Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.16 22/55] net: filter: fix possible use after free | Date | Mon, 13 Oct 2014 04:24:36 +0200 |
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3.16-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet <edumazet@google.com>
[ No appicable upstream commit, this bug has been subsequently been fixed as a side effect of other changes. ]
If kmemdup() fails, we free fp->orig_prog and return -ENOMEM
sk_attach_filter() -> sk_filter_uncharge(sk, fp) -> sk_filter_release(fp) -> call_rcu(&fp->rcu, sk_filter_release_rcu) -> sk_filter_release_rcu() -> sk_release_orig_filter() fprog = fp->orig_prog; // not NULL, but points to freed memory kfree(fprog->filter); // use after free, potential corruption kfree(fprog); // double free or corruption
Note: This was fixed in 3.17+ with commit 278571baca2a ("net: filter: simplify socket charging")
Found by AddressSanitizer
Signed-off-by: Eric Dumazet <edumazet@google.com> Fixes: a3ea269b8bcdb ("net: filter: keep original BPF program around") Acked-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/core/filter.c | 1 + 1 file changed, 1 insertion(+)
--- a/net/core/filter.c +++ b/net/core/filter.c @@ -1318,6 +1318,7 @@ static int sk_store_orig_filter(struct s fkprog->filter = kmemdup(fp->insns, fsize, GFP_KERNEL); if (!fkprog->filter) { kfree(fp->orig_prog); + fp->orig_prog = NULL; return -ENOMEM; }
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