aboutsummaryrefslogtreecommitdiffstats
path: root/target/linux/bcm27xx/patches-5.4/950-0479-drm-modes-parse_cmdline-Fix-possible-reference-past-.patch
blob: 9b514c3a2525346079b49df126e23fd9fd395da1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
From fade8b3cf37785297b4f8a9bbd13ab107208af5a Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Mon, 18 Nov 2019 16:51:22 +0100
Subject: [PATCH] drm/modes: parse_cmdline: Fix possible reference past
 end of string

Commit 8582e244e5fe72d2e9ace186fa8f3ed3bb4122e1 upstream.

Before this commit, if the last option of a video=... option is for
example "rotate" without a "=<value>" after it then delim will point to
the terminating 0 of the string, and value which is sets to <delim + 1>
will point one position past the end of the string.

This commit fixes this by enforcing that the contents of delim equals '='
as it should be for options which take a value, this check is done in a
new drm_mode_parse_cmdline_int helper function which factors out the
common integer parsing code for all the options which take an int.

Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191118155134.30468-1-hdegoede@redhat.com
---
 drivers/gpu/drm/drm_modes.c | 68 ++++++++++++++++---------------------
 1 file changed, 30 insertions(+), 38 deletions(-)

--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -1568,11 +1568,34 @@ static int drm_mode_parse_cmdline_res_mo
 	return 0;
 }
 
+static int drm_mode_parse_cmdline_int(const char *delim, unsigned int *int_ret)
+{
+	const char *value;
+	char *endp;
+
+	/*
+	 * delim must point to the '=', otherwise it is a syntax error and
+	 * if delim points to the terminating zero, then delim + 1 wil point
+	 * past the end of the string.
+	 */
+	if (*delim != '=')
+		return -EINVAL;
+
+	value = delim + 1;
+	*int_ret = simple_strtol(value, &endp, 10);
+
+	/* Make sure we have parsed something */
+	if (endp == value)
+		return -EINVAL;
+
+	return 0;
+}
+
 static int drm_mode_parse_cmdline_options(char *str, size_t len,
 					  const struct drm_connector *connector,
 					  struct drm_cmdline_mode *mode)
 {
-	unsigned int rotation = 0;
+	unsigned int deg, margin, rotation = 0;
 	char *sep = str;
 
 	while ((sep = strchr(sep, ','))) {
@@ -1588,13 +1611,7 @@ static int drm_mode_parse_cmdline_option
 		}
 
 		if (!strncmp(option, "rotate", delim - option)) {
-			const char *value = delim + 1;
-			unsigned int deg;
-
-			deg = simple_strtol(value, &sep, 10);
-
-			/* Make sure we have parsed something */
-			if (sep == value)
+			if (drm_mode_parse_cmdline_int(delim, &deg))
 				return -EINVAL;
 
 			switch (deg) {
@@ -1619,57 +1636,32 @@ static int drm_mode_parse_cmdline_option
 			}
 		} else if (!strncmp(option, "reflect_x", delim - option)) {
 			rotation |= DRM_MODE_REFLECT_X;
-			sep = delim;
 		} else if (!strncmp(option, "reflect_y", delim - option)) {
 			rotation |= DRM_MODE_REFLECT_Y;
-			sep = delim;
 		} else if (!strncmp(option, "margin_right", delim - option)) {
-			const char *value = delim + 1;
-			unsigned int margin;
-
-			margin = simple_strtol(value, &sep, 10);
-
-			/* Make sure we have parsed something */
-			if (sep == value)
+			if (drm_mode_parse_cmdline_int(delim, &margin))
 				return -EINVAL;
 
 			mode->tv_margins.right = margin;
 		} else if (!strncmp(option, "margin_left", delim - option)) {
-			const char *value = delim + 1;
-			unsigned int margin;
-
-			margin = simple_strtol(value, &sep, 10);
-
-			/* Make sure we have parsed something */
-			if (sep == value)
+			if (drm_mode_parse_cmdline_int(delim, &margin))
 				return -EINVAL;
 
 			mode->tv_margins.left = margin;
 		} else if (!strncmp(option, "margin_top", delim - option)) {
-			const char *value = delim + 1;
-			unsigned int margin;
-
-			margin = simple_strtol(value, &sep, 10);
-
-			/* Make sure we have parsed something */
-			if (sep == value)
+			if (drm_mode_parse_cmdline_int(delim, &margin))
 				return -EINVAL;
 
 			mode->tv_margins.top = margin;
 		} else if (!strncmp(option, "margin_bottom", delim - option)) {
-			const char *value = delim + 1;
-			unsigned int margin;
-
-			margin = simple_strtol(value, &sep, 10);
-
-			/* Make sure we have parsed something */
-			if (sep == value)
+			if (drm_mode_parse_cmdline_int(delim, &margin))
 				return -EINVAL;
 
 			mode->tv_margins.bottom = margin;
 		} else {
 			return -EINVAL;
 		}
+		sep = delim;
 	}
 
 	if (!(rotation & DRM_MODE_ROTATE_MASK))