* [PATCH] e1000: avoid null pointer dereference on invalid stat type
@ 2017-09-21 22:01 Colin King
2017-09-22 11:50 ` Dan Carpenter
0 siblings, 1 reply; 3+ messages in thread
From: Colin King @ 2017-09-21 22:01 UTC (permalink / raw)
To: Jeff Kirsher, intel-wired-lan, netdev; +Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
Currently if the stat type is invalid then data[i] is being set
either by dereferencing a null pointer p, or it is reading from
an incorrect previous location if we had a valid stat type
previously. Fix this by nullify pointer p if a stat type is
invalid and only setting data if p is not null.
Detected by CoverityScan, CID#113385 ("Explicit null dereferenced")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
drivers/net/ethernet/intel/e1000/e1000_ethtool.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/intel/e1000/e1000_ethtool.c b/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
index ec8aa4562cc9..2ef6f08b580b 100644
--- a/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
+++ b/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
@@ -1824,11 +1824,12 @@ static void e1000_get_ethtool_stats(struct net_device *netdev,
{
struct e1000_adapter *adapter = netdev_priv(netdev);
int i;
- char *p = NULL;
const struct e1000_stats *stat = e1000_gstrings_stats;
e1000_update_stats(adapter);
for (i = 0; i < E1000_GLOBAL_STATS_LEN; i++) {
+ char *p;
+
switch (stat->type) {
case NETDEV_STATS:
p = (char *)netdev + stat->stat_offset;
@@ -1837,12 +1838,13 @@ static void e1000_get_ethtool_stats(struct net_device *netdev,
p = (char *)adapter + stat->stat_offset;
break;
default:
+ p = NULL;
WARN_ONCE(1, "Invalid E1000 stat type: %u index %d\n",
stat->type, i);
break;
}
- if (stat->sizeof_stat == sizeof(u64))
+ if (p && stat->sizeof_stat == sizeof(u64))
data[i] = *(u64 *)p;
else
data[i] = *(u32 *)p;
--
2.14.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] e1000: avoid null pointer dereference on invalid stat type
2017-09-21 22:01 [PATCH] e1000: avoid null pointer dereference on invalid stat type Colin King
@ 2017-09-22 11:50 ` Dan Carpenter
2017-09-22 11:55 ` Colin Ian King
0 siblings, 1 reply; 3+ messages in thread
From: Dan Carpenter @ 2017-09-22 11:50 UTC (permalink / raw)
To: Colin King
Cc: Jeff Kirsher, intel-wired-lan, netdev, kernel-janitors,
linux-kernel
On Thu, Sep 21, 2017 at 11:01:58PM +0100, Colin King wrote:
> @@ -1837,12 +1838,13 @@ static void e1000_get_ethtool_stats(struct net_device *netdev,
> p = (char *)adapter + stat->stat_offset;
> break;
> default:
> + p = NULL;
> WARN_ONCE(1, "Invalid E1000 stat type: %u index %d\n",
> stat->type, i);
> break;
> }
>
> - if (stat->sizeof_stat == sizeof(u64))
> + if (p && stat->sizeof_stat == sizeof(u64))
> data[i] = *(u64 *)p;
> else
> data[i] = *(u32 *)p;
^^^^^^^^
The else side will still crash.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] e1000: avoid null pointer dereference on invalid stat type
2017-09-22 11:50 ` Dan Carpenter
@ 2017-09-22 11:55 ` Colin Ian King
0 siblings, 0 replies; 3+ messages in thread
From: Colin Ian King @ 2017-09-22 11:55 UTC (permalink / raw)
To: Dan Carpenter
Cc: Jeff Kirsher, intel-wired-lan, netdev, kernel-janitors,
linux-kernel
On 22/09/17 12:50, Dan Carpenter wrote:
> On Thu, Sep 21, 2017 at 11:01:58PM +0100, Colin King wrote:
>> @@ -1837,12 +1838,13 @@ static void e1000_get_ethtool_stats(struct net_device *netdev,
>> p = (char *)adapter + stat->stat_offset;
>> break;
>> default:
>> + p = NULL;
>> WARN_ONCE(1, "Invalid E1000 stat type: %u index %d\n",
>> stat->type, i);
>> break;
>> }
>>
>> - if (stat->sizeof_stat == sizeof(u64))
>> + if (p && stat->sizeof_stat == sizeof(u64))
>> data[i] = *(u64 *)p;
>> else
>> data[i] = *(u32 *)p;
> ^^^^^^^^
>
> The else side will still crash.
>
> regards,
> dan carpenter
>
Thanks, stupid me. I'll fix that up.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-09-21 22:01 [PATCH] e1000: avoid null pointer dereference on invalid stat type Colin King
2017-09-22 11:50 ` Dan Carpenter
2017-09-22 11:55 ` Colin Ian King
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