From b3e0a9cb6a6799fc13925ae3b90cf9214a96896b Mon Sep 17 00:00:00 2001
From: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Date: Fri, 15 Oct 2021 00:03:45 -0500
Subject: [PATCH] powerpc/vas: Fix potential NULL pointer dereference
Git-commit: 61cb9ac66b30374c7fd8a8b2a3c4f8f432c72e36
Patch-mainline: v5.16-rc1
References: stable-5.14.19

commit 61cb9ac66b30374c7fd8a8b2a3c4f8f432c72e36 upstream.

(!ptr && !ptr->foo) strikes again. :)

The expression (!ptr && !ptr->foo) is bogus and in case ptr is NULL,
it leads to a NULL pointer dereference: ptr->foo.

Fix this by converting && to ||

This issue was detected with the help of Coccinelle, and audited and
fixed manually.

Fixes: 1a0d0d5ed5e3 ("powerpc/vas: Add platform specific user window operations")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211015050345.GA1161918@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 arch/powerpc/platforms/book3s/vas-api.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/book3s/vas-api.c b/arch/powerpc/platforms/book3s/vas-api.c
index 30172e52e16b..4d82c92ddd52 100644
--- a/arch/powerpc/platforms/book3s/vas-api.c
+++ b/arch/powerpc/platforms/book3s/vas-api.c
@@ -303,7 +303,7 @@ static int coproc_ioc_tx_win_open(struct file *fp, unsigned long arg)
 		return -EINVAL;
 	}
 
-	if (!cp_inst->coproc->vops && !cp_inst->coproc->vops->open_win) {
+	if (!cp_inst->coproc->vops || !cp_inst->coproc->vops->open_win) {
 		pr_err("VAS API is not registered\n");
 		return -EACCES;
 	}
@@ -373,7 +373,7 @@ static int coproc_mmap(struct file *fp, struct vm_area_struct *vma)
 		return -EINVAL;
 	}
 
-	if (!cp_inst->coproc->vops && !cp_inst->coproc->vops->paste_addr) {
+	if (!cp_inst->coproc->vops || !cp_inst->coproc->vops->paste_addr) {
 		pr_err("%s(): VAS API is not registered\n", __func__);
 		return -EACCES;
 	}
-- 
2.26.2