commit fcea70f840f36eefdd8550f9b4ed4ead099844cc
author Maciej Żenczykowski <maze@google.com> Sun Oct 08 23:35:00 2023 -0700
committer Maciej Żenczykowski <maze@google.com> Mon Oct 09 00:32:36 2023 -0700
tree 974c802fbeb591b7dca19c251cdd0ccb0141fdd6
parent 02519f86ad4729c0273092c45e5be925eff34559

netbpfload: remove support for limiting program types

No need for this, as we simply only support network
program types in the first place.

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I163e21fd4d4089882cf37fc68bc4299003b514d7

netbpfload/loader.cpp

diff --git a/netbpfload/loader.cpp b/netbpfload/loader.cpp
index f403339..82ce6d5 100644
--- a/netbpfload/loader.cpp
+++ b/netbpfload/loader.cpp
@@ -178,6 +178,10 @@
  *
  * However, be aware that you should not be directly using the SECTION() macro.
  * Instead use the DEFINE_(BPF|XDP)_(PROG|MAP)... & LICENSE/CRITICAL macros.
+ *
+ * Programs shipped inside the tethering apex should be limited to networking stuff,
+ * as KPROBE, PERF_EVENT, TRACEPOINT are dangerous to use from mainline updatable code,
+ * since they are less stable abi/api and may conflict with platform uses of bpf.
  */
 sectionType sectionNameTypes[] = {
         {"bind4/",         BPF_PROG_TYPE_CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_BIND},
@@ -387,19 +391,10 @@
     return 0;
 }
 
-static enum bpf_prog_type getFuseProgType() {
-    int result = BPF_PROG_TYPE_UNSPEC;
-    ifstream("/sys/fs/fuse/bpf_prog_type_fuse") >> result;
-    return static_cast<bpf_prog_type>(result);
-}
-
 static enum bpf_prog_type getSectionType(string& name) {
     for (auto& snt : sectionNameTypes)
         if (StartsWith(name, snt.name)) return snt.type;
 
-    // TODO Remove this code when fuse-bpf is upstream and this BPF_PROG_TYPE_FUSE is fixed
-    if (StartsWith(name, "fuse/")) return getFuseProgType();
-
     return BPF_PROG_TYPE_UNSPEC;
 }
 
@@ -409,6 +404,7 @@
     return BPF_ATTACH_TYPE_UNSPEC;
 }
 
+/*
 static string getSectionName(enum bpf_prog_type type)
 {
     for (auto& snt : sectionNameTypes)
@@ -417,6 +413,7 @@
 
     return "UNKNOWN SECTION NAME " + std::to_string(type);
 }
+*/
 
 static int readProgDefs(ifstream& elfFile, vector<struct bpf_prog_def>& pd,
                         size_t sizeOfBpfProgDef) {
@@ -496,22 +493,8 @@
     return 0;
 }
 
-static bool IsAllowed(bpf_prog_type type, const bpf_prog_type* allowed, size_t numAllowed) {
-    if (allowed == nullptr) return true;
-
-    for (size_t i = 0; i < numAllowed; i++) {
-        if (allowed[i] == BPF_PROG_TYPE_UNSPEC) {
-            if (type == getFuseProgType()) return true;
-        } else if (type == allowed[i])
-            return true;
-    }
-
-    return false;
-}
-
 /* Read a section by its index - for ex to get sec hdr strtab blob */
-static int readCodeSections(ifstream& elfFile, vector<codeSection>& cs, size_t sizeOfBpfProgDef,
-                            const bpf_prog_type* allowed, size_t numAllowed) {
+static int readCodeSections(ifstream& elfFile, vector<codeSection>& cs, size_t sizeOfBpfProgDef) {
     vector<Elf64_Shdr> shTable;
     int entries, ret = 0;
 
@@ -538,11 +521,6 @@
 
         if (ptype == BPF_PROG_TYPE_UNSPEC) continue;
 
-        if (!IsAllowed(ptype, allowed, numAllowed)) {
-            ALOGE("Program type %s not permitted here", getSectionName(ptype).c_str());
-            return -1;
-        }
-
         // This must be done before '/' is replaced with '_'.
         cs_temp.expected_attach_type = getExpectedAttachType(name);
 
@@ -1204,8 +1182,7 @@
         return -1;
     }
 
-    ret = readCodeSections(elfFile, cs, sizeOfBpfProgDef, location.allowedProgTypes,
-                           location.allowedProgTypesLength);
+    ret = readCodeSections(elfFile, cs, sizeOfBpfProgDef);
     if (ret) {
         ALOGE("Couldn't read all code sections in %s", elfPath);
         return ret;