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| author | Philipp Stephani <phst@google.com> | 2021-04-19 21:10:20 +0200 |
|---|---|---|
| committer | Philipp Stephani <phst@google.com> | 2021-04-19 21:11:21 +0200 |
| commit | 27af0a3dc8b6b45879904bbc5d54b0677f84a5ff (patch) | |
| tree | 17e77e80807b653ec4dfea9294e82ea2c9bbe2cb /lib-src | |
| parent | ab287a148fc274d79fb13004aa7ab76fe1058450 (diff) | |
| download | emacs-27af0a3dc8b6b45879904bbc5d54b0677f84a5ff.tar.gz | |
Seccomp filter: deal with arch_prctl(ARCH_CET_STATUS, ...).
The dynamic loader of GNU libc 2.28 uses this system call to
initialize CPU information, see
https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/x86/cpu-features.c;hb=glibc-2.28#l28.
Simulating an older kernel by returning EINVAL should be the most
harmless rule here.
The ARCH_CET_STATUS symbol isn't yet exposed by the kernel headers;
see the FIXME at the top of
https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/x86/include/asm/prctl.h;hb=glibc-2.28.
* lib-src/seccomp-filter.c (ARCH_CET_STATUS): Define if not
already present. Inline the value because there doesn't seem to
be a header file exporting this constant yet.
(main): Make ARCH_CET_STATUS subfunction of arch_prctl return EINVAL.
Diffstat (limited to 'lib-src')
| -rw-r--r-- | lib-src/seccomp-filter.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/lib-src/seccomp-filter.c b/lib-src/seccomp-filter.c index 8f8a990661c..31d0809f8f0 100644 --- a/lib-src/seccomp-filter.c +++ b/lib-src/seccomp-filter.c @@ -60,6 +60,10 @@ variants of those files that can be used to sandbox Emacs before #include "verify.h" +#ifndef ARCH_CET_STATUS +#define ARCH_CET_STATUS 0x3001 +#endif + static ATTRIBUTE_FORMAT_PRINTF (2, 3) _Noreturn void fail (int error, const char *format, ...) { @@ -345,6 +349,8 @@ main (int argc, char **argv) RULE (SCMP_ACT_ALLOW, SCMP_SYS (set_tid_address)); RULE (SCMP_ACT_ALLOW, SCMP_SYS (arch_prctl), SCMP_A0_32 (SCMP_CMP_EQ, ARCH_SET_FS)); + RULE (SCMP_ACT_ERRNO (EINVAL), SCMP_SYS (arch_prctl), + SCMP_A0_32 (SCMP_CMP_EQ, ARCH_CET_STATUS)); RULE (SCMP_ACT_ALLOW, SCMP_SYS (statfs)); /* We want to allow starting the Emacs binary itself with the |