From b3f40703408e57cad492802b777448a068b1f671 Mon Sep 17 00:00:00 2001 From: Jeremy Boone Date: Mon, 12 Feb 2018 17:56:37 -0500 Subject: [PATCH] Atmel TPM: Fix potential buffer overruns Ensure that the Atmel TPM driver performs sufficient validation of the length returned in the TPM response header. This patch prevents memory corruption if the header contains a length value that is larger than the destination buffer. Signed-off-by: Jeremy Boone --- drivers/tpm/tpm_atmel_twi.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/tpm/tpm_atmel_twi.c b/drivers/tpm/tpm_atmel_twi.c index eba654b15d..4fd772dc4f 100644 --- a/drivers/tpm/tpm_atmel_twi.c +++ b/drivers/tpm/tpm_atmel_twi.c @@ -106,13 +106,23 @@ static int tpm_atmel_twi_xfer(struct udevice *dev, udelay(100); } if (!res) { - *recv_len = get_unaligned_be32(recvbuf + 2); - if (*recv_len > 10) + unsigned int hdr_recv_len; + hdr_recv_len = get_unaligned_be32(recvbuf + 2); + if (hdr_recv_len < 10) { + puts("tpm response header too small\n"); + return -1; + } else if (hdr_recv_len > *recv_len) { + puts("tpm response length is bigger than receive buffer\n"); + return -1; + } else { + *recv_len = hdr_recv_len; #ifndef CONFIG_DM_I2C res = i2c_read(0x29, 0, 0, recvbuf, *recv_len); #else res = dm_i2c_read(dev, 0, recvbuf, *recv_len); #endif + + } } if (res) { printf("i2c_read returned %d (rlen=%d)\n", res, *recv_len); -- 2.25.1