From 684624c11e8ddb169f0e9966373b5a0ef4faa853 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Wed, 4 Sep 2019 20:28:35 +0200
Subject: [PATCH] csi: don't ignore the color space identifier in SGRs

Only a color space ID of '2' means the sequence is an RGB
sequence. Update existing code to verify this, and ignore sequences
with other color space IDs.

Except color space ID '5', which is the same as a regular 38;5;<idx>
sequence, but using sub-parameters instead (38:2:5:<idx>).
---
 csi.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 73 insertions(+), 10 deletions(-)

diff --git a/csi.c b/csi.c
index 1e456064..f6f890e3 100644
--- a/csi.c
+++ b/csi.c
@@ -109,6 +109,7 @@ csi_sgr(struct terminal *term)
             break;
 
         case 38: {
+            /* Indexed: 38;5;<idx> */
             if (term->vt.params.idx - i - 1 >= 2 &&
                 term->vt.params.v[i + 1].value == 5)
             {
@@ -119,6 +120,7 @@ csi_sgr(struct terminal *term)
 
             }
 
+            /* RGB: 38;2;<r>;<g>;<b> */
             else if (term->vt.params.idx - i - 1 >= 4 &&
                      term->vt.params.v[i + 1].value == 2)
             {
@@ -130,11 +132,21 @@ csi_sgr(struct terminal *term)
                 i += 4;
             }
 
-            else if (term->vt.params.v[i].sub.idx > 0) {
+            /* Sub-parameter style: 38:2:... */
+            else if (term->vt.params.v[i].sub.idx >= 2 &&
+                     term->vt.params.v[i].sub.value[0] == 2)
+            {
                 const struct vt_param *param = &term->vt.params.v[i];
+                const int color_space_id = param->sub.value[1];
+
+                switch (color_space_id) {
+                case 0:   /* Implementation defined - we map it to '2' */
+                case 2: { /* RGB - 38:2:2:<r>:<g>:<b> */
+                    if (param->sub.idx < 5) {
+                        UNHANDLED_SGR();
+                        break;
+                    }
 
-                if (param->sub.value[0] == 2 && param->sub.idx >= 5) {
-                    int color_space_id __attribute__((unused)) = param->sub.value[1];
                     uint8_t r = param->sub.value[2];
                     uint8_t g = param->sub.value[3];
                     uint8_t b = param->sub.value[4];
@@ -144,10 +156,30 @@ csi_sgr(struct terminal *term)
 
                     term->vt.attrs.have_fg = 1;
                     term->vt.attrs.fg = r << 16 | g << 8 | b;
-                } else
+                    break;
+                }
+
+                case 5: { /* Indexed - 38:2:5:<idx> */
+                    if (param->sub.idx < 3) {
+                        UNHANDLED_SGR();
+                        break;
+                    }
+
+                    uint8_t idx = param->sub.value[2];
+                    term->vt.attrs.have_fg = 1;
+                    term->vt.attrs.fg = term->colors.table[idx];
+                    break;
+                }
+
+                case 1: /* Transparent */
+                case 3: /* CMY */
+                case 4: /* CMYK */
                     UNHANDLED_SGR();
+                    break;
+                }
             }
 
+            /* Unrecognized */
             else
                 UNHANDLED_SGR();
 
@@ -172,6 +204,7 @@ csi_sgr(struct terminal *term)
             break;
 
         case 48: {
+            /* Indexed: 48;5;<idx> */
             if (term->vt.params.idx - i - 1 >= 2 &&
                 term->vt.params.v[i + 1].value == 5)
             {
@@ -179,10 +212,12 @@ csi_sgr(struct terminal *term)
                 term->vt.attrs.have_bg = 1;
                 term->vt.attrs.bg = term->colors.table[idx];
                 i += 2;
+
             }
 
+            /* RGB: 48;2;<r>;<g>;<b> */
             else if (term->vt.params.idx - i - 1 >= 4 &&
-                       term->vt.params.v[i + 1].value == 2)
+                     term->vt.params.v[i + 1].value == 2)
             {
                 uint8_t r = term->vt.params.v[i + 2].value;
                 uint8_t g = term->vt.params.v[i + 3].value;
@@ -190,14 +225,23 @@ csi_sgr(struct terminal *term)
                 term->vt.attrs.have_bg = 1;
                 term->vt.attrs.bg = r << 16 | g << 8 | b;
                 i += 4;
-
             }
 
-            else if (term->vt.params.v[i].sub.idx > 0) {
+            /* Sub-parameter style: 48:2:... */
+            else if (term->vt.params.v[i].sub.idx >= 2 &&
+                     term->vt.params.v[i].sub.value[0] == 2)
+            {
                 const struct vt_param *param = &term->vt.params.v[i];
+                const int color_space_id = param->sub.value[1];
+
+                switch (color_space_id) {
+                case 0:   /* Implementation defined - we map it to '2' */
+                case 2: { /* RGB - 48:2:2:<r>:<g>:<b> */
+                    if (param->sub.idx < 5) {
+                        UNHANDLED_SGR();
+                        break;
+                    }
 
-                if (param->sub.value[0] == 2 && param->sub.idx >= 5) {
-                    int color_space_id __attribute__((unused)) = param->sub.value[1];
                     uint8_t r = param->sub.value[2];
                     uint8_t g = param->sub.value[3];
                     uint8_t b = param->sub.value[4];
@@ -207,8 +251,27 @@ csi_sgr(struct terminal *term)
 
                     term->vt.attrs.have_bg = 1;
                     term->vt.attrs.bg = r << 16 | g << 8 | b;
-                } else
+                    break;
+                }
+
+                case 5: { /* Indexed - 48:2:5:<idx> */
+                    if (param->sub.idx < 3) {
+                        UNHANDLED_SGR();
+                        break;
+                    }
+
+                    uint8_t idx = param->sub.value[2];
+                    term->vt.attrs.have_bg = 1;
+                    term->vt.attrs.bg = term->colors.table[idx];
+                    break;
+                }
+
+                case 1: /* Transparent */
+                case 3: /* CMY */
+                case 4: /* CMYK */
                     UNHANDLED_SGR();
+                    break;
+                }
             }
 
             else