Merge branch 'bpf-fixes'

Daniel Borkmann says:

====================
Couple of BPF fixes

This set contains three BPF fixes for net, one that addresses the
complaint from Geert wrt static allocations, and the other is a fix
wrt mem accounting that I found recently during testing and there's
still one more fix on the map value marking.

Thanks!

v1 -> v2:
  - Patch 1 as is.
  - Fixed kbuild bot issue by letting charging helpers stay in the
    syscall.c, since there locked_vm is valid and only export the
    ones needed by bpf_prog_realloc(). Add empty stubs in case the
    bpf syscall is not enabled.
  - Added patch 3 that addresses one more issue in map val marking.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/bpf.h

@@ -216,7 +216,7 @@ u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);
 u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 
 bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
-void bpf_prog_calc_digest(struct bpf_prog *fp);
+int bpf_prog_calc_digest(struct bpf_prog *fp);
 
 const struct bpf_func_proto *bpf_get_trace_printk_proto(void);
 
@@ -238,6 +238,8 @@ struct bpf_prog * __must_check bpf_prog_add(struct bpf_prog *prog, int i);
 void bpf_prog_sub(struct bpf_prog *prog, int i);
 struct bpf_prog * __must_check bpf_prog_inc(struct bpf_prog *prog);
 void bpf_prog_put(struct bpf_prog *prog);
+int __bpf_prog_charge(struct user_struct *user, u32 pages);
+void __bpf_prog_uncharge(struct user_struct *user, u32 pages);
 
 struct bpf_map *bpf_map_get_with_uref(u32 ufd);
 struct bpf_map *__bpf_map_get(struct fd f);
@@ -318,6 +320,15 @@ static inline struct bpf_prog * __must_check bpf_prog_inc(struct bpf_prog *prog)
 {
 	return ERR_PTR(-EOPNOTSUPP);
 }
+
+static inline int __bpf_prog_charge(struct user_struct *user, u32 pages)
+{
+	return 0;
+}
+
+static inline void __bpf_prog_uncharge(struct user_struct *user, u32 pages)
+{
+}
 #endif /* CONFIG_BPF_SYSCALL */
 
 /* verifier prototypes for helper functions called from eBPF programs */

include/linux/filter.h

@@ -57,9 +57,6 @@ struct bpf_prog_aux;
 /* BPF program can access up to 512 bytes of stack space. */
 #define MAX_BPF_STACK	512
 
-/* Maximum BPF program size in bytes. */
-#define MAX_BPF_SIZE	(BPF_MAXINSNS * sizeof(struct bpf_insn))
-
 /* Helper macros for filter block array initializers. */
 
 /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
@@ -517,6 +514,17 @@ static __always_inline u32 bpf_prog_run_xdp(const struct bpf_prog *prog,
 	return BPF_PROG_RUN(prog, xdp);
 }
 
+static inline u32 bpf_prog_insn_size(const struct bpf_prog *prog)
+{
+	return prog->len * sizeof(struct bpf_insn);
+}
+
+static inline u32 bpf_prog_digest_scratch_size(const struct bpf_prog *prog)
+{
+	return round_up(bpf_prog_insn_size(prog) +
+			sizeof(__be64) + 1, SHA_MESSAGE_BYTES);
+}
+
 static inline unsigned int bpf_prog_size(unsigned int proglen)
 {
 	return max(sizeof(struct bpf_prog),

kernel/bpf/core.c

@@ -105,19 +105,29 @@ struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
 	gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
 			  gfp_extra_flags;
 	struct bpf_prog *fp;
+	u32 pages, delta;
+	int ret;
 
 	BUG_ON(fp_old == NULL);
 
 	size = round_up(size, PAGE_SIZE);
-	if (size <= fp_old->pages * PAGE_SIZE)
+	pages = size / PAGE_SIZE;
+	if (pages <= fp_old->pages)
 		return fp_old;
 
+	delta = pages - fp_old->pages;
+	ret = __bpf_prog_charge(fp_old->aux->user, delta);
+	if (ret)
+		return NULL;
+
 	fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
-	if (fp != NULL) {
+	if (fp == NULL) {
+		__bpf_prog_uncharge(fp_old->aux->user, delta);
+	} else {
 		kmemcheck_annotate_bitfield(fp, meta);
 
 		memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
-		fp->pages = size / PAGE_SIZE;
+		fp->pages = pages;
 		fp->aux->prog = fp;
 
 		/* We keep fp->aux from fp_old around in the new
@@ -136,28 +146,29 @@ void __bpf_prog_free(struct bpf_prog *fp)
 	vfree(fp);
 }
 
-#define SHA_BPF_RAW_SIZE						\
-	round_up(MAX_BPF_SIZE + sizeof(__be64) + 1, SHA_MESSAGE_BYTES)
-
-/* Called under verifier mutex. */
-void bpf_prog_calc_digest(struct bpf_prog *fp)
+int bpf_prog_calc_digest(struct bpf_prog *fp)
 {
 	const u32 bits_offset = SHA_MESSAGE_BYTES - sizeof(__be64);
-	static u32 ws[SHA_WORKSPACE_WORDS];
-	static u8 raw[SHA_BPF_RAW_SIZE];
-	struct bpf_insn *dst = (void *)raw;
+	u32 raw_size = bpf_prog_digest_scratch_size(fp);
+	u32 ws[SHA_WORKSPACE_WORDS];
 	u32 i, bsize, psize, blocks;
+	struct bpf_insn *dst;
 	bool was_ld_map;
-	u8 *todo = raw;
+	u8 *raw, *todo;
 	__be32 *result;
 	__be64 *bits;
 
+	raw = vmalloc(raw_size);
+	if (!raw)
+		return -ENOMEM;
+
 	sha_init(fp->digest);
 	memset(ws, 0, sizeof(ws));
 
 	/* We need to take out the map fd for the digest calculation
 	 * since they are unstable from user space side.
 	 */
+	dst = (void *)raw;
 	for (i = 0, was_ld_map = false; i < fp->len; i++) {
 		dst[i] = fp->insnsi[i];
 		if (!was_ld_map &&
@@ -177,12 +188,13 @@ void bpf_prog_calc_digest(struct bpf_prog *fp)
 		}
 	}
 
-	psize = fp->len * sizeof(struct bpf_insn);
-	memset(&raw[psize], 0, sizeof(raw) - psize);
+	psize = bpf_prog_insn_size(fp);
+	memset(&raw[psize], 0, raw_size - psize);
 	raw[psize++] = 0x80;
 
 	bsize  = round_up(psize, SHA_MESSAGE_BYTES);
 	blocks = bsize / SHA_MESSAGE_BYTES;
+	todo   = raw;
 	if (bsize - psize >= sizeof(__be64)) {
 		bits = (__be64 *)(todo + bsize - sizeof(__be64));
 	} else {
@@ -199,6 +211,9 @@ void bpf_prog_calc_digest(struct bpf_prog *fp)
 	result = (__force __be32 *)fp->digest;
 	for (i = 0; i < SHA_DIGEST_WORDS; i++)
 		result[i] = cpu_to_be32(fp->digest[i]);
+
+	vfree(raw);
+	return 0;
 }
 
 static bool bpf_is_jmp_and_has_target(const struct bpf_insn *insn)

kernel/bpf/syscall.c

@@ -615,19 +615,39 @@ static void free_used_maps(struct bpf_prog_aux *aux)
 	kfree(aux->used_maps);
 }
 
+int __bpf_prog_charge(struct user_struct *user, u32 pages)
+{
+	unsigned long memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+	unsigned long user_bufs;
+
+	if (user) {
+		user_bufs = atomic_long_add_return(pages, &user->locked_vm);
+		if (user_bufs > memlock_limit) {
+			atomic_long_sub(pages, &user->locked_vm);
+			return -EPERM;
+		}
+	}
+
+	return 0;
+}
+
+void __bpf_prog_uncharge(struct user_struct *user, u32 pages)
+{
+	if (user)
+		atomic_long_sub(pages, &user->locked_vm);
+}
+
 static int bpf_prog_charge_memlock(struct bpf_prog *prog)
 {
 	struct user_struct *user = get_current_user();
-	unsigned long memlock_limit;
+	int ret;
 
-	memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
-
-	atomic_long_add(prog->pages, &user->locked_vm);
-	if (atomic_long_read(&user->locked_vm) > memlock_limit) {
-		atomic_long_sub(prog->pages, &user->locked_vm);
+	ret = __bpf_prog_charge(user, prog->pages);
+	if (ret) {
 		free_uid(user);
-		return -EPERM;
+		return ret;
 	}
+
 	prog->aux->user = user;
 	return 0;
 }
@@ -636,7 +656,7 @@ static void bpf_prog_uncharge_memlock(struct bpf_prog *prog)
 {
 	struct user_struct *user = prog->aux->user;
 
-	atomic_long_sub(prog->pages, &user->locked_vm);
+	__bpf_prog_uncharge(user, prog->pages);
 	free_uid(user);
 }
 
@@ -811,7 +831,7 @@ static int bpf_prog_load(union bpf_attr *attr)
 
 	err = -EFAULT;
 	if (copy_from_user(prog->insns, u64_to_user_ptr(attr->insns),
-			   prog->len * sizeof(struct bpf_insn)) != 0)
+			   bpf_prog_insn_size(prog)) != 0)
 		goto free_prog;
 
 	prog->orig_prog = NULL;

kernel/bpf/verifier.c

@@ -462,14 +462,19 @@ static void init_reg_state(struct bpf_reg_state *regs)
 	regs[BPF_REG_1].type = PTR_TO_CTX;
 }
 
-static void mark_reg_unknown_value(struct bpf_reg_state *regs, u32 regno)
+static void __mark_reg_unknown_value(struct bpf_reg_state *regs, u32 regno)
 {
-	BUG_ON(regno >= MAX_BPF_REG);
 	regs[regno].type = UNKNOWN_VALUE;
 	regs[regno].id = 0;
 	regs[regno].imm = 0;
 }
 
+static void mark_reg_unknown_value(struct bpf_reg_state *regs, u32 regno)
+{
+	BUG_ON(regno >= MAX_BPF_REG);
+	__mark_reg_unknown_value(regs, regno);
+}
+
 static void reset_reg_range_values(struct bpf_reg_state *regs, u32 regno)
 {
 	regs[regno].min_value = BPF_REGISTER_MIN_RANGE;
@@ -1976,7 +1981,7 @@ static void mark_map_reg(struct bpf_reg_state *regs, u32 regno, u32 id,
 		 */
 		reg->id = 0;
 		if (type == UNKNOWN_VALUE)
-			mark_reg_unknown_value(regs, regno);
+			__mark_reg_unknown_value(regs, regno);
 	}
 }
 
@@ -2931,6 +2936,10 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env)
 	int insn_cnt = env->prog->len;
 	int i, j, err;
 
+	err = bpf_prog_calc_digest(env->prog);
+	if (err)
+		return err;
+
 	for (i = 0; i < insn_cnt; i++, insn++) {
 		if (BPF_CLASS(insn->code) == BPF_LDX &&
 		    (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0)) {
@@ -3178,8 +3187,6 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr)
 		log_level = 0;
 	}
 
-	bpf_prog_calc_digest(env->prog);
-
 	ret = replace_map_fd_with_map_ptr(env);
 	if (ret < 0)
 		goto skip_full_check;