From: Florian Müllner <fmuellner@gnome.org>
Date: Fri, 21 Jun 2024 00:36:39 +0000 (+0200)
Subject: st/theme-node: Fix potential NULL pointer dereferences
X-Git-Tag: archive/raspbian/50.5-1+rpi1~1^2~226^2^2~63
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=dc6f7a1289c7fa316180b9dc837561422675907e;p=gnome-shell.git

st/theme-node: Fix potential NULL pointer dereferences

If the new CSS functions added in commit c593aecbde3
are used wrongly, an expected argument may be missing.

The code checks for that, but only after dereferencing
it to assign the next argument. Fix that by splitting
up the checks.

Spotted by coverity.
CID: #462818
Fixes: c593aecbde ("st/theme-node: Implement extensions for accent
color")

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3380>
---

diff --git a/src/st/st-theme-node.c b/src/st/st-theme-node.c
index 9ea539e31..0817e51fc 100644
--- a/src/st/st-theme-node.c
+++ b/src/st/st-theme-node.c
@@ -617,13 +617,17 @@ get_color_from_transparentize_term (StThemeNode *node,
                                     CRTerm      *term,
                                     CoglColor   *color)
 {
-  CRTerm *color_arg = term->ext_content.func_param;
-  CRTerm *amount_arg = color_arg->next;
+  CRTerm *color_arg, *amount_arg;
   CoglColor base_color;
   CRNum *amount_num;
   double amount;
 
-  if (!color_arg || !amount_arg)
+  color_arg = term->ext_content.func_param;
+  if (!color_arg)
+    return VALUE_NOT_FOUND;
+
+  amount_arg = color_arg->next;
+  if (!amount_arg)
     return VALUE_NOT_FOUND;
 
   if (get_color_from_term (node, color_arg, &base_color) != VALUE_FOUND)
@@ -656,14 +660,21 @@ get_color_from_mix_term (StThemeNode *node,
                          CRTerm      *term,
                          CoglColor   *color)
 {
-  CRTerm *color1_arg = term->ext_content.func_param;
-  CRTerm *color2_arg = color1_arg->next;
-  CRTerm *factor_arg = color2_arg->next;
+  CRTerm *color1_arg, *color2_arg, *factor_arg;
   CoglColor color1, color2;
   CRNum *factor_num;
   double factor;
 
-  if (!color1_arg || !color2_arg || !factor_arg)
+  color1_arg = term->ext_content.func_param;
+  if (!color1_arg)
+    return VALUE_NOT_FOUND;
+
+  color2_arg = color1_arg->next;
+  if (!color2_arg)
+    return VALUE_NOT_FOUND;
+
+  factor_arg = color2_arg->next;
+  if (!factor_arg)
     return VALUE_NOT_FOUND;
 
   if (get_color_from_term (node, color1_arg, &color1) != VALUE_FOUND ||
@@ -706,14 +717,18 @@ get_color_from_lighten_term (StThemeNode *node,
                              CRTerm      *term,
                              CoglColor   *color)
 {
-  CRTerm *color_arg = term->ext_content.func_param;
-  CRTerm *factor_arg = color_arg->next;
+  CRTerm *color_arg, *factor_arg;
   CoglColor base_color;
   CRNum *factor_num;
   double factor;
   float hue, luminance, saturation;
 
-  if (!color_arg || !factor_arg)
+  color_arg = term->ext_content.func_param;
+  if (!color_arg)
+    return VALUE_NOT_FOUND;
+
+  factor_arg = color_arg->next;
+  if (!factor_arg)
     return VALUE_NOT_FOUND;
 
   if (get_color_from_term (node, color_arg, &base_color) != VALUE_FOUND)
@@ -746,14 +761,18 @@ get_color_from_darken_term (StThemeNode *node,
                             CRTerm      *term,
                             CoglColor   *color)
 {
-  CRTerm *color_arg = term->ext_content.func_param;
-  CRTerm *factor_arg = color_arg->next;
+  CRTerm *color_arg, *factor_arg;
   CoglColor base_color;
   CRNum *factor_num;
   double factor;
   float hue, luminance, saturation;
 
-  if (!color_arg || !factor_arg)
+  color_arg = term->ext_content.func_param;
+  if (!color_arg)
+    return VALUE_NOT_FOUND;
+
+  factor_arg = color_arg->next;
+  if (!factor_arg)
     return VALUE_NOT_FOUND;
 
   if (get_color_from_term (node, color_arg, &base_color) != VALUE_FOUND)