Re: [PATCH v4 4/6] treewide: use get_random_u32() when possible

From: Rolf Eike Beer <hidden>
Date: 2022-10-07 20:41:43
Also in: dri-devel, kernel-janitors, linux-block, linux-crypto, linux-doc, linux-fsdevel, linux-media, linux-mips, linux-mm, linux-mmc, linux-nvme, linux-patches, linux-rdma, linux-s390, linux-um, linux-usb, linux-wireless, lkml, loongarch, sparclinux

quoted hunk ↗ jump to hunk

diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index 7c37e09c92da..18c4f0e3e906 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c

@@ -288,7 +288,7 @@ __get_wchan(struct task_struct *p)

 static inline unsigned long brk_rnd(void)
 {
-	return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT;
+	return (get_random_u32() & BRK_RND_MASK) << PAGE_SHIFT;
 }

Can't this be

  prandom_u32_max(BRK_RND_MASK + 1) << PAGE_SHIFT

? More similar code with other masks follows below.

quoted hunk ↗ jump to hunk

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c

b/drivers/gpu/drm/i915/i915_gem_gtt.c index 329ff75b80b9..7bd1861ddbdf
100644

--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -137,12 +137,12 @@ static u64 random_offset(u64 start, u64 end, u64 len,

u64 align) range = round_down(end - len, align) - round_up(start, align);
 	if (range) {
 		if (sizeof(unsigned long) == sizeof(u64)) {
-			addr = get_random_long();
+			addr = get_random_u64();
 		} else {
-			addr = get_random_int();
+			addr = get_random_u32();
 			if (range > U32_MAX) {
 				addr <<= 32;
-				addr |= get_random_int();
+				addr |= get_random_u32();
 			}
 		}
 		div64_u64_rem(addr, range, &addr);

How about 

 		if (sizeof(unsigned long) == sizeof(u64) || range > 
U32_MAX)
			addr = get_random_u64();
 		else
			addr = get_random_u32();

quoted hunk ↗ jump to hunk

diff --git a/drivers/infiniband/hw/cxgb4/cm.c

b/drivers/infiniband/hw/cxgb4/cm.c index 14392c942f49..499a425a3379 100644

--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c

@@ -734,7 +734,7 @@ static int send_connect(struct c4iw_ep *ep)
 				   &ep->com.remote_addr;
 	int ret;
 	enum chip_type adapter_type = ep->com.dev->rdev.lldi.adapter_type;
-	u32 isn = (prandom_u32() & ~7UL) - 1;
+	u32 isn = (get_random_u32() & ~7UL) - 1;
 	struct net_device *netdev;
 	u64 params;

@@ -2469,7 +2469,7 @@ static int accept_cr(struct c4iw_ep *ep, struct

sk_buff *skb, }

 	if (!is_t4(adapter_type)) {
-		u32 isn = (prandom_u32() & ~7UL) - 1;
+		u32 isn = (get_random_u32() & ~7UL) - 1;

u32 isn = get_random_u32() | 0x7;

Same code comes later again.

quoted hunk ↗ jump to hunk

diff --git a/drivers/mtd/nand/raw/nandsim.c b/drivers/mtd/nand/raw/nandsim.c
index 50bcf745e816..4bdaf4aa7007 100644
--- a/drivers/mtd/nand/raw/nandsim.c
+++ b/drivers/mtd/nand/raw/nandsim.c

@@ -1402,7 +1402,7 @@ static int ns_do_read_error(struct nandsim *ns, int

num)

 static void ns_do_bit_flips(struct nandsim *ns, int num)
 {
-	if (bitflips && prandom_u32() < (1 << 22)) {
+	if (bitflips && get_random_u32() < (1 << 22)) {

Doing "get_random_u16() < (1 << 6)" should have the same probability with only 
2 bytes of random, no?

quoted hunk ↗ jump to hunk

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
ac452a0111a9..b71ce6c5b512 100644

--- a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c
+++ b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_cm.c

@@ -1063,7 +1063,7 @@ static void chtls_pass_accept_rpl(struct sk_buff *skb,

opt2 |= WND_SCALE_EN_V(WSCALE_OK(tp));
 	rpl5->opt0 = cpu_to_be64(opt0);
 	rpl5->opt2 = cpu_to_be32(opt2);
-	rpl5->iss = cpu_to_be32((prandom_u32() & ~7UL) - 1);
+	rpl5->iss = cpu_to_be32((get_random_u32() & ~7UL) - 1);
 	set_wr_txq(skb, CPL_PRIORITY_SETUP, csk->port_id);
 	t4_set_arp_err_handler(skb, sk, chtls_accept_rpl_arp_failure);
 	cxgb4_l2t_send(csk->egress_dev, skb, csk->l2t_entry);

diff --git a/drivers/net/ethernet/rocker/rocker_main.c

b/drivers/net/ethernet/rocker/rocker_main.c index
fc83ec23bd1d..8c3bbafabb07 100644

--- a/drivers/net/ethernet/rocker/rocker_main.c
+++ b/drivers/net/ethernet/rocker/rocker_main.c

@@ -139,9 +139,9 @@ static int rocker_reg_test(const struct rocker *rocker)
 		return -EIO;
 	}

-	rnd = prandom_u32();
+	rnd = get_random_u32();
 	rnd <<= 31;
-	rnd |= prandom_u32();
+	rnd |= get_random_u32();

quoted hunk ↗ jump to hunk

 	rocker_write64(rocker, TEST_REG64, rnd);
 	test_reg = rocker_read64(rocker, TEST_REG64);
 	if (test_reg != rnd * 2) {

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pno.c

b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pno.c index
fabfbb0b40b0..374e1cc07a63 100644

--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pno.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pno.c

@@ -177,7 +177,7 @@ static int brcmf_pno_set_random(struct brcmf_if *ifp,

struct brcmf_pno_info *pi) memcpy(pfn_mac.mac, mac_addr, ETH_ALEN);
 	for (i = 0; i < ETH_ALEN; i++) {
 		pfn_mac.mac[i] &= mac_mask[i];
-		pfn_mac.mac[i] |= get_random_int() & ~(mac_mask[i]);
+		pfn_mac.mac[i] |= get_random_u32() & ~(mac_mask[i]);

quoted hunk ↗ jump to hunk

diff --git a/lib/reed_solomon/test_rslib.c b/lib/reed_solomon/test_rslib.c
index 4d241bdc88aa..848e7eb5da92 100644
--- a/lib/reed_solomon/test_rslib.c
+++ b/lib/reed_solomon/test_rslib.c

@@ -164,7 +164,7 @@ static int get_rcw_we(struct rs_control *rs, struct

wspace *ws,

 	/* Load c with random data and encode */
 	for (i = 0; i < dlen; i++)
-		c[i] = prandom_u32() & nn;
+		c[i] = get_random_u32() & nn;

quoted hunk ↗ jump to hunk

@@ -178,7 +178,7 @@ static int get_rcw_we(struct rs_control *rs, struct

wspace *ws, for (i = 0; i < errs; i++) {
 		do {
 			/* Error value must be nonzero */
-			errval = prandom_u32() & nn;
+			errval = get_random_u32() & nn;
 		} while (errval == 0);

quoted hunk ↗ jump to hunk

@@ -206,7 +206,7 @@ static int get_rcw_we(struct rs_control *rs, struct

wspace *ws, /* Erasure with corrupted symbol */
 			do {
 				/* Error value must be nonzero */
-				errval = prandom_u32() & nn;
+				errval = get_random_u32() & nn;
 			} while (errval == 0);

quoted hunk ↗ jump to hunk

diff --git a/lib/test_fprobe.c b/lib/test_fprobe.c
index ed70637a2ffa..e0381b3ec410 100644
--- a/lib/test_fprobe.c
+++ b/lib/test_fprobe.c

@@ -145,7 +145,7 @@ static unsigned long get_ftrace_location(void *func)
 static int fprobe_test_init(struct kunit *test)
 {
 	do {
-		rand1 = prandom_u32();
+		rand1 = get_random_u32();
 	} while (rand1 <= div_factor);

quoted hunk ↗ jump to hunk

diff --git a/lib/test_kprobes.c b/lib/test_kprobes.c
index a5edc2ebc947..eeb1d728d974 100644
--- a/lib/test_kprobes.c
+++ b/lib/test_kprobes.c

@@ -341,7 +341,7 @@ static int kprobes_test_init(struct kunit *test)
 	stacktrace_driver = kprobe_stacktrace_driver;

 	do {
-		rand1 = prandom_u32();
+		rand1 = get_random_u32();
 	} while (rand1 <= div_factor);
 	return 0;
 }

quoted hunk ↗ jump to hunk

diff --git a/lib/test_rhashtable.c b/lib/test_rhashtable.c
index 5a1dd4736b56..b358a74ed7ed 100644
--- a/lib/test_rhashtable.c
+++ b/lib/test_rhashtable.c

@@ -291,7 +291,7 @@ static int __init test_rhltable(unsigned int entries)
 	if (WARN_ON(err))
 		goto out_free;

-	k = prandom_u32();
+	k = get_random_u32();
 	ret = 0;
 	for (i = 0; i < entries; i++) {
 		rhl_test_objects[i].value.id = k;

@@ -369,12 +369,12 @@ static int __init test_rhltable(unsigned int entries)
 	pr_info("test %d random rhlist add/delete operations\n", entries);
 	for (j = 0; j < entries; j++) {
 		u32 i = prandom_u32_max(entries);
-		u32 prand = prandom_u32();
+		u32 prand = get_random_u32();

 		cond_resched();

 		if (prand == 0)
-			prand = prandom_u32();
+			prand = get_random_u32();

 		if (prand & 1) {
 			prand >>= 1;

quoted hunk ↗ jump to hunk

diff --git a/net/ipv4/tcp_cdg.c b/net/ipv4/tcp_cdg.c
index ddc7ba0554bd..efcd145f06db 100644
--- a/net/ipv4/tcp_cdg.c
+++ b/net/ipv4/tcp_cdg.c

@@ -243,7 +243,7 @@ static bool tcp_cdg_backoff(struct sock *sk, u32 grad)
 	struct cdg *ca = inet_csk_ca(sk);
 	struct tcp_sock *tp = tcp_sk(sk);

-	if (prandom_u32() <= nexp_u32(grad * backoff_factor))
+	if (get_random_u32() <= nexp_u32(grad * backoff_factor))
 		return false;

 	if (use_ineff) {

quoted hunk ↗ jump to hunk

diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index ceb85c67ce39..18481eb76a0a 100644
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c

@@ -220,7 +220,7 @@ static struct ip6_flowlabel *fl_intern(struct net *net,
 	spin_lock_bh(&ip6_fl_lock);
 	if (label == 0) {
 		for (;;) {
-			fl->label =

htonl(prandom_u32())&IPV6_FLOWLABEL_MASK;

+			fl->label =

htonl(get_random_u32())&IPV6_FLOWLABEL_MASK;

 			if (fl->label) {
 				lfl = __fl_lookup(net, fl-
label);
 				if (!lfl)

quoted hunk ↗ jump to hunk

diff --git a/net/netfilter/ipvs/ip_vs_conn.c

b/net/netfilter/ipvs/ip_vs_conn.c index fb67f1ca2495..8c04bb57dd6f 100644

--- a/net/netfilter/ipvs/ip_vs_conn.c
+++ b/net/netfilter/ipvs/ip_vs_conn.c

@@ -1308,7 +1308,7 @@ void ip_vs_random_dropentry(struct netns_ipvs *ipvs)
 	 * Randomly scan 1/32 of the whole table every second
 	 */
 	for (idx = 0; idx < (ip_vs_conn_tab_size>>5); idx++) {
-		unsigned int hash = prandom_u32() &

ip_vs_conn_tab_mask;

+		unsigned int hash = get_random_u32() &

ip_vs_conn_tab_mask;

 		hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash],

c_list) {

 			if (cp->ipvs != ipvs)

quoted hunk ↗ jump to hunk

diff --git a/net/rds/bind.c b/net/rds/bind.c
index 5b5fb4ca8d3e..052776ddcc34 100644
--- a/net/rds/bind.c
+++ b/net/rds/bind.c

@@ -104,7 +104,7 @@ static int rds_add_bound(struct rds_sock *rs, const

struct in6_addr *addr, return -EINVAL;
 		last = rover;
 	} else {
-		rover = max_t(u16, prandom_u32(), 2);
+		rover = max_t(u16, get_random_u32(), 2);
 		last = rover - 1;
 	}

quoted hunk ↗ jump to hunk

diff --git a/net/sunrpc/auth_gss/gss_krb5_wrap.c

b/net/sunrpc/auth_gss/gss_krb5_wrap.c index 5f96e75f9eec..48337687848c
100644

--- a/net/sunrpc/auth_gss/gss_krb5_wrap.c
+++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c

@@ -130,8 +130,8 @@ gss_krb5_make_confounder(char *p, u32 conflen)

 	/* initialize to random value */
 	if (i == 0) {
-		i = prandom_u32();
-		i = (i << 32) | prandom_u32();
+		i = get_random_u32();
+		i = (i << 32) | get_random_u32();
 	}

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