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ppc/pnv: Fix potential overflow in I2C model 

Coverity warns that "i2c_bus_busy(i2c->busses[i]) << i" might overflow
because the expression is evaluated using 32-bit arithmetic and then
used in a context expecting a uint64_t.

While we are at it, introduce a PNV_I2C_MAX_BUSSES constant and check
the number of busses at realize time.

Fixes: Coverity CID 1523918
Cc: Glenn Miles <milesg@linux.vnet.ibm.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Glenn Miles <milesg@linux.vnet.ibm.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
This commit is contained in:
Cédric Le Goater 2023-11-09 18:15:25 +01:00
parent af9264da80
commit 8bc5ae046d
1 changed files with 7 additions and 1 deletions
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8
hw/ppc/pnv_i2c.c
View File

@ -151,6 +151,7 @@
#define I2C_RESET_S_SDA_REG 0x11
#define PNV_I2C_FIFO_SIZE 8
#define PNV_I2C_MAX_BUSSES 64
static I2CBus *pnv_i2c_get_bus(PnvI2C *i2c)
{
@ -437,7 +438,7 @@ static uint64_t pnv_i2c_xscom_read(void *opaque, hwaddr addr,
case I2C_PORT_BUSY_REG: /* compute busy bit for each port */
val = 0;
for (i = 0; i < i2c->num_busses; i++) {
val |= i2c_bus_busy(i2c->busses[i]) << i;
val |= (uint64_t)i2c_bus_busy(i2c->busses[i]) << i;
}
break;
@ -641,6 +642,11 @@ static void pnv_i2c_realize(DeviceState *dev, Error **errp)
assert(i2c->chip);
if (i2c->num_busses > PNV_I2C_MAX_BUSSES) {
error_setg(errp, "Invalid number of busses: %u", i2c->num_busses);
return;
}
pnv_xscom_region_init(&i2c->xscom_regs, OBJECT(i2c), &pnv_i2c_xscom_ops,
i2c, "xscom-i2c", PNV9_XSCOM_I2CM_SIZE);