diff options
| author | Jia-Ju Bai <baijiaju@tsinghua.edu.cn> | 2020-05-30 16:42:08 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2020-06-23 15:09:43 +0200 |
| commit | 6499a0db9b0f1e903d52f8244eacc1d4be00eea2 (patch) | |
| tree | e5c4c00e9129804e6cedd597c1792998926283d2 | |
| parent | bc76369b89bbbbd01b2a3852287ea8092b59d012 (diff) | |
| download | linux-6499a0db9b0f1e903d52f8244eacc1d4be00eea2.tar.bz2 | |
media: pci: ttpci: av7110: fix possible buffer overflow caused by bad DMA value in debiirq()
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 <baijiaju@tsinghua.edu.cn>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
| -rw-r--r-- | drivers/media/pci/ttpci/av7110.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/media/pci/ttpci/av7110.c b/drivers/media/pci/ttpci/av7110.c index d0cdee1c6eb0..bf36b1e22b63 100644 --- a/drivers/media/pci/ttpci/av7110.c +++ b/drivers/media/pci/ttpci/av7110.c @@ -406,14 +406,15 @@ 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, |