| Message ID | DB3PR10MB6835E073F668AD24F57AE64AE8A5A@DB3PR10MB6835.EURPRD10.PROD.OUTLOOK.COM (mailing list archive) |
|---|---|
| State | Rejected |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Prevent out-of-bounds read/write in bcmasp_netfilt_rd and bcmasp_netfilt_wr | expand |
On Fri, Nov 03, 2023 at 05:57:48PM +0530, Yuran Pereira wrote: > The functions `bcmasp_netfilt_rd` and `bcmasp_netfilt_wr` both call > `bcmasp_netfilt_get_reg_offset` which, when it fails, returns `-EINVAL`. > This could lead to an out-of-bounds read or write when `rx_filter_core_rl` > or `rx_filter_core_wl` is called. > > This patch adds a check in both functions to return immediately if > `bcmasp_netfilt_get_reg_offset` fails. This prevents potential out-of-bounds read > or writes, and ensures that no undefined or buggy behavior would originate from > the failure of `bcmasp_netfilt_get_reg_offset`. > > Addresses-Coverity-IDs: 1544536 ("Out-of-bounds access") > Signed-off-by: Yuran Pereira <yuran.pereira@hotmail.com> > --- > drivers/net/ethernet/broadcom/asp2/bcmasp.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/net/ethernet/broadcom/asp2/bcmasp.c b/drivers/net/ethernet/broadcom/asp2/bcmasp.c > index 29b04a274d07..8b90b761bdec 100644 > --- a/drivers/net/ethernet/broadcom/asp2/bcmasp.c > +++ b/drivers/net/ethernet/broadcom/asp2/bcmasp.c > @@ -227,6 +227,8 @@ static void bcmasp_netfilt_wr(struct bcmasp_priv *priv, > > reg_offset = bcmasp_netfilt_get_reg_offset(priv, nfilt, reg_type, > offset); > + if (reg_offset < 0) > + return; > > rx_filter_core_wl(priv, val, reg_offset); > } > @@ -244,6 +246,8 @@ static u32 bcmasp_netfilt_rd(struct bcmasp_priv *priv, > > reg_offset = bcmasp_netfilt_get_reg_offset(priv, nfilt, reg_type, > offset); > + if (reg_offset < 0) > + return 0; Shouldn't you return an error here? thanks greg k-h
Hello Greg, On Fri, Nov 03, 2023 at 01:57:13PM +0100, Greg KH wrote: > > reg_offset = bcmasp_netfilt_get_reg_offset(priv, nfilt, reg_type, > > offset); > > + if (reg_offset < 0) > > + return 0; > > Shouldn't you return an error here? Yes, I think that makes sense. I might just return `reg_offset` since it is bound to be -EINVAL when bcmasp_netfilt_get_reg_offset fails. But that now makes me wonder whether the previous check in that function which currently returns 0, shouldn't be returning `-EINVAL` instead. ``` static u32 bcmasp_netfilt_rd(struct bcmasp_priv *priv, ... { if (!IS_ALIGNED(offset, 4) || offset > MAX_WAKE_FILTER_SIZE) return 0; <----- Should this one be -EINVAL? } ``` Thank you for the feedback. Yuran
I guess that explains why the first check returns 0.
```
static int bcmasp_netfilt_wr_m_wake(struct bcmasp_priv *priv,
...
{
...
if (first_byte && (!IS_ALIGNED(offset, 4) || size < 3)) {
match_val = bcmasp_netfilt_rd(priv, nfilt,
ASP_NETFILT_MATCH,
ALIGN_DOWN(offset, 4));
mask_val = bcmasp_netfilt_rd(priv, nfilt,
ASP_NETFILT_MASK,
ALIGN_DOWN(offset, 4));
}
shift = (3 - (offset % 4)) * 8;
match_val &= ~GENMASK(shift + 7, shift);
mask_val &= ~GENMASK(shift + 7, shift);
match_val |= (u32)(*((u8 *)match) << shift);
mask_val |= (u32)(*((u8 *)mask) << shift);
```
On a second thought, it might not be a good idea to return
an error without modifying the caller, since the caller of
this function currently uses this return value without checking
if it's an error.
I guess that explains why the first check returns 0.
```
static int bcmasp_netfilt_wr_m_wake(struct bcmasp_priv *priv,
...
{
...
if (first_byte && (!IS_ALIGNED(offset, 4) || size < 3)) {
match_val = bcmasp_netfilt_rd(priv, nfilt,
ASP_NETFILT_MATCH,
ALIGN_DOWN(offset, 4));
mask_val = bcmasp_netfilt_rd(priv, nfilt,
ASP_NETFILT_MASK,
ALIGN_DOWN(offset, 4));
}
shift = (3 - (offset % 4)) * 8;
match_val &= ~GENMASK(shift + 7, shift);
mask_val &= ~GENMASK(shift + 7, shift);
match_val |= (u32)(*((u8 *)match) << shift);
mask_val |= (u32)(*((u8 *)mask) << shift);
```
On 11/3/23 5:57 AM, Greg KH wrote: > On Fri, Nov 03, 2023 at 05:57:48PM +0530, Yuran Pereira wrote: >> The functions `bcmasp_netfilt_rd` and `bcmasp_netfilt_wr` both call >> `bcmasp_netfilt_get_reg_offset` which, when it fails, returns `-EINVAL`. >> This could lead to an out-of-bounds read or write when `rx_filter_core_rl` >> or `rx_filter_core_wl` is called. >> >> This patch adds a check in both functions to return immediately if >> `bcmasp_netfilt_get_reg_offset` fails. This prevents potential out-of-bounds read >> or writes, and ensures that no undefined or buggy behavior would originate from >> the failure of `bcmasp_netfilt_get_reg_offset`. >> >> Addresses-Coverity-IDs: 1544536 ("Out-of-bounds access") >> Signed-off-by: Yuran Pereira <yuran.pereira@hotmail.com> >> --- >> drivers/net/ethernet/broadcom/asp2/bcmasp.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/net/ethernet/broadcom/asp2/bcmasp.c b/drivers/net/ethernet/broadcom/asp2/bcmasp.c >> index 29b04a274d07..8b90b761bdec 100644 >> --- a/drivers/net/ethernet/broadcom/asp2/bcmasp.c >> +++ b/drivers/net/ethernet/broadcom/asp2/bcmasp.c >> @@ -227,6 +227,8 @@ static void bcmasp_netfilt_wr(struct bcmasp_priv *priv, >> >> reg_offset = bcmasp_netfilt_get_reg_offset(priv, nfilt, reg_type, >> offset); >> + if (reg_offset < 0) >> + return; >> >> rx_filter_core_wl(priv, val, reg_offset); >> } >> @@ -244,6 +246,8 @@ static u32 bcmasp_netfilt_rd(struct bcmasp_priv *priv, >> >> reg_offset = bcmasp_netfilt_get_reg_offset(priv, nfilt, reg_type, >> offset); >> + if (reg_offset < 0) >> + return 0; > > Shouldn't you return an error here? > > thanks > > greg k-h As long as offset is less than MAX_WAKE_FILTER_SIZE we don't need to worry about error checking. This is already checked before we call netfilt_get_reg_offset() in both cases. Instead of returning -EINVAL in neffilt_get_reg_offset() lets return 0. This will silence the coverity check. In practice we will never hit this logic. Thanks, Justin
On Fri, Nov 03, 2023 at 11:23:16AM -0700, Justin Chen wrote: > > > On 11/3/23 5:57 AM, Greg KH wrote: > > On Fri, Nov 03, 2023 at 05:57:48PM +0530, Yuran Pereira wrote: > > > The functions `bcmasp_netfilt_rd` and `bcmasp_netfilt_wr` both call > > > `bcmasp_netfilt_get_reg_offset` which, when it fails, returns `-EINVAL`. > > > This could lead to an out-of-bounds read or write when `rx_filter_core_rl` > > > or `rx_filter_core_wl` is called. > > > > > > This patch adds a check in both functions to return immediately if > > > `bcmasp_netfilt_get_reg_offset` fails. This prevents potential out-of-bounds read > > > or writes, and ensures that no undefined or buggy behavior would originate from > > > the failure of `bcmasp_netfilt_get_reg_offset`. > > > > > > Addresses-Coverity-IDs: 1544536 ("Out-of-bounds access") > > > Signed-off-by: Yuran Pereira <yuran.pereira@hotmail.com> > > > --- > > > drivers/net/ethernet/broadcom/asp2/bcmasp.c | 4 ++++ > > > 1 file changed, 4 insertions(+) > > > > > > diff --git a/drivers/net/ethernet/broadcom/asp2/bcmasp.c b/drivers/net/ethernet/broadcom/asp2/bcmasp.c > > > index 29b04a274d07..8b90b761bdec 100644 > > > --- a/drivers/net/ethernet/broadcom/asp2/bcmasp.c > > > +++ b/drivers/net/ethernet/broadcom/asp2/bcmasp.c > > > @@ -227,6 +227,8 @@ static void bcmasp_netfilt_wr(struct bcmasp_priv *priv, > > > reg_offset = bcmasp_netfilt_get_reg_offset(priv, nfilt, reg_type, > > > offset); > > > + if (reg_offset < 0) > > > + return; > > > rx_filter_core_wl(priv, val, reg_offset); > > > } > > > @@ -244,6 +246,8 @@ static u32 bcmasp_netfilt_rd(struct bcmasp_priv *priv, > > > reg_offset = bcmasp_netfilt_get_reg_offset(priv, nfilt, reg_type, > > > offset); > > > + if (reg_offset < 0) > > > + return 0; > > > > Shouldn't you return an error here? > > > > thanks > > > > greg k-h > > As long as offset is less than MAX_WAKE_FILTER_SIZE we don't need to worry > about error checking. This is already checked before we call > netfilt_get_reg_offset() in both cases. Instead of returning -EINVAL in > neffilt_get_reg_offset() lets return 0. This will silence the coverity > check. In practice we will never hit this logic. Then don't change it, coverity is incorrect here. greg k-h
diff --git a/drivers/net/ethernet/broadcom/asp2/bcmasp.c b/drivers/net/ethernet/broadcom/asp2/bcmasp.c index 29b04a274d07..8b90b761bdec 100644 --- a/drivers/net/ethernet/broadcom/asp2/bcmasp.c +++ b/drivers/net/ethernet/broadcom/asp2/bcmasp.c @@ -227,6 +227,8 @@ static void bcmasp_netfilt_wr(struct bcmasp_priv *priv, reg_offset = bcmasp_netfilt_get_reg_offset(priv, nfilt, reg_type, offset); + if (reg_offset < 0) + return; rx_filter_core_wl(priv, val, reg_offset); } @@ -244,6 +246,8 @@ static u32 bcmasp_netfilt_rd(struct bcmasp_priv *priv, reg_offset = bcmasp_netfilt_get_reg_offset(priv, nfilt, reg_type, offset); + if (reg_offset < 0) + return 0; return rx_filter_core_rl(priv, reg_offset); }
The functions `bcmasp_netfilt_rd` and `bcmasp_netfilt_wr` both call `bcmasp_netfilt_get_reg_offset` which, when it fails, returns `-EINVAL`. This could lead to an out-of-bounds read or write when `rx_filter_core_rl` or `rx_filter_core_wl` is called. This patch adds a check in both functions to return immediately if `bcmasp_netfilt_get_reg_offset` fails. This prevents potential out-of-bounds read or writes, and ensures that no undefined or buggy behavior would originate from the failure of `bcmasp_netfilt_get_reg_offset`. Addresses-Coverity-IDs: 1544536 ("Out-of-bounds access") Signed-off-by: Yuran Pereira <yuran.pereira@hotmail.com> --- drivers/net/ethernet/broadcom/asp2/bcmasp.c | 4 ++++ 1 file changed, 4 insertions(+)