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38 lines
1.2 KiB
38 lines
1.2 KiB
12 months ago
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From b6aacc5eb73ef0d41bdff9cd62672d4dc7a62e0d Mon Sep 17 00:00:00 2001
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From: XScreenSaver owners <xscreensaver-owner@fedoraproject.org>
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Date: Fri, 1 Sep 2023 17:32:57 +0900
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Subject: [PATCH 2/2] convert_ximage_to_rgba32: avoid integer overflow on left
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shift
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gcc -fsanitize=undefined shows the following undefined behavior:
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../../../hacks/glx/grab-ximage.c:213:21: runtime error: left shift of 255 by 24 places cannot be represented in type 'int'
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This is because of integral promotion from unsigned char to int, not to unsigned int.
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To avoid this error, cast to unsigned long type.
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---
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hacks/glx/grab-ximage.c | 4 ++--
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1 file changed, 2 insertions(+), 2 deletions(-)
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diff --git a/hacks/glx/grab-ximage.c b/hacks/glx/grab-ximage.c
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index defefda..9d3a2d6 100644
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--- a/hacks/glx/grab-ximage.c
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+++ b/hacks/glx/grab-ximage.c
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@@ -207,10 +207,10 @@ convert_ximage_to_rgba32 (Screen *screen, XImage *image)
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sb = spread_map[2][sb];
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}
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- cp = ((sr << crpos) |
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+ cp = ((((unsigned long)sr) << crpos) |
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(sg << cgpos) |
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(sb << cbpos) |
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- (0xFF << capos));
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+ (0xFFUL << capos));
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XPutPixel (to, x, y, cp);
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}
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--
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2.41.0
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