From 092e72c9edab16d4d6ad10c683a95047d53b6db4 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Wed, 25 Oct 2017 11:04:47 +0100 Subject: [PATCH] efi/efi_test: Prevent an Oops in efi_runtime_query_capsulecaps() If "qcaps.capsule_count" is ULONG_MAX then "qcaps.capsule_count + 1" will overflow to zero and kcalloc() will return the ZERO_SIZE_PTR. We try to dereference it inside the loop and crash. Signed-off-by: Dan Carpenter Signed-off-by: Matt Fleming Signed-off-by: Ard Biesheuvel Acked-by: Ivan Hu Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Fixes: ff6301dabc3c ("efi: Add efi_test driver for exporting UEFI runtime service interfaces") Link: http://lkml.kernel.org/r/20171025100448.26056-2-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar --- drivers/firmware/efi/test/efi_test.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/firmware/efi/test/efi_test.c b/drivers/firmware/efi/test/efi_test.c index 08129b7b80ab..41c48a1e8baa 100644 --- a/drivers/firmware/efi/test/efi_test.c +++ b/drivers/firmware/efi/test/efi_test.c @@ -593,6 +593,9 @@ static long efi_runtime_query_capsulecaps(unsigned long arg) if (copy_from_user(&qcaps, qcaps_user, sizeof(qcaps))) return -EFAULT; + if (qcaps.capsule_count == ULONG_MAX) + return -EINVAL; + capsules = kcalloc(qcaps.capsule_count + 1, sizeof(efi_capsule_header_t), GFP_KERNEL); if (!capsules) -- 2.20.1