From 7e3cf0843fe505491baa05e355e83e6997e089dd Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Wed, 5 Oct 2022 17:23:53 +0200 Subject: [PATCH] treewide: use get_random_{u8,u16}() when possible, part 1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Kees Cook Reviewed-by: Yury Norov Acked-by: Jakub Kicinski Acked-by: Toke Høiland-Jørgensen # for sch_cake Signed-off-by: Jason A. Donenfeld --- arch/arm/kernel/signal.c | 2 +- arch/arm64/kernel/syscall.c | 2 +- crypto/testmgr.c | 8 ++++---- drivers/media/common/v4l2-tpg/v4l2-tpg-core.c | 2 +- drivers/media/test-drivers/vivid/vivid-radio-rx.c | 4 ++-- .../net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c | 2 +- drivers/net/hamradio/baycom_epp.c | 2 +- drivers/net/hamradio/hdlcdrv.c | 2 +- drivers/net/hamradio/yam.c | 2 +- drivers/net/wireguard/selftest/allowedips.c | 4 ++-- drivers/net/wireless/st/cw1200/wsm.c | 2 +- drivers/scsi/lpfc/lpfc_hbadisc.c | 6 +++--- lib/cmdline_kunit.c | 4 ++-- net/dccp/ipv4.c | 4 ++-- net/ipv4/datagram.c | 2 +- net/ipv4/ip_output.c | 2 +- net/ipv4/tcp_ipv4.c | 4 ++-- net/mac80211/scan.c | 2 +- net/netfilter/nf_nat_core.c | 4 ++-- net/sched/sch_cake.c | 6 +++--- net/sctp/socket.c | 2 +- 21 files changed, 34 insertions(+), 34 deletions(-) diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index ea128e32e8ca..e07f359254c3 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -655,7 +655,7 @@ struct page *get_signal_page(void) PAGE_SIZE / sizeof(u32)); /* Give the signal return code some randomness */ - offset = 0x200 + (get_random_int() & 0x7fc); + offset = 0x200 + (get_random_u16() & 0x7fc); signal_return_offset = offset; /* Copy signal return handlers into the page */ diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index 733451fe7e41..d72e8f23422d 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -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]. */ - 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) diff --git a/crypto/testmgr.c b/crypto/testmgr.c index bff4833dbe7c..bcd059caa1c8 100644 --- a/crypto/testmgr.c +++ b/crypto/testmgr.c @@ -927,7 +927,7 @@ static void generate_random_bytes(u8 *buf, size_t count) b = 0xff; break; default: - b = (u8)prandom_u32(); + b = get_random_u8(); break; } memset(buf, b, count); @@ -935,8 +935,8 @@ static void generate_random_bytes(u8 *buf, size_t count) break; case 2: /* Ascending or descending bytes, plus optional mutations */ - increment = (u8)prandom_u32(); - b = (u8)prandom_u32(); + increment = get_random_u8(); + b = get_random_u8(); for (i = 0; i < count; i++, b += increment) buf[i] = b; mutate_buffer(buf, count); @@ -944,7 +944,7 @@ static void generate_random_bytes(u8 *buf, size_t count) default: /* Fully random bytes */ for (i = 0; i < count; i++) - buf[i] = (u8)prandom_u32(); + buf[i] = get_random_u8(); } } diff --git a/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c b/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c index 9b7bcdce6e44..303d02b1d71c 100644 --- a/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c +++ b/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c @@ -870,7 +870,7 @@ static void precalculate_color(struct tpg_data *tpg, int k) g = tpg_colors[col].g; b = tpg_colors[col].b; } 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) { r = g = b = tpg->qual_offset + prandom_u32_max(196); } else if (k >= TPG_COLOR_RAMP) { diff --git a/drivers/media/test-drivers/vivid/vivid-radio-rx.c b/drivers/media/test-drivers/vivid/vivid-radio-rx.c index 232cab508f48..8bd09589fb15 100644 --- a/drivers/media/test-drivers/vivid/vivid-radio-rx.c +++ b/drivers/media/test-drivers/vivid/vivid-radio-rx.c @@ -104,8 +104,8 @@ retry: break; case 2: rds.block |= V4L2_RDS_BLOCK_ERROR; - rds.lsb = prandom_u32_max(256); - rds.msb = prandom_u32_max(256); + rds.lsb = get_random_u8(); + rds.msb = get_random_u8(); break; case 3: /* Skip block altogether */ if (i) diff --git a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c index f90bfba4b303..eda129d0143e 100644 --- a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c +++ b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c @@ -1466,7 +1466,7 @@ static void make_established(struct sock *sk, u32 snd_isn, unsigned int opt) tp->write_seq = snd_isn; tp->snd_nxt = 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); if (tp->rcv_wnd > (RCV_BUFSIZ_M << 10)) diff --git a/drivers/net/hamradio/baycom_epp.c b/drivers/net/hamradio/baycom_epp.c index 7df78a721b04..791b4a53d69f 100644 --- a/drivers/net/hamradio/baycom_epp.c +++ b/drivers/net/hamradio/baycom_epp.c @@ -438,7 +438,7 @@ static int transmit(struct baycom_state *bc, int cnt, unsigned char stat) if ((--bc->hdlctx.slotcnt) > 0) return 0; 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; } } diff --git a/drivers/net/hamradio/hdlcdrv.c b/drivers/net/hamradio/hdlcdrv.c index bef904325a0f..2263029d1a20 100644 --- a/drivers/net/hamradio/hdlcdrv.c +++ b/drivers/net/hamradio/hdlcdrv.c @@ -377,7 +377,7 @@ void hdlcdrv_arbitrate(struct net_device *dev, struct hdlcdrv_state *s) if ((--s->hdlctx.slotcnt) > 0) return; 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; start_tx(dev, s); } diff --git a/drivers/net/hamradio/yam.c b/drivers/net/hamradio/yam.c index 97a6cc5c7ae8..2ed2f836f09a 100644 --- a/drivers/net/hamradio/yam.c +++ b/drivers/net/hamradio/yam.c @@ -626,7 +626,7 @@ static void yam_arbitrate(struct net_device *dev) yp->slotcnt = yp->slot / 10; /* is random > persist ? */ - if (prandom_u32_max(256) > yp->pers) + if (get_random_u8() > yp->pers) return; yam_start_tx(dev, yp); diff --git a/drivers/net/wireguard/selftest/allowedips.c b/drivers/net/wireguard/selftest/allowedips.c index 41db10f9be49..dd897c0740a2 100644 --- a/drivers/net/wireguard/selftest/allowedips.c +++ b/drivers/net/wireguard/selftest/allowedips.c @@ -310,7 +310,7 @@ static __init bool randomized_test(void) for (k = 0; k < 4; ++k) mutated[k] = (mutated[k] & mutate_mask[k]) | (~mutate_mask[k] & - prandom_u32_max(256)); + get_random_u8()); cidr = prandom_u32_max(32) + 1; peer = peers[prandom_u32_max(NUM_PEERS)]; if (wg_allowedips_insert_v4(&t, @@ -354,7 +354,7 @@ static __init bool randomized_test(void) for (k = 0; k < 4; ++k) mutated[k] = (mutated[k] & mutate_mask[k]) | (~mutate_mask[k] & - prandom_u32_max(256)); + get_random_u8()); cidr = prandom_u32_max(128) + 1; peer = peers[prandom_u32_max(NUM_PEERS)]; if (wg_allowedips_insert_v6(&t, diff --git a/drivers/net/wireless/st/cw1200/wsm.c b/drivers/net/wireless/st/cw1200/wsm.c index 5a3e7a626702..4a9e4b5d3547 100644 --- a/drivers/net/wireless/st/cw1200/wsm.c +++ b/drivers/net/wireless/st/cw1200/wsm.c @@ -1594,7 +1594,7 @@ static int cw1200_get_prio_queue(struct cw1200_common *priv, edca = &priv->edca.params[i]; score = ((edca->aifns + edca->cwmin) << 16) + ((edca->cwmax - edca->cwmin) * - (get_random_int() & 0xFFFF)); + get_random_u16()); if (score < best && (winner < 0 || i != 3)) { best = score; winner = i; diff --git a/drivers/scsi/lpfc/lpfc_hbadisc.c b/drivers/scsi/lpfc/lpfc_hbadisc.c index c7f834ba8edb..d38ebd7281b9 100644 --- a/drivers/scsi/lpfc/lpfc_hbadisc.c +++ b/drivers/scsi/lpfc/lpfc_hbadisc.c @@ -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 * use through a sequence of @fcf_cnt eligible FCF records with equal * probability. To perform integer manunipulation of random numbers with - * size unit32_t, the lower 16 bits of the 32-bit random number returned - * from prandom_u32() are taken as the random random number generated. + * size unit32_t, a 16-bit random number returned from get_random_u16() is + * taken as the random random number generated. * * Returns true when outcome is for the newly read FCF record should be * 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; /* Get 16-bit uniform random number */ - rand_num = 0xFFFF & prandom_u32(); + rand_num = get_random_u16(); /* Decision with probability 1/fcf_cnt */ if ((fcf_cnt * rand_num) < 0xFFFF) diff --git a/lib/cmdline_kunit.c b/lib/cmdline_kunit.c index a72a2c16066e..d4572dbc9145 100644 --- a/lib/cmdline_kunit.c +++ b/lib/cmdline_kunit.c @@ -76,7 +76,7 @@ static void cmdline_test_lead_int(struct kunit *test) int rc = cmdline_test_values[i]; 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 */ offset = strlen(in) - strlen(str) + !!(rc == 2); 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 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 * will advance the pointer. diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index 6a6e121dc00c..713b7b8dad7e 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -144,7 +144,7 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) inet->inet_daddr, inet->inet_sport, inet->inet_dport); - inet->inet_id = prandom_u32(); + inet->inet_id = get_random_u16(); err = dccp_connect(sk); 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)); newinet->mc_index = inet_iif(skb); 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) goto put_and_exit; diff --git a/net/ipv4/datagram.c b/net/ipv4/datagram.c index 405a8c2aea64..0ee7fd259730 100644 --- a/net/ipv4/datagram.c +++ b/net/ipv4/datagram.c @@ -73,7 +73,7 @@ int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len reuseport_has_conns(sk, true); sk->sk_state = TCP_ESTABLISHED; sk_set_txhash(sk); - inet->inet_id = prandom_u32(); + inet->inet_id = get_random_u16(); sk_dst_set(sk, &rt->dst); err = 0; diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 1ae83ad629b2..922c87ef1ab5 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -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. */ if (sk->sk_protocol == IPPROTO_TCP) - iph->id = (__force __be16)prandom_u32(); + iph->id = (__force __be16)get_random_u16(); else __ip_select_ident(net, iph, 1); } diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 6376ad915765..7a250ef9d1b7 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -323,7 +323,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) inet->inet_daddr); } - inet->inet_id = prandom_u32(); + inet->inet_id = get_random_u16(); if (tcp_fastopen_defer_connect(sk, &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; if (inet_opt) 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. * ECT bits are set later in tcp_init_transfer(). diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c index 0e8c4f48c36d..dc3cdee51e66 100644 --- a/net/mac80211/scan.c +++ b/net/mac80211/scan.c @@ -641,7 +641,7 @@ static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata, if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) { struct ieee80211_hdr *hdr = (void *)skb->data; 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; hdr->seq_ctrl = diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c index d8e6380f6337..18319a6e6806 100644 --- a/net/netfilter/nf_nat_core.c +++ b/net/netfilter/nf_nat_core.c @@ -468,7 +468,7 @@ find_free_id: if (range->flags & NF_NAT_RANGE_PROTO_OFFSET) off = (ntohs(*keyptr) - ntohs(range->base_proto.all)); else - off = prandom_u32(); + off = get_random_u16(); attempts = range_size; if (attempts > max_attempts) @@ -490,7 +490,7 @@ another_round: if (attempts >= range_size || attempts < 16) return; attempts /= 2; - off = prandom_u32(); + off = get_random_u16(); goto another_round; } diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c index 55c6879d2c7e..7193d25932ce 100644 --- a/net/sched/sch_cake.c +++ b/net/sched/sch_cake.c @@ -2092,11 +2092,11 @@ retry: WARN_ON(host_load > CAKE_QUEUES); - /* The shifted prandom_u32() is a way to apply dithering to - * avoid accumulating roundoff errors + /* The get_random_u16() is a way to apply dithering to avoid + * accumulating roundoff errors */ 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); goto retry; diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 1e354ba44960..83628c347744 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -9448,7 +9448,7 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk, newinet->inet_rcv_saddr = inet->inet_rcv_saddr; newinet->inet_dport = htons(asoc->peer.port); newinet->pmtudisc = inet->pmtudisc; - newinet->inet_id = prandom_u32(); + newinet->inet_id = get_random_u16(); newinet->uc_ttl = inet->uc_ttl; newinet->mc_loop = 1;