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authorMarcin Koƛcielnicki <mwk@0x04.net>2019-11-21 00:20:15 +0100
committerFlorian Weimer <fweimer@redhat.com>2019-11-21 12:56:44 +0100
commitd5dfad4326fc683c813df1e37bbf5cf920591c8e (patch)
treecaf191d9e8e3dc6f42b0b5e2a04370ecc2858198 /sysdeps
parent2a764c6ee848dfe92cb2921ed3b14085f15d9e79 (diff)
downloadglibc-d5dfad4326fc683c813df1e37bbf5cf920591c8e.tar.gz
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").
Diffstat (limited to 'sysdeps')
-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 0e95221908..e3af239faa 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;