From 535c9841b6c78a71e8e9bb2810fe886c6661f37c Mon Sep 17 00:00:00 2001 From: =?utf8?q?Marcin=20Ko=C5=9Bcielnicki?= Date: Thu, 21 Nov 2019 00:20:15 +0100 Subject: [PATCH] [PATCH] rtld: Check __libc_enable_secure before honoring LD_PREFER_MAP_32BIT_EXEC (CVE-2019-19126) [BZ #25204] The problem was introduced in glibc 2.23, in commit b9eb92ab05204df772eb4929eccd018637c9f3e9 ("Add Prefer_MAP_32BIT_EXEC to map executable pages with MAP_32BIT"). Gbp-Pq: Topic all Gbp-Pq: Name git-CVE-2019-19126-rtld-Check-__libc_enable_secure-before-honoring-LD_P.diff --- sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h b/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h index 194369174..ac694c032 100644 --- a/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h +++ b/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h @@ -31,7 +31,8 @@ environment variable, LD_PREFER_MAP_32BIT_EXEC. */ #define EXTRA_LD_ENVVARS \ case 21: \ - if (memcmp (envline, "PREFER_MAP_32BIT_EXEC", 21) == 0) \ + if (!__libc_enable_secure \ + && memcmp (envline, "PREFER_MAP_32BIT_EXEC", 21) == 0) \ GLRO(dl_x86_cpu_features).feature[index_arch_Prefer_MAP_32BIT_EXEC] \ |= bit_arch_Prefer_MAP_32BIT_EXEC; \ break; -- 2.30.2