[PATCH 0/5] UDF fixes

[PATCH 0/5] UDF fixes

[Jan Kara]

Hello,

I plan to queue these five UDF fixes into my tree. Review is welcome.

								Honza

[PATCH 1/5] udf: Fix races with i_size changes during readpage

[Jan Kara]

__udf_adinicb_readpage() uses i_size several times. When truncate
changes i_size while the function is running, it can observe several
different values and thus e.g. expose uninitialized parts of page to
userspace. Also use i_size_read() in the function since it does not hold
inode_lock. Since i_size is guaranteed to be small, this cannot really
cause any issues even on 32-bit archs but let's be careful.

CC: stable@vger.kernel.org
Fixes: 9c2fc0de1a6e638fe58c354a463f544f42a90a09
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/udf/file.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/udf/file.c b/fs/udf/file.c
index f5eb2d5b3bac..e06d2c15749a 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -43,10 +43,15 @@ static void __udf_adinicb_readpage(struct page *page)
 	struct inode *inode = page->mapping->host;
 	char *kaddr;
 	struct udf_inode_info *iinfo = UDF_I(inode);
+	loff_t isize = i_size_read(inode);
 
+	/*
+	 * We have to be careful here as truncate can change i_size under us.
+	 * So just sample it once and use the same value everywhere.
+	 */
 	kaddr = kmap_atomic(page);
-	memcpy(kaddr, iinfo->i_ext.i_data + iinfo->i_lenEAttr, inode->i_size);
-	memset(kaddr + inode->i_size, 0, PAGE_SIZE - inode->i_size);
+	memcpy(kaddr, iinfo->i_ext.i_data + iinfo->i_lenEAttr, isize);
+	memset(kaddr + isize, 0, PAGE_SIZE - isize);
 	flush_dcache_page(page);
 	SetPageUptodate(page);
 	kunmap_atomic(kaddr);
-- 
2.12.3

[PATCH 2/5] udf: Use i_size_read() in udf_adinicb_writepage()

[Jan Kara]

We don't hold inode_lock in udf_adinicb_writepage() so use i_size_read()
to get i_size. This cannot cause real problems is i_size is guaranteed
to be small but let's be careful.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/udf/file.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/udf/file.c b/fs/udf/file.c
index e06d2c15749a..356c2bf148a5 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -76,7 +76,8 @@ static int udf_adinicb_writepage(struct page *page,
 	BUG_ON(!PageLocked(page));
 
 	kaddr = kmap_atomic(page);
-	memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr, kaddr, inode->i_size);
+	memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr, kaddr,
+		i_size_read(inode));
 	SetPageUptodate(page);
 	kunmap_atomic(kaddr);
 	mark_inode_dirty(inode);
-- 
2.12.3

[PATCH 3/5] udf: Fix deadlock between writeback and udf_setsize()

[Jan Kara]

udf_setsize() called truncate_setsize() with i_data_sem held. Thus
truncate_pagecache() called from truncate_setsize() could lock a page
under i_data_sem which can deadlock as page lock ranks below
i_data_sem - e. g. writeback can hold page lock and try to acquire
i_data_sem to map a block.

Fix the problem by moving truncate_setsize() calls from under
i_data_sem. It is safe for us to change i_size without holding
i_data_sem as all the places that depend on i_size being stable already
hold inode_lock.

CC: stable@vger.kernel.org
Fixes: 7e49b6f2480cb9a9e7322a91592e56a5c85361f5
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/udf/inode.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 98c510e17203..18fdb9d90812 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1222,8 +1222,8 @@ int udf_setsize(struct inode *inode, loff_t newsize)
 			return err;
 		}
 set_size:
-		truncate_setsize(inode, newsize);
 		up_write(&iinfo->i_data_sem);
+		truncate_setsize(inode, newsize);
 	} else {
 		if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
 			down_write(&iinfo->i_data_sem);
@@ -1240,9 +1240,9 @@ int udf_setsize(struct inode *inode, loff_t newsize)
 					  udf_get_block);
 		if (err)
 			return err;
+		truncate_setsize(inode, newsize);
 		down_write(&iinfo->i_data_sem);
 		udf_clear_extent_cache(inode);
-		truncate_setsize(inode, newsize);
 		udf_truncate_extents(inode);
 		up_write(&iinfo->i_data_sem);
 	}
-- 
2.12.3

[PATCH 4/5] udf: Use time64_to_tm for timestamp conversion

[Jan Kara]

UDF on-disk time stamp is stored in a form very similar to struct tm.
Use time64_to_tm() for conversion of seconds since epoch to year, month,
... format and then just copy this as necessary to UDF on-disk
structure to simplify the code.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/udf/udftime.c | 45 +++++++++++----------------------------------
 1 file changed, 11 insertions(+), 34 deletions(-)

diff --git a/fs/udf/udftime.c b/fs/udf/udftime.c
index 77c331f1a770..b9dadc7e5c35 100644
--- a/fs/udf/udftime.c
+++ b/fs/udf/udftime.c
@@ -38,6 +38,7 @@
 
 #include <linux/types.h>
 #include <linux/kernel.h>
+#include <linux/time.h>
 
 #define EPOCH_YEAR 1970
 
@@ -81,9 +82,6 @@ static time_t year_seconds[MAX_YEAR_SECONDS] = {
 /*2038*/ SPY(68, 17, 0)
 };
 
-#define SECS_PER_HOUR	(60 * 60)
-#define SECS_PER_DAY	(SECS_PER_HOUR * 24)
-
 struct timespec *
 udf_disk_stamp_to_time(struct timespec *dest, struct timestamp src)
 {
@@ -119,9 +117,9 @@ udf_disk_stamp_to_time(struct timespec *dest, struct timestamp src)
 struct timestamp *
 udf_time_to_disk_stamp(struct timestamp *dest, struct timespec ts)
 {
-	long int days, rem, y;
-	const unsigned short int *ip;
+	long seconds;
 	int16_t offset;
+	struct tm tm;
 
 	offset = -sys_tz.tz_minuteswest;
 
@@ -130,35 +128,14 @@ udf_time_to_disk_stamp(struct timestamp *dest, struct timespec ts)
 
 	dest->typeAndTimezone = cpu_to_le16(0x1000 | (offset & 0x0FFF));
 
-	ts.tv_sec += offset * 60;
-	days = ts.tv_sec / SECS_PER_DAY;
-	rem = ts.tv_sec % SECS_PER_DAY;
-	dest->hour = rem / SECS_PER_HOUR;
-	rem %= SECS_PER_HOUR;
-	dest->minute = rem / 60;
-	dest->second = rem % 60;
-	y = 1970;
-
-#define DIV(a, b) ((a) / (b) - ((a) % (b) < 0))
-#define LEAPS_THRU_END_OF(y) (DIV (y, 4) - DIV (y, 100) + DIV (y, 400))
-
-	while (days < 0 || days >= (__isleap(y) ? 366 : 365)) {
-		long int yg = y + days / 365 - (days % 365 < 0);
-
-		/* Adjust DAYS and Y to match the guessed year.  */
-		days -= ((yg - y) * 365
-			 + LEAPS_THRU_END_OF(yg - 1)
-			 - LEAPS_THRU_END_OF(y - 1));
-		y = yg;
-	}
-	dest->year = cpu_to_le16(y);
-	ip = __mon_yday[__isleap(y)];
-	for (y = 11; days < (long int)ip[y]; --y)
-		continue;
-	days -= ip[y];
-	dest->month = y + 1;
-	dest->day = days + 1;
-
+	seconds = ts.tv_sec + offset * 60;
+	time64_to_tm(seconds, 0, &tm);
+	dest->year = cpu_to_le16(tm.tm_year + 1900);
+	dest->month = tm.tm_mon + 1;
+	dest->day = tm.tm_mday;
+	dest->hour = tm.tm_hour;
+	dest->minute = tm.tm_min;
+	dest->second = tm.tm_sec;
 	dest->centiseconds = ts.tv_nsec / 10000000;
 	dest->hundredsOfMicroseconds = (ts.tv_nsec / 1000 -
 					dest->centiseconds * 10000) / 100;
-- 
2.12.3

[PATCH 5/5] udf: Convert udf_disk_stamp_to_time() to use mktime64()

[Jan Kara]

Convert udf_disk_stamp_to_time() to use mktime64() to simplify the code.
As a bonus we get working timestamp conversion for dates before epoch
and after 2038 (both of which are allowed by UDF standard).

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/udf/udftime.c | 53 ++---------------------------------------------------
 1 file changed, 2 insertions(+), 51 deletions(-)

diff --git a/fs/udf/udftime.c b/fs/udf/udftime.c
index b9dadc7e5c35..14626b34d13e 100644
--- a/fs/udf/udftime.c
+++ b/fs/udf/udftime.c
@@ -40,52 +40,9 @@
 #include <linux/kernel.h>
 #include <linux/time.h>
 
-#define EPOCH_YEAR 1970
-
-#ifndef __isleap
-/* Nonzero if YEAR is a leap year (every 4 years,
-   except every 100th isn't, and every 400th is).  */
-#define	__isleap(year)	\
-  ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
-#endif
-
-/* How many days come before each month (0-12).  */
-static const unsigned short int __mon_yday[2][13] = {
-	/* Normal years.  */
-	{0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365},
-	/* Leap years.  */
-	{0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366}
-};
-
-#define MAX_YEAR_SECONDS	69
-#define SPD			0x15180	/*3600*24 */
-#define SPY(y, l, s)		(SPD * (365 * y + l) + s)
-
-static time_t year_seconds[MAX_YEAR_SECONDS] = {
-/*1970*/ SPY(0,   0, 0), SPY(1,   0, 0), SPY(2,   0, 0), SPY(3,   1, 0),
-/*1974*/ SPY(4,   1, 0), SPY(5,   1, 0), SPY(6,   1, 0), SPY(7,   2, 0),
-/*1978*/ SPY(8,   2, 0), SPY(9,   2, 0), SPY(10,  2, 0), SPY(11,  3, 0),
-/*1982*/ SPY(12,  3, 0), SPY(13,  3, 0), SPY(14,  3, 0), SPY(15,  4, 0),
-/*1986*/ SPY(16,  4, 0), SPY(17,  4, 0), SPY(18,  4, 0), SPY(19,  5, 0),
-/*1990*/ SPY(20,  5, 0), SPY(21,  5, 0), SPY(22,  5, 0), SPY(23,  6, 0),
-/*1994*/ SPY(24,  6, 0), SPY(25,  6, 0), SPY(26,  6, 0), SPY(27,  7, 0),
-/*1998*/ SPY(28,  7, 0), SPY(29,  7, 0), SPY(30,  7, 0), SPY(31,  8, 0),
-/*2002*/ SPY(32,  8, 0), SPY(33,  8, 0), SPY(34,  8, 0), SPY(35,  9, 0),
-/*2006*/ SPY(36,  9, 0), SPY(37,  9, 0), SPY(38,  9, 0), SPY(39, 10, 0),
-/*2010*/ SPY(40, 10, 0), SPY(41, 10, 0), SPY(42, 10, 0), SPY(43, 11, 0),
-/*2014*/ SPY(44, 11, 0), SPY(45, 11, 0), SPY(46, 11, 0), SPY(47, 12, 0),
-/*2018*/ SPY(48, 12, 0), SPY(49, 12, 0), SPY(50, 12, 0), SPY(51, 13, 0),
-/*2022*/ SPY(52, 13, 0), SPY(53, 13, 0), SPY(54, 13, 0), SPY(55, 14, 0),
-/*2026*/ SPY(56, 14, 0), SPY(57, 14, 0), SPY(58, 14, 0), SPY(59, 15, 0),
-/*2030*/ SPY(60, 15, 0), SPY(61, 15, 0), SPY(62, 15, 0), SPY(63, 16, 0),
-/*2034*/ SPY(64, 16, 0), SPY(65, 16, 0), SPY(66, 16, 0), SPY(67, 17, 0),
-/*2038*/ SPY(68, 17, 0)
-};
-
 struct timespec *
 udf_disk_stamp_to_time(struct timespec *dest, struct timestamp src)
 {
-	int yday;
 	u16 typeAndTimezone = le16_to_cpu(src.typeAndTimezone);
 	u16 year = le16_to_cpu(src.year);
 	uint8_t type = typeAndTimezone >> 12;
@@ -100,15 +57,9 @@ udf_disk_stamp_to_time(struct timespec *dest, struct timestamp src)
 	} else
 		offset = 0;
 
-	if ((year < EPOCH_YEAR) ||
-	    (year >= EPOCH_YEAR + MAX_YEAR_SECONDS)) {
-		return NULL;
-	}
-	dest->tv_sec = year_seconds[year - EPOCH_YEAR];
+	dest->tv_sec = mktime64(year, src.month, src.day, src.hour, src.minute,
+			src.second);
 	dest->tv_sec -= offset * 60;
-
-	yday = ((__mon_yday[__isleap(year)][src.month - 1]) + src.day - 1);
-	dest->tv_sec += (((yday * 24) + src.hour) * 60 + src.minute) * 60 + src.second;
 	dest->tv_nsec = 1000 * (src.centiseconds * 10000 +
 			src.hundredsOfMicroseconds * 100 + src.microseconds);
 	return dest;
-- 
2.12.3