2019-12-03 10:00:08

by Dan Carpenter

Subject: [PATCH] brcmfmac: Fix use after free in brcmf_sdio_readframes()

The brcmu_pkt_buf_free_skb() function frees "pkt" so it leads to a
static checker warning:

drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c:1974 brcmf_sdio_readframes()
error: dereferencing freed memory 'pkt'

It looks like there was supposed to be a continue after we free "pkt".

Fixes: 4754fceeb9a6 ("brcmfmac: streamline SDIO read frame routine")
Signed-off-by: Dan Carpenter <[email protected]>
---
Static analysis. Not tested.

drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
index 264ad63232f8..1dea0178832e 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
@@ -1935,6 +1935,7 @@ static uint brcmf_sdio_readframes(struct brcmf_sdio *bus, uint maxframes)
BRCMF_SDIO_FT_NORMAL)) {
rd->len = 0;
brcmu_pkt_buf_free_skb(pkt);
+ continue;
}
bus->sdcnt.rx_readahead_cnt++;
if (rd->len != roundup(rd_new.len, 16)) {
--
2.11.0

2019-12-03 18:45:20

by Franky Lin

Subject: Re: [PATCH] brcmfmac: Fix use after free in brcmf_sdio_readframes()

On Tue, Dec 3, 2019 at 1:59 AM Dan Carpenter <[email protected]> wrote:
>
> The brcmu_pkt_buf_free_skb() function frees "pkt" so it leads to a
> static checker warning:
>
> drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c:1974 brcmf_sdio_readframes()
> error: dereferencing freed memory 'pkt'
>
> It looks like there was supposed to be a continue after we free "pkt".

Good catch!

Acked-by: Franky Lin <[email protected]>

>
> Fixes: 4754fceeb9a6 ("brcmfmac: streamline SDIO read frame routine")
> Signed-off-by: Dan Carpenter <[email protected]>
> ---
> Static analysis. Not tested.
>
> drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> index 264ad63232f8..1dea0178832e 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> @@ -1935,6 +1935,7 @@ static uint brcmf_sdio_readframes(struct brcmf_sdio *bus, uint maxframes)
> BRCMF_SDIO_FT_NORMAL)) {
> rd->len = 0;
> brcmu_pkt_buf_free_skb(pkt);
> + continue;
> }
> bus->sdcnt.rx_readahead_cnt++;
> if (rd->len != roundup(rd_new.len, 16)) {
> --
> 2.11.0
>