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[76.251.165.188]) by smtp.gmail.com with ESMTPSA id a75sm709467oii.55.2020.09.03.13.59.59 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Thu, 03 Sep 2020 13:59:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=rlfytk/HxGcRvQ43QKeVZDlvKaRhllUNtWQbE6mYVCc=; b=U1A+Ihoqs14Ap+tzZ9MDJuzdSwiT12iqB4x2y0I/xN1lTnml1p4BCBFQd0pPbb9isl Rk0yhQKklzGWQkJSUCNiVbAv4tPs6Yr47szSYmeCX5azHT7g4iaRdFcfPSKa6PwASEZ0 Oj5aIuJ9NNWef0vc9MLu1lioL8WLNdr5w0fdiI0ZVDGILDovtByHD1f2arJmd47Dabgt Wb8uX9rXtLfIWSsHXT/35BwIVlt37NkMQS36HENFUpAoyg2ZlzbKXM8SJeWxs2UbG68W NhDW4WzDTTd53Vyax1PzGP2tZlyBryMUeCJrqPq1uAF7eZCITv3UqPYt1DyWgaWIPnlA tFnA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; bh=rlfytk/HxGcRvQ43QKeVZDlvKaRhllUNtWQbE6mYVCc=; b=X8HaUSj6IJHCThV0YZoK8R0P6O6wuZZaOcD2ncsAtvULiPgzB0RISLRjgWXoyQh3Ng kvmAKylSIxclR3iFRsC8xdUYC2AqQa1wuGo9EIOiNWmWGJe13k9HUmrAu+ZiCPqk1B5k cun6vNW20SDOz+lYLqmBraJs4X7sfHPyvpWIHMBD3CjoxEvMyNSXm7xFXDuqPFc7DKGP VBQ9nHu2JoR+8YxRfOZ8b2/WM7GPEzO1H7CyAYS6wCotSHDuqvVwiicXYKmzByM7nnmH YktI6CO91stxGTeCN3hgnJT8fJCYxtrLMWuRJIRdQMW4o5kne4TntAKbl9wEs8GklIPi 00Mw== X-Gm-Message-State: AOAM530sAm8yLsA84mTbaXhHifLRFcUsFS2uM5TBh/imOajAXDQ9Mgu/ kBvCjjDyhU2IICBxnECTBwSdwlCWZUc= X-Google-Smtp-Source: ABdhPJzICnhV8rm0nVYYCpfU/wU6GQn/BMzRcIWxPt8YB0OMN0wG6kI5jsAd5BMBN+0kfd+d5W27eA== X-Received: by 2002:a9d:7f84:: with SMTP id t4mr3163361otp.192.1599166800161; Thu, 03 Sep 2020 14:00:00 -0700 (PDT) From: Michael Roth To: qemu-devel@nongnu.org Subject: [PATCH 16/77] ati-vga: check mm_index before recursive call (CVE-2020-13800) Date: Thu, 3 Sep 2020 15:58:34 -0500 Message-Id: <20200903205935.27832-17-mdroth@linux.vnet.ibm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200903205935.27832-1-mdroth@linux.vnet.ibm.com> References: <20200903205935.27832-1-mdroth@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::32c; envelope-from=flukshun@gmail.com; helo=mail-ot1-x32c.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FORGED_FROMDOMAIN=0.249, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Gerd Hoffmann , qemu-stable@nongnu.org, Prasad J Pandit Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) From: Prasad J Pandit While accessing VGA registers via ati_mm_read/write routines, a guest may set 's->regs.mm_index' such that it leads to infinite recursion. Check mm_index value to avoid such recursion. Log an error message for wrong values. Reported-by: Ren Ding Reported-by: Hanqing Zhao Reported-by: Yi Ren Message-id: 20200604090830.33885-1-ppandit@redhat.com Suggested-by: BALATON Zoltan Suggested-by: Philippe Mathieu-Daud=C3=A9 Signed-off-by: Prasad J Pandit Signed-off-by: Gerd Hoffmann (cherry picked from commit a98610c429d52db0937c1e48659428929835c455) Signed-off-by: Michael Roth --- hw/display/ati.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/hw/display/ati.c b/hw/display/ati.c index 58ec8291d4..9228f1b242 100644 --- a/hw/display/ati.c +++ b/hw/display/ati.c @@ -285,8 +285,11 @@ static uint64_t ati_mm_read(void *opaque, hwaddr addr,= unsigned int size) if (idx <=3D s->vga.vram_size - size) { val =3D ldn_le_p(s->vga.vram_ptr + idx, size); } - } else { + } else if (s->regs.mm_index > MM_DATA + 3) { val =3D ati_mm_read(s, s->regs.mm_index + addr - MM_DATA, size= ); + } else { + qemu_log_mask(LOG_GUEST_ERROR, + "ati_mm_read: mm_index too small: %u\n", s->regs.mm_index); } break; case BIOS_0_SCRATCH ... BUS_CNTL - 1: @@ -520,8 +523,11 @@ static void ati_mm_write(void *opaque, hwaddr addr, if (idx <=3D s->vga.vram_size - size) { stn_le_p(s->vga.vram_ptr + idx, size, data); } - } else { + } else if (s->regs.mm_index > MM_DATA + 3) { ati_mm_write(s, s->regs.mm_index + addr - MM_DATA, data, size); + } else { + qemu_log_mask(LOG_GUEST_ERROR, + "ati_mm_write: mm_index too small: %u\n", s->regs.mm_index= ); } break; case BIOS_0_SCRATCH ... BUS_CNTL - 1: --=20 2.17.1