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authorStephan Mueller <smueller@chronox.de>2017-08-16 11:56:24 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-09-07 08:34:10 +0200
commitd95827490c39d20c148b3c4c3d250f9cce294eb5 (patch)
parentab3ee6b53d678b37b90934fb67b01d5fc7aa3a85 (diff)
crypto: algif_skcipher - only call put_page on referenced and used pages
commit 445a582738de6802669aeed9c33ca406c23c3b1f upstream. 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. Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 7 insertions, 2 deletions
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index f5e9f9310b48..b3b0004ea8ac 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -86,8 +86,13 @@ 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 && atomic_read(&page->_count))
+ put_page(page);
+ }