Messages in this thread | | | Date | Fri, 11 Apr 2014 15:50:27 +0200 | From | Mateusz Guzik <> | Subject | Re: [PATCH] net: ipv4: current group_info should be put after using. |
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On Fri, Apr 11, 2014 at 10:53:21PM -0400, Wang, Xiaoming wrote: > This is a typical refcount leak exploitable by unprivileged users. > Current group_info had been got in ping_init_sock and > group_info->usage increased. But the usage hasn't decreased > anywhere in ping. This will make this group_info never freed. >
The patch is fine, however I had a brainfart with my last sentence about commit message, sorry for that.
group_info *can be freed* by malicious user while still being pointed to by something, that's the biggest problem with refcount leaks, therefore this message needs some reworking.
I think that discussion about various consequences of refcount leak in commit message is not necessary.
how about:
Plug a group_info refcount leak in ping_init.
group_info is only needed during initialization and the code failed to release the reference on exit.
While here move grabbing the reference to a place where it is actually needed.
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Please cc: me if you resend the patch.
Thanks, -- Mateusz Guzik
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