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authorJeremy Boone <jeremy.boone@nccgroup.trust>2018-02-08 12:30:01 -0800
committerJames Morris <james.morris@microsoft.com>2018-02-26 15:43:44 -0800
commit9b8cb28d7c62568a5916bdd7ea1c9176d7f8f2ed (patch)
treec22b00d42dc3bfe21697fe7f4f164850d5c08693 /drivers/char
parentf9d4d9b5a5ef2f017bc344fb65a58a902517173b (diff)
downloadlinux-9b8cb28d7c62568a5916bdd7ea1c9176d7f8f2ed.tar.bz2
tpm_i2c_infineon: fix potential buffer overruns caused by bit glitches on the bus
Discrete TPMs are often connected over slow serial buses which, on some platforms, can have glitches causing bit flips. In all the driver _recv() functions, we need to use a u32 to unmarshal the response size, otherwise a bit flip of the 31st bit would cause the expected variable to go negative, which would then try to read a huge amount of data. Also sanity check that the expected amount of data is large enough for the TPM header. Signed-off-by: Jeremy Boone <jeremy.boone@nccgroup.trust> Cc: stable@vger.kernel.org Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: James Morris <james.morris@microsoft.com>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/tpm/tpm_i2c_infineon.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/char/tpm/tpm_i2c_infineon.c b/drivers/char/tpm/tpm_i2c_infineon.c
index c1dd39eaaeeb..6116cd05e228 100644
--- a/drivers/char/tpm/tpm_i2c_infineon.c
+++ b/drivers/char/tpm/tpm_i2c_infineon.c
@@ -473,7 +473,8 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
{
int size = 0;
- int expected, status;
+ int status;
+ u32 expected;
if (count < TPM_HEADER_SIZE) {
size = -EIO;
@@ -488,7 +489,7 @@ static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
}
expected = be32_to_cpu(*(__be32 *)(buf + 2));
- if ((size_t) expected > count) {
+ if (((size_t) expected > count) || (expected < TPM_HEADER_SIZE)) {
size = -EIO;
goto out;
}