[PATCH v2 00/11] introduce random32_get_bytes() and random32_get_bytes_state()

[PATCH v2 00/11] introduce random32_get_bytes() and random32_get_bytes_state()

[Akinobu Mita]

This patchset introduces new functions into random32 library for
getting the requested number of pseudo-random bytes.

Before introducing these new functions into random32 library,
prandom32() and prandom32_seed() with "prandom32" prefix are
renamed to random32_state() and srandom32_state() respectively.

The purpose of this renaming is to prevent some kernel developers
from assuming that prandom32() and random32() might imply that only
prandom32() was the one using a pseudo-random number generator by
prandom32's "p", and the result may be a very embarassing security
exposure.

Changelog

* v2
- rename prandom32 to random32_state
- dropped lib/uuid.c patch
- add bnx2 and mtd_stresstest patches

Akinobu Mita (11):
  random32: rename prandom32 to random32_state
  random32: introduce random32_get_bytes() and
    random32_get_bytes_state()
  bnx2x: use random32_get_bytes()
  mtd: nandsim: use random32_get_bytes
  ubifs: use random32_get_bytes
  mtd: mtd_nandecctest: use random32_get_bytes instead of
    get_random_bytes()
  mtd: mtd_oobtest: convert to use random32_get_bytes_state()
  mtd: mtd_pagetest: convert to use random32_get_bytes_state()
  mtd: mtd_speedtest: use random32_get_bytes
  mtd: mtd_subpagetest: convert to use random32_get_bytes_state()
  mtd: mtd_stresstest: use random32_get_bytes()

 drivers/mtd/nand/nandsim.c                      |  5 +--
 drivers/mtd/tests/mtd_nandecctest.c             |  2 +-
 drivers/mtd/tests/mtd_oobtest.c                 | 49 +++++++-------------
 drivers/mtd/tests/mtd_pagetest.c                | 43 ++++++------------
 drivers/mtd/tests/mtd_speedtest.c               |  9 +---
 drivers/mtd/tests/mtd_stresstest.c              |  3 +-
 drivers/mtd/tests/mtd_subpagetest.c             | 42 +++++------------
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c |  5 +--
 drivers/scsi/fcoe/fcoe_ctlr.c                   |  4 +-
 fs/ubifs/debug.c                                |  8 ++--
 include/linux/random.h                          |  8 ++--
 lib/interval_tree_test_main.c                   |  7 +--
 lib/random32.c                                  | 60 ++++++++++++++++++++-----
 lib/rbtree_test.c                               |  6 +--
 14 files changed, 112 insertions(+), 139 deletions(-)

Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
Cc: Eilon Greenstein <eilong@broadcom.com>
Cc: netdev@vger.kernel.org
Cc: Robert Love <robert.w.love@intel.com>
Cc: devel@open-fcoe.org
Cc: Michel Lespinasse <walken@google.com>

-- 
1.7.11.7

[PATCH v2 02/11] random32: introduce random32_get_bytes() and random32_get_bytes_state()

[Akinobu Mita]

Add functions to get the requested number of pseudo-random bytes.

The difference from get_random_bytes() is that it generates pseudo-random
numbers by random32().  It is fast, suitable for generating random bytes
for testing, and reproducible if random32_get_bytes_state() is used.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
Cc: Eilon Greenstein <eilong@broadcom.com>
Cc: netdev@vger.kernel.org
---
* v2
- rename prandom32_get_bytes to random32_get_bytes_state

 include/linux/random.h |  2 ++
 lib/random32.c         | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/include/linux/random.h b/include/linux/random.h
index bb96f79..4176762 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -27,8 +27,10 @@ unsigned long randomize_range(unsigned long start, unsigned long end, unsigned l
 
 u32 random32(void);
 void srandom32(u32 seed);
+void random32_get_bytes(void *buf, int nbytes);
 
 u32 random32_state(struct rnd_state *);
+void random32_get_bytes_state(struct rnd_state *state, void *buf, int nbytes);
 
 /*
  * Handle minimum values for seeds
diff --git a/lib/random32.c b/lib/random32.c
index 7a3e0c7..9557417 100644
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -61,6 +61,44 @@ u32 random32_state(struct rnd_state *state)
 EXPORT_SYMBOL(random32_state);
 
 /**
+ *	random32_get_bytes_state - get the pseudo-random bytes
+ *	@state: pointer to state structure holding seeded state.
+ *	@buf: where to copy the pseudo-random bytes to
+ *	@bytes: the requested number of bytes
+ *
+ *	This is used for pseudo-randomness with no outside seeding.
+ *	For more random results, use random32_get_bytes().
+ */
+void random32_get_bytes_state(struct rnd_state *state, void *buf, int bytes)
+{
+	unsigned char *p = buf;
+
+	for (; bytes > 0 && ((unsigned long)p) % sizeof(u32); bytes--, p++)
+		*p = random32_state(state);
+
+	for (; bytes > sizeof(u32) - 1; bytes -= sizeof(u32), p += sizeof(u32))
+		*(u32 *)p = random32_state(state);
+
+	for (; bytes > 0; bytes--, p++)
+		*p = random32_state(state);
+}
+EXPORT_SYMBOL(random32_get_bytes_state);
+
+/**
+ *	random32_get_bytes - get the requested number of pseudo-random bytes
+ *	@buf: where to copy the pseudo-random bytes to
+ *	@bytes: the requested number of bytes
+ */
+void random32_get_bytes(void *buf, int bytes)
+{
+	struct rnd_state *state = &get_cpu_var(net_rand_state);
+
+	random32_get_bytes_state(state, buf, bytes);
+	put_cpu_var(state);
+}
+EXPORT_SYMBOL(random32_get_bytes);
+
+/**
  *	random32 - pseudo random number generator
  *
  *	A 32 bit pseudo-random number is generated using a fast
-- 
1.7.11.7

[PATCH v2 04/11] mtd: nandsim: use random32_get_bytes

[Akinobu Mita]

This also removes unnecessary memset call which is immediately overwritten
with random bytes.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
no change from v1

 drivers/mtd/nand/nandsim.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/mtd/nand/nandsim.c b/drivers/mtd/nand/nandsim.c
index a932c48..d074b4c 100644
--- a/drivers/mtd/nand/nandsim.c
+++ b/drivers/mtd/nand/nandsim.c
@@ -1397,10 +1397,7 @@ int do_read_error(struct nandsim *ns, int num)
 	unsigned int page_no = ns->regs.row;
 
 	if (read_error(page_no)) {
-		int i;
-		memset(ns->buf.byte, 0xFF, num);
-		for (i = 0; i < num; ++i)
-			ns->buf.byte[i] = random32();
+		random32_get_bytes(ns->buf.byte, num);
 		NS_WARN("simulating read error in page %u\n", page_no);
 		return 1;
 	}
-- 
1.7.11.7

[PATCH v2 05/11] ubifs: use random32_get_bytes

[Akinobu Mita]

This also converts filling memory loop to use memset.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: linux-mtd@lists.infradead.org
---
no change from v1

 fs/ubifs/debug.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/fs/ubifs/debug.c b/fs/ubifs/debug.c
index 6291163..f3e4a25 100644
--- a/fs/ubifs/debug.c
+++ b/fs/ubifs/debug.c
@@ -2560,7 +2560,7 @@ static int power_cut_emulated(struct ubifs_info *c, int lnum, int write)
 static int corrupt_data(const struct ubifs_info *c, const void *buf,
 			unsigned int len)
 {
-	unsigned int from, to, i, ffs = chance(1, 2);
+	unsigned int from, to, ffs = chance(1, 2);
 	unsigned char *p = (void *)buf;
 
 	from = random32() % (len + 1);
@@ -2571,11 +2571,9 @@ static int corrupt_data(const struct ubifs_info *c, const void *buf,
 		   ffs ? "0xFFs" : "random data");
 
 	if (ffs)
-		for (i = from; i < to; i++)
-			p[i] = 0xFF;
+		memset(p + from, 0xFF, to - from);
 	else
-		for (i = from; i < to; i++)
-			p[i] = random32() % 0x100;
+		random32_get_bytes(p + from, to - from);
 
 	return to;
 }
-- 
1.7.11.7

[PATCH v2 06/11] mtd: mtd_nandecctest: use random32_get_bytes instead of get_random_bytes()

[Akinobu Mita]

Using random32_get_bytes() is enough.  Because this data is only used
for testing, not used for cryptographic use.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
no change from v1

 drivers/mtd/tests/mtd_nandecctest.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/tests/mtd_nandecctest.c b/drivers/mtd/tests/mtd_nandecctest.c
index a5fb9b0..0ddcbec 100644
--- a/drivers/mtd/tests/mtd_nandecctest.c
+++ b/drivers/mtd/tests/mtd_nandecctest.c
@@ -253,7 +253,7 @@ static int nand_ecc_test_run(const size_t size)
 		goto error;
 	}
 
-	get_random_bytes(correct_data, size);
+	random32_get_bytes(correct_data, size);
 	__nand_calculate_ecc(correct_data, size, correct_ecc);
 
 	for (i = 0; i < ARRAY_SIZE(nand_ecc_test); i++) {
-- 
1.7.11.7

[PATCH v2 07/11] mtd: mtd_oobtest: convert to use random32_get_bytes_state()

[Akinobu Mita]

This removes home-brewed pseudo-random number generator and use
random32_get_bytes_state().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
* v2
- rename prandom32_get_bytes to random32_get_bytes_state

 drivers/mtd/tests/mtd_oobtest.c | 49 ++++++++++++++---------------------------
 1 file changed, 16 insertions(+), 33 deletions(-)

diff --git a/drivers/mtd/tests/mtd_oobtest.c b/drivers/mtd/tests/mtd_oobtest.c
index ed9b628..ef42622 100644
--- a/drivers/mtd/tests/mtd_oobtest.c
+++ b/drivers/mtd/tests/mtd_oobtest.c
@@ -27,6 +27,7 @@
 #include <linux/mtd/mtd.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/random.h>
 
 #define PRINT_PREF KERN_INFO "mtd_oobtest: "
 
@@ -46,26 +47,7 @@ static int use_offset;
 static int use_len;
 static int use_len_max;
 static int vary_offset;
-static unsigned long next = 1;
-
-static inline unsigned int simple_rand(void)
-{
-	next = next * 1103515245 + 12345;
-	return (unsigned int)((next / 65536) % 32768);
-}
-
-static inline void simple_srand(unsigned long seed)
-{
-	next = seed;
-}
-
-static void set_random_data(unsigned char *buf, size_t len)
-{
-	size_t i;
-
-	for (i = 0; i < len; ++i)
-		buf[i] = simple_rand();
-}
+static struct rnd_state rnd_state;
 
 static int erase_eraseblock(int ebnum)
 {
@@ -130,7 +112,7 @@ static int write_eraseblock(int ebnum)
 	loff_t addr = ebnum * mtd->erasesize;
 
 	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
-		set_random_data(writebuf, use_len);
+		random32_get_bytes_state(&rnd_state, writebuf, use_len);
 		ops.mode      = MTD_OPS_AUTO_OOB;
 		ops.len       = 0;
 		ops.retlen    = 0;
@@ -183,7 +165,7 @@ static int verify_eraseblock(int ebnum)
 	loff_t addr = ebnum * mtd->erasesize;
 
 	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
-		set_random_data(writebuf, use_len);
+		random32_get_bytes_state(&rnd_state, writebuf, use_len);
 		ops.mode      = MTD_OPS_AUTO_OOB;
 		ops.len       = 0;
 		ops.retlen    = 0;
@@ -275,7 +257,7 @@ static int verify_eraseblock_in_one_go(int ebnum)
 	loff_t addr = ebnum * mtd->erasesize;
 	size_t len = mtd->ecclayout->oobavail * pgcnt;
 
-	set_random_data(writebuf, len);
+	random32_get_bytes_state(&rnd_state, writebuf, len);
 	ops.mode      = MTD_OPS_AUTO_OOB;
 	ops.len       = 0;
 	ops.retlen    = 0;
@@ -426,12 +408,12 @@ static int __init mtd_oobtest_init(void)
 	if (err)
 		goto out;
 
-	simple_srand(1);
+	srandom32_state(&rnd_state, 1);
 	err = write_whole_device();
 	if (err)
 		goto out;
 
-	simple_srand(1);
+	srandom32_state(&rnd_state, 1);
 	err = verify_all_eraseblocks();
 	if (err)
 		goto out;
@@ -446,13 +428,13 @@ static int __init mtd_oobtest_init(void)
 	if (err)
 		goto out;
 
-	simple_srand(3);
+	srandom32_state(&rnd_state, 3);
 	err = write_whole_device();
 	if (err)
 		goto out;
 
 	/* Check all eraseblocks */
-	simple_srand(3);
+	srandom32_state(&rnd_state, 3);
 	printk(PRINT_PREF "verifying all eraseblocks\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
@@ -481,7 +463,7 @@ static int __init mtd_oobtest_init(void)
 	use_len = mtd->ecclayout->oobavail;
 	use_len_max = mtd->ecclayout->oobavail;
 	vary_offset = 1;
-	simple_srand(5);
+	srandom32_state(&rnd_state, 5);
 
 	err = write_whole_device();
 	if (err)
@@ -492,7 +474,7 @@ static int __init mtd_oobtest_init(void)
 	use_len = mtd->ecclayout->oobavail;
 	use_len_max = mtd->ecclayout->oobavail;
 	vary_offset = 1;
-	simple_srand(5);
+	srandom32_state(&rnd_state, 5);
 	err = verify_all_eraseblocks();
 	if (err)
 		goto out;
@@ -651,7 +633,7 @@ static int __init mtd_oobtest_init(void)
 		goto out;
 
 	/* Write all eraseblocks */
-	simple_srand(11);
+	srandom32_state(&rnd_state, 11);
 	printk(PRINT_PREF "writing OOBs of whole device\n");
 	for (i = 0; i < ebcnt - 1; ++i) {
 		int cnt = 2;
@@ -661,7 +643,7 @@ static int __init mtd_oobtest_init(void)
 			continue;
 		addr = (i + 1) * mtd->erasesize - mtd->writesize;
 		for (pg = 0; pg < cnt; ++pg) {
-			set_random_data(writebuf, sz);
+			random32_get_bytes_state(&rnd_state, writebuf, sz);
 			ops.mode      = MTD_OPS_AUTO_OOB;
 			ops.len       = 0;
 			ops.retlen    = 0;
@@ -683,12 +665,13 @@ static int __init mtd_oobtest_init(void)
 	printk(PRINT_PREF "written %u eraseblocks\n", i);
 
 	/* Check all eraseblocks */
-	simple_srand(11);
+	srandom32_state(&rnd_state, 11);
 	printk(PRINT_PREF "verifying all eraseblocks\n");
 	for (i = 0; i < ebcnt - 1; ++i) {
 		if (bbt[i] || bbt[i + 1])
 			continue;
-		set_random_data(writebuf, mtd->ecclayout->oobavail * 2);
+		random32_get_bytes_state(&rnd_state, writebuf,
+					mtd->ecclayout->oobavail * 2);
 		addr = (i + 1) * mtd->erasesize - mtd->writesize;
 		ops.mode      = MTD_OPS_AUTO_OOB;
 		ops.len       = 0;
-- 
1.7.11.7

[PATCH v2 08/11] mtd: mtd_pagetest: convert to use random32_get_bytes_state()

[Akinobu Mita]

This removes home-brewed pseudo-random number generator and use
random32_get_bytes_state().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
* v2
- rename prandom32_get_bytes to random32_get_bytes_state

 drivers/mtd/tests/mtd_pagetest.c | 43 ++++++++++++----------------------------
 1 file changed, 13 insertions(+), 30 deletions(-)

diff --git a/drivers/mtd/tests/mtd_pagetest.c b/drivers/mtd/tests/mtd_pagetest.c
index 252ddb0..d95a16c 100644
--- a/drivers/mtd/tests/mtd_pagetest.c
+++ b/drivers/mtd/tests/mtd_pagetest.c
@@ -27,6 +27,7 @@
 #include <linux/mtd/mtd.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/random.h>
 
 #define PRINT_PREF KERN_INFO "mtd_pagetest: "
 
@@ -45,26 +46,7 @@ static int bufsize;
 static int ebcnt;
 static int pgcnt;
 static int errcnt;
-static unsigned long next = 1;
-
-static inline unsigned int simple_rand(void)
-{
-	next = next * 1103515245 + 12345;
-	return (unsigned int)((next / 65536) % 32768);
-}
-
-static inline void simple_srand(unsigned long seed)
-{
-	next = seed;
-}
-
-static void set_random_data(unsigned char *buf, size_t len)
-{
-	size_t i;
-
-	for (i = 0; i < len; ++i)
-		buf[i] = simple_rand();
-}
+static struct rnd_state rnd_state;
 
 static int erase_eraseblock(int ebnum)
 {
@@ -98,7 +80,7 @@ static int write_eraseblock(int ebnum)
 	size_t written;
 	loff_t addr = ebnum * mtd->erasesize;
 
-	set_random_data(writebuf, mtd->erasesize);
+	random32_get_bytes_state(&rnd_state, writebuf, mtd->erasesize);
 	cond_resched();
 	err = mtd_write(mtd, addr, mtd->erasesize, &written, writebuf);
 	if (err || written != mtd->erasesize)
@@ -124,7 +106,7 @@ static int verify_eraseblock(int ebnum)
 	for (i = 0; i < ebcnt && bbt[ebcnt - i - 1]; ++i)
 		addrn -= mtd->erasesize;
 
-	set_random_data(writebuf, mtd->erasesize);
+	random32_get_bytes_state(&rnd_state, writebuf, mtd->erasesize);
 	for (j = 0; j < pgcnt - 1; ++j, addr += pgsize) {
 		/* Do a read to set the internal dataRAMs to different data */
 		err = mtd_read(mtd, addr0, bufsize, &read, twopages);
@@ -160,7 +142,8 @@ static int verify_eraseblock(int ebnum)
 	}
 	/* Check boundary between eraseblocks */
 	if (addr <= addrn - pgsize - pgsize && !bbt[ebnum + 1]) {
-		unsigned long oldnext = next;
+		struct rnd_state old_state = rnd_state;
+
 		/* Do a read to set the internal dataRAMs to different data */
 		err = mtd_read(mtd, addr0, bufsize, &read, twopages);
 		if (mtd_is_bitflip(err))
@@ -188,13 +171,13 @@ static int verify_eraseblock(int ebnum)
 			return err;
 		}
 		memcpy(boundary, writebuf + mtd->erasesize - pgsize, pgsize);
-		set_random_data(boundary + pgsize, pgsize);
+		random32_get_bytes_state(&rnd_state, boundary + pgsize, pgsize);
 		if (memcmp(twopages, boundary, bufsize)) {
 			printk(PRINT_PREF "error: verify failed at %#llx\n",
 			       (long long)addr);
 			errcnt += 1;
 		}
-		next = oldnext;
+		rnd_state = old_state;
 	}
 	return err;
 }
@@ -326,7 +309,7 @@ static int erasecrosstest(void)
 		return err;
 
 	printk(PRINT_PREF "writing 1st page of block %d\n", ebnum);
-	set_random_data(writebuf, pgsize);
+	random32_get_bytes_state(&rnd_state, writebuf, pgsize);
 	strcpy(writebuf, "There is no data like this!");
 	err = mtd_write(mtd, addr0, pgsize, &written, writebuf);
 	if (err || written != pgsize) {
@@ -359,7 +342,7 @@ static int erasecrosstest(void)
 		return err;
 
 	printk(PRINT_PREF "writing 1st page of block %d\n", ebnum);
-	set_random_data(writebuf, pgsize);
+	random32_get_bytes_state(&rnd_state, writebuf, pgsize);
 	strcpy(writebuf, "There is no data like this!");
 	err = mtd_write(mtd, addr0, pgsize, &written, writebuf);
 	if (err || written != pgsize) {
@@ -417,7 +400,7 @@ static int erasetest(void)
 		return err;
 
 	printk(PRINT_PREF "writing 1st page of block %d\n", ebnum);
-	set_random_data(writebuf, pgsize);
+	random32_get_bytes_state(&rnd_state, writebuf, pgsize);
 	err = mtd_write(mtd, addr0, pgsize, &written, writebuf);
 	if (err || written != pgsize) {
 		printk(PRINT_PREF "error: write failed at %#llx\n",
@@ -565,7 +548,7 @@ static int __init mtd_pagetest_init(void)
 	printk(PRINT_PREF "erased %u eraseblocks\n", i);
 
 	/* Write all eraseblocks */
-	simple_srand(1);
+	srandom32_state(&rnd_state, 1);
 	printk(PRINT_PREF "writing whole device\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
@@ -580,7 +563,7 @@ static int __init mtd_pagetest_init(void)
 	printk(PRINT_PREF "written %u eraseblocks\n", i);
 
 	/* Check all eraseblocks */
-	simple_srand(1);
+	srandom32_state(&rnd_state, 1);
 	printk(PRINT_PREF "verifying all eraseblocks\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
-- 
1.7.11.7

[PATCH v2 09/11] mtd: mtd_speedtest: use random32_get_bytes

[Akinobu Mita]

Use random32_get_bytes instead of equivalent local function.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
no change from v1

 drivers/mtd/tests/mtd_speedtest.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/drivers/mtd/tests/mtd_speedtest.c b/drivers/mtd/tests/mtd_speedtest.c
index 42b0f74..57f0383 100644
--- a/drivers/mtd/tests/mtd_speedtest.c
+++ b/drivers/mtd/tests/mtd_speedtest.c
@@ -49,13 +49,6 @@ static int pgcnt;
 static int goodebcnt;
 static struct timeval start, finish;
 
-static void set_random_data(unsigned char *buf, size_t len)
-{
-	size_t i;
-
-	for (i = 0; i < len; ++i)
-		buf[i] = random32();
-}
 
 static int erase_eraseblock(int ebnum)
 {
@@ -396,7 +389,7 @@ static int __init mtd_speedtest_init(void)
 		goto out;
 	}
 
-	set_random_data(iobuf, mtd->erasesize);
+	random32_get_bytes(iobuf, mtd->erasesize);
 
 	err = scan_for_bad_eraseblocks();
 	if (err)
-- 
1.7.11.7

[PATCH v2 10/11] mtd: mtd_subpagetest: convert to use random32_get_bytes_state()

[Akinobu Mita]

This removes home-brewed pseudo-random number generator and use
random32_get_bytes_state().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
* v2
- rename prandom32_get_bytes to random32_get_bytes_state

 drivers/mtd/tests/mtd_subpagetest.c | 42 +++++++++++--------------------------
 1 file changed, 12 insertions(+), 30 deletions(-)

diff --git a/drivers/mtd/tests/mtd_subpagetest.c b/drivers/mtd/tests/mtd_subpagetest.c
index 9667bf5..0e8b28c 100644
--- a/drivers/mtd/tests/mtd_subpagetest.c
+++ b/drivers/mtd/tests/mtd_subpagetest.c
@@ -26,6 +26,7 @@
 #include <linux/mtd/mtd.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/random.h>
 
 #define PRINT_PREF KERN_INFO "mtd_subpagetest: "
 
@@ -43,26 +44,7 @@ static int bufsize;
 static int ebcnt;
 static int pgcnt;
 static int errcnt;
-static unsigned long next = 1;
-
-static inline unsigned int simple_rand(void)
-{
-	next = next * 1103515245 + 12345;
-	return (unsigned int)((next / 65536) % 32768);
-}
-
-static inline void simple_srand(unsigned long seed)
-{
-	next = seed;
-}
-
-static void set_random_data(unsigned char *buf, size_t len)
-{
-	size_t i;
-
-	for (i = 0; i < len; ++i)
-		buf[i] = simple_rand();
-}
+static struct rnd_state rnd_state;
 
 static inline void clear_data(unsigned char *buf, size_t len)
 {
@@ -119,7 +101,7 @@ static int write_eraseblock(int ebnum)
 	int err = 0;
 	loff_t addr = ebnum * mtd->erasesize;
 
-	set_random_data(writebuf, subpgsize);
+	random32_get_bytes_state(&rnd_state, writebuf, subpgsize);
 	err = mtd_write(mtd, addr, subpgsize, &written, writebuf);
 	if (unlikely(err || written != subpgsize)) {
 		printk(PRINT_PREF "error: write failed at %#llx\n",
@@ -133,7 +115,7 @@ static int write_eraseblock(int ebnum)
 
 	addr += subpgsize;
 
-	set_random_data(writebuf, subpgsize);
+	random32_get_bytes_state(&rnd_state, writebuf, subpgsize);
 	err = mtd_write(mtd, addr, subpgsize, &written, writebuf);
 	if (unlikely(err || written != subpgsize)) {
 		printk(PRINT_PREF "error: write failed at %#llx\n",
@@ -157,7 +139,7 @@ static int write_eraseblock2(int ebnum)
 	for (k = 1; k < 33; ++k) {
 		if (addr + (subpgsize * k) > (ebnum + 1) * mtd->erasesize)
 			break;
-		set_random_data(writebuf, subpgsize * k);
+		random32_get_bytes_state(&rnd_state, writebuf, subpgsize * k);
 		err = mtd_write(mtd, addr, subpgsize * k, &written, writebuf);
 		if (unlikely(err || written != subpgsize * k)) {
 			printk(PRINT_PREF "error: write failed at %#llx\n",
@@ -193,7 +175,7 @@ static int verify_eraseblock(int ebnum)
 	int err = 0;
 	loff_t addr = ebnum * mtd->erasesize;
 
-	set_random_data(writebuf, subpgsize);
+	random32_get_bytes_state(&rnd_state, writebuf, subpgsize);
 	clear_data(readbuf, subpgsize);
 	err = mtd_read(mtd, addr, subpgsize, &read, readbuf);
 	if (unlikely(err || read != subpgsize)) {
@@ -220,7 +202,7 @@ static int verify_eraseblock(int ebnum)
 
 	addr += subpgsize;
 
-	set_random_data(writebuf, subpgsize);
+	random32_get_bytes_state(&rnd_state, writebuf, subpgsize);
 	clear_data(readbuf, subpgsize);
 	err = mtd_read(mtd, addr, subpgsize, &read, readbuf);
 	if (unlikely(err || read != subpgsize)) {
@@ -257,7 +239,7 @@ static int verify_eraseblock2(int ebnum)
 	for (k = 1; k < 33; ++k) {
 		if (addr + (subpgsize * k) > (ebnum + 1) * mtd->erasesize)
 			break;
-		set_random_data(writebuf, subpgsize * k);
+		random32_get_bytes_state(&rnd_state, writebuf, subpgsize * k);
 		clear_data(readbuf, subpgsize * k);
 		err = mtd_read(mtd, addr, subpgsize * k, &read, readbuf);
 		if (unlikely(err || read != subpgsize * k)) {
@@ -430,7 +412,7 @@ static int __init mtd_subpagetest_init(void)
 		goto out;
 
 	printk(PRINT_PREF "writing whole device\n");
-	simple_srand(1);
+	srandom32_state(&rnd_state, 1);
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
@@ -443,7 +425,7 @@ static int __init mtd_subpagetest_init(void)
 	}
 	printk(PRINT_PREF "written %u eraseblocks\n", i);
 
-	simple_srand(1);
+	srandom32_state(&rnd_state, 1);
 	printk(PRINT_PREF "verifying all eraseblocks\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
@@ -466,7 +448,7 @@ static int __init mtd_subpagetest_init(void)
 		goto out;
 
 	/* Write all eraseblocks */
-	simple_srand(3);
+	srandom32_state(&rnd_state, 3);
 	printk(PRINT_PREF "writing whole device\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
@@ -481,7 +463,7 @@ static int __init mtd_subpagetest_init(void)
 	printk(PRINT_PREF "written %u eraseblocks\n", i);
 
 	/* Check all eraseblocks */
-	simple_srand(3);
+	srandom32_state(&rnd_state, 3);
 	printk(PRINT_PREF "verifying all eraseblocks\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
-- 
1.7.11.7

[PATCH v2 11/11] mtd: mtd_stresstest: use random32_get_bytes()

[Akinobu Mita]

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
new patch from v2

 drivers/mtd/tests/mtd_stresstest.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/mtd/tests/mtd_stresstest.c b/drivers/mtd/tests/mtd_stresstest.c
index cb268ce..158d30f 100644
--- a/drivers/mtd/tests/mtd_stresstest.c
+++ b/drivers/mtd/tests/mtd_stresstest.c
@@ -282,8 +282,7 @@ static int __init mtd_stresstest_init(void)
 	}
 	for (i = 0; i < ebcnt; i++)
 		offsets[i] = mtd->erasesize;
-	for (i = 0; i < bufsize; i++)
-		writebuf[i] = random32();
+	random32_get_bytes(writebuf, bufsize);
 
 	err = scan_for_bad_eraseblocks();
 	if (err)
-- 
1.7.11.7

Re: [PATCH v2 00/11] introduce random32_get_bytes() and random32_get_bytes_state()

[Valdis.Kletnieks]

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On Sun, 04 Nov 2012 00:43:31 +0900, Akinobu Mita said:
> This patchset introduces new functions into random32 library for
> getting the requested number of pseudo-random bytes.
>
> Before introducing these new functions into random32 library,
> prandom32() and prandom32_seed() with "prandom32" prefix are
> renamed to random32_state() and srandom32_state() respectively.
>
> The purpose of this renaming is to prevent some kernel developers
> from assuming that prandom32() and random32() might imply that only
> prandom32() was the one using a pseudo-random number generator by
> prandom32's "p", and the result may be a very embarassing security
> exposure.

Out of curiosity, why the '32'?  I'm just waiting for some kernel developer to
do something stupid with this on a 64-bit arch because they think it's a 32-bit API. ;)

Should we bite the bullet and lose the 32, as long as we're churning the code *anyhow*?


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RE: [PATCH v2 00/11] introduce random32_get_bytes() and random32_get_bytes_state()

[David Laight]

> On Sun, 04 Nov 2012 00:43:31 +0900, Akinobu Mita said:
> > This patchset introduces new functions into random32 library for
> > getting the requested number of pseudo-random bytes.
> >
> > Before introducing these new functions into random32 library,
> > prandom32() and prandom32_seed() with "prandom32" prefix are
> > renamed to random32_state() and srandom32_state() respectively.
> >
> > The purpose of this renaming is to prevent some kernel developers
> > from assuming that prandom32() and random32() might imply that only
> > prandom32() was the one using a pseudo-random number generator by
> > prandom32's "p", and the result may be a very embarassing security
> > exposure.
> 
> Out of curiosity, why the '32'?  I'm just waiting for some kernel developer to
> do something stupid with this on a 64-bit arch because they think it's a 32-bit API. ;)
> 
> Should we bite the bullet and lose the 32, as long as we're churning the code *anyhow*?

Also why remove the 'pseudo' part of the name?
It is an important part of the name.

	David

Re: [PATCH v2 00/11] introduce random32_get_bytes() and random32_get_bytes_state()

[Akinobu Mita]

2012/11/6 David Laight <David.Laight@aculab.com>:
>> On Sun, 04 Nov 2012 00:43:31 +0900, Akinobu Mita said:
>> > This patchset introduces new functions into random32 library for
>> > getting the requested number of pseudo-random bytes.
>> >
>> > Before introducing these new functions into random32 library,
>> > prandom32() and prandom32_seed() with "prandom32" prefix are
>> > renamed to random32_state() and srandom32_state() respectively.
>> >
>> > The purpose of this renaming is to prevent some kernel developers
>> > from assuming that prandom32() and random32() might imply that only
>> > prandom32() was the one using a pseudo-random number generator by
>> > prandom32's "p", and the result may be a very embarassing security
>> > exposure.
>>
>> Out of curiosity, why the '32'?  I'm just waiting for some kernel developer to
>> do something stupid with this on a 64-bit arch because they think it's a 32-bit API. ;)
>>
>> Should we bite the bullet and lose the 32, as long as we're churning the code *anyhow*?
>
> Also why remove the 'pseudo' part of the name?
> It is an important part of the name.

Thanks for the heads-up.  Then, what is the ideal function name for
pseudo-random library?

I propose the following renaming, 'p' prefix is restored and '32' is
removed for not returning 32bit pseudo-random number functions.

void prandom_seed(u32 seed);    /* rename from srandom32() */
u32 prandom32(void);            /* rename from random32() */
void prandom_get_byte(void *buf, int bytes);

void prandom_seed_state(struct rnd_state *state, u64 seed);
                                        /* rename from prandom32_seed() */
u32 prandom32_state(struct rnd_state *state);   /* rename from prandom32() */
void prandom_get_byte_state(struct rnd_state *state, void *buf, int bytes);