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Message-ID: References: <20220606151312.6a9d098c85ed060d36519600@linux-foundation.org> <20220608021922.n2izu7n4yoadknkx@zlang-mailbox> <20220612044230.murerhsa765akogj@zlang-mailbox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655060875; a=rsa-sha256; cv=none; b=qOUQffBFZF5yjYHreAIwzuomhs64Lep+X4BFs+u0PLF2a6pwG7q14rk9FBr8H3nc+hyORt YICk5dXHesZqKesHkKAuWUZ0HcXAR6gUKUuCYx3bfV4OzvmphLF4eiV10nuHBYEJLIZ/14 zRSlAmTDC04TVJ5V17hgTftenO6Ae3Y= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=E02cn2lO; spf=pass (imf26.hostedemail.com: domain of urezki@gmail.com designates 209.85.208.176 as permitted sender) smtp.mailfrom=urezki@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655060875; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=/lRrX5aKWLjE/LdPrNz1fAnJtllQTJwoJoNcjGrmnxk=; b=GcJvVsaIFYo8yn76i8+gAE4yjwQRK8rBov2UTfphL8z/Ph4ILDRCJsC8ezZ7Es6vBjwAEi JTIsHHkC1GGF8goy0Cn+7B68iIK+eBdvMmLR1g8QSuBd+XqF3uZSD4NcaFs/L3vga8IYcR x5g5c9ZM4k1Mt6hEHn/Vp7/4f4kkeEI= X-Rspamd-Queue-Id: 10898140086 Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=E02cn2lO; spf=pass (imf26.hostedemail.com: domain of urezki@gmail.com designates 209.85.208.176 as permitted sender) smtp.mailfrom=urezki@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Rspam-User: X-Rspamd-Server: rspam06 X-Stat-Signature: ktm4qfejdiawgb17bp7qzfcxz3yhzis1 X-HE-Tag: 1655060874-268455 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > On Sun, Jun 12, 2022 at 03:03:20PM +0200, Uladzislau Rezki wrote: > > > @@ -181,8 +181,9 @@ static inline void check_heap_object(const void *ptr, unsigned long n, > > > return; > > > } > > > > > > - offset = ptr - area->addr; > > > - if (offset + n > get_vm_area_size(area)) > > > + /* XXX: We should also abort for free vmap_areas */ > > > + offset = (unsigned long)ptr - area->va_start; > > > > > I was a bit confused about "offset" and why it is needed here. It is always zero. > > So we can get rid of it to make it less confused. From the other hand a zero offset > > contributes to nothing. > > I don't think offset is necessarily zero. 'ptr' is a pointer somewhere > in the object, not necessarily the start of the object. > Right you are. Just checked the __find_vmap_area() it returns VA of the address it belongs to. Initially i was thinking that addr have to be exactly as va->start only, so i was wrong. > > > > > > + if (offset + n >= area->va_end) > > > > > I think it is a bit wrong. As i see it, "n" is a size and what we would like to do > > here is boundary check: > > > > > > if (n > va_size(area)) > > usercopy_abort("vmalloc", NULL, to_user, 0, n); > > > > Hmm ... we should probably be more careful about wrapping. > > if (n > area->va_end - addr) > usercopy_abort("vmalloc", NULL, to_user, offset, n); > > ... and that goes for the whole function actually. I'll split that into > a separate change. > Based on that offset can be > 0, checking "offset + n" with va->va_end is OK. if (offset + n > area->va_end) usercopy_abort("vmalloc", NULL, to_user, offset, n); -- Uladzislau Rezki