This requires a very weird input from the serial interface but can cause
an overflow in input_buf (keys) overwriting the next variable (npending)
with the user choice:
(pahole output)
struct grub_terminfo_input_state {
int input_buf[6]; /* 0 24 */
int npending; /* 24 4 */ <- CORRUPT
...snip...
The magic string requires causing this is "ESC,O,],0,1,2,q" and we overflow
npending with "q" (aka increase npending to 161). The simplest fix is to
just to disallow overwrites input_buf, which exactly what this patch does.
Fixes: CID 292449
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>