treewide: use get_random_{u8,u16}() when possible, part 1

Rather than truncate a 32-bit value to a 16-bit value or an 8-bit value,
simply use the get_random_{u8,u16}() functions, which are faster than
wasting the additional bytes from a 32-bit value. This was done
mechanically with this coccinelle script:

@@
expression E;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u16;
typedef __be16;
typedef __le16;
typedef u8;
@@
(
- (get_random_u32() & 0xffff)
+ get_random_u16()
|
- (get_random_u32() & 0xff)
+ get_random_u8()
|
- (get_random_u32() % 65536)
+ get_random_u16()
|
- (get_random_u32() % 256)
+ get_random_u8()
|
- (get_random_u32() >> 16)
+ get_random_u16()
|
- (get_random_u32() >> 24)
+ get_random_u8()
|
- (u16)get_random_u32()
+ get_random_u16()
|
- (u8)get_random_u32()
+ get_random_u8()
|
- (__be16)get_random_u32()
+ (__be16)get_random_u16()
|
- (__le16)get_random_u32()
+ (__le16)get_random_u16()
|
- prandom_u32_max(65536)
+ get_random_u16()
|
- prandom_u32_max(256)
+ get_random_u8()
|
- E->inet_id = get_random_u32()
+ E->inet_id = get_random_u16()
)

@@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u16;
identifier v;
@@
- u16 v = get_random_u32();
+ u16 v = get_random_u16();

@@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u8;
identifier v;
@@
- u8 v = get_random_u32();
+ u8 v = get_random_u8();

@@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u16;
u16 v;
@@
-  v = get_random_u32();
+  v = get_random_u16();

@@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u8;
u8 v;
@@
-  v = get_random_u32();
+  v = get_random_u8();

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

        ((T)get_random_u32()@p & (LITERAL))

// Examine limits
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
        value = int(literal, 16)
elif literal[0] in '123456789':
        value = int(literal, 10)
if value is None:
        print("I don't know how to handle %s" % (literal))
        cocci.include_match(False)
elif value < 256:
        coccinelle.RESULT = cocci.make_ident("get_random_u8")
elif value < 65536:
        coccinelle.RESULT = cocci.make_ident("get_random_u16")
else:
        print("Skipping large mask of %s" % (literal))
        cocci.include_match(False)

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
identifier add_one.RESULT;
identifier FUNC;
@@

-       (FUNC()@p & (LITERAL))
+       (RESULT() & LITERAL)

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> # for sch_cake
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2022-10-05 17:23:53 +02:00
parent 8b3ccbc1f1
commit 7e3cf0843f
21 changed files with 34 additions and 34 deletions

View File

@ -655,7 +655,7 @@ struct page *get_signal_page(void)
PAGE_SIZE / sizeof(u32)); PAGE_SIZE / sizeof(u32));
/* Give the signal return code some randomness */ /* Give the signal return code some randomness */
offset = 0x200 + (get_random_int() & 0x7fc); offset = 0x200 + (get_random_u16() & 0x7fc);
signal_return_offset = offset; signal_return_offset = offset;
/* Copy signal return handlers into the page */ /* Copy signal return handlers into the page */

View File

@ -67,7 +67,7 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno,
* *
* The resulting 5 bits of entropy is seen in SP[8:4]. * The resulting 5 bits of entropy is seen in SP[8:4].
*/ */
choose_random_kstack_offset(get_random_int() & 0x1FF); choose_random_kstack_offset(get_random_u16() & 0x1FF);
} }
static inline bool has_syscall_work(unsigned long flags) static inline bool has_syscall_work(unsigned long flags)

View File

@ -927,7 +927,7 @@ static void generate_random_bytes(u8 *buf, size_t count)
b = 0xff; b = 0xff;
break; break;
default: default:
b = (u8)prandom_u32(); b = get_random_u8();
break; break;
} }
memset(buf, b, count); memset(buf, b, count);
@ -935,8 +935,8 @@ static void generate_random_bytes(u8 *buf, size_t count)
break; break;
case 2: case 2:
/* Ascending or descending bytes, plus optional mutations */ /* Ascending or descending bytes, plus optional mutations */
increment = (u8)prandom_u32(); increment = get_random_u8();
b = (u8)prandom_u32(); b = get_random_u8();
for (i = 0; i < count; i++, b += increment) for (i = 0; i < count; i++, b += increment)
buf[i] = b; buf[i] = b;
mutate_buffer(buf, count); mutate_buffer(buf, count);
@ -944,7 +944,7 @@ static void generate_random_bytes(u8 *buf, size_t count)
default: default:
/* Fully random bytes */ /* Fully random bytes */
for (i = 0; i < count; i++) for (i = 0; i < count; i++)
buf[i] = (u8)prandom_u32(); buf[i] = get_random_u8();
} }
} }

View File

@ -870,7 +870,7 @@ static void precalculate_color(struct tpg_data *tpg, int k)
g = tpg_colors[col].g; g = tpg_colors[col].g;
b = tpg_colors[col].b; b = tpg_colors[col].b;
} else if (tpg->pattern == TPG_PAT_NOISE) { } else if (tpg->pattern == TPG_PAT_NOISE) {
r = g = b = prandom_u32_max(256); r = g = b = get_random_u8();
} else if (k == TPG_COLOR_RANDOM) { } else if (k == TPG_COLOR_RANDOM) {
r = g = b = tpg->qual_offset + prandom_u32_max(196); r = g = b = tpg->qual_offset + prandom_u32_max(196);
} else if (k >= TPG_COLOR_RAMP) { } else if (k >= TPG_COLOR_RAMP) {

View File

@ -104,8 +104,8 @@ retry:
break; break;
case 2: case 2:
rds.block |= V4L2_RDS_BLOCK_ERROR; rds.block |= V4L2_RDS_BLOCK_ERROR;
rds.lsb = prandom_u32_max(256); rds.lsb = get_random_u8();
rds.msb = prandom_u32_max(256); rds.msb = get_random_u8();
break; break;
case 3: /* Skip block altogether */ case 3: /* Skip block altogether */
if (i) if (i)

View File

@ -1466,7 +1466,7 @@ static void make_established(struct sock *sk, u32 snd_isn, unsigned int opt)
tp->write_seq = snd_isn; tp->write_seq = snd_isn;
tp->snd_nxt = snd_isn; tp->snd_nxt = snd_isn;
tp->snd_una = snd_isn; tp->snd_una = snd_isn;
inet_sk(sk)->inet_id = prandom_u32(); inet_sk(sk)->inet_id = get_random_u16();
assign_rxopt(sk, opt); assign_rxopt(sk, opt);
if (tp->rcv_wnd > (RCV_BUFSIZ_M << 10)) if (tp->rcv_wnd > (RCV_BUFSIZ_M << 10))

View File

@ -438,7 +438,7 @@ static int transmit(struct baycom_state *bc, int cnt, unsigned char stat)
if ((--bc->hdlctx.slotcnt) > 0) if ((--bc->hdlctx.slotcnt) > 0)
return 0; return 0;
bc->hdlctx.slotcnt = bc->ch_params.slottime; bc->hdlctx.slotcnt = bc->ch_params.slottime;
if (prandom_u32_max(256) > bc->ch_params.ppersist) if (get_random_u8() > bc->ch_params.ppersist)
return 0; return 0;
} }
} }

View File

@ -377,7 +377,7 @@ void hdlcdrv_arbitrate(struct net_device *dev, struct hdlcdrv_state *s)
if ((--s->hdlctx.slotcnt) > 0) if ((--s->hdlctx.slotcnt) > 0)
return; return;
s->hdlctx.slotcnt = s->ch_params.slottime; s->hdlctx.slotcnt = s->ch_params.slottime;
if (prandom_u32_max(256) > s->ch_params.ppersist) if (get_random_u8() > s->ch_params.ppersist)
return; return;
start_tx(dev, s); start_tx(dev, s);
} }

View File

@ -626,7 +626,7 @@ static void yam_arbitrate(struct net_device *dev)
yp->slotcnt = yp->slot / 10; yp->slotcnt = yp->slot / 10;
/* is random > persist ? */ /* is random > persist ? */
if (prandom_u32_max(256) > yp->pers) if (get_random_u8() > yp->pers)
return; return;
yam_start_tx(dev, yp); yam_start_tx(dev, yp);

View File

@ -310,7 +310,7 @@ static __init bool randomized_test(void)
for (k = 0; k < 4; ++k) for (k = 0; k < 4; ++k)
mutated[k] = (mutated[k] & mutate_mask[k]) | mutated[k] = (mutated[k] & mutate_mask[k]) |
(~mutate_mask[k] & (~mutate_mask[k] &
prandom_u32_max(256)); get_random_u8());
cidr = prandom_u32_max(32) + 1; cidr = prandom_u32_max(32) + 1;
peer = peers[prandom_u32_max(NUM_PEERS)]; peer = peers[prandom_u32_max(NUM_PEERS)];
if (wg_allowedips_insert_v4(&t, if (wg_allowedips_insert_v4(&t,
@ -354,7 +354,7 @@ static __init bool randomized_test(void)
for (k = 0; k < 4; ++k) for (k = 0; k < 4; ++k)
mutated[k] = (mutated[k] & mutate_mask[k]) | mutated[k] = (mutated[k] & mutate_mask[k]) |
(~mutate_mask[k] & (~mutate_mask[k] &
prandom_u32_max(256)); get_random_u8());
cidr = prandom_u32_max(128) + 1; cidr = prandom_u32_max(128) + 1;
peer = peers[prandom_u32_max(NUM_PEERS)]; peer = peers[prandom_u32_max(NUM_PEERS)];
if (wg_allowedips_insert_v6(&t, if (wg_allowedips_insert_v6(&t,

View File

@ -1594,7 +1594,7 @@ static int cw1200_get_prio_queue(struct cw1200_common *priv,
edca = &priv->edca.params[i]; edca = &priv->edca.params[i];
score = ((edca->aifns + edca->cwmin) << 16) + score = ((edca->aifns + edca->cwmin) << 16) +
((edca->cwmax - edca->cwmin) * ((edca->cwmax - edca->cwmin) *
(get_random_int() & 0xFFFF)); get_random_u16());
if (score < best && (winner < 0 || i != 3)) { if (score < best && (winner < 0 || i != 3)) {
best = score; best = score;
winner = i; winner = i;

View File

@ -2156,8 +2156,8 @@ lpfc_check_pending_fcoe_event(struct lpfc_hba *phba, uint8_t unreg_fcf)
* This function makes an running random selection decision on FCF record to * This function makes an running random selection decision on FCF record to
* use through a sequence of @fcf_cnt eligible FCF records with equal * use through a sequence of @fcf_cnt eligible FCF records with equal
* probability. To perform integer manunipulation of random numbers with * probability. To perform integer manunipulation of random numbers with
* size unit32_t, the lower 16 bits of the 32-bit random number returned * size unit32_t, a 16-bit random number returned from get_random_u16() is
* from prandom_u32() are taken as the random random number generated. * taken as the random random number generated.
* *
* Returns true when outcome is for the newly read FCF record should be * Returns true when outcome is for the newly read FCF record should be
* chosen; otherwise, return false when outcome is for keeping the previously * chosen; otherwise, return false when outcome is for keeping the previously
@ -2169,7 +2169,7 @@ lpfc_sli4_new_fcf_random_select(struct lpfc_hba *phba, uint32_t fcf_cnt)
uint32_t rand_num; uint32_t rand_num;
/* Get 16-bit uniform random number */ /* Get 16-bit uniform random number */
rand_num = 0xFFFF & prandom_u32(); rand_num = get_random_u16();
/* Decision with probability 1/fcf_cnt */ /* Decision with probability 1/fcf_cnt */
if ((fcf_cnt * rand_num) < 0xFFFF) if ((fcf_cnt * rand_num) < 0xFFFF)

View File

@ -76,7 +76,7 @@ static void cmdline_test_lead_int(struct kunit *test)
int rc = cmdline_test_values[i]; int rc = cmdline_test_values[i];
int offset; int offset;
sprintf(in, "%u%s", get_random_int() % 256, str); sprintf(in, "%u%s", get_random_u8(), str);
/* Only first '-' after the number will advance the pointer */ /* Only first '-' after the number will advance the pointer */
offset = strlen(in) - strlen(str) + !!(rc == 2); offset = strlen(in) - strlen(str) + !!(rc == 2);
cmdline_do_one_test(test, in, rc, offset); cmdline_do_one_test(test, in, rc, offset);
@ -94,7 +94,7 @@ static void cmdline_test_tail_int(struct kunit *test)
int rc = strcmp(str, "") ? (strcmp(str, "-") ? 0 : 1) : 1; int rc = strcmp(str, "") ? (strcmp(str, "-") ? 0 : 1) : 1;
int offset; int offset;
sprintf(in, "%s%u", str, get_random_int() % 256); sprintf(in, "%s%u", str, get_random_u8());
/* /*
* Only first and leading '-' not followed by integer * Only first and leading '-' not followed by integer
* will advance the pointer. * will advance the pointer.

View File

@ -144,7 +144,7 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
inet->inet_daddr, inet->inet_daddr,
inet->inet_sport, inet->inet_sport,
inet->inet_dport); inet->inet_dport);
inet->inet_id = prandom_u32(); inet->inet_id = get_random_u16();
err = dccp_connect(sk); err = dccp_connect(sk);
rt = NULL; rt = NULL;
@ -443,7 +443,7 @@ struct sock *dccp_v4_request_recv_sock(const struct sock *sk,
RCU_INIT_POINTER(newinet->inet_opt, rcu_dereference(ireq->ireq_opt)); RCU_INIT_POINTER(newinet->inet_opt, rcu_dereference(ireq->ireq_opt));
newinet->mc_index = inet_iif(skb); newinet->mc_index = inet_iif(skb);
newinet->mc_ttl = ip_hdr(skb)->ttl; newinet->mc_ttl = ip_hdr(skb)->ttl;
newinet->inet_id = prandom_u32(); newinet->inet_id = get_random_u16();
if (dst == NULL && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL) if (dst == NULL && (dst = inet_csk_route_child_sock(sk, newsk, req)) == NULL)
goto put_and_exit; goto put_and_exit;

View File

@ -73,7 +73,7 @@ int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len
reuseport_has_conns(sk, true); reuseport_has_conns(sk, true);
sk->sk_state = TCP_ESTABLISHED; sk->sk_state = TCP_ESTABLISHED;
sk_set_txhash(sk); sk_set_txhash(sk);
inet->inet_id = prandom_u32(); inet->inet_id = get_random_u16();
sk_dst_set(sk, &rt->dst); sk_dst_set(sk, &rt->dst);
err = 0; err = 0;

View File

@ -172,7 +172,7 @@ int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
* Avoid using the hashed IP ident generator. * Avoid using the hashed IP ident generator.
*/ */
if (sk->sk_protocol == IPPROTO_TCP) if (sk->sk_protocol == IPPROTO_TCP)
iph->id = (__force __be16)prandom_u32(); iph->id = (__force __be16)get_random_u16();
else else
__ip_select_ident(net, iph, 1); __ip_select_ident(net, iph, 1);
} }

View File

@ -323,7 +323,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
inet->inet_daddr); inet->inet_daddr);
} }
inet->inet_id = prandom_u32(); inet->inet_id = get_random_u16();
if (tcp_fastopen_defer_connect(sk, &err)) if (tcp_fastopen_defer_connect(sk, &err))
return err; return err;
@ -1543,7 +1543,7 @@ struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
inet_csk(newsk)->icsk_ext_hdr_len = 0; inet_csk(newsk)->icsk_ext_hdr_len = 0;
if (inet_opt) if (inet_opt)
inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
newinet->inet_id = prandom_u32(); newinet->inet_id = get_random_u16();
/* Set ToS of the new socket based upon the value of incoming SYN. /* Set ToS of the new socket based upon the value of incoming SYN.
* ECT bits are set later in tcp_init_transfer(). * ECT bits are set later in tcp_init_transfer().

View File

@ -641,7 +641,7 @@ static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) { if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
struct ieee80211_hdr *hdr = (void *)skb->data; struct ieee80211_hdr *hdr = (void *)skb->data;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
u16 sn = get_random_u32(); u16 sn = get_random_u16();
info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO; info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO;
hdr->seq_ctrl = hdr->seq_ctrl =

View File

@ -468,7 +468,7 @@ find_free_id:
if (range->flags & NF_NAT_RANGE_PROTO_OFFSET) if (range->flags & NF_NAT_RANGE_PROTO_OFFSET)
off = (ntohs(*keyptr) - ntohs(range->base_proto.all)); off = (ntohs(*keyptr) - ntohs(range->base_proto.all));
else else
off = prandom_u32(); off = get_random_u16();
attempts = range_size; attempts = range_size;
if (attempts > max_attempts) if (attempts > max_attempts)
@ -490,7 +490,7 @@ another_round:
if (attempts >= range_size || attempts < 16) if (attempts >= range_size || attempts < 16)
return; return;
attempts /= 2; attempts /= 2;
off = prandom_u32(); off = get_random_u16();
goto another_round; goto another_round;
} }

View File

@ -2092,11 +2092,11 @@ retry:
WARN_ON(host_load > CAKE_QUEUES); WARN_ON(host_load > CAKE_QUEUES);
/* The shifted prandom_u32() is a way to apply dithering to /* The get_random_u16() is a way to apply dithering to avoid
* avoid accumulating roundoff errors * accumulating roundoff errors
*/ */
flow->deficit += (b->flow_quantum * quantum_div[host_load] + flow->deficit += (b->flow_quantum * quantum_div[host_load] +
(prandom_u32() >> 16)) >> 16; get_random_u16()) >> 16;
list_move_tail(&flow->flowchain, &b->old_flows); list_move_tail(&flow->flowchain, &b->old_flows);
goto retry; goto retry;

View File

@ -9448,7 +9448,7 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk,
newinet->inet_rcv_saddr = inet->inet_rcv_saddr; newinet->inet_rcv_saddr = inet->inet_rcv_saddr;
newinet->inet_dport = htons(asoc->peer.port); newinet->inet_dport = htons(asoc->peer.port);
newinet->pmtudisc = inet->pmtudisc; newinet->pmtudisc = inet->pmtudisc;
newinet->inet_id = prandom_u32(); newinet->inet_id = get_random_u16();
newinet->uc_ttl = inet->uc_ttl; newinet->uc_ttl = inet->uc_ttl;
newinet->mc_loop = 1; newinet->mc_loop = 1;