Mailing List Archive

[PATCH][netfilter] Avoid a possible NULL pointer deref in recent_seq_open()
EHLO,

There is a small problem in
net/ipv4/netfilter/ipt_recent.c::recent_seq_open().

If the call to seq_open() returns != 0 then the code calls
kfree(st) but then on the very next line proceeds to
dereference the pointer - not good.

Problem spotted by the Coverity checker.

Proposed patch to deal with it below.

Compile tested only.


Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
---

net/ipv4/netfilter/ipt_recent.c | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/net/ipv4/netfilter/ipt_recent.c b/net/ipv4/netfilter/ipt_recent.c
index 3218043..6d0c0f7 100644
--- a/net/ipv4/netfilter/ipt_recent.c
+++ b/net/ipv4/netfilter/ipt_recent.c
@@ -387,12 +387,17 @@ static int recent_seq_open(struct inode *inode, struct file *file)
st = kzalloc(sizeof(*st), GFP_KERNEL);
if (st == NULL)
return -ENOMEM;
+
ret = seq_open(file, &recent_seq_ops);
- if (ret)
+ if (ret) {
kfree(st);
+ goto out;
+ }
+
st->table = pde->data;
seq = file->private_data;
seq->private = st;
+out:
return ret;
}
Re: [PATCH][netfilter] Avoid a possible NULL pointer deref in recent_seq_open() [ In reply to ]
Jesper Juhl wrote:
> There is a small problem in
> net/ipv4/netfilter/ipt_recent.c::recent_seq_open().
>
> If the call to seq_open() returns != 0 then the code calls
> kfree(st) but then on the very next line proceeds to
> dereference the pointer - not good.


Applied, thanks Jesper.