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| author | Marcin Kościelnicki <mwk@0x04.net> | 2019-11-21 00:20:15 +0100 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2019-11-22 14:09:58 +0100 |
| commit | b039fd85db0717aca309b61925d00a5a6547a649 (patch) | |
| tree | 0d2e5bb4a86694aa15af4e0fe4604e587982bdfb | |
| parent | 8337b12d0b80b0f26ec88156b8dd4972a9cb34c3 (diff) | |
| download | glibc-release/2.23/master.tar.gz glibc-release/2.23/master.tar.xz glibc-release/2.23/master.zip | |
rtld: Check __libc_enable_secure before honoring LD_PREFER_MAP_32BIT_EXEC (CVE-2019-19126) [BZ #25204] release/2.23/master
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)
| -rw-r--r-- | NEWS | 7 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h | 3 |
2 files changed, 9 insertions, 1 deletions
diff --git a/NEWS b/NEWS index 9bbcfd137a..82b0baa5fa 100644 --- a/NEWS +++ b/NEWS @@ -28,6 +28,12 @@ Security related changes: (denial of service) in some Go applications compiled with gccgo. Reported by Andreas Schwab. (CVE-2016-6323) + CVE-2019-19126: ld.so failed to ignore the LD_PREFER_MAP_32BIT_EXEC + environment variable during program execution after a security + transition, allowing local attackers to restrict the possible mapping + addresses for loaded libraries and thus bypass ASLR for a setuid + program. Reported by Marcin Kościelnicki. + The following bugs are resolved with this release: [19679] gcc-4.9.3 C++ exception handling broken due to unaligned stack @@ -49,6 +55,7 @@ The following bugs are resolved with this release: [21666] Avoid .symver on common symbols [22641] x86: Fix mis-merge of XSAVE ld.so trampoline selection [22715] x86-64: Properly align La_x86_64_retval to VEC_SIZE + [25204] Ignore LD_PREFER_MAP_32BIT_EXEC for SUID programs Version 2.23 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 a759934fdd..b13bba65d2 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_Prefer_MAP_32BIT_EXEC] \ |= bit_Prefer_MAP_32BIT_EXEC; \ break; |