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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2023-11-06 17:25:36 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2023-11-21 16:15:42 -0300 |
| commit | 9c96c87d60eafa4d78406e606e92b42bd4b570ad (patch) | |
| tree | f2b1db62e65cdf8cae4e058bea8e40aae847dc16 /manual | |
| parent | a72a4eb10b2d9aef7a53f9d2facf166a685d85fb (diff) | |
| download | glibc-9c96c87d60eafa4d78406e606e92b42bd4b570ad.zip glibc-9c96c87d60eafa4d78406e606e92b42bd4b570ad.tar.gz glibc-9c96c87d60eafa4d78406e606e92b42bd4b570ad.tar.bz2 | |
elf: Ignore GLIBC_TUNABLES for setuid/setgid binaries
The tunable privilege levels were a retrofit to try and keep the malloc
tunable environment variables' behavior unchanged across security
boundaries. However, CVE-2023-4911 shows how tricky can be
tunable parsing in a security-sensitive environment.
Not only parsing, but the malloc tunable essentially changes some
semantics on setuid/setgid processes. Although it is not a direct
security issue, allowing users to change setuid/setgid semantics is not
a good security practice, and requires extra code and analysis to check
if each tunable is safe to use on all security boundaries.
It also means that security opt-in features, like aarch64 MTE, would
need to be explicit enabled by an administrator with a wrapper script
or with a possible future system-wide tunable setting.
Co-authored-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: DJ Delorie <dj@redhat.com>
Diffstat (limited to 'manual')
| -rw-r--r-- | manual/README.tunables | 9 |
1 files changed, 0 insertions, 9 deletions
diff --git a/manual/README.tunables b/manual/README.tunables index 605ddd7..72ae00d 100644 --- a/manual/README.tunables +++ b/manual/README.tunables @@ -59,15 +59,6 @@ The list of allowed attributes are: - env_alias: An alias environment variable -- security_level: Specify security level of the tunable for AT_SECURE - binaries. Valid values are: - - SXID_ERASE: (default) Do not read and do not pass on to - child processes. - SXID_IGNORE: Do not read, but retain for non-AT_SECURE - child processes. - NONE: Read all the time. - 2. Use TUNABLE_GET/TUNABLE_SET/TUNABLE_SET_WITH_BOUNDS to get and set tunables. 3. OPTIONAL: If tunables in a namespace are being used multiple times within a |