From: Fedor Pchelkin Date: Wed, 11 Jun 2025 19:20:10 +0000 (+0300) Subject: s390/pkey: Prevent overflow in size calculation for memdup_user() X-Git-Tag: v6.16-rc4~21^2~1 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7360ee47599af91a1d5f4e74d635d9408a54e489;p=thirdparty%2Fkernel%2Flinux.git s390/pkey: Prevent overflow in size calculation for memdup_user() Number of apqn target list entries contained in 'nr_apqns' variable is determined by userspace via an ioctl call so the result of the product in calculation of size passed to memdup_user() may overflow. In this case the actual size of the allocated area and the value describing it won't be in sync leading to various types of unpredictable behaviour later. Use a proper memdup_array_user() helper which returns an error if an overflow is detected. Note that it is different from when nr_apqns is initially zero - that case is considered valid and should be handled in subsequent pkey_handler implementations. Found by Linux Verification Center (linuxtesting.org). Fixes: f2bbc96e7cfa ("s390/pkey: add CCA AES cipher key support") Cc: stable@vger.kernel.org Signed-off-by: Fedor Pchelkin Reviewed-by: Holger Dengler Reviewed-by: Heiko Carstens Link: https://lore.kernel.org/r/20250611192011.206057-1-pchelkin@ispras.ru Signed-off-by: Alexander Gordeev --- diff --git a/drivers/s390/crypto/pkey_api.c b/drivers/s390/crypto/pkey_api.c index cef60770f68bc..b3fcdcae379ea 100644 --- a/drivers/s390/crypto/pkey_api.c +++ b/drivers/s390/crypto/pkey_api.c @@ -86,7 +86,7 @@ static void *_copy_apqns_from_user(void __user *uapqns, size_t nr_apqns) if (!uapqns || nr_apqns == 0) return NULL; - return memdup_user(uapqns, nr_apqns * sizeof(struct pkey_apqn)); + return memdup_array_user(uapqns, nr_apqns, sizeof(struct pkey_apqn)); } static int pkey_ioctl_genseck(struct pkey_genseck __user *ugs)