[PATCH 2/2] staging: media: tegra-video: add missing error checks in vi_tpg_fmts_bitmap_init()

[Alexandru Hossu <hossu.alexandru@gmail.com>]

tegra_get_format_idx_by_code() returns -1 when the requested format is
not found in the SoC format table. vi_tpg_fmts_bitmap_init() does not
check this return value before passing it to bitmap_set(). A negative
index converted to unsigned would result in an out-of-bounds memory
access, corrupting adjacent kernel memory.

Add WARN_ON() guards so that any future SoC addition or Kconfig change
that exposes this path fails loudly rather than silently corrupting memory.

Signed-off-by: Alexandru Hossu <hossu.alexandru@gmail.com>
---
 drivers/staging/media/tegra-video/vi.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/media/tegra-video/vi.c b/drivers/staging/media/tegra-video/vi.c
index afc7327ef318..d1d934e361f7 100644
--- a/drivers/staging/media/tegra-video/vi.c
+++ b/drivers/staging/media/tegra-video/vi.c
@@ -1017,7 +1017,7 @@ static int tegra_channel_setup_ctrl_handler(struct tegra_vi_channel *chan)
 }
 
 /* VI only support 2 formats in TPG mode */
-static void vi_tpg_fmts_bitmap_init(struct tegra_vi_channel *chan)
+static int vi_tpg_fmts_bitmap_init(struct tegra_vi_channel *chan)
 {
 	int index;
 
@@ -1025,12 +1025,22 @@ static void vi_tpg_fmts_bitmap_init(struct tegra_vi_channel *chan)
 
 	index = tegra_get_format_idx_by_code(chan->vi,
 					     MEDIA_BUS_FMT_SRGGB10_1X10, 0);
+	if (index < 0) {
+		dev_err(chan->vi->dev, "format SRGGB10_1X10 not found\n");
+		return -EINVAL;
+	}
 	bitmap_set(chan->tpg_fmts_bitmap, index, 1);
 
 	index = tegra_get_format_idx_by_code(chan->vi,
 					     MEDIA_BUS_FMT_RGB888_1X32_PADHI,
 					     0);
+	if (index < 0) {
+		dev_err(chan->vi->dev, "format RGB888_1X32_PADHI not found\n");
+		return -EINVAL;
+	}
 	bitmap_set(chan->tpg_fmts_bitmap, index, 1);
+
+	return 0;
 }
 
 static int vi_fmts_bitmap_init(struct tegra_vi_channel *chan)
@@ -1410,7 +1420,9 @@ int tegra_v4l2_nodes_setup_tpg(struct tegra_video_device *vid)
 			goto cleanup;
 
 		v4l2_set_subdev_hostdata(&csi_chan->subdev, vi_chan);
-		vi_tpg_fmts_bitmap_init(vi_chan);
+		ret = vi_tpg_fmts_bitmap_init(vi_chan);
+		if (ret < 0)
+			goto cleanup;
 		csi_chan = list_next_entry(csi_chan, list);
 	}
 
-- 
2.53.0