• Jeff Moyer's avatar
    [PATCH] raw: don't allow the creation of a raw device with minor number 0 · 38584c14
    Jeff Moyer authored
    
    
    Minor number 0 (under the raw major) is reserved for the rawctl device
    file, which is used to query, set, and unset raw device bindings.  However,
    the ioctl interface does not protect the user from specifying a raw device
    with minor number 0:
    
    $ sudo ./raw /dev/raw/raw0 /dev/VolGroup00/swap
    /dev/raw/raw0:  bound to major 253, minor 2
    $ ls -l /dev/rawctl
    ls: /dev/rawctl: No such file or directory
    $ ls -l /dev/raw/raw0
    crw------- 1 root root 162, 0 Jan 12 10:51 /dev/raw/raw0
    $ sudo ./raw -qa
    Cannot open master raw device '/dev/rawctl' (No such file or directory)
    
    As you can see, this prevents any further raw operations from
    succeeding.  The fix (from Steve Fernandez) is quite simple--do not
    allow the allocation of minor number 0.
    Signed-off-by: default avatarJeff Moyer <jmoyer@redhat.com>
    Cc: Steven Fernandez <sfernand@redhat.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    38584c14
raw.c 6.91 KB