Initial version of the Seccomp sandbox. Imported from http://code.google.com/p/seccompsandbox/

Make the seccomp sandbox dependant on the --enable-seccomp-sandbox flag

Review URL: http://codereview.chromium.org/165310


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@23087 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 151 insertions, 0 deletions

diff --git a/sandbox/linux/seccomp/tls.h b/sandbox/linux/seccomp/tls.h
new file mode 100644
index 0000000..8eae697
--- /dev/null
+++ b/sandbox/linux/seccomp/tls.h
@@ -0,0 +1,151 @@
+#ifndef TLS_H__
+#define TLS_H__
+
+#include <asm/ldt.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+
+namespace playground {
+
+class TLS {
+ private:
+  class SysCalls {
+   public:
+    #define SYS_CPLUSPLUS
+    #define SYS_ERRNO     my_errno
+    #define SYS_INLINE    inline
+    #define SYS_PREFIX    -1
+    #undef  SYS_LINUX_SYSCALL_SUPPORT_H
+    #include "linux_syscall_support.h"
+    SysCalls() : my_errno(0) { }
+    int my_errno;
+  };
+
+ public:
+  static void *allocateTLS() {
+    SysCalls sys;
+    #if defined(__x86_64__)
+    void *addr = sys.mmap(0, 4096, PROT_READ|PROT_WRITE,
+                          MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+    if (sys.arch_prctl(ARCH_SET_GS, addr) < 0) {
+      return NULL;
+    }
+    #elif defined(__i386__)
+    void *addr = sys.mmap2(0, 4096, PROT_READ|PROT_WRITE,
+                           MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+    struct user_desc u;
+    u.entry_number    = (typeof u.entry_number)-1;
+    u.base_addr       = (int)addr;
+    u.limit           = 0xfffff;
+    u.seg_32bit       = 1;
+    u.contents        = 0;
+    u.read_exec_only  = 0;
+    u.limit_in_pages  = 1;
+    u.seg_not_present = 0;
+    u.useable         = 1;
+    if (sys.set_thread_area(&u) < 0) {
+      return NULL;
+    }
+    asm volatile(
+        "movw %w0, %%fs"
+        :
+        : "q"(8*u.entry_number+3));
+    #else
+    #error Unsupported target platform
+    #endif
+    return addr;
+  }
+
+  static void freeTLS() {
+    SysCalls sys;
+    void *addr;
+    #if defined(__x86_64__)
+    sys.arch_prctl(ARCH_GET_GS, &addr);
+    #elif defined(__i386__)
+    struct user_desc u;
+    sys.get_thread_area(&u);
+    addr = (void *)u.base_addr;
+    #else
+    #error Unsupported target platform
+    #endif
+    sys.munmap(addr, 4096);
+  }
+
+  template<class T> static inline bool setTLSValue(int idx, T val) {
+    #if defined(__x86_64__)
+    if (idx < 0 || idx >= 4096/8) {
+      return false;
+    }
+    asm volatile(
+        "movq %0, %%gs:(%1)\n"
+        :
+        : "q"((void *)val), "q"(8ll * idx));
+    #elif defined(__i386__)
+    if (idx < 0 || idx >= 4096/8) {
+      return false;
+    }
+    if (sizeof(T) == 8) {
+      asm volatile(
+          "movl %0, %%fs:(%1)\n"
+          :
+          : "r"((unsigned)val), "r"(8 * idx));
+      asm volatile(
+          "movl %0, %%fs:(%1)\n"
+          :
+          : "r"((unsigned)((unsigned long long)val >> 32)), "r"(8 * idx + 4));
+    } else {
+      asm volatile(
+          "movl %0, %%fs:(%1)\n"
+          :
+          : "r"(val), "r"(8 * idx));
+    }
+    #else
+    #error Unsupported target platform
+    #endif
+    return true;
+  }
+
+  template<class T> static inline T getTLSValue(int idx) {
+    #if defined(__x86_64__)
+    long long rc;
+    if (idx < 0 || idx >= 4096/8) {
+      return 0;
+    }
+    asm volatile(
+        "movq %%gs:(%1), %0\n"
+        : "=q"(rc)
+        : "q"(8ll * idx));
+    return (T)rc;
+    #elif defined(__i386__)
+    if (idx < 0 || idx >= 4096/8) {
+      return 0;
+    }
+    if (sizeof(T) == 8) {
+      unsigned lo, hi;
+      asm volatile(
+          "movl %%fs:(%1), %0\n"
+          : "=r"(lo)
+          : "r"(8 * idx));
+      asm volatile(
+          "movl %%fs:(%1), %0\n"
+          : "=r"(hi)
+          : "r"(8 * idx + 4));
+      return (T)((unsigned long long)lo + ((unsigned long long)hi << 32));
+    } else {
+      long rc;
+      asm volatile(
+          "movl %%fs:(%1), %0\n"
+          : "=r"(rc)
+          : "r"(8 * idx));
+      return (T)rc;
+    }
+    #else
+    #error Unsupported target platform
+    #endif
+  }
+
+};
+
+} // namespace
+#endif