[PATCH 5.4 116/215] mmc: core: Avoid negative index with array access

Greg Kroah-Hartman
2024-04-11T10:19:39Z

From: Mikko Rapeli <mikko.rapeli@linaro.org>

commit cf55a7acd1ed38afe43bba1c8a0935b51d1dc014 upstream.

Commit 4d0c8d0aef63 ("mmc: core: Use mrq.sbc in close-ended ffu") assigns
prev_idata = idatas[i - 1], but doesn't check that the iterator i is
greater than zero. Let's fix this by adding a check.

Fixes: 4d0c8d0aef63 ("mmc: core: Use mrq.sbc in close-ended ffu")
Link: https://lore.kernel.org/all/20231129092535.3278-1-avri.altman@wdc.com/
Cc: stable@vger.kernel.org
Signed-off-by: Mikko Rapeli <mikko.rapeli@linaro.org>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Tested-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Link: https://lore.kernel.org/r/20240313133744.2405325-2-mikko.rapeli@linaro.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/mmc/core/block.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -511,7 +511,7 @@ static int __mmc_blk_ioctl_cmd(struct mm
if (idata->flags & MMC_BLK_IOC_DROP)
return 0;

- if (idata->flags & MMC_BLK_IOC_SBC)
+ if (idata->flags & MMC_BLK_IOC_SBC && i > 0)
prev_idata = idatas[i - 1];

/*