From c6b0dcb82d4db07a2f32c09a8c09c85a5f57248e Mon Sep 17 00:00:00 2001
From: Olivier Fourdan <ofourdan@redhat.com>
Date: Thu, 20 Jan 2022 10:20:38 +0100
Subject: [PATCH] render: Fix build with gcc 12
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The xserver fails to compile with the latest gcc 12:

 render/picture.c: In function ‘CreateSolidPicture’:
 render/picture.c:874:26: error: array subscript ‘union _SourcePict[0]’ is partly outside array bounds of ‘unsigned char[16]’ [-Werror=array-bounds]
  874 |     pPicture->pSourcePict->type = SourcePictTypeSolidFill;
      |                          ^~
 render/picture.c:868:45: note: object of size 16 allocated by ‘malloc’
  868 |     pPicture->pSourcePict = (SourcePictPtr) malloc(sizeof(PictSolidFill));
      |                                             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 render/picture.c: In function ‘CreateLinearGradientPicture’:
 render/picture.c:906:26: error: array subscript ‘union _SourcePict[0]’ is partly outside array bounds of ‘unsigned char[32]’ [-Werror=array-bounds]
  906 |     pPicture->pSourcePict->linear.type = SourcePictTypeLinear;
      |                          ^~
 render/picture.c:899:45: note: object of size 32 allocated by ‘malloc’
  899 |     pPicture->pSourcePict = (SourcePictPtr) malloc(sizeof(PictLinearGradient));
      |                                             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 render/picture.c: In function ‘CreateConicalGradientPicture’:
 render/picture.c:989:26: error: array subscript ‘union _SourcePict[0]’ is partly outside array bounds of ‘unsigned char[32]’ [-Werror=array-bounds]
  989 |     pPicture->pSourcePict->conical.type = SourcePictTypeConical;
      |                          ^~
 render/picture.c:982:45: note: object of size 32 allocated by ‘malloc’
  982 |     pPicture->pSourcePict = (SourcePictPtr) malloc(sizeof(PictConicalGradient));
      |                                             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 cc1: some warnings being treated as errors
 ninja: build stopped: subcommand failed.

This is because gcc 12 has become stricter and raises a warning now.

Fix the warning/error by allocating enough memory to store the union
struct.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Acked-by: Michel Dänzer <mdaenzer@redhat.com>
Closes: https://gitlab.freedesktop.org/xorg/xserver/-/issues/1256
---
 render/picture.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/render/picture.c b/render/picture.c
index afa0d258fa..2be4b1954f 100644
--- a/render/picture.c
+++ b/render/picture.c
@@ -865,7 +865,7 @@ CreateSolidPicture(Picture pid, xRenderColor * color, int *error)
     }
 
     pPicture->id = pid;
-    pPicture->pSourcePict = (SourcePictPtr) malloc(sizeof(PictSolidFill));
+    pPicture->pSourcePict = (SourcePictPtr) malloc(sizeof(SourcePict));
     if (!pPicture->pSourcePict) {
         *error = BadAlloc;
         free(pPicture);
@@ -896,7 +896,7 @@ CreateLinearGradientPicture(Picture pid, xPointFixed * p1, xPointFixed * p2,
     }
 
     pPicture->id = pid;
-    pPicture->pSourcePict = (SourcePictPtr) malloc(sizeof(PictLinearGradient));
+    pPicture->pSourcePict = (SourcePictPtr) malloc(sizeof(SourcePict));
     if (!pPicture->pSourcePict) {
         *error = BadAlloc;
         free(pPicture);
@@ -936,7 +936,7 @@ CreateRadialGradientPicture(Picture pid, xPointFixed * inner,
     }
 
     pPicture->id = pid;
-    pPicture->pSourcePict = (SourcePictPtr) malloc(sizeof(PictRadialGradient));
+    pPicture->pSourcePict = (SourcePictPtr) malloc(sizeof(SourcePict));
     if (!pPicture->pSourcePict) {
         *error = BadAlloc;
         free(pPicture);
@@ -979,7 +979,7 @@ CreateConicalGradientPicture(Picture pid, xPointFixed * center, xFixed angle,
     }
 
     pPicture->id = pid;
-    pPicture->pSourcePict = (SourcePictPtr) malloc(sizeof(PictConicalGradient));
+    pPicture->pSourcePict = (SourcePictPtr) malloc(sizeof(SourcePict));
     if (!pPicture->pSourcePict) {
         *error = BadAlloc;
         free(pPicture);
-- 
GitLab