From cc1087eb22db5776a15a02034ce16b2f7ca77536 Mon Sep 17 00:00:00 2001 From: Zhang Enpei Date: Wed, 2 Jul 2025 12:12:19 +0800 Subject: [PATCH] tpm_tis_spi: Account for SPI header when allocating TPM SPI xfer buffer commit 1547183852dcdfcc25878db7dd3620509217b0cd upstream. [ Upstream commit 195aba96b854dd664768f382cd1db375d8181f88 ] The TPM SPI transfer mechanism uses MAX_SPI_FRAMESIZE for computing the maximum transfer length and the size of the transfer buffer. As such, it does not account for the 4 bytes of header that prepends the SPI data frame. This can result in out-of-bounds accesses and was confirmed with KASAN. Introduce SPI_HDRSIZE to account for the header and use to allocate the transfer buffer. Fixes: a86a42ac2bd6 ("tpm_tis_spi: Add hardware wait polling") Signed-off-by: Matthew R. Ochs Tested-by: Carol Soto Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen Signed-off-by: Sasha Levin Fixes: CVE-2024-36477 Signed-off-by: Enpei Zhang Signed-off-by: Wenya Zhang Reviewed-by: Xuexin Jiang --- drivers/char/tpm/tpm_tis_spi_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/char/tpm/tpm_tis_spi_main.c b/drivers/char/tpm/tpm_tis_spi_main.c index c5c3197ee29f..4bdad9e3667f 100644 --- a/drivers/char/tpm/tpm_tis_spi_main.c +++ b/drivers/char/tpm/tpm_tis_spi_main.c @@ -37,6 +37,7 @@ #include "tpm_tis_spi.h" #define MAX_SPI_FRAMESIZE 64 +#define SPI_HDRSIZE 4 /* * TCG SPI flow control is documented in section 6.4 of the spec[1]. In short, @@ -247,7 +248,7 @@ static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr, int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy, int irq, const struct tpm_tis_phy_ops *phy_ops) { - phy->iobuf = devm_kmalloc(&spi->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL); + phy->iobuf = devm_kmalloc(&spi->dev, SPI_HDRSIZE + MAX_SPI_FRAMESIZE, GFP_KERNEL); if (!phy->iobuf) return -ENOMEM; -- Gitee