• J
    ext4: fix offset overflow on 32-bit archs in ext4_iomap_begin() · fe23cb65
    Jiri Slaby 提交于
    ext4_iomap_begin() has a bug where offset returned in the iomap
    structure will be truncated to unsigned long size. On 64-bit
    architectures this is fine but on 32-bit architectures obviously not.
    Not many places actually use the offset stored in the iomap structure
    but one of visible failures is in SEEK_HOLE / SEEK_DATA implementation.
    If we create a file like:
    
    dd if=/dev/urandom of=file bs=1k seek=8m count=1
    
    then
    
    lseek64("file", 0x100000000ULL, SEEK_DATA)
    
    wrongly returns 0x100000000 on unfixed kernel while it should return
    0x200000000. Avoid the overflow by proper type cast.
    
    Fixes: 545052e9 ("ext4: Switch to iomap for SEEK_HOLE / SEEK_DATA")
    Signed-off-by: NJiri Slaby <jslaby@suse.cz>
    Signed-off-by: NJan Kara <jack@suse.cz>
    Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
    Cc: stable@vger.kernel.org # v4.15
    fe23cb65
inode.c 177.1 KB