Commit ae08ea97 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'bpf-fixes' 



Daniel Borkmann says:

====================
Various BPF fixes

Follow-up to fix incorrect pruning when alignment tracking is
in use and to properly clear regs after call to not leave stale
data behind, also a fix that adds bpf_clone_redirect to the
bpf_helper_changes_pkt_data helper and exposes correct map_flags
for lpm map into fdinfo. For details, please see individual
patches.

v1 -> v2:
  - Reworked first patch so that env->strict_alignment is the
    final indicator on whether we have to deal with strict
    alignment rather than having CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
    checks on various locations, so only checking env->strict_alignment
    is sufficient after that. Thanks for spotting, Dave!
  - Added patch 3 and 4.
  - Rest as is.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 5990baaa 614d0d77

include/linux/filter.h

+10 −0
Original line number Diff line number Diff line
@@ -272,6 +272,16 @@ struct bpf_prog_aux; 
		.off   = OFF,					\

		.imm   = IMM })



/* Unconditional jumps, goto pc + off16 */



#define BPF_JMP_A(OFF)						\

	((struct bpf_insn) {					\

		.code  = BPF_JMP | BPF_JA,			\

		.dst_reg = 0,					\

		.src_reg = 0,					\

		.off   = OFF,					\

		.imm   = 0 })



/* Function call */



#define BPF_EMIT_CALL(FUNC)					\

kernel/bpf/arraymap.c

+1 −0
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr) 
	array->map.key_size = attr->key_size;

	array->map.value_size = attr->value_size;

	array->map.max_entries = attr->max_entries;

	array->map.map_flags = attr->map_flags;

	array->elem_size = elem_size;



	if (!percpu)

kernel/bpf/lpm_trie.c

+1 −0
Original line number Diff line number Diff line
@@ -432,6 +432,7 @@ static struct bpf_map *trie_alloc(union bpf_attr *attr) 
	trie->map.key_size = attr->key_size;

	trie->map.value_size = attr->value_size;

	trie->map.max_entries = attr->max_entries;

	trie->map.map_flags = attr->map_flags;

	trie->data_size = attr->key_size -

			  offsetof(struct bpf_lpm_trie_key, data);

	trie->max_prefixlen = trie->data_size * 8;

kernel/bpf/stackmap.c

+1 −0
Original line number Diff line number Diff line
@@ -88,6 +88,7 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr) 
	smap->map.key_size = attr->key_size;

	smap->map.value_size = value_size;

	smap->map.max_entries = attr->max_entries;

	smap->map.map_flags = attr->map_flags;

	smap->n_buckets = n_buckets;

	smap->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;

kernel/bpf/verifier.c

+26 −30
Original line number Diff line number Diff line
@@ -463,19 +463,22 @@ 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

};



static void mark_reg_not_init(struct bpf_reg_state *regs, u32 regno)

{

	BUG_ON(regno >= MAX_BPF_REG);



	memset(&regs[regno], 0, sizeof(regs[regno]));

	regs[regno].type = NOT_INIT;

	regs[regno].min_value = BPF_REGISTER_MIN_RANGE;

	regs[regno].max_value = BPF_REGISTER_MAX_RANGE;

}



static void init_reg_state(struct bpf_reg_state *regs)

{

	int i;



	for (i = 0; i < MAX_BPF_REG; i++) {

		regs[i].type = NOT_INIT;

		regs[i].imm = 0;

		regs[i].min_value = BPF_REGISTER_MIN_RANGE;

		regs[i].max_value = BPF_REGISTER_MAX_RANGE;

		regs[i].min_align = 0;

		regs[i].aux_off = 0;

		regs[i].aux_off_align = 0;

	}

	for (i = 0; i < MAX_BPF_REG; i++)

		mark_reg_not_init(regs, i);



	/* frame pointer */

	regs[BPF_REG_FP].type = FRAME_PTR;
@@ -843,9 +846,6 @@ static int check_ptr_alignment(struct bpf_verifier_env *env, 
{

	bool strict = env->strict_alignment;



	if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))

		strict = true;



	switch (reg->type) {

	case PTR_TO_PACKET:

		return check_pkt_ptr_alignment(reg, off, size, strict);
@@ -1349,7 +1349,6 @@ static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx) 
	struct bpf_verifier_state *state = &env->cur_state;

	const struct bpf_func_proto *fn = NULL;

	struct bpf_reg_state *regs = state->regs;

	struct bpf_reg_state *reg;

	struct bpf_call_arg_meta meta;

	bool changes_data;

	int i, err;
@@ -1416,11 +1415,8 @@ static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx) 
	}



	/* reset caller saved regs */

	for (i = 0; i < CALLER_SAVED_REGS; i++) {

		reg = regs + caller_saved[i];

		reg->type = NOT_INIT;

		reg->imm = 0;

	}

	for (i = 0; i < CALLER_SAVED_REGS; i++)

		mark_reg_not_init(regs, caller_saved[i]);



	/* update return register */

	if (fn->ret_type == RET_INTEGER) {
@@ -2448,7 +2444,6 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) 
{

	struct bpf_reg_state *regs = env->cur_state.regs;

	u8 mode = BPF_MODE(insn->code);

	struct bpf_reg_state *reg;

	int i, err;



	if (!may_access_skb(env->prog->type)) {
@@ -2481,11 +2476,8 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) 
	}



	/* reset caller saved regs to unreadable */

	for (i = 0; i < CALLER_SAVED_REGS; i++) {

		reg = regs + caller_saved[i];

		reg->type = NOT_INIT;

		reg->imm = 0;

	}

	for (i = 0; i < CALLER_SAVED_REGS; i++)

		mark_reg_not_init(regs, caller_saved[i]);



	/* mark destination R0 register as readable, since it contains

	 * the value fetched from the packet
@@ -2696,7 +2688,8 @@ err_free: 
/* the following conditions reduce the number of explored insns

 * from ~140k to ~80k for ultra large programs that use a lot of ptr_to_packet

 */

static bool compare_ptrs_to_packet(struct bpf_reg_state *old,

static bool compare_ptrs_to_packet(struct bpf_verifier_env *env,

				   struct bpf_reg_state *old,

				   struct bpf_reg_state *cur)

{

	if (old->id != cur->id)
@@ -2739,7 +2732,7 @@ static bool compare_ptrs_to_packet(struct bpf_reg_state *old, 
	 * 'if (R4 > data_end)' and all further insn were already good with r=20,

	 * so they will be good with r=30 and we can prune the search.

	 */

	if (old->off <= cur->off &&

	if (!env->strict_alignment && old->off <= cur->off &&

	    old->off >= old->range && cur->off >= cur->range)

		return true;
@@ -2810,7 +2803,7 @@ static bool states_equal(struct bpf_verifier_env *env, 
			continue;



		if (rold->type == PTR_TO_PACKET && rcur->type == PTR_TO_PACKET &&

		    compare_ptrs_to_packet(rold, rcur))

		    compare_ptrs_to_packet(env, rold, rcur))

			continue;



		return false;
@@ -3588,10 +3581,10 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr) 
	} else {

		log_level = 0;

	}

	if (attr->prog_flags & BPF_F_STRICT_ALIGNMENT)



	env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT);

	if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))

		env->strict_alignment = true;

	else

		env->strict_alignment = false;



	ret = replace_map_fd_with_map_ptr(env);

	if (ret < 0)
@@ -3697,7 +3690,10 @@ int bpf_analyzer(struct bpf_prog *prog, const struct bpf_ext_analyzer_ops *ops, 
	mutex_lock(&bpf_verifier_lock);



	log_level = 0;



	env->strict_alignment = false;

	if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))

		env->strict_alignment = true;



	env->explored_states = kcalloc(env->prog->len,

				       sizeof(struct bpf_verifier_state_list *),

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