Messages in this thread | | | From | Ajay Garg <> | Date | Sun, 7 Nov 2021 02:14:36 +0530 | Subject | Re: [PATCH] tty: vt: keyboard: do not copy an extra-byte in copy_to_user |
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> > > > That's the whole point of the discussion :) > > > > The method "vt_do_kdgkb_ioctl" does not manage "func_table[kb_func]". > > Thus, the method does not know whether or not > > strlen(func_table[kb_func]) < sizeof(user_kdgkb->kb_string). > > > > It manages. The code under `case KDSKBSENT:` sets func_table[] entries > via vt_kdskbsent(). > > kbs = strndup_user(..., sizeof(user_kdgkb->kb_string)); > > is used to allocate buffer for the func_table[] entry. That's my main > point :)
func_table is set in vt_kdskbent, which itself is external.
More importantly, vt_kdskbent is handled in case KDSKBSENT:, while the strlcpy issue we are dealing with is in case KDGKBSENT: In case KDGKBSENT, following are managed :
ssize_t len = sizeof(user_kdgkb->kb_string); kbs = kmalloc(len, GFP_KERNEL);
while func_table[kb_func] is external entity here, so no assumption ought to be made for it, just my 2 cents though :)
Anyhow, really, it is the maintainers' choice now :), since there isn't a burning (compilation/runtime) issue.
> > > > > With regards, > Pavel Skripkin
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