[PATCH v3 00/11] rename random32 to prandom and introduce prandom_bytes()

[PATCH v3 00/11] rename random32 to prandom and introduce prandom_bytes()

[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,
rename all random32 functions to have 'prandom_' prefix.  As a result
the function prototypes are as follows:

void prandom_seed(u32 seed);	/* rename from srandom32() */
u32 prandom_u32(void);		/* rename from random32() */
void prandom_bytes(void *buf, int nbytes);

void prandom_seed_state(struct rnd_state *state, u64 seed);
				/* rename from prandom32_seed() */
u32 prandom_u32_state(struct rnd_state *state);
				/* rename from prandom32() */
void prandom_bytes_state(struct rnd_state *state, void *buf, int nbytes);

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.  This concern was expressed by Theodore Ts'o.

Changelog

* v3
- change common prefix from 'random32_' to 'prandom_'
- ensure prandom_bytes_state() generates same bytes with same rnd_state

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

Akinobu Mita (11):
  random32: rename random32 to prandom
  prandom: introduce prandom_bytes() and prandom_bytes_state()
  bnx2x: use prandom_bytes()
  mtd: nandsim: use prandom_bytes
  ubifs: use prandom_bytes
  mtd: mtd_nandecctest: use prandom_bytes instead of get_random_bytes()
  mtd: mtd_oobtest: convert to use prandom library
  mtd: mtd_pagetest: convert to use prandom library
  mtd: mtd_speedtest: use prandom_bytes
  mtd: mtd_subpagetest: convert to use prandom library
  mtd: mtd_stresstest: use prandom_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                          | 19 +++--
 lib/interval_tree_test_main.c                   |  7 +-
 lib/random32.c                                  | 97 +++++++++++++++++++------
 lib/rbtree_test.c                               |  6 +-
 14 files changed, 145 insertions(+), 154 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 v3 02/11] prandom: introduce prandom_bytes() and prandom_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 prandom_u32().  It doesn't consume the entropy pool, and the
sequence is reproducible if the same rnd_state is used.  So it is suitable
for generating random bytes for testing.

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
---
* v3
- rename random32_get_bytes_state to prandom_bytes_state
- ensure prandom_bytes_state() generates same bytes with same rnd_state

* v2
- rename prandom32_get_bytes to random32_get_bytes_state

 include/linux/random.h |  2 ++
 lib/random32.c         | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/include/linux/random.h b/include/linux/random.h
index db6debc..d984608 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -26,6 +26,7 @@ unsigned int get_random_int(void);
 unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len);
 
 u32 prandom_u32(void);
+void prandom_bytes(void *buf, int nbytes);
 void prandom_seed(u32 seed);
 
 /*
@@ -36,6 +37,7 @@ void prandom_seed(u32 seed);
 #define srandom32(seed) prandom_seed(seed)
 
 u32 prandom_u32_state(struct rnd_state *);
+void prandom_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 d1830fa..52280d5 100644
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -77,6 +77,55 @@ u32 prandom_u32(void)
 }
 EXPORT_SYMBOL(prandom_u32);
 
+/*
+ *	prandom_bytes_state - get the requested number of 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 prandom_bytes().
+ */
+void prandom_bytes_state(struct rnd_state *state, void *buf, int bytes)
+{
+	unsigned char *p = buf;
+	int i;
+
+	for (i = 0; i < round_down(bytes, sizeof(u32)); i += sizeof(u32)) {
+		u32 random = prandom_u32_state(state);
+		int j;
+
+		for (j = 0; j < sizeof(u32); j++) {
+			p[i + j] = random;
+			random >>= BITS_PER_BYTE;
+		}
+	}
+	if (i < bytes) {
+		u32 random = prandom_u32_state(state);
+
+		for (; i < bytes; i++) {
+			p[i] = random;
+			random >>= BITS_PER_BYTE;
+		}
+	}
+}
+EXPORT_SYMBOL(prandom_bytes_state);
+
+/**
+ *	prandom_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 prandom_bytes(void *buf, int bytes)
+{
+	struct rnd_state *state = &get_cpu_var(net_rand_state);
+
+	prandom_bytes_state(state, buf, bytes);
+	put_cpu_var(state);
+}
+EXPORT_SYMBOL(prandom_bytes);
+
 /**
  *	prandom_seed - add entropy to pseudo random number generator
  *	@seed: seed value
-- 
1.7.11.7

[PATCH v3 04/11] mtd: nandsim: use prandom_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
---
* v3
- rename random32_get_bytes to prandom_bytes

 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..c3c13e6 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();
+		prandom_bytes(ns->buf.byte, num);
 		NS_WARN("simulating read error in page %u\n", page_no);
 		return 1;
 	}
-- 
1.7.11.7

[PATCH v3 05/11] ubifs: use prandom_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
---
* v3
- rename random32_get_bytes to prandom_bytes

 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..12817ff 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;
+		prandom_bytes(p + from, to - from);
 
 	return to;
 }
-- 
1.7.11.7

[PATCH v3 06/11] mtd: mtd_nandecctest: use prandom_bytes instead of get_random_bytes()

[Akinobu Mita]

Using prandom_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
---
* v3
- rename random32_get_bytes to prandom_bytes

 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..9b7b9fa 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);
+	prandom_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 v3 07/11] mtd: mtd_oobtest: convert to use prandom library

[Akinobu Mita]

This removes home-brewed pseudo-random number generator and use
prandom library.

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
---
* v3
- rename 'random32_*' to 'prandom_*'

* 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..81d02e2 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);
+		prandom_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);
+		prandom_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);
+	prandom_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);
+	prandom_seed_state(&rnd_state, 1);
 	err = write_whole_device();
 	if (err)
 		goto out;
 
-	simple_srand(1);
+	prandom_seed_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);
+	prandom_seed_state(&rnd_state, 3);
 	err = write_whole_device();
 	if (err)
 		goto out;
 
 	/* Check all eraseblocks */
-	simple_srand(3);
+	prandom_seed_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);
+	prandom_seed_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);
+	prandom_seed_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);
+	prandom_seed_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);
+			prandom_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);
+	prandom_seed_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);
+		prandom_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 v3 08/11] mtd: mtd_pagetest: convert to use prandom library

[Akinobu Mita]

This removes home-brewed pseudo-random number generator and use
prandom library.

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
---
* v3
- rename 'random32_*' to 'prandom_*'

* 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..4197280 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);
+	prandom_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);
+	prandom_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);
+		prandom_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);
+	prandom_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);
+	prandom_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);
+	prandom_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);
+	prandom_seed_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);
+	prandom_seed_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 v3 09/11] mtd: mtd_speedtest: use prandom_bytes

[Akinobu Mita]

Use prandom_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
---
* v3
- rename random32_get_bytes to prandom_bytes

 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..73e205d 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);
+	prandom_bytes(iobuf, mtd->erasesize);
 
 	err = scan_for_bad_eraseblocks();
 	if (err)
-- 
1.7.11.7

[PATCH v3 10/11] mtd: mtd_subpagetest: convert to use prandom library

[Akinobu Mita]

This removes home-brewed pseudo-random number generator and use
prandom library.

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
---
* v3
- rename 'random32_*' to 'prandom_*'

* 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..5b47e2b 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);
+	prandom_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);
+	prandom_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);
+		prandom_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);
+	prandom_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);
+	prandom_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);
+		prandom_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);
+	prandom_seed_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);
+	prandom_seed_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);
+	prandom_seed_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);
+	prandom_seed_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 v3 11/11] mtd: mtd_stresstest: use prandom_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
---
* v3
- rename random32_get_bytes to prandom_bytes

 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..3edc79e 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();
+	prandom_bytes(writebuf, bufsize);
 
 	err = scan_for_bad_eraseblocks();
 	if (err)
-- 
1.7.11.7

Re: [PATCH v3 00/11] rename random32 to prandom and introduce prandom_bytes()

[Andrew Morton]

On Tue, 13 Nov 2012 22:36:59 +0900
Akinobu Mita <akinobu.mita@gmail.com> wrote:

> 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,
> rename all random32 functions to have 'prandom_' prefix.  As a result
> the function prototypes are as follows:
> 
> void prandom_seed(u32 seed);	/* rename from srandom32() */
> u32 prandom_u32(void);		/* rename from random32() */
> void prandom_bytes(void *buf, int nbytes);
> 
> void prandom_seed_state(struct rnd_state *state, u64 seed);
> 				/* rename from prandom32_seed() */
> u32 prandom_u32_state(struct rnd_state *state);
> 				/* rename from prandom32() */
> void prandom_bytes_state(struct rnd_state *state, void *buf, int nbytes);
> 
> 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.  This concern was expressed by Theodore Ts'o.

There were a large number of rejects in MTD code, due to pending
changes in linux-next.  It's all quite mechanical stuff which I
fixed up.  Please check the result.