STMicro TPM: Fix potential buffer overruns
This patch prevents integer underflow when the length was too small,
which could lead to memory corruption.
Signed-off-by: Jeremy Boone <jeremy.boone@nccgroup.trust>
diff --git a/drivers/tpm/tpm_tis_st33zp24_i2c.c b/drivers/tpm/tpm_tis_st33zp24_i2c.c
index c8d0125..245218f 100644
--- a/drivers/tpm/tpm_tis_st33zp24_i2c.c
+++ b/drivers/tpm/tpm_tis_st33zp24_i2c.c
@@ -303,7 +303,8 @@
static int st33zp24_i2c_recv(struct udevice *dev, u8 *buf, size_t count)
{
struct tpm_chip *chip = dev_get_priv(dev);
- int size, expected;
+ int size;
+ unsigned int expected;
if (!chip)
return -ENODEV;
@@ -320,7 +321,7 @@
}
expected = get_unaligned_be32(buf + 2);
- if (expected > count) {
+ if (expected > count || expected < TPM_HEADER_SIZE) {
size = -EIO;
goto out;
}
diff --git a/drivers/tpm/tpm_tis_st33zp24_spi.c b/drivers/tpm/tpm_tis_st33zp24_spi.c
index dcf55ee..c4c5e05 100644
--- a/drivers/tpm/tpm_tis_st33zp24_spi.c
+++ b/drivers/tpm/tpm_tis_st33zp24_spi.c
@@ -431,7 +431,8 @@
static int st33zp24_spi_recv(struct udevice *dev, u8 *buf, size_t count)
{
struct tpm_chip *chip = dev_get_priv(dev);
- int size, expected;
+ int size;
+ unsigned int expected;
if (!chip)
return -ENODEV;
@@ -448,7 +449,7 @@
}
expected = get_unaligned_be32(buf + 2);
- if (expected > count) {
+ if (expected > count || expected < TPM_HEADER_SIZE) {
size = -EIO;
goto out;
}