ static int sanitize_val_alu(struct bpf_verifier_env *env,
  return update_alu_sanitation_state(aux, BPF_ALU_NON_POINTER, 0);
 }
 
+static bool sanitize_needed(u8 opcode)
+{
+ return opcode == BPF_ADD || opcode == BPF_SUB;
+}
+
 static int sanitize_ptr_alu(struct bpf_verifier_env *env,
  struct bpf_insn *insn,
  const struct bpf_reg_state *ptr_reg,
+ const struct bpf_reg_state *off_reg,
  struct bpf_reg_state *dst_reg,
- bool off_is_neg)
+ struct bpf_insn_aux_data *tmp_aux,
+ const bool commit_window)
 {
+ struct bpf_insn_aux_data *aux = commit_window ? cur_aux(env) : tmp_aux;
  struct bpf_verifier_state *vstate = env->cur_state;
- struct bpf_insn_aux_data *aux = cur_aux(env);
+ bool off_is_neg = off_reg->smin_value < 0;
  bool ptr_is_dst_reg = ptr_reg == dst_reg;
  u8 opcode = BPF_OP(insn->code);
  u32 alu_state, alu_limit;
@@ -4358,18 +4377,33 @@ static int sanitize_ptr_alu(struct bpf_verifier_env *env,
  if (vstate->speculative)
  goto do_sim;
 
- alu_state = off_is_neg ? BPF_ALU_NEG_VALUE : 0;
- alu_state |= ptr_is_dst_reg ?
- BPF_ALU_SANITIZE_SRC : BPF_ALU_SANITIZE_DST;
-
- err = retrieve_ptr_limit(ptr_reg, &alu_limit, opcode, off_is_neg);
+ err = retrieve_ptr_limit(ptr_reg, off_reg, &alu_limit, opcode);
  if (err < 0)
  return err;
 
+ if (commit_window) {
+ /* In commit phase we narrow the masking window based on
+ * the observed pointer move after the simulated operation.
+ */
+ alu_state = tmp_aux->alu_state;
+ alu_limit = abs(tmp_aux->alu_limit - alu_limit);
+ } else {
+ alu_state = off_is_neg ? BPF_ALU_NEG_VALUE : 0;
+ alu_state |= ptr_is_dst_reg ?
+ BPF_ALU_SANITIZE_SRC : BPF_ALU_SANITIZE_DST;
+ }
+
  err = update_alu_sanitation_state(aux, alu_state, alu_limit);
  if (err < 0)
  return err;
 do_sim:
+ /* If we're in commit phase, we're done here given we already
+ * pushed the truncated dst_reg into the speculative verification
+ * stack.
+ */
+ if (commit_window)
+ return 0;
+
  /* Simulate and find potential out-of-bounds access under
  * speculative execution from truncation as a result of
  * masking when off was not within expected range. If off
@@ -4386,7 +4420,81 @@ static int sanitize_ptr_alu(struct bpf_verifier_env *env,
  ret = push_stack(env, env->insn_idx + 1, env->insn_idx, true);
  if (!ptr_is_dst_reg && ret)
  *dst_reg = tmp;
- return !ret ? -EFAULT : 0;
+ return !ret ? REASON_STACK : 0;
+}
+
+static int sanitize_err(struct bpf_verifier_env *env,
+ const struct bpf_insn *insn, int reason,
+ const struct bpf_reg_state *off_reg,
+ const struct bpf_reg_state *dst_reg)
+{
+ static const char *err = "pointer arithmetic with it prohibited for !root";
+ const char *op = BPF_OP(insn->code) == BPF_ADD ? "add" : "sub";
+ u32 dst = insn->dst_reg, src = insn->src_reg;
+
+ switch (reason) {
+ case REASON_BOUNDS:
+ verbose(env, "R%d has unknown scalar with mixed signed bounds, %s\n",
+ off_reg == dst_reg ? dst : src, err);
+ break;
+ case REASON_TYPE:
+ verbose(env, "R%d has pointer with unsupported alu operation, %s\n",
+ off_reg == dst_reg ? src : dst, err);
+ break;
+ case REASON_PATHS:
+ verbose(env, "R%d tried to %s from different maps, paths or scalars, %s\n",
+ dst, op, err);
+ break;
+ case REASON_LIMIT:
+ verbose(env, "R%d tried to %s beyond pointer bounds, %s\n",
+ dst, op, err);
+ break;
+ case REASON_STACK:
+ verbose(env, "R%d could not be pushed for speculative verification, %s\n",
+ dst, err);
+ break;
+ default:
+ verbose(env, "verifier internal error: unknown reason (%d)\n",
+ reason);
+ break;
+ }
+
+ return -EACCES;
+}
+
+static int sanitize_check_bounds(struct bpf_verifier_env *env,
+ const struct bpf_insn *insn,
+ const struct bpf_reg_state *dst_reg)
+{
+ u32 dst = insn->dst_reg;
+
+ /* For unprivileged we require that resulting offset must be in bounds
+ * in order to be able to sanitize access later on.
+ */
+ if (env->allow_ptr_leaks)
+ return 0;
+
+ switch (dst_reg->type) {
+ case PTR_TO_STACK:
+ if (check_stack_access(env, dst_reg, dst_reg->off +
+ dst_reg->var_off.value, 1)) {
+ verbose(env, "R%d stack pointer arithmetic goes out of range, "
+ "prohibited for !root\n", dst);
+ return -EACCES;
+ }
+ break;
+ case PTR_TO_MAP_VALUE:
+ if (check_map_access(env, dst, dst_reg->off, 1, false)) {
+ verbose(env, "R%d pointer arithmetic of map value goes out of range, "
+ "prohibited for !root\n", dst);
+ return -EACCES;
+ }
+ break;
+ default:
+ break;
+ }
+
+ return 0;
 }
 
 /* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off.
@@ -4407,8 +4515,9 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
  smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value;
  u64 umin_val = off_reg->umin_value, umax_val = off_reg->umax_value,
  umin_ptr = ptr_reg->umin_value, umax_ptr = ptr_reg->umax_value;
- u32 dst = insn->dst_reg, src = insn->src_reg;
+ struct bpf_insn_aux_data tmp_aux = {};
  u8 opcode = BPF_OP(insn->code);
+ u32 dst = insn->dst_reg;
  int ret;
 
  dst_reg = &regs[dst];
@@ -4451,13 +4560,6 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
  verbose(env, "R%d pointer arithmetic on %s prohibited\n",
  dst, reg_type_str[ptr_reg->type]);
  return -EACCES;
- case PTR_TO_MAP_VALUE:
- if (!env->allow_ptr_leaks && !known && (smin_val < 0) != (smax_val < 0)) {
- verbose(env, "R%d has unknown scalar with mixed signed bounds, pointer arithmetic with it prohibited for !root\n",
- off_reg == dst_reg ? dst : src);
- return -EACCES;
- }
- /* fall-through */
  default:
  break;
  }
@@ -4472,13 +4574,15 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
  !check_reg_sane_offset(env, ptr_reg, ptr_reg->type))
  return -EINVAL;
 
+ if (sanitize_needed(opcode)) {
+ ret = sanitize_ptr_alu(env, insn, ptr_reg, off_reg, dst_reg,
+ &tmp_aux, false);
+ if (ret < 0)
+ return sanitize_err(env, insn, ret, off_reg, dst_reg);
+ }
+
  switch (opcode) {
  case BPF_ADD:
- ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0);
- if (ret < 0) {
- verbose(env, "R%d tried to add from different maps, paths, or prohibited types\n", dst);
- return ret;
- }
  /* We can take a fixed offset as long as it doesn't overflow
  * the s32 'off' field
  */
@@ -4529,11 +4633,6 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
  }
  break;
  case BPF_SUB:
- ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0);
- if (ret < 0) {
- verbose(env, "R%d tried to sub from different maps, paths, or prohibited types\n", dst);
- return ret;
- }
  if (dst_reg == off_reg) {
  /* scalar -= pointer. Creates an unknown scalar */
  verbose(env, "R%d tried to subtract pointer from scalar\n",
@@ -4614,22 +4713,13 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
  __reg_deduce_bounds(dst_reg);
  __reg_bound_offset(dst_reg);
 
- /* For unprivileged we require that resulting offset must be in bounds
- * in order to be able to sanitize access later on.
- */
- if (!env->allow_ptr_leaks) {
- if (dst_reg->type == PTR_TO_MAP_VALUE &&
- check_map_access(env, dst, dst_reg->off, 1, false)) {
- verbose(env, "R%d pointer arithmetic of map value goes out of range, "
- "prohibited for !root\n", dst);
- return -EACCES;
- } else if (dst_reg->type == PTR_TO_STACK &&
- check_stack_access(env, dst_reg, dst_reg->off +
- dst_reg->var_off.value, 1)) {
- verbose(env, "R%d stack pointer arithmetic goes out of range, "
- "prohibited for !root\n", dst);
- return -EACCES;
- }
+ if (sanitize_check_bounds(env, insn, dst_reg) < 0)
+ return -EACCES;
+ if (sanitize_needed(opcode)) {
+ ret = sanitize_ptr_alu(env, insn, dst_reg, off_reg, dst_reg,
+ &tmp_aux, true);
+ if (ret < 0)
+ return sanitize_err(env, insn, ret, off_reg, dst_reg);
  }
 
  return 0;
@@ -4650,7 +4740,6 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
  s64 smin_val, smax_val;
  u64 umin_val, umax_val;
  u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32;
- u32 dst = insn->dst_reg;
  int ret;
 
  if (insn_bitness == 32) {
@@ -4684,13 +4773,14 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
  return 0;
  }
 
+ if (sanitize_needed(opcode)) {
+ ret = sanitize_val_alu(env, insn);
+ if (ret < 0)
+ return sanitize_err(env, insn, ret, NULL, NULL);
+ }
+
  switch (opcode) {
  case BPF_ADD:
- ret = sanitize_val_alu(env, insn);
- if (ret < 0) {
- verbose(env, "R%d tried to add from different pointers or scalars\n", dst);
- return ret;
- }
  if (signed_add_overflows(dst_reg->smin_value, smin_val) ||
  signed_add_overflows(dst_reg->smax_value, smax_val)) {
  dst_reg->smin_value = S64_MIN;
@@ -4710,11 +4800,6 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
  dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off);
  break;
  case BPF_SUB:
- ret = sanitize_val_alu(env, insn);
- if (ret < 0) {
- verbose(env, "R%d tried to sub from different pointers or scalars\n", dst);
- return ret;
- }
  if (signed_sub_overflows(dst_reg->smin_value, smax_val) ||
  signed_sub_overflows(dst_reg->smax_value, smin_val)) {
  /* Overflow possible, we know nothing */