From: Jia-Ju Bai Date: Sat, 30 May 2020 14:42:08 +0000 (+0200) Subject: media: pci: ttpci: av7110: fix possible buffer overflow caused by bad DMA value in... X-Git-Tag: v4.9.235~69 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a41513268f99815dc9a3e4a13c2347a51245dc85;p=platform%2Fkernel%2Flinux-amlogic.git media: pci: ttpci: av7110: fix possible buffer overflow caused by bad DMA value in debiirq() [ Upstream commit 6499a0db9b0f1e903d52f8244eacc1d4be00eea2 ] The value av7110->debi_virt is stored in DMA memory, and it is assigned to data, and thus data[0] can be modified at any time by malicious hardware. In this case, "if (data[0] < 2)" can be passed, but then data[0] can be changed into a large number, which may cause buffer overflow when the code "av7110->ci_slot[data[0]]" is used. To fix this possible bug, data[0] is assigned to a local variable, which replaces the use of data[0]. Signed-off-by: Jia-Ju Bai Signed-off-by: Sean Young Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- diff --git a/drivers/media/pci/ttpci/av7110.c b/drivers/media/pci/ttpci/av7110.c index 382caf200ba1..c313f51688f4 100644 --- a/drivers/media/pci/ttpci/av7110.c +++ b/drivers/media/pci/ttpci/av7110.c @@ -426,14 +426,15 @@ static void debiirq(unsigned long cookie) case DATA_CI_GET: { u8 *data = av7110->debi_virt; + u8 data_0 = data[0]; - if ((data[0] < 2) && data[2] == 0xff) { + if (data_0 < 2 && data[2] == 0xff) { int flags = 0; if (data[5] > 0) flags |= CA_CI_MODULE_PRESENT; if (data[5] > 5) flags |= CA_CI_MODULE_READY; - av7110->ci_slot[data[0]].flags = flags; + av7110->ci_slot[data_0].flags = flags; } else ci_get_data(&av7110->ci_rbuffer, av7110->debi_virt,