• Eric Biggers's avatar
    fscrypto: don't use on-stack buffer for filename encryption · 08ae877f
    Eric Biggers authored
    With the new (in 4.9) option to use a virtually-mapped stack
    (CONFIG_VMAP_STACK), stack buffers cannot be used as input/output for
    the scatterlist crypto API because they may not be directly mappable to
    struct page.  For short filenames, fname_encrypt() was encrypting a
    stack buffer holding the padded filename.  Fix it by encrypting the
    filename in-place in the output buffer, thereby making the temporary
    buffer unnecessary.
    
    This bug could most easily be observed in a CONFIG_DEBUG_SG kernel
    because this allowed the BUG in sg_set_buf() to be triggered.
    
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
    Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
    08ae877f
fname.c 10.3 KB