• Arjan van de Ven's avatar
    x86: Use __builtin_object_size() to validate the buffer size for copy_from_user() · 9f0cf4ad
    Arjan van de Ven authored
    gcc (4.x) supports the __builtin_object_size() builtin, which
    reports the size of an object that a pointer point to, when known
    at compile time. If the buffer size is not known at compile time, a
    constant -1 is returned.
    
    This patch uses this feature to add a sanity check to
    copy_from_user(); if the target buffer is known to be smaller than
    the copy size, the copy is aborted and a WARNing is emitted in
    memory debug mode.
    
    These extra checks compile away when the object size is not known,
    or if both the buffer size and the copy length are constants.
    Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
    LKML-Reference: <20090926143301.2c396b94@infradead.org>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    9f0cf4ad
compiler-gcc4.h 1.44 KB