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>
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 28556fc..45af0fe 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -86,8 +86,13 @@
}
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);
}