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authorStephan Mueller <smueller@chronox.de>2017-08-16 11:56:24 +0200
committerHerbert Xu <herbert@gondor.apana.org.au>2017-08-22 14:45:48 +0800
commit445a582738de6802669aeed9c33ca406c23c3b1f (patch)
tree0d07bd2145a3444c51f59e8a8db9095e0e9ceac5
parent549f64153c354e69fc19534f7d7e867de1992f95 (diff)
crypto: algif_skcipher - only call put_page on referenced and used pages
For asynchronous operation, SGs are allocated without a page mapped to them or with a page that is not used (ref-counted). If the SGL is freed, the code must only call put_page for an SG if there was a page assigned and ref-counted in the first place. This fixes a kernel crash when using io_submit with more than one iocb using the sendmsg and sendpage (vmsplice/splice) interface. Cc: <stable@vger.kernel.org> Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r--crypto/algif_skcipher.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 43839b00fe6c..903605dbc1a5 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -87,8 +87,13 @@ static void skcipher_free_async_sgls(struct skcipher_async_req *sreq)
}
sgl = sreq->tsg;
n = sg_nents(sgl);
- for_each_sg(sgl, sg, n, i)
- put_page(sg_page(sg));
+ for_each_sg(sgl, sg, n, i) {
+ struct page *page = sg_page(sg);
+
+ /* some SGs may not have a page mapped */
+ if (page && page_ref_count(page))
+ put_page(page);
+ }
kfree(sreq->tsg);
}