From: James Bates Date: Wed, 2 Oct 2013 16:43:39 +0000 (+0200) Subject: efifb: prevent null-deref when iterating dmi_list X-Git-Tag: next-20131105~38^2~10 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=55aa42f2e690157e254a6a6989f5f4ac928b35c8;p=karo-tx-linux.git efifb: prevent null-deref when iterating dmi_list 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 Signed-off-by: David Herrmann Signed-off-by: Tomi Valkeinen --- diff --git a/drivers/video/efifb.c b/drivers/video/efifb.c index 7f9ff75d0db2..fcb950031246 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;