[PATCH v3 0/4] More tunable fixes

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

The 680c597e9c3 commit made loader reject ill-formatted strings by
first tracking all set tunables and then applying them. However, it does
not take into consideration if the same tunable is set multiple times,
where parse_tunables_string appends the found tunable without checking
if it was already in the list. It leads to a stack-based buffer overflow
if the tunable is specified more than the total number of
tunables (BZ 31686).

While fixing this issue, I noted that the new glibc.rtld.enable_secure
check could be optimized a bit to avoid the string comparison on the
tunable loop.

I also found an issue where it does have the handle case where the
environment alias is handled before the GLIBC_TUNABLES, which will
change the tunable even if glibc.rtld.enable_secure it set to 0.  Fixing
it allows us to optimize the environment alias parsing a bit, since only
tunable with aliases need to be checked (instead of the whole list).

Changes from v2:
* Fixed typos and improve comments.

Changes from v1:
* Do not change tunables internal position.

Adhemerval Zanella (4):
  elf: Only process multiple tunable once (BZ 31686)
  elf: Remove glibc.rtld.enable_secure check from parse_tunables_string
  support: Add envp argument to support_capture_subprogram
  elf: Make glibc.rtld.enable_secure ignore alias environment variables

 elf/dl-tunables.c                          | 114 +++++++++++------
 elf/tst-audit18.c                          |   2 +-
 elf/tst-audit19b.c                         |   2 +-
 elf/tst-audit22.c                          |   2 +-
 elf/tst-audit23.c                          |   2 +-
 elf/tst-audit25a.c                         |   4 +-
 elf/tst-audit25b.c                         |   4 +-
 elf/tst-glibc-hwcaps-2-cache.c             |   2 +-
 elf/tst-rtld-run-static.c                  |   4 +-
 elf/tst-tunables-enable_secure.c           | 136 ++++++++++++++++++---
 elf/tst-tunables.c                         |  63 +++++++++-
 scripts/gen-tunables.awk                   |  16 ++-
 support/capture_subprocess.h               |   9 +-
 support/subprocess.h                       |   7 +-
 support/support_capture_subprocess.c       |   5 +-
 support/support_subprocess.c               |   5 +-
 support/tst-support_capture_subprocess.c   |   2 +-
 sysdeps/aarch64/multiarch/memset_generic.S |   4 +
 sysdeps/sparc/sparc64/rtld-memset.c        |   3 +
 sysdeps/x86/tst-hwcap-tunables.c           |   2 +-
 20 files changed, 310 insertions(+), 78 deletions(-)

-- 
2.43.0