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f2fs: fix potential .flags overflow on 32bit architecture

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f2fs_inode_info.flags is unsigned long variable, it has 32 bits
in 32bit architecture, since we introduced FI_MMAP_FILE flag
when we support data compression, we may access memory cross
the border of .flags field, corrupting .i_sem field, result in
below deadlock.

To fix this issue, let's expand .flags as an array to grab enough
space to store new flags.

Call Trace:
 __schedule+0x8d0/0x13fc
 ? mark_held_locks+0xac/0x100
 schedule+0xcc/0x260
 rwsem_down_write_slowpath+0x3ab/0x65d
 down_write+0xc7/0xe0
 f2fs_drop_nlink+0x3d/0x600 [f2fs]
 f2fs_delete_inline_entry+0x300/0x440 [f2fs]
 f2fs_delete_entry+0x3a1/0x7f0 [f2fs]
 f2fs_unlink+0x500/0x790 [f2fs]
 vfs_unlink+0x211/0x490
 do_unlinkat+0x483/0x520
 sys_unlink+0x4a/0x70
 do_fast_syscall_32+0x12b/0x683
 entry_SYSENTER_32+0xaa/0x102

Fixes: 4c8ff7095b ("f2fs: support data compression")
Tested-by: Ondrej Jirman <megous@megous.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Chao Yu
2020-03-23 11:18:07 +08:00
committed by Jaegeuk Kim
parent 79bbefb19f
commit 7653b9d875
2 changed files with 50 additions and 51 deletions
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2
fs/f2fs/inode.c
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@@ -362,7 +362,7 @@ static int do_read_inode(struct inode *inode)
fi->i_flags = le32_to_cpu(ri->i_flags);
if (S_ISREG(inode->i_mode))
fi->i_flags &= ~F2FS_PROJINHERIT_FL;
fi->flags = 0;
bitmap_zero(fi->flags, FI_MAX);
fi->i_advise = ri->i_advise;
fi->i_pino = le32_to_cpu(ri->i_pino);
fi->i_dir_level = ri->i_dir_level;