From: Ignacy Gawędzki <ignacy.gawedzki@xxxxxxxxxxxxxxxxxxxxxxx>
[ Upstream commit 1c4cff0cf55011792125b6041bc4e9713e46240f ]
The gnet_stats_copy_app() function gets called, more often than not, with its
second argument a pointer to an automatic variable in the caller's stack.
Therefore, to avoid copying garbage afterwards when calling
gnet_stats_finish_copy(), this data is better copied to a dynamically allocated
memory that gets freed after use.
[xiyou.wangcong@xxxxxxxxx: remove a useless kfree()]
Signed-off-by: Ignacy Gawędzki <ignacy.gawedzki@xxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
net/core/gen_stats.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/net/core/gen_stats.c b/net/core/gen_stats.c
index 0c08062..1e2f46a 100644
--- a/net/core/gen_stats.c
+++ b/net/core/gen_stats.c
@@ -32,6 +32,9 @@ gnet_stats_copy(struct gnet_dump *d, int type, void *buf, int size)
return 0;
nla_put_failure:
+ kfree(d->xstats);
+ d->xstats = NULL;
+ d->xstats_len = 0;
spin_unlock_bh(d->lock);
return -1;
}
@@ -305,7 +308,9 @@ int
gnet_stats_copy_app(struct gnet_dump *d, void *st, int len)
{
if (d->compat_xstats) {
- d->xstats = st;
+ d->xstats = kmemdup(st, len, GFP_ATOMIC);
+ if (!d->xstats)
+ goto err_out;
d->xstats_len = len;
}
@@ -313,6 +318,11 @@ gnet_stats_copy_app(struct gnet_dump *d, void *st, int len)
return gnet_stats_copy(d, TCA_STATS_APP, st, len);
return 0;
+
+err_out:
+ d->xstats_len = 0;
+ spin_unlock_bh(d->lock);
+ return -1;
}
EXPORT_SYMBOL(gnet_stats_copy_app);
@@ -345,6 +355,9 @@ gnet_stats_finish_copy(struct gnet_dump *d)
return -1;
}
+ kfree(d->xstats);
+ d->xstats = NULL;
+ d->xstats_len = 0;
spin_unlock_bh(d->lock);
return 0;
}
--
2.1.0
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