Manpages - seccomp_arch_add.3

seccomp_arch_add, seccomp_arch_remove, seccomp_arch_exist, seccomp_arch_native - Manage seccomp filter architectures

  #include <seccomp.h>

  typedef void * scmp_filter_ctx;

  #define SCMP_ARCH_NATIVE
  #define SCMP_ARCH_X86
  #define SCMP_ARCH_X86_64
  #define SCMP_ARCH_X32
  #define SCMP_ARCH_ARM
  #define SCMP_ARCH_AARCH64
  #define SCMP_ARCH_MIPS
  #define SCMP_ARCH_MIPS64
  #define SCMP_ARCH_MIPS64N32
  #define SCMP_ARCH_MIPSEL
  #define SCMP_ARCH_MIPSEL64
  #define SCMP_ARCH_MIPSEL64N32
  #define SCMP_ARCH_PPC
  #define SCMP_ARCH_PPC64
  #define SCMP_ARCH_PPC64LE
  #define SCMP_ARCH_S390
  #define SCMP_ARCH_S390X
  #define SCMP_ARCH_PARISC
  #define SCMP_ARCH_PARISC64
  #define SCMP_ARCH_RISCV64

  uint32_t seccomp_arch_resolve_name(const char *arch_name);
  uint32_t seccomp_arch_native();
  int seccomp_arch_exist(const scmp_filter_ctx ctx, uint32_t arch_token);
  int seccomp_arch_add(scmp_filter_ctx ctx, uint32_t arch_token);
  int seccomp_arch_remove(scmp_filter_ctx ctx, uint32_t arch_token);

  Link with -lseccomp.

The seccomp_arch_exist*() function tests to see if a given architecture has been added to the seccomp filter in ctx, where the seccomp_arch_add*() and *seccomp_arch_remove*() add and remove, respectively, architectures from the seccomp filter. In all three functions, the architecture values given in arch_token should be the *SCMP_ARCH_ defined constants; with the SCMP_ARCH_NATIVE constant always referring to the native compiled architecture. The seccomp_arch_native*() function returns the system’s architecture such that it will match one of the SCMP_ARCH_ constants. While the seccomp_arch_resolve_name*() function also returns a SCMP_ARCH_ constant, the returned token matches the name of the architecture passed as an argument to the function.

When a seccomp filter is initialized with the call to *seccomp_init*(3) the native architecture is automatically added to the filter.

While it is possible to remove all architectures from a filter, most of the libseccomp APIs will fail if the filter does not contain at least one architecture.

When adding a new architecture to an existing filter, the existing rules will not be added to the new architecture. However, rules added after adding the new architecture will be added to all of the architectures in the filter.

The *seccomp_arch_add*(), *seccomp_arch_remove*(), and *seccomp_arch_exist*() functions return zero on success or one of the following error codes on failure:

-EDOM

Architecture specific failure.

-EEXIST

In the case of *seccomp_arch_add*() the architecture already exists and in the case of *seccomp_arch_remove*() the architecture does not exist.

-EINVAL

Invalid input, either the context or architecture token is invalid.

-ENOMEM

The library was unable to allocate enough memory.

  #include <seccomp.h>

  int main(int argc, char *argv[])
  {
  	int rc = -1;
  	scmp_filter_ctx ctx;

  	ctx = seccomp_init(SCMP_ACT_KILL);
  	if (ctx == NULL)
  		goto out;

  	if (seccomp_arch_exist(ctx, SCMP_ARCH_X86) == -EEXIST) {
  		rc = seccomp_arch_add(ctx, SCMP_ARCH_X86);
  		if (rc != 0)
  			goto out_all;
  		rc = seccomp_arch_remove(ctx, SCMP_ARCH_NATIVE);
  		if (rc != 0)
  			goto out_all;
  	}

  	/* ... */

  out:
  	seccomp_release(ctx);
  	return -rc;
  }

While the seccomp filter can be generated independent of the kernel, kernel support is required to load and enforce the seccomp filter generated by libseccomp.

The libseccomp project site, with more information and the source code repository, can be found at https://github.com/seccomp/libseccomp. This tool, as well as the libseccomp library, is currently under development, please report any bugs at the project site or directly to the author.

Paul Moore <paul@paul-moore.com>

*seccomp_init*(3), *seccomp_reset*(3), *seccomp_merge*(3)