| Message ID | 1508484229-19706-3-git-send-email-elena.reshetova@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 2017-10-20 at 10:23 +0300, Elena Reshetova wrote: > atomic_t variables are currently used to implement reference > counters with the following properties: > - counter is initialized to 1 using atomic_set() > - a resource is freed upon counter reaching zero > - once counter reaches zero, its further > increments aren't allowed > - counter schema uses basic atomic operations > (set, inc, inc_not_zero, dec_and_test, etc.) > > Such atomic variables should be converted to a newly provided > refcount_t type and API that prevents accidental counter overflows > and underflows. This is important since overflows and underflows > can lead to use-after-free situation and be exploitable. > > The variable mtk_eth.dma_refcnt is used as pure reference counter. > Convert it to refcount_t and fix up the operations. > > Suggested-by: Kees Cook <keescook@chromium.org> > Reviewed-by: David Windsor <dwindsor@gmail.com> > Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> > Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> > --- > drivers/net/ethernet/mediatek/mtk_eth_soc.c | 8 +++++--- > drivers/net/ethernet/mediatek/mtk_eth_soc.h | 4 +++- > 2 files changed, 8 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c > index 5e81a72..54adfd9 100644 > --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c > +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c > @@ -1817,7 +1817,7 @@ static int mtk_open(struct net_device *dev) > struct mtk_eth *eth = mac->hw; > > /* we run 2 netdevs on the same dma ring so we only bring it up once */ > - if (!atomic_read(ð->dma_refcnt)) { > + if (!refcount_read(ð->dma_refcnt)) { > int err = mtk_start_dma(eth); > > if (err) > @@ -1827,8 +1827,10 @@ static int mtk_open(struct net_device *dev) > napi_enable(ð->rx_napi); > mtk_tx_irq_enable(eth, MTK_TX_DONE_INT); > mtk_rx_irq_enable(eth, MTK_RX_DONE_INT); > + refcount_set(ð->dma_refcnt, 1); the existing driver seems to have a missing initial atomic_set for the eth->dma_refcnt. > } > - atomic_inc(ð->dma_refcnt); > + else > + refcount_inc(ð->dma_refcnt); > how about add the initial refcount_set into probe handler, and keep logic else unchanged ? > phy_start(dev->phydev); > netif_start_queue(dev); > @@ -1868,7 +1870,7 @@ static int mtk_stop(struct net_device *dev) > phy_stop(dev->phydev); > > /* only shutdown DMA if this is the last user */ > - if (!atomic_dec_and_test(ð->dma_refcnt)) > + if (!refcount_dec_and_test(ð->dma_refcnt)) > return 0; > > mtk_tx_irq_disable(eth, MTK_TX_DONE_INT); > diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h > index 3d3c24a..a3af466 100644 > --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h > +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h > @@ -15,6 +15,8 @@ > #ifndef MTK_ETH_H > #define MTK_ETH_H > > +#include <linux/refcount.h> > + > #define MTK_QDMA_PAGE_SIZE 2048 > #define MTK_MAX_RX_LENGTH 1536 > #define MTK_TX_DMA_BUF_LEN 0x3fff > @@ -632,7 +634,7 @@ struct mtk_eth { > struct regmap *pctl; > u32 chip_id; > bool hwlro; > - atomic_t dma_refcnt; > + refcount_t dma_refcnt; > struct mtk_tx_ring tx_ring; > struct mtk_rx_ring rx_ring[MTK_MAX_RX_RING_NUM]; > struct mtk_rx_ring rx_ring_qdma;
> On Fri, 2017-10-20 at 10:23 +0300, Elena Reshetova wrote: > > atomic_t variables are currently used to implement reference > > counters with the following properties: > > - counter is initialized to 1 using atomic_set() > > - a resource is freed upon counter reaching zero > > - once counter reaches zero, its further > > increments aren't allowed > > - counter schema uses basic atomic operations > > (set, inc, inc_not_zero, dec_and_test, etc.) > > > > Such atomic variables should be converted to a newly provided > > refcount_t type and API that prevents accidental counter overflows > > and underflows. This is important since overflows and underflows > > can lead to use-after-free situation and be exploitable. > > > > The variable mtk_eth.dma_refcnt is used as pure reference counter. > > Convert it to refcount_t and fix up the operations. > > > > Suggested-by: Kees Cook <keescook@chromium.org> > > Reviewed-by: David Windsor <dwindsor@gmail.com> > > Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> > > Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> > > --- > > drivers/net/ethernet/mediatek/mtk_eth_soc.c | 8 +++++--- > > drivers/net/ethernet/mediatek/mtk_eth_soc.h | 4 +++- > > 2 files changed, 8 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c > b/drivers/net/ethernet/mediatek/mtk_eth_soc.c > > index 5e81a72..54adfd9 100644 > > --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c > > +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c > > @@ -1817,7 +1817,7 @@ static int mtk_open(struct net_device *dev) > > struct mtk_eth *eth = mac->hw; > > > > /* we run 2 netdevs on the same dma ring so we only bring it up once > */ > > - if (!atomic_read(ð->dma_refcnt)) { > > + if (!refcount_read(ð->dma_refcnt)) { > > int err = mtk_start_dma(eth); > > > > if (err) > > @@ -1827,8 +1827,10 @@ static int mtk_open(struct net_device *dev) > > napi_enable(ð->rx_napi); > > mtk_tx_irq_enable(eth, MTK_TX_DONE_INT); > > mtk_rx_irq_enable(eth, MTK_RX_DONE_INT); > > + refcount_set(ð->dma_refcnt, 1); > > the existing driver seems to have a missing initial atomic_set for the > eth->dma_refcnt. > > > } > > - atomic_inc(ð->dma_refcnt); > > + else > > + refcount_inc(ð->dma_refcnt); > > > > how about add the initial refcount_set into probe handler, and keep > logic else unchanged ? Sure, I guess you mean mtk_probe() function? I can move the refcount_set to be there and remove this change. Should I resend the modified patch to you (maybe then two of the ethernet patches)? Best Regards, Elena. > > > phy_start(dev->phydev); > > netif_start_queue(dev); > > @@ -1868,7 +1870,7 @@ static int mtk_stop(struct net_device *dev) > > phy_stop(dev->phydev); > > > > /* only shutdown DMA if this is the last user */ > > - if (!atomic_dec_and_test(ð->dma_refcnt)) > > + if (!refcount_dec_and_test(ð->dma_refcnt)) > > return 0; > > > > mtk_tx_irq_disable(eth, MTK_TX_DONE_INT); > > diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h > b/drivers/net/ethernet/mediatek/mtk_eth_soc.h > > index 3d3c24a..a3af466 100644 > > --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h > > +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h > > @@ -15,6 +15,8 @@ > > #ifndef MTK_ETH_H > > #define MTK_ETH_H > > > > +#include <linux/refcount.h> > > + > > #define MTK_QDMA_PAGE_SIZE 2048 > > #define MTK_MAX_RX_LENGTH 1536 > > #define MTK_TX_DMA_BUF_LEN 0x3fff > > @@ -632,7 +634,7 @@ struct mtk_eth { > > struct regmap *pctl; > > u32 chip_id; > > bool hwlro; > > - atomic_t dma_refcnt; > > + refcount_t dma_refcnt; > > struct mtk_tx_ring tx_ring; > > struct mtk_rx_ring > rx_ring[MTK_MAX_RX_RING_NUM]; > > struct mtk_rx_ring rx_ring_qdma; >
On Fri, 2017-10-20 at 10:37 +0000, Reshetova, Elena wrote: > > On Fri, 2017-10-20 at 10:23 +0300, Elena Reshetova wrote: > > > atomic_t variables are currently used to implement reference > > > counters with the following properties: > > > - counter is initialized to 1 using atomic_set() > > > - a resource is freed upon counter reaching zero > > > - once counter reaches zero, its further > > > increments aren't allowed > > > - counter schema uses basic atomic operations > > > (set, inc, inc_not_zero, dec_and_test, etc.) > > > > > > Such atomic variables should be converted to a newly provided > > > refcount_t type and API that prevents accidental counter overflows > > > and underflows. This is important since overflows and underflows > > > can lead to use-after-free situation and be exploitable. > > > > > > The variable mtk_eth.dma_refcnt is used as pure reference counter. > > > Convert it to refcount_t and fix up the operations. > > > > > > Suggested-by: Kees Cook <keescook@chromium.org> > > > Reviewed-by: David Windsor <dwindsor@gmail.com> > > > Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> > > > Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> > > > --- > > > drivers/net/ethernet/mediatek/mtk_eth_soc.c | 8 +++++--- > > > drivers/net/ethernet/mediatek/mtk_eth_soc.h | 4 +++- > > > 2 files changed, 8 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c > > b/drivers/net/ethernet/mediatek/mtk_eth_soc.c > > > index 5e81a72..54adfd9 100644 > > > --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c > > > +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c > > > @@ -1817,7 +1817,7 @@ static int mtk_open(struct net_device *dev) > > > struct mtk_eth *eth = mac->hw; > > > > > > /* we run 2 netdevs on the same dma ring so we only bring it up once > > */ > > > - if (!atomic_read(ð->dma_refcnt)) { > > > + if (!refcount_read(ð->dma_refcnt)) { > > > int err = mtk_start_dma(eth); > > > > > > if (err) > > > @@ -1827,8 +1827,10 @@ static int mtk_open(struct net_device *dev) > > > napi_enable(ð->rx_napi); > > > mtk_tx_irq_enable(eth, MTK_TX_DONE_INT); > > > mtk_rx_irq_enable(eth, MTK_RX_DONE_INT); > > > + refcount_set(ð->dma_refcnt, 1); > > > > the existing driver seems to have a missing initial atomic_set for the > > eth->dma_refcnt. > > > > > } > > > - atomic_inc(ð->dma_refcnt); > > > + else > > > + refcount_inc(ð->dma_refcnt); > > > > > > > how about add the initial refcount_set into probe handler, and keep > > logic else unchanged ? > > Sure, I guess you mean mtk_probe() function? I can move the refcount_set to be there > and remove this change. > > Should I resend the modified patch to you (maybe then two of the ethernet patches)? > > Best Regards, > Elena. The entire series has been applies to net-next, I think I can make the follow-ups patches relative to your work. Sean > > > > > phy_start(dev->phydev); > > > netif_start_queue(dev); > > > @@ -1868,7 +1870,7 @@ static int mtk_stop(struct net_device *dev) > > > phy_stop(dev->phydev); > > > > > > /* only shutdown DMA if this is the last user */ > > > - if (!atomic_dec_and_test(ð->dma_refcnt)) > > > + if (!refcount_dec_and_test(ð->dma_refcnt)) > > > return 0; > > > > > > mtk_tx_irq_disable(eth, MTK_TX_DONE_INT); > > > diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h > > b/drivers/net/ethernet/mediatek/mtk_eth_soc.h > > > index 3d3c24a..a3af466 100644 > > > --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h > > > +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h > > > @@ -15,6 +15,8 @@ > > > #ifndef MTK_ETH_H > > > #define MTK_ETH_H > > > > > > +#include <linux/refcount.h> > > > + > > > #define MTK_QDMA_PAGE_SIZE 2048 > > > #define MTK_MAX_RX_LENGTH 1536 > > > #define MTK_TX_DMA_BUF_LEN 0x3fff > > > @@ -632,7 +634,7 @@ struct mtk_eth { > > > struct regmap *pctl; > > > u32 chip_id; > > > bool hwlro; > > > - atomic_t dma_refcnt; > > > + refcount_t dma_refcnt; > > > struct mtk_tx_ring tx_ring; > > > struct mtk_rx_ring > > rx_ring[MTK_MAX_RX_RING_NUM]; > > > struct mtk_rx_ring rx_ring_qdma; > > >
> On Fri, 2017-10-20 at 10:37 +0000, Reshetova, Elena wrote: > > > On Fri, 2017-10-20 at 10:23 +0300, Elena Reshetova wrote: > > > > atomic_t variables are currently used to implement reference > > > > counters with the following properties: > > > > - counter is initialized to 1 using atomic_set() > > > > - a resource is freed upon counter reaching zero > > > > - once counter reaches zero, its further > > > > increments aren't allowed > > > > - counter schema uses basic atomic operations > > > > (set, inc, inc_not_zero, dec_and_test, etc.) > > > > > > > > Such atomic variables should be converted to a newly provided > > > > refcount_t type and API that prevents accidental counter overflows > > > > and underflows. This is important since overflows and underflows > > > > can lead to use-after-free situation and be exploitable. > > > > > > > > The variable mtk_eth.dma_refcnt is used as pure reference counter. > > > > Convert it to refcount_t and fix up the operations. > > > > > > > > Suggested-by: Kees Cook <keescook@chromium.org> > > > > Reviewed-by: David Windsor <dwindsor@gmail.com> > > > > Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> > > > > Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> > > > > --- > > > > drivers/net/ethernet/mediatek/mtk_eth_soc.c | 8 +++++--- > > > > drivers/net/ethernet/mediatek/mtk_eth_soc.h | 4 +++- > > > > 2 files changed, 8 insertions(+), 4 deletions(-) > > > > > > > > diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c > > > b/drivers/net/ethernet/mediatek/mtk_eth_soc.c > > > > index 5e81a72..54adfd9 100644 > > > > --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c > > > > +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c > > > > @@ -1817,7 +1817,7 @@ static int mtk_open(struct net_device *dev) > > > > struct mtk_eth *eth = mac->hw; > > > > > > > > /* we run 2 netdevs on the same dma ring so we only bring it up once > > > */ > > > > - if (!atomic_read(ð->dma_refcnt)) { > > > > + if (!refcount_read(ð->dma_refcnt)) { > > > > int err = mtk_start_dma(eth); > > > > > > > > if (err) > > > > @@ -1827,8 +1827,10 @@ static int mtk_open(struct net_device *dev) > > > > napi_enable(ð->rx_napi); > > > > mtk_tx_irq_enable(eth, MTK_TX_DONE_INT); > > > > mtk_rx_irq_enable(eth, MTK_RX_DONE_INT); > > > > + refcount_set(ð->dma_refcnt, 1); > > > > > > the existing driver seems to have a missing initial atomic_set for the > > > eth->dma_refcnt. > > > > > > > } > > > > - atomic_inc(ð->dma_refcnt); > > > > + else > > > > + refcount_inc(ð->dma_refcnt); > > > > > > > > > > how about add the initial refcount_set into probe handler, and keep > > > logic else unchanged ? > > > > Sure, I guess you mean mtk_probe() function? I can move the refcount_set to be > there > > and remove this change. > > > > Should I resend the modified patch to you (maybe then two of the ethernet > patches)? > > > > Best Regards, > > Elena. > > The entire series has been applies to net-next, I think I can make the > follow-ups patches relative to your work. > > Sean Yes, I just noticed that David took them all. Sure, if you want to send the follow up yourself, I certainly would not mind, I still have many of these recount patches for different parts of kernel :) Thank you! Best Regards, Elena. > > > > > > > > phy_start(dev->phydev); > > > > netif_start_queue(dev); > > > > @@ -1868,7 +1870,7 @@ static int mtk_stop(struct net_device *dev) > > > > phy_stop(dev->phydev); > > > > > > > > /* only shutdown DMA if this is the last user */ > > > > - if (!atomic_dec_and_test(ð->dma_refcnt)) > > > > + if (!refcount_dec_and_test(ð->dma_refcnt)) > > > > return 0; > > > > > > > > mtk_tx_irq_disable(eth, MTK_TX_DONE_INT); > > > > diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h > > > b/drivers/net/ethernet/mediatek/mtk_eth_soc.h > > > > index 3d3c24a..a3af466 100644 > > > > --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h > > > > +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h > > > > @@ -15,6 +15,8 @@ > > > > #ifndef MTK_ETH_H > > > > #define MTK_ETH_H > > > > > > > > +#include <linux/refcount.h> > > > > + > > > > #define MTK_QDMA_PAGE_SIZE 2048 > > > > #define MTK_MAX_RX_LENGTH 1536 > > > > #define MTK_TX_DMA_BUF_LEN 0x3fff > > > > @@ -632,7 +634,7 @@ struct mtk_eth { > > > > struct regmap *pctl; > > > > u32 chip_id; > > > > bool hwlro; > > > > - atomic_t dma_refcnt; > > > > + refcount_t dma_refcnt; > > > > struct mtk_tx_ring tx_ring; > > > > struct mtk_rx_ring > > > rx_ring[MTK_MAX_RX_RING_NUM]; > > > > struct mtk_rx_ring rx_ring_qdma; > > > > > >
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c index 5e81a72..54adfd9 100644 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c @@ -1817,7 +1817,7 @@ static int mtk_open(struct net_device *dev) struct mtk_eth *eth = mac->hw; /* we run 2 netdevs on the same dma ring so we only bring it up once */ - if (!atomic_read(ð->dma_refcnt)) { + if (!refcount_read(ð->dma_refcnt)) { int err = mtk_start_dma(eth); if (err) @@ -1827,8 +1827,10 @@ static int mtk_open(struct net_device *dev) napi_enable(ð->rx_napi); mtk_tx_irq_enable(eth, MTK_TX_DONE_INT); mtk_rx_irq_enable(eth, MTK_RX_DONE_INT); + refcount_set(ð->dma_refcnt, 1); } - atomic_inc(ð->dma_refcnt); + else + refcount_inc(ð->dma_refcnt); phy_start(dev->phydev); netif_start_queue(dev); @@ -1868,7 +1870,7 @@ static int mtk_stop(struct net_device *dev) phy_stop(dev->phydev); /* only shutdown DMA if this is the last user */ - if (!atomic_dec_and_test(ð->dma_refcnt)) + if (!refcount_dec_and_test(ð->dma_refcnt)) return 0; mtk_tx_irq_disable(eth, MTK_TX_DONE_INT); diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h index 3d3c24a..a3af466 100644 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h @@ -15,6 +15,8 @@ #ifndef MTK_ETH_H #define MTK_ETH_H +#include <linux/refcount.h> + #define MTK_QDMA_PAGE_SIZE 2048 #define MTK_MAX_RX_LENGTH 1536 #define MTK_TX_DMA_BUF_LEN 0x3fff @@ -632,7 +634,7 @@ struct mtk_eth { struct regmap *pctl; u32 chip_id; bool hwlro; - atomic_t dma_refcnt; + refcount_t dma_refcnt; struct mtk_tx_ring tx_ring; struct mtk_rx_ring rx_ring[MTK_MAX_RX_RING_NUM]; struct mtk_rx_ring rx_ring_qdma;