media: cx25821: prevent out-of-bounds read on array card

Currently an out of range dev->nr is detected by just reporting the
issue and later on an out-of-bounds read on array card occurs because
of this. Fix this by checking the upper range of dev->nr with the size
of array card (removes the hard coded size), move this check earlier
and also exit with the error -ENOSYS to avoid the later out-of-bounds
array read.

Detected by CoverityScan, CID#711191 ("Out-of-bounds-read")

Fixes: commit 02b20b0b4c ("V4L/DVB (12730): Add conexant cx25821 driver")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
[hans.verkuil@cisco.com: %ld -> %zd]
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Colin Ian King 2018-01-31 12:33:09 -05:00 committed by Mauro Carvalho Chehab
parent 7b73ce9d4c
commit 67300abdbe

View file

@ -867,6 +867,10 @@ static int cx25821_dev_setup(struct cx25821_dev *dev)
dev->nr = ++cx25821_devcount;
sprintf(dev->name, "cx25821[%d]", dev->nr);
if (dev->nr >= ARRAY_SIZE(card)) {
CX25821_INFO("dev->nr >= %zd", ARRAY_SIZE(card));
return -ENODEV;
}
if (dev->pci->device != 0x8210) {
pr_info("%s(): Exiting. Incorrect Hardware device = 0x%02x\n",
__func__, dev->pci->device);
@ -882,9 +886,6 @@ static int cx25821_dev_setup(struct cx25821_dev *dev)
dev->channels[i].sram_channels = &cx25821_sram_channels[i];
}
if (dev->nr > 1)
CX25821_INFO("dev->nr > 1!");
/* board config */
dev->board = 1; /* card[dev->nr]; */
dev->_max_num_decoders = MAX_DECODERS;