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-rw-r--r--kernel/bpf/verifier.c41
1 files changed, 7 insertions, 34 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 668e07903c8f..eec9f90ba030 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -126,31 +126,6 @@
126 * are set to NOT_INIT to indicate that they are no longer readable. 126 * are set to NOT_INIT to indicate that they are no longer readable.
127 */ 127 */
128 128
129/* types of values stored in eBPF registers */
130enum bpf_reg_type {
131 NOT_INIT = 0, /* nothing was written into register */
132 UNKNOWN_VALUE, /* reg doesn't contain a valid pointer */
133 PTR_TO_CTX, /* reg points to bpf_context */
134 CONST_PTR_TO_MAP, /* reg points to struct bpf_map */
135 PTR_TO_MAP_VALUE, /* reg points to map element value */
136 PTR_TO_MAP_VALUE_OR_NULL,/* points to map elem value or NULL */
137 FRAME_PTR, /* reg == frame_pointer */
138 PTR_TO_STACK, /* reg == frame_pointer + imm */
139 CONST_IMM, /* constant integer value */
140
141 /* PTR_TO_PACKET represents:
142 * skb->data
143 * skb->data + imm
144 * skb->data + (u16) var
145 * skb->data + (u16) var + imm
146 * if (range > 0) then [ptr, ptr + range - off) is safe to access
147 * if (id > 0) means that some 'var' was added
148 * if (off > 0) menas that 'imm' was added
149 */
150 PTR_TO_PACKET,
151 PTR_TO_PACKET_END, /* skb->data + headlen */
152};
153
154struct reg_state { 129struct reg_state {
155 enum bpf_reg_type type; 130 enum bpf_reg_type type;
156 union { 131 union {
@@ -695,10 +670,10 @@ static int check_packet_access(struct verifier_env *env, u32 regno, int off,
695 670
696/* check access to 'struct bpf_context' fields */ 671/* check access to 'struct bpf_context' fields */
697static int check_ctx_access(struct verifier_env *env, int off, int size, 672static int check_ctx_access(struct verifier_env *env, int off, int size,
698 enum bpf_access_type t) 673 enum bpf_access_type t, enum bpf_reg_type *reg_type)
699{ 674{
700 if (env->prog->aux->ops->is_valid_access && 675 if (env->prog->aux->ops->is_valid_access &&
701 env->prog->aux->ops->is_valid_access(off, size, t)) { 676 env->prog->aux->ops->is_valid_access(off, size, t, reg_type)) {
702 /* remember the offset of last byte accessed in ctx */ 677 /* remember the offset of last byte accessed in ctx */
703 if (env->prog->aux->max_ctx_offset < off + size) 678 if (env->prog->aux->max_ctx_offset < off + size)
704 env->prog->aux->max_ctx_offset = off + size; 679 env->prog->aux->max_ctx_offset = off + size;
@@ -798,21 +773,19 @@ static int check_mem_access(struct verifier_env *env, u32 regno, int off,
798 mark_reg_unknown_value(state->regs, value_regno); 773 mark_reg_unknown_value(state->regs, value_regno);
799 774
800 } else if (reg->type == PTR_TO_CTX) { 775 } else if (reg->type == PTR_TO_CTX) {
776 enum bpf_reg_type reg_type = UNKNOWN_VALUE;
777
801 if (t == BPF_WRITE && value_regno >= 0 && 778 if (t == BPF_WRITE && value_regno >= 0 &&
802 is_pointer_value(env, value_regno)) { 779 is_pointer_value(env, value_regno)) {
803 verbose("R%d leaks addr into ctx\n", value_regno); 780 verbose("R%d leaks addr into ctx\n", value_regno);
804 return -EACCES; 781 return -EACCES;
805 } 782 }
806 err = check_ctx_access(env, off, size, t); 783 err = check_ctx_access(env, off, size, t, &reg_type);
807 if (!err && t == BPF_READ && value_regno >= 0) { 784 if (!err && t == BPF_READ && value_regno >= 0) {
808 mark_reg_unknown_value(state->regs, value_regno); 785 mark_reg_unknown_value(state->regs, value_regno);
809 if (off == offsetof(struct __sk_buff, data) && 786 if (env->allow_ptr_leaks)
810 env->allow_ptr_leaks)
811 /* note that reg.[id|off|range] == 0 */ 787 /* note that reg.[id|off|range] == 0 */
812 state->regs[value_regno].type = PTR_TO_PACKET; 788 state->regs[value_regno].type = reg_type;
813 else if (off == offsetof(struct __sk_buff, data_end) &&
814 env->allow_ptr_leaks)
815 state->regs[value_regno].type = PTR_TO_PACKET_END;
816 } 789 }
817 790
818 } else if (reg->type == FRAME_PTR || reg->type == PTR_TO_STACK) { 791 } else if (reg->type == FRAME_PTR || reg->type == PTR_TO_STACK) {