linux/fs/ext4, branch v3.2.2

ext4: fix undefined behavior in ext4_fill_flex_info()

2012-01-26T00:13:07Z

commit d50f2ab6f050311dbf7b8f5501b25f0bf64a439b upstream. Commit 503358ae01b70ce6909d19dd01287093f6b6271c ("ext4: avoid divide by zero when trying to mount a corrupted file system") fixes CVE-2009-4307 by performing a sanity check on s_log_groups_per_flex, since it can be set to a bogus value by an attacker. sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex; groups_per_flex = 1 << sbi->s_log_groups_per_flex; if (groups_per_flex < 2) { ... } This patch fixes two potential issues in the previous commit. 1) The sanity check might only work on architectures like PowerPC. On x86, 5 bits are used for the shifting amount. That means, given a large s_log_groups_per_flex value like 36, groups_per_flex = 1 << 36 is essentially 1 << 4 = 16, rather than 0. This will bypass the check, leaving s_log_groups_per_flex and groups_per_flex inconsistent. 2) The sanity check relies on undefined behavior, i.e., oversized shift. A standard-confirming C compiler could rewrite the check in unexpected ways. Consider the following equivalent form, assuming groups_per_flex is unsigned for simplicity. groups_per_flex = 1 << sbi->s_log_groups_per_flex; if (groups_per_flex == 0 || groups_per_flex == 1) { We compile the code snippet using Clang 3.0 and GCC 4.6. Clang will completely optimize away the check groups_per_flex == 0, leaving the patched code as vulnerable as the original. GCC keeps the check, but there is no guarantee that future versions will do the same. Signed-off-by: Xi Wang Signed-off-by: "Theodore Ts'o" Signed-off-by: Greg Kroah-Hartman

ext4: add missing ext4_resize_end on error paths

2012-01-26T00:13:07Z

commit 014a1770371a028d22f364718c805f4216911ecd upstream. Online resize ioctls 'EXT4_IOC_GROUP_EXTEND' and 'EXT4_IOC_GROUP_ADD' call ext4_resize_begin() to check permissions and to set the EXT4_RESIZING bit lock, they do their work and they must finish with ext4_resize_end() which calls clear_bit_unlock() to unlock and to avoid -EBUSY errors for the next resize operations. This patch adds the missing ext4_resize_end() calls on error paths. Patch tested. Signed-off-by: Djalal Harouni Signed-off-by: "Theodore Ts'o" Signed-off-by: Greg Kroah-Hartman

ext4: handle EOF correctly in ext4_bio_write_page()

2011-12-14T03:29:12Z

We need to zero out part of a page which beyond EOF before setting uptodate, otherwise, mapread or write will see non-zero data beyond EOF. Signed-off-by: Yongqiang Yang Signed-off-by: "Theodore Ts'o" Cc: stable@kernel.org

ext4: remove a wrong BUG_ON in ext4_ext_convert_to_initialized

2011-12-14T03:13:42Z

If a file is fallocated on a hole, map->m_lblk + map->m_len may be greater than ee_block + ee_len. Signed-off-by: Yongqiang Yang Signed-off-by: "Theodore Ts'o" Cc: stable@kernel.org

ext4: correctly handle pages w/o buffers in ext4_discard_partial_buffers()

2011-12-14T03:05:05Z

If a page has been read into memory and never been written, it has no buffers, but we should handle the page in truncate or punch hole. VFS code of writing operations has handled holes correctly, so this patch removes the code handling holes in writing operations. Signed-off-by: Yongqiang Yang Signed-off-by: "Theodore Ts'o" Cc: stable@kernel.org

ext4: avoid potential hang in mpage_submit_io() when blocksize < pagesize

2011-12-14T02:51:55Z

If there is an unwritten but clean buffer in a page and there is a dirty buffer after the buffer, then mpage_submit_io does not write the dirty buffer out. As a result, da_writepages loops forever. This patch fixes the problem by checking dirty flag. Signed-off-by: Yongqiang Yang Signed-off-by: "Theodore Ts'o" Cc: stable@kernel.org

ext4: avoid hangs in ext4_da_should_update_i_disksize()

2011-12-14T02:41:15Z

If the pte mapping in generic_perform_write() is unmapped between iov_iter_fault_in_readable() and iov_iter_copy_from_user_atomic(), the "copied" parameter to ->end_write can be zero. ext4 couldn't cope with it with delayed allocations enabled. This skips the i_disksize enlargement logic if copied is zero and no new data was appeneded to the inode. gdb> bt #0 0xffffffff811afe80 in ext4_da_should_update_i_disksize (file=0xffff88003f606a80, mapping=0xffff88001d3824e0, pos=0x1\ 08000, len=0x1000, copied=0x0, page=0xffffea0000d792e8, fsdata=0x0) at fs/ext4/inode.c:2467 #1 ext4_da_write_end (file=0xffff88003f606a80, mapping=0xffff88001d3824e0, pos=0x108000, len=0x1000, copied=0x0, page=0\ xffffea0000d792e8, fsdata=0x0) at fs/ext4/inode.c:2512 #2 0xffffffff810d97f1 in generic_perform_write (iocb=, iov=, nr_segs=, pos=0x108000, ppos=0xffff88001e26be40, count=, written=0x0) at mm/filemap.c:2440 #3 generic_file_buffered_write (iocb=, iov=, nr_segs=, p\ os=0x108000, ppos=0xffff88001e26be40, count=, written=0x0) at mm/filemap.c:2482 #4 0xffffffff810db5d1 in __generic_file_aio_write (iocb=0xffff88001e26bde8, iov=0xffff88001e26bec8, nr_segs=0x1, ppos=0\ xffff88001e26be40) at mm/filemap.c:2600 #5 0xffffffff810db853 in generic_file_aio_write (iocb=0xffff88001e26bde8, iov=0xffff88001e26bec8, nr_segs=, pos=) at mm/filemap.c:2632 #6 0xffffffff811a71aa in ext4_file_write (iocb=0xffff88001e26bde8, iov=0xffff88001e26bec8, nr_segs=0x1, pos=0x108000) a\ t fs/ext4/file.c:136 #7 0xffffffff811375aa in do_sync_write (filp=0xffff88003f606a80, buf=, len=, \ ppos=0xffff88001e26bf48) at fs/read_write.c:406 #8 0xffffffff81137e56 in vfs_write (file=0xffff88003f606a80, buf=0x1ec2960

, count=0x4\ 000, pos=0xffff88001e26bf48) at fs/read_write.c:435 #9 0xffffffff8113816c in sys_write (fd=, buf=0x1ec2960

, count=0x\ 4000) at fs/read_write.c:487 #10 #11 0x00007f120077a390 in __brk_reservation_fn_dmi_alloc__ () #12 0x0000000000000000 in ?? () gdb> print offset $22 = 0xffffffffffffffff gdb> print idx $23 = 0xffffffff gdb> print inode->i_blkbits $24 = 0xc gdb> up #1 ext4_da_write_end (file=0xffff88003f606a80, mapping=0xffff88001d3824e0, pos=0x108000, len=0x1000, copied=0x0, page=0\ xffffea0000d792e8, fsdata=0x0) at fs/ext4/inode.c:2512 2512 if (ext4_da_should_update_i_disksize(page, end)) { gdb> print start $25 = 0x0 gdb> print end $26 = 0xffffffffffffffff gdb> print pos $27 = 0x108000 gdb> print new_i_size $28 = 0x108000 gdb> print ((struct ext4_inode_info *)((char *)inode-((int)(&((struct ext4_inode_info *)0)->vfs_inode))))->i_disksize $29 = 0xd9000 gdb> down 2467 for (i = 0; i < idx; i++) gdb> print i $30 = 0xd44acbee This is 100% reproducible with some autonuma development code tuned in a very aggressive manner (not normal way even for knumad) which does "exotic" changes to the ptes. It wouldn't normally trigger but I don't see why it can't happen normally if the page is added to swap cache in between the two faults leading to "copied" being zero (which then hangs in ext4). So it should be fixed. Especially possible with lumpy reclaim (albeit disabled if compaction is enabled) as that would ignore the young bits in the ptes. Signed-off-by: Andrea Arcangeli Signed-off-by: "Theodore Ts'o" Cc: stable@kernel.org

ext4: display the correct mount option in /proc/mounts for [no]init_itable

2011-12-13T03:06:18Z

/proc/mounts was showing the mount option [no]init_inode_table when the correct mount option that will be accepted by parse_options() is [no]init_itable. Signed-off-by: "Theodore Ts'o" Cc: stable@kernel.org

ext4: Fix crash due to getting bogus eh_depth value on big-endian systems

2011-12-12T16:00:56Z

Commit 1939dd84b3 ("ext4: cleanup ext4_ext_grow_indepth code") added a reference to ext4_extent_header.eh_depth, but forget to pass the value read through le16_to_cpu. The result is a crash on big-endian machines, such as this crash on a POWER7 server: attempt to access beyond end of device sda8: rw=0, want=776392648163376, limit=168558560 Unable to handle kernel paging request for data at address 0x6b6b6b6b6b6b6bcb Faulting instruction address: 0xc0000000001f5f38 cpu 0x14: Vector: 300 (Data Access) at [c000001bd1aaecf0] pc: c0000000001f5f38: .__brelse+0x18/0x60 lr: c0000000002e07a4: .ext4_ext_drop_refs+0x44/0x80 sp: c000001bd1aaef70 msr: 9000000000009032 dar: 6b6b6b6b6b6b6bcb dsisr: 40000000 current = 0xc000001bd15b8010 paca = 0xc00000000ffe4600 pid = 19911, comm = flush-8:0 enter ? for help [c000001bd1aaeff0] c0000000002e07a4 .ext4_ext_drop_refs+0x44/0x80 [c000001bd1aaf090] c0000000002e0c58 .ext4_ext_find_extent+0x408/0x4c0 [c000001bd1aaf180] c0000000002e145c .ext4_ext_insert_extent+0x2bc/0x14c0 [c000001bd1aaf2c0] c0000000002e3fb8 .ext4_ext_map_blocks+0x628/0x1710 [c000001bd1aaf420] c0000000002b2974 .ext4_map_blocks+0x224/0x310 [c000001bd1aaf4d0] c0000000002b7f2c .mpage_da_map_and_submit+0xbc/0x490 [c000001bd1aaf5a0] c0000000002b8688 .write_cache_pages_da+0x2c8/0x430 [c000001bd1aaf720] c0000000002b8b28 .ext4_da_writepages+0x338/0x670 [c000001bd1aaf8d0] c000000000157280 .do_writepages+0x40/0x90 [c000001bd1aaf940] c0000000001ea830 .writeback_single_inode+0xe0/0x530 [c000001bd1aafa00] c0000000001eb680 .writeback_sb_inodes+0x210/0x300 [c000001bd1aafb20] c0000000001ebc84 .__writeback_inodes_wb+0xd4/0x140 [c000001bd1aafbe0] c0000000001ebfec .wb_writeback+0x2fc/0x3e0 [c000001bd1aafce0] c0000000001ed770 .wb_do_writeback+0x2f0/0x300 [c000001bd1aafdf0] c0000000001ed848 .bdi_writeback_thread+0xc8/0x340 [c000001bd1aafed0] c0000000000c5494 .kthread+0xb4/0xc0 [c000001bd1aaff90] c000000000021f48 .kernel_thread+0x54/0x70 This is due to getting ext_depth(inode) == 0x101 and therefore running off the end of the path array in ext4_ext_drop_refs into following unallocated structures. This fixes it by adding the necessary le16_to_cpu. Signed-off-by: Paul Mackerras Signed-off-by: "Theodore Ts'o"

ext4: fix ext4_end_io_dio() racing against fsync()

2011-12-12T15:53:02Z

We need to make sure iocb->private is cleared *before* we put the io_end structure on i_completed_io_list. Otherwise fsync() could potentially run on another CPU and free the iocb structure out from under us. Reported-by: Kent Overstreet Signed-off-by: "Theodore Ts'o" Cc: stable@kernel.org