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24 lines
1.1 KiB
24 lines
1.1 KiB
commit d5dfad4326fc683c813df1e37bbf5cf920591c8e |
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Author: Marcin Kościelnicki <mwk@0x04.net> |
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Date: Thu Nov 21 00:20:15 2019 +0100 |
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rtld: Check __libc_enable_secure before honoring LD_PREFER_MAP_32BIT_EXEC (CVE-2019-19126) [BZ #25204] |
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The problem was introduced in glibc 2.23, in commit |
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b9eb92ab05204df772eb4929eccd018637c9f3e9 |
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("Add Prefer_MAP_32BIT_EXEC to map executable pages with MAP_32BIT"). |
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diff --git a/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h b/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h |
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index 1531437359c0ec06..82495780a06d8a05 100644 |
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--- a/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h |
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+++ b/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h |
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@@ -31,7 +31,8 @@ |
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environment variable, LD_PREFER_MAP_32BIT_EXEC. */ |
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#define EXTRA_LD_ENVVARS \ |
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case 21: \ |
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- if (memcmp (envline, "PREFER_MAP_32BIT_EXEC", 21) == 0) \ |
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+ if (!__libc_enable_secure \ |
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+ && memcmp (envline, "PREFER_MAP_32BIT_EXEC", 21) == 0) \ |
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GLRO(dl_x86_cpu_features).feature[index_Prefer_MAP_32BIT_EXEC] \ |
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|= bit_Prefer_MAP_32BIT_EXEC; \ |
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break;
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