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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2017-11-17 16:04:29 -0200 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2018-03-05 18:08:27 -0300 |
| commit | 68448be208ee06e76665918b37b0a57e3e00c8b4 (patch) | |
| tree | 07c9ed97d7afa4a6516db76079638e7329c12504 /bits | |
| parent | 8d965cde7a2bc18a010325607f6f526db86cdaf0 (diff) | |
i386: Fix i386 sigaction sa_restorer initialization (BZ#21269)
This patch fixes the i386 sa_restorer field initialization for sigaction
syscall for kernel with vDSO. As described in bug report, i386 Linux
(and compat on x86_64) interprets SA_RESTORER clear with nonzero
sa_restorer as a request for stack switching if the SS segment is 'funny'.
This means that anything that tries to mix glibc's signal handling with
segmentation (for instance through modify_ldt syscall) is randomly broken
depending on what values lands in sa_restorer.
The testcase added is based on Linux test tools/testing/selftests/x86/ldt_gdt.c,
more specifically in do_multicpu_tests function. The main changes are:
- C11 atomics instead of plain access.
- Remove x86_64 support which simplifies the syscall handling and fallbacks.
- Replicate only the test required to trigger the issue.
Checked on i686-linux-gnu.
[BZ #21269]
* sysdeps/unix/sysv/linux/i386/Makefile (tests): Add tst-bz21269.
* sysdeps/unix/sysv/linux/i386/sigaction.c (SET_SA_RESTORER): Clear
sa_restorer for vDSO case.
* sysdeps/unix/sysv/linux/i386/tst-bz21269.c: New file.
Diffstat (limited to 'bits')
0 files changed, 0 insertions, 0 deletions