[PATCH v2 0/1] f2fs: fix sanity_check_raw_super on big endian machines

[PATCH v2 0/1] f2fs: fix sanity_check_raw_super on big endian machines

[Martin Blumenstingl]

Big endian machines (at least the one I have access to) cannot mount
f2fs filesystems anymore.
This is with Linux 4.14.89 but I suspect that 4.9.144 (and later) is
affected as well.

commit 0cfe75c5b01199 ("f2fs: enhance sanity_check_raw_super() to avoid
potential overflows") treats the "block_count" from struct
f2fs_super_block as 32-bit little endian value instead of a 64-bit
little endian value.

I tested this fix on top of Linux 4.14.49 but it seems that all stable
and mainline kernel versions are affected:
- 4.9.144 and later because 0cfe75c5b01199 was backported there
- 4.14.86 and later because 0cfe75c5b01199 was backported there
- 4.19
- 4.20-rcX


changes since v1 at [0]:
- change the printk format for block_count from "%u" to "%llu" (thanks
  to "kbuild test robot" for spotting this)
- added Chao Yu's reviewed by


[0] https://lore.kernel.org/patchwork/cover/1027285/


Martin Blumenstingl (1):
  f2fs: fix validation of the block count in sanity_check_raw_super

 fs/f2fs/super.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

-- 
2.20.1

[PATCH v2 0/1] f2fs: fix sanity_check_raw_super on big endian machines

[Martin Blumenstingl via Linux-f2fs-devel]

Big endian machines (at least the one I have access to) cannot mount
f2fs filesystems anymore.
This is with Linux 4.14.89 but I suspect that 4.9.144 (and later) is
affected as well.

commit 0cfe75c5b01199 ("f2fs: enhance sanity_check_raw_super() to avoid
potential overflows") treats the "block_count" from struct
f2fs_super_block as 32-bit little endian value instead of a 64-bit
little endian value.

I tested this fix on top of Linux 4.14.49 but it seems that all stable
and mainline kernel versions are affected:
- 4.9.144 and later because 0cfe75c5b01199 was backported there
- 4.14.86 and later because 0cfe75c5b01199 was backported there
- 4.19
- 4.20-rcX


changes since v1 at [0]:
- change the printk format for block_count from "%u" to "%llu" (thanks
  to "kbuild test robot" for spotting this)
- added Chao Yu's reviewed by


[0] https://lore.kernel.org/patchwork/cover/1027285/


Martin Blumenstingl (1):
  f2fs: fix validation of the block count in sanity_check_raw_super

 fs/f2fs/super.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

-- 
2.20.1

[PATCH v2 1/1] f2fs: fix validation of the block count in sanity_check_raw_super

[Martin Blumenstingl]

Treat "block_count" from struct f2fs_super_block as 64-bit little endian
value in sanity_check_raw_super() because struct f2fs_super_block
declares "block_count" as "__le64".

This fixes a bug where the superblock validation fails on big endian
devices with the following error:
  F2FS-fs (sda1): Wrong segment_count / block_count (61439 > 0)
  F2FS-fs (sda1): Can't find valid F2FS filesystem in 1th superblock
  F2FS-fs (sda1): Wrong segment_count / block_count (61439 > 0)
  F2FS-fs (sda1): Can't find valid F2FS filesystem in 2th superblock
As result of this the partition cannot be mounted.

With this patch applied the superblock validation works fine and the
partition can be mounted again:
  F2FS-fs (sda1): Mounted with checkpoint version = 7c84

My little endian x86-64 hardware was able to mount the partition without
this fix.
To confirm that mounting f2fs filesystems works on big endian machines
again I tested this on a 32-bit MIPS big endian (lantiq) device.

Fixes: 0cfe75c5b01199 ("f2fs: enhance sanity_check_raw_super() to avoid potential overflows")
Cc: stable@vger.kernel.org
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
---
 fs/f2fs/super.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index af58b2cc21b8..d3911d3f948b 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2496,10 +2496,10 @@ static int sanity_check_raw_super(struct f2fs_sb_info *sbi,
 		return 1;
 	}
 
-	if (segment_count > (le32_to_cpu(raw_super->block_count) >> 9)) {
+	if (segment_count > (le64_to_cpu(raw_super->block_count) >> 9)) {
 		f2fs_msg(sb, KERN_INFO,
-			"Wrong segment_count / block_count (%u > %u)",
-			segment_count, le32_to_cpu(raw_super->block_count));
+			"Wrong segment_count / block_count (%u > %llu)",
+			segment_count, le64_to_cpu(raw_super->block_count));
 		return 1;
 	}
 
-- 
2.20.1

[PATCH v2 1/1] f2fs: fix validation of the block count in sanity_check_raw_super

[Martin Blumenstingl via Linux-f2fs-devel]

Treat "block_count" from struct f2fs_super_block as 64-bit little endian
value in sanity_check_raw_super() because struct f2fs_super_block
declares "block_count" as "__le64".

This fixes a bug where the superblock validation fails on big endian
devices with the following error:
  F2FS-fs (sda1): Wrong segment_count / block_count (61439 > 0)
  F2FS-fs (sda1): Can't find valid F2FS filesystem in 1th superblock
  F2FS-fs (sda1): Wrong segment_count / block_count (61439 > 0)
  F2FS-fs (sda1): Can't find valid F2FS filesystem in 2th superblock
As result of this the partition cannot be mounted.

With this patch applied the superblock validation works fine and the
partition can be mounted again:
  F2FS-fs (sda1): Mounted with checkpoint version = 7c84

My little endian x86-64 hardware was able to mount the partition without
this fix.
To confirm that mounting f2fs filesystems works on big endian machines
again I tested this on a 32-bit MIPS big endian (lantiq) device.

Fixes: 0cfe75c5b01199 ("f2fs: enhance sanity_check_raw_super() to avoid potential overflows")
Cc: stable@vger.kernel.org
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
---
 fs/f2fs/super.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index af58b2cc21b8..d3911d3f948b 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2496,10 +2496,10 @@ static int sanity_check_raw_super(struct f2fs_sb_info *sbi,
 		return 1;
 	}
 
-	if (segment_count > (le32_to_cpu(raw_super->block_count) >> 9)) {
+	if (segment_count > (le64_to_cpu(raw_super->block_count) >> 9)) {
 		f2fs_msg(sb, KERN_INFO,
-			"Wrong segment_count / block_count (%u > %u)",
-			segment_count, le32_to_cpu(raw_super->block_count));
+			"Wrong segment_count / block_count (%u > %llu)",
+			segment_count, le64_to_cpu(raw_super->block_count));
 		return 1;
 	}
 
-- 
2.20.1