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    SubjectRe: [PATCH v3] efifb: prevent null-deref when iterating dmi_list
    On 02/10/13 19:43, David Herrmann wrote:
    > From: James Bates <james.h.bates@gmail.com>
    >
    > The dmi_list array is initialized using gnu designated initializers, and
    > therefore may contain fewer explicitly defined entries as there are
    > elements in it. This is because the enum above with M_xyz constants
    > contains more items than the designated initializer. Those elements not
    > explicitly initialized are implicitly set to 0.
    >
    > Now efifb_setup() loops through all these array elements, and performs
    > a strcmp on each item. For non explicitly initialized elements this will
    > be a null pointer:
    >
    > This patch swaps the check order in the if statement, thus checks first
    > whether dmi_list[i].base is null.
    >
    > Signed-off-by: James Bates <james.h.bates@gmail.com>
    > Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
    > ---
    > v3: fixes the "Author" field and James' email address
    >
    > drivers/video/efifb.c | 4 ++--
    > 1 file changed, 2 insertions(+), 2 deletions(-)
    >
    > diff --git a/drivers/video/efifb.c b/drivers/video/efifb.c
    > index 7f9ff75..fcb9500 100644
    > --- a/drivers/video/efifb.c
    > +++ b/drivers/video/efifb.c
    > @@ -108,8 +108,8 @@ static int efifb_setup(char *options)
    > if (!*this_opt) continue;
    >
    > for (i = 0; i < M_UNKNOWN; i++) {
    > - if (!strcmp(this_opt, efifb_dmi_list[i].optname) &&
    > - efifb_dmi_list[i].base != 0) {
    > + if (efifb_dmi_list[i].base != 0 &&
    > + !strcmp(this_opt, efifb_dmi_list[i].optname)) {
    > screen_info.lfb_base = efifb_dmi_list[i].base;
    > screen_info.lfb_linelength = efifb_dmi_list[i].stride;
    > screen_info.lfb_width = efifb_dmi_list[i].width;
    >

    Thanks, queued for 3.13.

    Tomi


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