fbdev: fix cea_modes array size (6080a893) · Commits · 戴 / test

CEA defines 64 modes, indexed from 1 to 64. modedb has cea_modes arrays, which contains 64 entries. However, the code uses the CEA indices directly, i.e. the first mode is at cea_modes[1]. This means the array is one too short. This does not cause references to uninitialized memory as the code in fbmon only allows indexes up to 63, and the cea_modes does not contain an entry for the mode 64 so it could not be used in any case. However, the code contains a check 'if (idx > ARRAY_SIZE(cea_modes)', and while that check is a no-op as at that point idx cannot be >= 63, it upsets static checkers. Fix this by increasing the cea_array size to be 65, and change the code to allow mode 64. Signed-off-by:

Tomi Valkeinen <tomi.valkeinen@ti.com> Reported-by:

Dan Carpenter <dan.carpenter@oracle.com>

drivers/video/fbdev/core/fbmon.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1072,9 +1072,9 @@ void fb_edid_add_monspecs(unsigned char edid, struct fb_monspecs specs)

		for (i = specs->modedb_len + num; i < specs->modedb_len + num + svd_n; i++) {
		int idx = svd[i - specs->modedb_len - num];
		if (!idx \|\| idx > 63) {
		if (!idx \|\| idx >= ARRAY_SIZE(cea_modes)) {
		pr_warning("Reserved SVD code %d\n", idx);
		} else if (idx > ARRAY_SIZE(cea_modes) \|\| !cea_modes[idx].xres) {
		} else if (!cea_modes[idx].xres) {
		pr_warning("Unimplemented SVD code %d\n", idx);
		} else {
		memcpy(&m[i], cea_modes + idx, sizeof(m[i]));

drivers/video/fbdev/core/modedb.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -289,7 +289,7 @@ static const struct fb_videomode modedb[] = {
		};

		#ifdef CONFIG_FB_MODE_HELPERS
		const struct fb_videomode cea_modes[64] = {
		const struct fb_videomode cea_modes[65] = {
		/* #1: 640x480p@59.94/60Hz */
		[1] = {
		NULL, 60, 640, 480, 39722, 48, 16, 33, 10, 96, 2, 0,

include/linux/fb.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -788,7 +788,7 @@ struct dmt_videomode {

		extern const char *fb_mode_option;
		extern const struct fb_videomode vesa_modes[];
		extern const struct fb_videomode cea_modes[64];
		extern const struct fb_videomode cea_modes[65];
		extern const struct dmt_videomode dmt_modes[];

		struct fb_modelist {

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