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crypto: af_alg - fix NULL pointer dereference in

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af_alg_free_areq_sgls()

If allocating the ->tsgl member of 'struct af_alg_async_req' failed,
during cleanup we dereferenced the NULL ->tsgl pointer in
af_alg_free_areq_sgls(), because ->tsgl_entries was nonzero.

Fix it by only freeing the ->tsgl list if it is non-NULL.

This affected both algif_skcipher and algif_aead.

Fixes: e870456d8e ("crypto: algif_skcipher - overhaul memory management")
Fixes: d887c52d6a ("crypto: algif_aead - overhaul memory management")
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: <stable@vger.kernel.org> # v4.14+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers 2017-11-28 00:46:24 -08:00 committed by Herbert Xu
parent b32a7dc8ae
commit 887207ed9e
1 changed files with 7 additions and 6 deletions
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13
crypto/af_alg.c
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@ -672,14 +672,15 @@ void af_alg_free_areq_sgls(struct af_alg_async_req *areq)
} }
tsgl = areq->tsgl; tsgl = areq->tsgl;
for_each_sg(tsgl, sg, areq->tsgl_entries, i) { if (tsgl) {
if (!sg_page(sg)) for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
continue; if (!sg_page(sg))
put_page(sg_page(sg)); continue;
} put_page(sg_page(sg));
}
if (areq->tsgl && areq->tsgl_entries)
sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl)); sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl));
}
} }
EXPORT_SYMBOL_GPL(af_alg_free_areq_sgls); EXPORT_SYMBOL_GPL(af_alg_free_areq_sgls);