about summary refs log tree commit diff
path: root/sysdeps/unix/sysv/linux
diff options
context:
space:
mode:
authorMarcin Koƛcielnicki <mwk@0x04.net>2019-11-21 00:20:15 +0100
committerFlorian Weimer <fweimer@redhat.com>2019-11-22 13:46:54 +0100
commit7966ce07e89fa4ccc8fdba00d4439fc652862462 (patch)
treea40a5fcae478b1a336ea11b70ee5ded1307a0808 /sysdeps/unix/sysv/linux
parentcedb3e47c68d319607736a820da2d5b3b8ddff6f (diff)
downloadglibc-7966ce07e89fa4ccc8fdba00d4439fc652862462.tar.gz
glibc-7966ce07e89fa4ccc8fdba00d4439fc652862462.tar.xz
glibc-7966ce07e89fa4ccc8fdba00d4439fc652862462.zip
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").

(cherry picked from commit d5dfad4326fc683c813df1e37bbf5cf920591c8e)
Diffstat (limited to 'sysdeps/unix/sysv/linux')
-rw-r--r--sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h3
1 files changed, 2 insertions, 1 deletions
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 194369174d..ac694c032e 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;