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V4L/DVB (9621): Avoid writing outside shadow.bytes[] array 

There were no check about the limits of shadow.bytes array. This offers
a risk of writing values outside the limits, overriding other data
areas.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Mauro Carvalho Chehab 2008-11-13 17:03:28 -03:00
parent 81cb5c4f7f
commit 494264379d
1 changed files with 27 additions and 3 deletions
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30
drivers/media/video/tvaudio.c
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@ -154,7 +154,7 @@ static int chip_write(struct CHIPSTATE *chip, int subaddr, int val)
{
unsigned char buffer[2];
if (-1 == subaddr) {
if (subaddr < 0) {
v4l_dbg(1, debug, chip->c, "%s: chip_write: 0x%x\n",
chip->c->name, val);
chip->shadow.bytes[1] = val;
@ -165,6 +165,13 @@ static int chip_write(struct CHIPSTATE *chip, int subaddr, int val)
return -1;
}
} else {
if (subaddr + 1 >= ARRAY_SIZE(chip->shadow.bytes)) {
v4l_info(chip->c,
"Tried to access a non-existent register: %d\n",
subaddr);
return -EINVAL;
}
v4l_dbg(1, debug, chip->c, "%s: chip_write: reg%d=0x%x\n",
chip->c->name, subaddr, val);
chip->shadow.bytes[subaddr+1] = val;
@ -179,12 +186,20 @@ static int chip_write(struct CHIPSTATE *chip, int subaddr, int val)
return 0;
}
static int chip_write_masked(struct CHIPSTATE *chip, int subaddr, int val, int mask)
static int chip_write_masked(struct CHIPSTATE *chip,
int subaddr, int val, int mask)
{
if (mask != 0) {
if (-1 == subaddr) {
if (subaddr < 0) {
val = (chip->shadow.bytes[1] & ~mask) | (val & mask);
} else {
if (subaddr + 1 >= ARRAY_SIZE(chip->shadow.bytes)) {
v4l_info(chip->c,
"Tried to access a non-existent register: %d\n",
subaddr);
return -EINVAL;
}
val = (chip->shadow.bytes[subaddr+1] & ~mask) | (val & mask);
}
}
@ -230,6 +245,15 @@ static int chip_cmd(struct CHIPSTATE *chip, char *name, audiocmd *cmd)
if (0 == cmd->count)
return 0;
if (cmd->count + cmd->bytes[0] - 1 >= ARRAY_SIZE(chip->shadow.bytes)) {
v4l_info(chip->c,
"Tried to access a non-existent register range: %d to %d\n",
cmd->bytes[0] + 1, cmd->bytes[0] + cmd->count - 1);
return -EINVAL;
}
/* FIXME: it seems that the shadow bytes are wrong bellow !*/
/* update our shadow register set; print bytes if (debug > 0) */
v4l_dbg(1, debug, chip->c, "%s: chip_cmd(%s): reg=%d, data:",
chip->c->name, name,cmd->bytes[0]);