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[0/2] make all tunables SXID_ERASE

Message ID 20231003201151.1406279-1-siddhesh@sourceware.org
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Series make all tunables SXID_ERASE | expand

Message

Siddhesh Poyarekar Oct. 3, 2023, 8:11 p.m. UTC 
The tunable privilege levels were a retrofit to try and keep the malloc
tunable envvar behaviour unchanged.  In retrospect, especially in the
light of CVE-2023-4911, I wonder if this feature of carrying allocator
tuning knobs (and more generally, tunables in general) has much value.

This patchset takes the first step by proposing to make all existing
tunables SXID_ERASE.  This will have the effect of deactivating tunables
parsing in the at_secure context for all current tunables, making it
trivial to drop GLIBC_TUNABLES form unsecvars.h in future, hopefully
soon.

Further, this paves the way for future cleanups to tunables parsing,
where we could simply skip over tunables parsing for
__libc_enable_secure instead of the complicated dance we're doing today.

Tested on x86_64.

Siddhesh Poyarekar (2):
  Make all malloc tunables SXID_ERASE
  aarch64: Make glibc.mem.tagging SXID_ERASE

 elf/dl-tunables.list          | 13 +++----------
 elf/tst-env-setuid-tunables.c | 25 ++-----------------------
 elf/tst-env-setuid.c          |  4 ++--
 sysdeps/generic/unsecvars.h   |  7 +++++++
 4 files changed, 14 insertions(+), 35 deletions(-)