Create APP_ZYGOTE seccomp policy.

The APP_ZYGOTE seccomp policy is identical to the APP seccomp policy,
with the exception of allowing setresgid(32), which the app zygote
needs to be able to do (within a certain range).

Bug: 111434506
Test: manual
Change-Id: I34864837c981d201225e3e2e5501c0415a9a7dc8
diff --git a/libc/Android.bp b/libc/Android.bp
index ddc2805..79cc709 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -2211,6 +2211,45 @@
     ],
 }
 
+// SECCOMP_BLACKLIST_APP_ZYGOTE.TXT = SECCOMP_BLACKLIST_APP.txt - setresgid*
+genrule {
+    name: "generate_app_zygote_blacklist",
+    out: ["SECCOMP_BLACKLIST_APP_ZYGOTE.TXT"],
+    srcs: ["SECCOMP_BLACKLIST_APP.TXT"],
+    cmd: "grep -v '^int[ \t]*setresgid' $(in) > $(out)",
+}
+
+cc_genrule {
+    name: "libseccomp_policy_app_zygote_sources",
+    recovery_available: true,
+    cmd: "$(location genseccomp) --out-dir=$(genDir) --name-modifier=app_zygote $(in)",
+
+    tools: [ "genseccomp" ],
+
+    srcs: [
+        "SYSCALLS.TXT",
+        "SECCOMP_WHITELIST_COMMON.TXT",
+        "SECCOMP_WHITELIST_APP.TXT",
+        "SECCOMP_BLACKLIST_COMMON.TXT",
+        ":generate_app_zygote_blacklist",
+        ":libseccomp_gen_syscall_nrs_arm",
+        ":libseccomp_gen_syscall_nrs_arm64",
+        ":libseccomp_gen_syscall_nrs_mips",
+        ":libseccomp_gen_syscall_nrs_mips64",
+        ":libseccomp_gen_syscall_nrs_x86",
+        ":libseccomp_gen_syscall_nrs_x86_64",
+    ],
+
+    out: [
+        "arm64_app_zygote_policy.cpp",
+        "arm_app_zygote_policy.cpp",
+        "mips64_app_zygote_policy.cpp",
+        "mips_app_zygote_policy.cpp",
+        "x86_64_app_zygote_policy.cpp",
+        "x86_app_zygote_policy.cpp",
+    ],
+}
+
 cc_genrule {
     name: "libseccomp_policy_app_sources",
     recovery_available: true,
@@ -2309,6 +2348,7 @@
     recovery_available: true,
     generated_sources: [
         "libseccomp_policy_app_sources",
+        "libseccomp_policy_app_zygote_sources",
         "libseccomp_policy_global_sources",
         "libseccomp_policy_system_sources",
     ],
diff --git a/libc/seccomp/include/seccomp_policy.h b/libc/seccomp/include/seccomp_policy.h
index 49280f4..bcbe285 100644
--- a/libc/seccomp/include/seccomp_policy.h
+++ b/libc/seccomp/include/seccomp_policy.h
@@ -20,5 +20,6 @@
 #include <linux/filter.h>
 
 bool set_app_seccomp_filter();
+bool set_app_zygote_seccomp_filter();
 bool set_system_seccomp_filter();
 bool set_global_seccomp_filter();
diff --git a/libc/seccomp/seccomp_bpfs.h b/libc/seccomp/seccomp_bpfs.h
index 797dfc5..d9e8047 100644
--- a/libc/seccomp/seccomp_bpfs.h
+++ b/libc/seccomp/seccomp_bpfs.h
@@ -21,6 +21,8 @@
 
 extern const struct sock_filter arm_app_filter[];
 extern const size_t arm_app_filter_size;
+extern const struct sock_filter arm_app_zygote_filter[];
+extern const size_t arm_app_zygote_filter_size;
 extern const struct sock_filter arm_system_filter[];
 extern const size_t arm_system_filter_size;
 extern const struct sock_filter arm_global_filter[];
@@ -28,6 +30,8 @@
 
 extern const struct sock_filter arm64_app_filter[];
 extern const size_t arm64_app_filter_size;
+extern const struct sock_filter arm64_app_zygote_filter[];
+extern const size_t arm64_app_zygote_filter_size;
 extern const struct sock_filter arm64_system_filter[];
 extern const size_t arm64_system_filter_size;
 extern const struct sock_filter arm64_global_filter[];
@@ -35,6 +39,8 @@
 
 extern const struct sock_filter x86_app_filter[];
 extern const size_t x86_app_filter_size;
+extern const struct sock_filter x86_app_zygote_filter[];
+extern const size_t x86_app_zygote_filter_size;
 extern const struct sock_filter x86_system_filter[];
 extern const size_t x86_system_filter_size;
 extern const struct sock_filter x86_global_filter[];
@@ -42,6 +48,8 @@
 
 extern const struct sock_filter x86_64_app_filter[];
 extern const size_t x86_64_app_filter_size;
+extern const struct sock_filter x86_64_app_zygote_filter[];
+extern const size_t x86_64_app_zygote_filter_size;
 extern const struct sock_filter x86_64_system_filter[];
 extern const size_t x86_64_system_filter_size;
 extern const struct sock_filter x86_64_global_filter[];
@@ -49,6 +57,8 @@
 
 extern const struct sock_filter mips_app_filter[];
 extern const size_t mips_app_filter_size;
+extern const struct sock_filter mips_app_zygote_filter[];
+extern const size_t mips_app_zygote_filter_size;
 extern const struct sock_filter mips_system_filter[];
 extern const size_t mips_system_filter_size;
 extern const struct sock_filter mips_global_filter[];
@@ -56,6 +66,8 @@
 
 extern const struct sock_filter mips64_app_filter[];
 extern const size_t mips64_app_filter_size;
+extern const struct sock_filter mips64_app_zygote_filter[];
+extern const size_t mips64_app_zygote_filter_size;
 extern const struct sock_filter mips64_system_filter[];
 extern const size_t mips64_system_filter_size;
 extern const struct sock_filter mips64_global_filter[];
diff --git a/libc/seccomp/seccomp_policy.cpp b/libc/seccomp/seccomp_policy.cpp
index 75871c0..d7fd7f6 100644
--- a/libc/seccomp/seccomp_policy.cpp
+++ b/libc/seccomp/seccomp_policy.cpp
@@ -33,6 +33,8 @@
 #define PRIMARY_ARCH AUDIT_ARCH_AARCH64
 static const struct sock_filter* primary_app_filter = arm64_app_filter;
 static const size_t primary_app_filter_size = arm64_app_filter_size;
+static const struct sock_filter* primary_app_zygote_filter = arm64_app_zygote_filter;
+static const size_t primary_app_zygote_filter_size = arm64_app_zygote_filter_size;
 static const struct sock_filter* primary_system_filter = arm64_system_filter;
 static const size_t primary_system_filter_size = arm64_system_filter_size;
 static const struct sock_filter* primary_global_filter = arm64_global_filter;
@@ -40,6 +42,8 @@
 #define SECONDARY_ARCH AUDIT_ARCH_ARM
 static const struct sock_filter* secondary_app_filter = arm_app_filter;
 static const size_t secondary_app_filter_size = arm_app_filter_size;
+static const struct sock_filter* secondary_app_zygote_filter = arm_app_zygote_filter;
+static const size_t secondary_app_zygote_filter_size = arm_app_zygote_filter_size;
 static const struct sock_filter* secondary_system_filter = arm_system_filter;
 static const size_t secondary_system_filter_size = arm_system_filter_size;
 static const struct sock_filter* secondary_global_filter = arm_global_filter;
@@ -51,6 +55,8 @@
 #define PRIMARY_ARCH AUDIT_ARCH_X86_64
 static const struct sock_filter* primary_app_filter = x86_64_app_filter;
 static const size_t primary_app_filter_size = x86_64_app_filter_size;
+static const struct sock_filter* primary_app_zygote_filter = x86_64_app_zygote_filter;
+static const size_t primary_app_zygote_filter_size = x86_64_app_zygote_filter_size;
 static const struct sock_filter* primary_system_filter = x86_64_system_filter;
 static const size_t primary_system_filter_size = x86_64_system_filter_size;
 static const struct sock_filter* primary_global_filter = x86_64_global_filter;
@@ -58,6 +64,8 @@
 #define SECONDARY_ARCH AUDIT_ARCH_I386
 static const struct sock_filter* secondary_app_filter = x86_app_filter;
 static const size_t secondary_app_filter_size = x86_app_filter_size;
+static const struct sock_filter* secondary_app_zygote_filter = x86_app_zygote_filter;
+static const size_t secondary_app_zygote_filter_size = x86_app_zygote_filter_size;
 static const struct sock_filter* secondary_system_filter = x86_system_filter;
 static const size_t secondary_system_filter_size = x86_system_filter_size;
 static const struct sock_filter* secondary_global_filter = x86_global_filter;
@@ -69,6 +77,8 @@
 #define PRIMARY_ARCH AUDIT_ARCH_MIPSEL64
 static const struct sock_filter* primary_app_filter = mips64_app_filter;
 static const size_t primary_app_filter_size = mips64_app_filter_size;
+static const struct sock_filter* primary_app_zygote_filter = mips64_app_zygote_filter;
+static const size_t primary_app_zygote_filter_size = mips64_app_zygote_filter_size;
 static const struct sock_filter* primary_system_filter = mips64_system_filter;
 static const size_t primary_system_filter_size = mips64_system_filter_size;
 static const struct sock_filter* primary_global_filter = mips64_global_filter;
@@ -76,6 +86,8 @@
 #define SECONDARY_ARCH AUDIT_ARCH_MIPSEL
 static const struct sock_filter* secondary_app_filter = mips_app_filter;
 static const size_t secondary_app_filter_size = mips_app_filter_size;
+static const struct sock_filter* secondary_app_zygote_filter = mips_app_zygote_filter;
+static const size_t secondary_app_zygote_filter_size = mips_app_zygote_filter_size;
 static const struct sock_filter* secondary_system_filter = mips_system_filter;
 static const size_t secondary_system_filter_size = mips_system_filter_size;
 static const struct sock_filter* secondary_global_filter = mips_global_filter;
@@ -142,6 +154,7 @@
 
 enum FilterType {
   APP,
+  APP_ZYGOTE,
   SYSTEM,
   GLOBAL
 };
@@ -158,6 +171,12 @@
         s = secondary_app_filter;
         s_size = secondary_app_filter_size;
         break;
+      case APP_ZYGOTE:
+        p = primary_app_zygote_filter;
+        p_size = primary_app_zygote_filter_size;
+        s = secondary_app_zygote_filter;
+        s_size = secondary_app_zygote_filter_size;
+        break;
       case SYSTEM:
         p = primary_system_filter;
         p_size = primary_system_filter_size;
@@ -209,6 +228,10 @@
     return _set_seccomp_filter(FilterType::APP);
 }
 
+bool set_app_zygote_seccomp_filter() {
+    return _set_seccomp_filter(FilterType::APP_ZYGOTE);
+}
+
 bool set_system_seccomp_filter() {
     return _set_seccomp_filter(FilterType::SYSTEM);
 }