2021-04-03 06:11:47

by Lv Yunlong

Subject: [PATCH] mtd: nand: gpmi: Fix a double free in gpmi_nand_init

If the callee gpmi_alloc_dma_buffer() failed to alloc memory for
this->raw_buffer, gpmi_free_dma_buffer() will be called to free
this->auxiliary_virt. But this->auxiliary_virt is still a non-NULL
and valid ptr.

Then gpmi_alloc_dma_buffer() returns err and gpmi_free_dma_buffer()
is called again to free this->auxiliary_virt in err_out. This causes
a double free.

As gpmi_free_dma_buffer() has already called in gpmi_alloc_dma_buffer's
error path, so it should return err directly instead of releasing the dma
buffer again.

Fixes: 4d02423e9afe6 ("mtd: nand: gpmi: Fix gpmi_nand_init() error path")
Signed-off-by: Lv Yunlong <[email protected]>
---
drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
index 3fa8c22d3f36..4d08e4ab5c1b 100644
--- a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
+++ b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
@@ -2449,7 +2449,7 @@ static int gpmi_nand_init(struct gpmi_nand_data *this)
this->bch_geometry.auxiliary_size = 128;
ret = gpmi_alloc_dma_buffer(this);
if (ret)
- goto err_out;
+ return ret;

nand_controller_init(&this->base);
this->base.ops = &gpmi_nand_controller_ops;
--
2.25.1

2021-04-07 20:38:56

by Miquel Raynal

Subject: Re: [PATCH] mtd: nand: gpmi: Fix a double free in gpmi_nand_init

On Sat, 2021-04-03 at 06:09:05 UTC, Lv Yunlong wrote:
> If the callee gpmi_alloc_dma_buffer() failed to alloc memory for
> this->raw_buffer, gpmi_free_dma_buffer() will be called to free
> this->auxiliary_virt. But this->auxiliary_virt is still a non-NULL
> and valid ptr.
>
> Then gpmi_alloc_dma_buffer() returns err and gpmi_free_dma_buffer()
> is called again to free this->auxiliary_virt in err_out. This causes
> a double free.
>
> As gpmi_free_dma_buffer() has already called in gpmi_alloc_dma_buffer's
> error path, so it should return err directly instead of releasing the dma
> buffer again.
>
> Fixes: 4d02423e9afe6 ("mtd: nand: gpmi: Fix gpmi_nand_init() error path")
> Signed-off-by: Lv Yunlong <[email protected]>

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git nand/next, thanks.

Miquel