On Tue, Jul 28, 2020 at 11:41:37AM +0300, Dan Carpenter wrote: > On Mon, Jul 27, 2020 at 05:02:35PM -0400, Peilin Ye wrote: > > hinfo_to_cinfo() does no operation on `cinfo` when `hinfo` is NULL, > > causing kioc_to_mimd() to copy uninitialized stack memory to userspace. > > Fix it by initializing `cinfo` with memset(). > > But "hinfo" can't be NULL so this patch isn't required. It's a bit > hard for Smatch to follow the code. > > We know that "opcode" is 82 so the buffer is allocated by mimd_to_kioc() > -> mraid_mm_attach_buf(). You are right. mraid_mm_ioctl() returns -ENOMEM and never reaches kioc_to_mimd() if mraid_mm_attach_buf() failed to get a buffer, so `hinfo` can never be NULL for kioc_to_mimd(). Next time I will trace the data flow more carefully. Thank you for pointing this out! Peilin Ye > Generally, don't silence static checker warnings unless it makes the > code more readable. It's the checker writer's job to fix their own code. > In this case, that's me, but parsing the code is quite complicated and I > don't have a plan for how to fix it. > > regards, > dan carpenter >
