[PATCH 2/3] udmabuf: also check for F_SEAL_FUTURE_WRITE

[Jann Horn]

When F_SEAL_FUTURE_WRITE was introduced, it was overlooked that udmabuf
must reject memfds with this flag, just like ones with F_SEAL_WRITE.
Fix it by adding F_SEAL_FUTURE_WRITE to SEALS_DENIED.

Fixes: ab3948f58ff8 ("mm/memfd: add an F_SEAL_FUTURE_WRITE seal to memfd")
Cc: stable at vger.kernel.org
Signed-off-by: Jann Horn <jannh at google.com>
---
 drivers/dma-buf/udmabuf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 662b9a26e06668bf59ab36d07c0648c7b02ee5ae..8ce77f5837d71a73be677cad014e05f29706057d 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -297,7 +297,7 @@ static const struct dma_buf_ops udmabuf_ops = {
 };
 
 #define SEALS_WANTED (F_SEAL_SHRINK)
-#define SEALS_DENIED (F_SEAL_WRITE)
+#define SEALS_DENIED (F_SEAL_WRITE|F_SEAL_FUTURE_WRITE)
 
 static int check_memfd_seals(struct file *memfd)
 {

-- 
2.47.0.338.g60cca15819-goog