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| author | Paul Eggert <eggert@cs.ucla.edu> | 2022-10-10 12:35:56 -0700 |
|---|---|---|
| committer | Paul Eggert <eggert@cs.ucla.edu> | 2022-10-10 12:36:38 -0700 |
| commit | 345de32a5db8ef165feeda77c99ce56e4d6e911c (patch) | |
| tree | 6ad41cbca2e50dfaaa7fdc20609e46440795b557 /lib-src | |
| parent | 8851a75ca7642ce071a23c24a81e22e443be0b05 (diff) | |
| download | emacs-345de32a5db8ef165feeda77c99ce56e4d6e911c.tar.gz emacs-345de32a5db8ef165feeda77c99ce56e4d6e911c.tar.bz2 emacs-345de32a5db8ef165feeda77c99ce56e4d6e911c.zip | |
Port bwrap/allows-stdout test to Ubuntu 22.04.1
Without this patch, Ubuntu 22.04.1 x86-64 "make check" reports a
failure in test/src/emacs-tests.el’s
emacs-tests/bwrap/allows-stdout. One can reproduce the bug
without using the Emacs executable, by running this script:
#!/bin/bash
export LC_ALL=C
exec strace -f -o /tmp/tr bwrap --ro-bind / / --seccomp 20 -- \
cat /dev/null 20< lib-src/seccomp-filter-exec.bpf
This script exits with status 159, because "cat" didn’t get
started (it got a SIGSYS signal early on).
The command "journalctl -g SECCOMP" indicated that rseq (syscall
334) was the problem. This syscall is issued by
/lib64/ld-linux-x86-64.so.2 before ‘main’ is called.
There’s another problem with the clone3 syscall, which is used by
pthread_create starting in glibc 2.34. pthread_create is called
by g_child_watch_source_new, which is called by
init_process_emacs.
* lib-src/seccomp-filter.c (main): Allow rseq, clone3. This
causes the test to pass. Perhaps a fancier, more accurate patch
could be written by someone who has the time.
Diffstat (limited to 'lib-src')
| -rw-r--r-- | lib-src/seccomp-filter.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/lib-src/seccomp-filter.c b/lib-src/seccomp-filter.c index 041bf5c749b..e45aa0c17f6 100644 --- a/lib-src/seccomp-filter.c +++ b/lib-src/seccomp-filter.c @@ -206,6 +206,9 @@ main (int argc, char **argv) SCMP_A2_32 (SCMP_CMP_MASKED_EQ, ~(PROT_NONE | PROT_READ | PROT_WRITE), 0)); + /* Allow restartable sequences. The dynamic linker uses them. */ + RULE (SCMP_ACT_ALLOW, SCMP_SYS (rseq)); + /* Futexes are used everywhere. */ RULE (SCMP_ACT_ALLOW, SCMP_SYS (futex), SCMP_A1_32 (SCMP_CMP_EQ, FUTEX_WAKE_PRIVATE)); @@ -324,6 +327,8 @@ main (int argc, char **argv) | CLONE_SETTLS | CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID), 0)); + /* glibc 2.34+ pthread_create uses clone3. */ + RULE (SCMP_ACT_ALLOW, SCMP_SYS (clone3)); RULE (SCMP_ACT_ALLOW, SCMP_SYS (sigaltstack)); RULE (SCMP_ACT_ALLOW, SCMP_SYS (set_robust_list)); |