-----Original Message----- From: Greg Malysa greg.malysa@timesys.com Sent: Tuesday, March 26, 2024 11:23 AM To: u-boot@lists.denx.de; Peng Fan peng.fan@nxp.com; Jaehoon Chung jh80.chung@samsung.com Cc: Ian Roberts ian.roberts@timesys.com; Nathan Barrett-Morrison nathan.morrison@timesys.com; Greg Malysa greg.malysa@timesys.com; Sean Anderson sean.anderson@seco.com; Tom Rini trini@konsulko.com Subject: [PATCH] mmc: sdhci: Fix potential ADMA descriptor table overflow
From: Ian Roberts ian.roberts@timesys.com
Change ADMA_TABLE_NO_ENTRIES to round the division up to fully contain CONFIG_SYS_MMC_MAX_BLK_COUNT, fixing potential buffer overflow of the ADMA descriptor table.
sdhci_prepare_adma_table() expecitily states it does _not_ check for overflow as the descriptor table size is dependent on CONFIG_SYS_MMC_MAX_BLK_COUNT. However, the ADMA_TABLE_NO_ENTRIES calculation does not round up the divison, so with the current u-boot defaults: max_mmc_transfer = (CONFIG_SYS_MMC_MAX_BLK_COUNT * MMC_MAX_BLOCK_LEN) = 65535 * 512 = 33553920 bytes. ADMA_TABLE_NO_ENTRIES = max_mmc_transfer / ADMA_MAX_LEN = 33553920 / 65532, which does not divide cleanly. actual_max_transfer = ADMA_TABLE_NO_ENTRIES * ADMA_MAX_LEN = 512 * 65532 = 33552384, which is smaller than max_mmc_transfer. This can cause sdhci_prepare_adma_table() to write one extra descriptor, overflowing the table when a transaction larger than actual_max_transfer is issued.
Co-developed-by: Nathan Barrett-Morrison nathan.morrison@timesys.com Signed-off-by: Nathan Barrett-Morrison nathan.morrison@timesys.com Signed-off-by: Greg Malysa greg.malysa@timesys.com Signed-off-by: Ian Roberts ian.roberts@timesys.com
Reviewed-by: Jaehoon Chung jh80.chung@samsung.com
Best Regards, Jaehoon Chung
include/sdhci.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/sdhci.h b/include/sdhci.h index a1b74e3bd7..fbc0f0391c 100644 --- a/include/sdhci.h +++ b/include/sdhci.h @@ -11,6 +11,7 @@
#include <linux/bitops.h> #include <linux/types.h> +#include <linux/kernel.h> #include <asm/io.h> #include <mmc.h> #include <asm/gpio.h> @@ -299,8 +300,8 @@ struct sdhci_ops { #else #define ADMA_DESC_LEN 8 #endif -#define ADMA_TABLE_NO_ENTRIES (CONFIG_SYS_MMC_MAX_BLK_COUNT * \
MMC_MAX_BLOCK_LEN) / ADMA_MAX_LEN+#define ADMA_TABLE_NO_ENTRIES DIV_ROUND_UP(CONFIG_SYS_MMC_MAX_BLK_COUNT * \
MMC_MAX_BLOCK_LEN, ADMA_MAX_LEN)#define ADMA_TABLE_SZ (ADMA_TABLE_NO_ENTRIES * ADMA_DESC_LEN)
-- 2.43.2