• Alex Elder's avatar
    xfs: zero proper structure size for geometry calls · eeb2036b
    Alex Elder authored
    Commit 493f3358 added this call to
    xfs_fs_geometry() in order to avoid passing kernel stack data back
    to user space:
    
    +       memset(geo, 0, sizeof(*geo));
    
    Unfortunately, one of the callers of that function passes the
    address of a smaller data type, cast to fit the type that
    xfs_fs_geometry() requires.  As a result, this can happen:
    
    Kernel panic - not syncing: stack-protector: Kernel stack is corrupted
    in: f87aca93
    
    Pid: 262, comm: xfs_fsr Not tainted 2.6.38-rc6-493f3358+ #1
    Call Trace:
    
    [<c12991ac>] ? panic+0x50/0x150
    [<c102ed71>] ? __stack_chk_fail+0x10/0x18
    [<f87aca93>] ? xfs_ioc_fsgeometry_v1+0x56/0x5d [xfs]
    
    Fix this by fixing that one caller to pass the right type and then
    copy out the subset it is interested in.
    
    Note: This patch is an alternative to one originally proposed by
    Eric Sandeen.
    Reported-by: default avatarJeffrey Hundstad <jeffrey.hundstad@mnsu.edu>
    Signed-off-by: default avatarAlex Elder <aelder@sgi.com>
    Reviewed-by: default avatarEric Sandeen <sandeen@redhat.com>
    Tested-by: default avatarJeffrey Hundstad <jeffrey.hundstad@mnsu.edu>
    eeb2036b
xfs_ioctl.c 34.6 KB