[PATCH 5.14 835/849] powerpc/vas: Fix potential NULL pointer dereference

[Greg Kroah-Hartman]

From: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>

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@xxxxxxxxxxxxxxx
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Reviewed-by: Tyrel Datwyler <tyreld@xxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20211015050345.GA1161918@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/powerpc/platforms/book3s/vas-api.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- 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
 		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,
 		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;
 	}