Messages in this thread | | | From | Ulf Hansson <> | Date | Thu, 22 Apr 2021 10:08:45 +0200 | Subject | Re: [PATCH 088/190] Revert "mmc_spi: add a status check for spi_sync_locked" |
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On Wed, 21 Apr 2021 at 15:19, Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote: > > Hi Greg, > > Thank you for the patch. > > On Wed, Apr 21, 2021 at 02:59:23PM +0200, Greg Kroah-Hartman wrote: > > This reverts commit 611025983b7976df0183390a63a2166411d177f1. > > > > Commits from @umn.edu addresses have been found to be submitted in "bad > > faith" to try to test the kernel community's ability to review "known > > malicious" changes. The result of these submissions can be found in a > > paper published at the 42nd IEEE Symposium on Security and Privacy > > entitled, "Open Source Insecurity: Stealthily Introducing > > Vulnerabilities via Hypocrite Commits" written by Qiushi Wu (University > > of Minnesota) and Kangjie Lu (University of Minnesota). > > > > Because of this, all submissions from this group must be reverted from > > the kernel tree and will need to be re-reviewed again to determine if > > they actually are a valid fix. Until that work is complete, remove this > > change to ensure that no problems are being introduced into the > > codebase. > > > > Cc: Kangjie Lu <kjlu@umn.edu> > > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > > Cc: Ulf Hansson <ulf.hansson@linaro.org> > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > > I don't spot an obvious issue with the original patch though. > > > --- > > drivers/mmc/host/mmc_spi.c | 4 ---- > > 1 file changed, 4 deletions(-) > > > > diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c > > index 02f4fd26e76a..cc40b050e302 100644 > > --- a/drivers/mmc/host/mmc_spi.c > > +++ b/drivers/mmc/host/mmc_spi.c > > @@ -800,10 +800,6 @@ mmc_spi_readblock(struct mmc_spi_host *host, struct spi_transfer *t, > > } > > > > status = spi_sync_locked(spi, &host->m); > > - if (status < 0) { > > - dev_dbg(&spi->dev, "read error %d\n", status); > > - return status; > > - }
Returning here means we never give back the ownership of the buffer to the CPU. Can that be considered as vulnerability?
If that is that a problem, I can point out that there is already one more case in this file, where this pattern is repeated. See mmc_spi_writeblock(). This code has been there since 2007.
> > > > if (host->dma_dev) { > > dma_sync_single_for_cpu(host->dma_dev, > > -- > Regards, > > Laurent Pinchart
Kind regards Uffe
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