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Maciej Żenczykowski60c159f2023-10-02 14:54:48 -07001/*
Maciej Żenczykowski283c25a2023-10-02 19:43:30 -07002 * Copyright (C) 2018-2023 The Android Open Source Project
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -07003 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
Maciej Żenczykowski3d141442024-04-20 00:03:04 +000017#define LOG_TAG "NetBpfLoad"
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -070018
19#include <errno.h>
20#include <fcntl.h>
21#include <linux/bpf.h>
22#include <linux/elf.h>
23#include <log/log.h>
24#include <stdint.h>
25#include <stdio.h>
26#include <stdlib.h>
27#include <string.h>
28#include <sysexits.h>
29#include <sys/stat.h>
30#include <sys/utsname.h>
31#include <sys/wait.h>
32#include <unistd.h>
33
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -070034#include "BpfSyscallWrappers.h"
35#include "bpf/BpfUtils.h"
36#include "bpf/bpf_map_def.h"
Maciej Żenczykowski40dfe532023-10-08 20:21:11 -070037#include "loader.h"
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -070038
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -070039#include <cstdlib>
40#include <fstream>
41#include <iostream>
42#include <optional>
43#include <string>
44#include <unordered_map>
45#include <vector>
46
47#include <android-base/cmsg.h>
48#include <android-base/file.h>
Elliott Hughes497e3e02023-10-09 22:18:08 +000049#include <android-base/properties.h>
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -070050#include <android-base/strings.h>
51#include <android-base/unique_fd.h>
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -070052
53#define BPF_FS_PATH "/sys/fs/bpf/"
54
55// Size of the BPF log buffer for verifier logging
56#define BPF_LOAD_LOG_SZ 0xfffff
57
58// Unspecified attach type is 0 which is BPF_CGROUP_INET_INGRESS.
59#define BPF_ATTACH_TYPE_UNSPEC BPF_CGROUP_INET_INGRESS
60
61using android::base::StartsWith;
62using android::base::unique_fd;
63using std::ifstream;
64using std::ios;
65using std::optional;
66using std::string;
67using std::vector;
68
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -070069namespace android {
70namespace bpf {
71
72const std::string& getBuildType() {
Elliott Hughes497e3e02023-10-09 22:18:08 +000073 static std::string t = android::base::GetProperty("ro.build.type", "unknown");
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -070074 return t;
75}
76
77static unsigned int page_size = static_cast<unsigned int>(getpagesize());
78
79constexpr const char* lookupSelinuxContext(const domain d, const char* const unspecified = "") {
80 switch (d) {
81 case domain::unspecified: return unspecified;
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -070082 case domain::tethering: return "fs_bpf_tethering";
83 case domain::net_private: return "fs_bpf_net_private";
84 case domain::net_shared: return "fs_bpf_net_shared";
85 case domain::netd_readonly: return "fs_bpf_netd_readonly";
86 case domain::netd_shared: return "fs_bpf_netd_shared";
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -070087 default: return "(unrecognized)";
88 }
89}
90
91domain getDomainFromSelinuxContext(const char s[BPF_SELINUX_CONTEXT_CHAR_ARRAY_SIZE]) {
92 for (domain d : AllDomains) {
93 // Not sure how to enforce this at compile time, so abort() bpfloader at boot instead
94 if (strlen(lookupSelinuxContext(d)) >= BPF_SELINUX_CONTEXT_CHAR_ARRAY_SIZE) abort();
95 if (!strncmp(s, lookupSelinuxContext(d), BPF_SELINUX_CONTEXT_CHAR_ARRAY_SIZE)) return d;
96 }
97 ALOGW("ignoring unrecognized selinux_context '%-32s'", s);
98 // We should return 'unrecognized' here, however: returning unspecified will
99 // result in the system simply using the default context, which in turn
100 // will allow future expansion by adding more restrictive selinux types.
101 // Older bpfloader will simply ignore that, and use the less restrictive default.
102 // This does mean you CANNOT later add a *less* restrictive type than the default.
103 //
104 // Note: we cannot just abort() here as this might be a mainline module shipped optional update
105 return domain::unspecified;
106}
107
108constexpr const char* lookupPinSubdir(const domain d, const char* const unspecified = "") {
109 switch (d) {
110 case domain::unspecified: return unspecified;
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700111 case domain::tethering: return "tethering/";
112 case domain::net_private: return "net_private/";
113 case domain::net_shared: return "net_shared/";
114 case domain::netd_readonly: return "netd_readonly/";
115 case domain::netd_shared: return "netd_shared/";
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700116 default: return "(unrecognized)";
117 }
118};
119
120domain getDomainFromPinSubdir(const char s[BPF_PIN_SUBDIR_CHAR_ARRAY_SIZE]) {
121 for (domain d : AllDomains) {
122 // Not sure how to enforce this at compile time, so abort() bpfloader at boot instead
123 if (strlen(lookupPinSubdir(d)) >= BPF_PIN_SUBDIR_CHAR_ARRAY_SIZE) abort();
124 if (!strncmp(s, lookupPinSubdir(d), BPF_PIN_SUBDIR_CHAR_ARRAY_SIZE)) return d;
125 }
126 ALOGE("unrecognized pin_subdir '%-32s'", s);
127 // pin_subdir affects the object's full pathname,
128 // and thus using the default would change the location and thus our code's ability to find it,
129 // hence this seems worth treating as a true error condition.
130 //
131 // Note: we cannot just abort() here as this might be a mainline module shipped optional update
132 // However, our callers will treat this as an error, and stop loading the specific .o,
133 // which will fail bpfloader if the .o is marked critical.
134 return domain::unrecognized;
135}
136
137static string pathToObjName(const string& path) {
138 // extract everything after the final slash, ie. this is the filename 'foo@1.o' or 'bar.o'
139 string filename = android::base::Split(path, "/").back();
140 // strip off everything from the final period onwards (strip '.o' suffix), ie. 'foo@1' or 'bar'
141 string name = filename.substr(0, filename.find_last_of('.'));
142 // strip any potential @1 suffix, this will leave us with just 'foo' or 'bar'
143 // this can be used to provide duplicate programs (mux based on the bpfloader version)
144 return name.substr(0, name.find_last_of('@'));
145}
146
147typedef struct {
148 const char* name;
149 enum bpf_prog_type type;
150 enum bpf_attach_type expected_attach_type;
151} sectionType;
152
153/*
154 * Map section name prefixes to program types, the section name will be:
155 * SECTION(<prefix>/<name-of-program>)
156 * For example:
157 * SECTION("tracepoint/sched_switch_func") where sched_switch_funcs
158 * is the name of the program, and tracepoint is the type.
159 *
160 * However, be aware that you should not be directly using the SECTION() macro.
161 * Instead use the DEFINE_(BPF|XDP)_(PROG|MAP)... & LICENSE/CRITICAL macros.
Maciej Żenczykowskifcea70f2023-10-08 23:35:00 -0700162 *
163 * Programs shipped inside the tethering apex should be limited to networking stuff,
164 * as KPROBE, PERF_EVENT, TRACEPOINT are dangerous to use from mainline updatable code,
165 * since they are less stable abi/api and may conflict with platform uses of bpf.
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700166 */
167sectionType sectionNameTypes[] = {
168 {"bind4/", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_BIND},
169 {"bind6/", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_BIND},
170 {"cgroupskb/", BPF_PROG_TYPE_CGROUP_SKB, BPF_ATTACH_TYPE_UNSPEC},
171 {"cgroupsock/", BPF_PROG_TYPE_CGROUP_SOCK, BPF_ATTACH_TYPE_UNSPEC},
172 {"connect4/", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_CONNECT},
173 {"connect6/", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_CONNECT},
174 {"egress/", BPF_PROG_TYPE_CGROUP_SKB, BPF_CGROUP_INET_EGRESS},
175 {"getsockopt/", BPF_PROG_TYPE_CGROUP_SOCKOPT, BPF_CGROUP_GETSOCKOPT},
176 {"ingress/", BPF_PROG_TYPE_CGROUP_SKB, BPF_CGROUP_INET_INGRESS},
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700177 {"lwt_in/", BPF_PROG_TYPE_LWT_IN, BPF_ATTACH_TYPE_UNSPEC},
178 {"lwt_out/", BPF_PROG_TYPE_LWT_OUT, BPF_ATTACH_TYPE_UNSPEC},
179 {"lwt_seg6local/", BPF_PROG_TYPE_LWT_SEG6LOCAL, BPF_ATTACH_TYPE_UNSPEC},
180 {"lwt_xmit/", BPF_PROG_TYPE_LWT_XMIT, BPF_ATTACH_TYPE_UNSPEC},
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700181 {"postbind4/", BPF_PROG_TYPE_CGROUP_SOCK, BPF_CGROUP_INET4_POST_BIND},
182 {"postbind6/", BPF_PROG_TYPE_CGROUP_SOCK, BPF_CGROUP_INET6_POST_BIND},
183 {"recvmsg4/", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_RECVMSG},
184 {"recvmsg6/", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_RECVMSG},
185 {"schedact/", BPF_PROG_TYPE_SCHED_ACT, BPF_ATTACH_TYPE_UNSPEC},
186 {"schedcls/", BPF_PROG_TYPE_SCHED_CLS, BPF_ATTACH_TYPE_UNSPEC},
187 {"sendmsg4/", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_SENDMSG},
188 {"sendmsg6/", BPF_PROG_TYPE_CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_SENDMSG},
189 {"setsockopt/", BPF_PROG_TYPE_CGROUP_SOCKOPT, BPF_CGROUP_SETSOCKOPT},
190 {"skfilter/", BPF_PROG_TYPE_SOCKET_FILTER, BPF_ATTACH_TYPE_UNSPEC},
191 {"sockops/", BPF_PROG_TYPE_SOCK_OPS, BPF_CGROUP_SOCK_OPS},
192 {"sysctl", BPF_PROG_TYPE_CGROUP_SYSCTL, BPF_CGROUP_SYSCTL},
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700193 {"xdp/", BPF_PROG_TYPE_XDP, BPF_ATTACH_TYPE_UNSPEC},
194};
195
196typedef struct {
197 enum bpf_prog_type type;
198 enum bpf_attach_type expected_attach_type;
199 string name;
200 vector<char> data;
201 vector<char> rel_data;
202 optional<struct bpf_prog_def> prog_def;
203
204 unique_fd prog_fd; /* fd after loading */
205} codeSection;
206
207static int readElfHeader(ifstream& elfFile, Elf64_Ehdr* eh) {
208 elfFile.seekg(0);
209 if (elfFile.fail()) return -1;
210
211 if (!elfFile.read((char*)eh, sizeof(*eh))) return -1;
212
213 return 0;
214}
215
216/* Reads all section header tables into an Shdr array */
217static int readSectionHeadersAll(ifstream& elfFile, vector<Elf64_Shdr>& shTable) {
218 Elf64_Ehdr eh;
219 int ret = 0;
220
221 ret = readElfHeader(elfFile, &eh);
222 if (ret) return ret;
223
224 elfFile.seekg(eh.e_shoff);
225 if (elfFile.fail()) return -1;
226
227 /* Read shdr table entries */
228 shTable.resize(eh.e_shnum);
229
230 if (!elfFile.read((char*)shTable.data(), (eh.e_shnum * eh.e_shentsize))) return -ENOMEM;
231
232 return 0;
233}
234
235/* Read a section by its index - for ex to get sec hdr strtab blob */
236static int readSectionByIdx(ifstream& elfFile, int id, vector<char>& sec) {
237 vector<Elf64_Shdr> shTable;
238 int ret = readSectionHeadersAll(elfFile, shTable);
239 if (ret) return ret;
240
241 elfFile.seekg(shTable[id].sh_offset);
242 if (elfFile.fail()) return -1;
243
244 sec.resize(shTable[id].sh_size);
245 if (!elfFile.read(sec.data(), shTable[id].sh_size)) return -1;
246
247 return 0;
248}
249
250/* Read whole section header string table */
251static int readSectionHeaderStrtab(ifstream& elfFile, vector<char>& strtab) {
252 Elf64_Ehdr eh;
253 int ret = readElfHeader(elfFile, &eh);
254 if (ret) return ret;
255
256 ret = readSectionByIdx(elfFile, eh.e_shstrndx, strtab);
257 if (ret) return ret;
258
259 return 0;
260}
261
262/* Get name from offset in strtab */
263static int getSymName(ifstream& elfFile, int nameOff, string& name) {
264 int ret;
265 vector<char> secStrTab;
266
267 ret = readSectionHeaderStrtab(elfFile, secStrTab);
268 if (ret) return ret;
269
270 if (nameOff >= (int)secStrTab.size()) return -1;
271
272 name = string((char*)secStrTab.data() + nameOff);
273 return 0;
274}
275
276/* Reads a full section by name - example to get the GPL license */
277static int readSectionByName(const char* name, ifstream& elfFile, vector<char>& data) {
278 vector<char> secStrTab;
279 vector<Elf64_Shdr> shTable;
280 int ret;
281
282 ret = readSectionHeadersAll(elfFile, shTable);
283 if (ret) return ret;
284
285 ret = readSectionHeaderStrtab(elfFile, secStrTab);
286 if (ret) return ret;
287
288 for (int i = 0; i < (int)shTable.size(); i++) {
289 char* secname = secStrTab.data() + shTable[i].sh_name;
290 if (!secname) continue;
291
292 if (!strcmp(secname, name)) {
293 vector<char> dataTmp;
294 dataTmp.resize(shTable[i].sh_size);
295
296 elfFile.seekg(shTable[i].sh_offset);
297 if (elfFile.fail()) return -1;
298
299 if (!elfFile.read((char*)dataTmp.data(), shTable[i].sh_size)) return -1;
300
301 data = dataTmp;
302 return 0;
303 }
304 }
305 return -2;
306}
307
308unsigned int readSectionUint(const char* name, ifstream& elfFile, unsigned int defVal) {
309 vector<char> theBytes;
310 int ret = readSectionByName(name, elfFile, theBytes);
311 if (ret) {
312 ALOGD("Couldn't find section %s (defaulting to %u [0x%x]).", name, defVal, defVal);
313 return defVal;
314 } else if (theBytes.size() < sizeof(unsigned int)) {
315 ALOGE("Section %s too short (defaulting to %u [0x%x]).", name, defVal, defVal);
316 return defVal;
317 } else {
318 // decode first 4 bytes as LE32 uint, there will likely be more bytes due to alignment.
319 unsigned int value = static_cast<unsigned char>(theBytes[3]);
320 value <<= 8;
321 value += static_cast<unsigned char>(theBytes[2]);
322 value <<= 8;
323 value += static_cast<unsigned char>(theBytes[1]);
324 value <<= 8;
325 value += static_cast<unsigned char>(theBytes[0]);
326 ALOGI("Section %s value is %u [0x%x]", name, value, value);
327 return value;
328 }
329}
330
331static int readSectionByType(ifstream& elfFile, int type, vector<char>& data) {
332 int ret;
333 vector<Elf64_Shdr> shTable;
334
335 ret = readSectionHeadersAll(elfFile, shTable);
336 if (ret) return ret;
337
338 for (int i = 0; i < (int)shTable.size(); i++) {
339 if ((int)shTable[i].sh_type != type) continue;
340
341 vector<char> dataTmp;
342 dataTmp.resize(shTable[i].sh_size);
343
344 elfFile.seekg(shTable[i].sh_offset);
345 if (elfFile.fail()) return -1;
346
347 if (!elfFile.read((char*)dataTmp.data(), shTable[i].sh_size)) return -1;
348
349 data = dataTmp;
350 return 0;
351 }
352 return -2;
353}
354
355static bool symCompare(Elf64_Sym a, Elf64_Sym b) {
356 return (a.st_value < b.st_value);
357}
358
359static int readSymTab(ifstream& elfFile, int sort, vector<Elf64_Sym>& data) {
360 int ret, numElems;
361 Elf64_Sym* buf;
362 vector<char> secData;
363
364 ret = readSectionByType(elfFile, SHT_SYMTAB, secData);
365 if (ret) return ret;
366
367 buf = (Elf64_Sym*)secData.data();
368 numElems = (secData.size() / sizeof(Elf64_Sym));
369 data.assign(buf, buf + numElems);
370
371 if (sort) std::sort(data.begin(), data.end(), symCompare);
372 return 0;
373}
374
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700375static enum bpf_prog_type getSectionType(string& name) {
376 for (auto& snt : sectionNameTypes)
377 if (StartsWith(name, snt.name)) return snt.type;
378
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700379 return BPF_PROG_TYPE_UNSPEC;
380}
381
382static enum bpf_attach_type getExpectedAttachType(string& name) {
383 for (auto& snt : sectionNameTypes)
384 if (StartsWith(name, snt.name)) return snt.expected_attach_type;
385 return BPF_ATTACH_TYPE_UNSPEC;
386}
387
Maciej Żenczykowskifcea70f2023-10-08 23:35:00 -0700388/*
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700389static string getSectionName(enum bpf_prog_type type)
390{
391 for (auto& snt : sectionNameTypes)
392 if (snt.type == type)
393 return string(snt.name);
394
395 return "UNKNOWN SECTION NAME " + std::to_string(type);
396}
Maciej Żenczykowskifcea70f2023-10-08 23:35:00 -0700397*/
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700398
399static int readProgDefs(ifstream& elfFile, vector<struct bpf_prog_def>& pd,
400 size_t sizeOfBpfProgDef) {
401 vector<char> pdData;
402 int ret = readSectionByName("progs", elfFile, pdData);
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700403 if (ret) return ret;
404
405 if (pdData.size() % sizeOfBpfProgDef) {
406 ALOGE("readProgDefs failed due to improper sized progs section, %zu %% %zu != 0",
407 pdData.size(), sizeOfBpfProgDef);
408 return -1;
409 };
410
411 int progCount = pdData.size() / sizeOfBpfProgDef;
412 pd.resize(progCount);
413 size_t trimmedSize = std::min(sizeOfBpfProgDef, sizeof(struct bpf_prog_def));
414
415 const char* dataPtr = pdData.data();
416 for (auto& p : pd) {
417 // First we zero initialize
418 memset(&p, 0, sizeof(p));
419 // Then we set non-zero defaults
420 p.bpfloader_max_ver = DEFAULT_BPFLOADER_MAX_VER; // v1.0
421 // Then we copy over the structure prefix from the ELF file.
422 memcpy(&p, dataPtr, trimmedSize);
423 // Move to next struct in the ELF file
424 dataPtr += sizeOfBpfProgDef;
425 }
426 return 0;
427}
428
429static int getSectionSymNames(ifstream& elfFile, const string& sectionName, vector<string>& names,
430 optional<unsigned> symbolType = std::nullopt) {
431 int ret;
432 string name;
433 vector<Elf64_Sym> symtab;
434 vector<Elf64_Shdr> shTable;
435
436 ret = readSymTab(elfFile, 1 /* sort */, symtab);
437 if (ret) return ret;
438
439 /* Get index of section */
440 ret = readSectionHeadersAll(elfFile, shTable);
441 if (ret) return ret;
442
443 int sec_idx = -1;
444 for (int i = 0; i < (int)shTable.size(); i++) {
445 ret = getSymName(elfFile, shTable[i].sh_name, name);
446 if (ret) return ret;
447
448 if (!name.compare(sectionName)) {
449 sec_idx = i;
450 break;
451 }
452 }
453
454 /* No section found with matching name*/
455 if (sec_idx == -1) {
456 ALOGW("No %s section could be found in elf object", sectionName.c_str());
457 return -1;
458 }
459
460 for (int i = 0; i < (int)symtab.size(); i++) {
461 if (symbolType.has_value() && ELF_ST_TYPE(symtab[i].st_info) != symbolType) continue;
462
463 if (symtab[i].st_shndx == sec_idx) {
464 string s;
465 ret = getSymName(elfFile, symtab[i].st_name, s);
466 if (ret) return ret;
467 names.push_back(s);
468 }
469 }
470
471 return 0;
472}
473
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700474/* Read a section by its index - for ex to get sec hdr strtab blob */
Maciej Żenczykowskifcea70f2023-10-08 23:35:00 -0700475static int readCodeSections(ifstream& elfFile, vector<codeSection>& cs, size_t sizeOfBpfProgDef) {
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700476 vector<Elf64_Shdr> shTable;
477 int entries, ret = 0;
478
479 ret = readSectionHeadersAll(elfFile, shTable);
480 if (ret) return ret;
481 entries = shTable.size();
482
483 vector<struct bpf_prog_def> pd;
484 ret = readProgDefs(elfFile, pd, sizeOfBpfProgDef);
485 if (ret) return ret;
486 vector<string> progDefNames;
487 ret = getSectionSymNames(elfFile, "progs", progDefNames);
488 if (!pd.empty() && ret) return ret;
489
490 for (int i = 0; i < entries; i++) {
491 string name;
492 codeSection cs_temp;
493 cs_temp.type = BPF_PROG_TYPE_UNSPEC;
494
495 ret = getSymName(elfFile, shTable[i].sh_name, name);
496 if (ret) return ret;
497
498 enum bpf_prog_type ptype = getSectionType(name);
499
500 if (ptype == BPF_PROG_TYPE_UNSPEC) continue;
501
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700502 // This must be done before '/' is replaced with '_'.
503 cs_temp.expected_attach_type = getExpectedAttachType(name);
504
505 string oldName = name;
506
507 // convert all slashes to underscores
508 std::replace(name.begin(), name.end(), '/', '_');
509
510 cs_temp.type = ptype;
511 cs_temp.name = name;
512
513 ret = readSectionByIdx(elfFile, i, cs_temp.data);
514 if (ret) return ret;
515 ALOGD("Loaded code section %d (%s)", i, name.c_str());
516
517 vector<string> csSymNames;
518 ret = getSectionSymNames(elfFile, oldName, csSymNames, STT_FUNC);
519 if (ret || !csSymNames.size()) return ret;
520 for (size_t i = 0; i < progDefNames.size(); ++i) {
521 if (!progDefNames[i].compare(csSymNames[0] + "_def")) {
522 cs_temp.prog_def = pd[i];
523 break;
524 }
525 }
526
527 /* Check for rel section */
528 if (cs_temp.data.size() > 0 && i < entries) {
529 ret = getSymName(elfFile, shTable[i + 1].sh_name, name);
530 if (ret) return ret;
531
532 if (name == (".rel" + oldName)) {
533 ret = readSectionByIdx(elfFile, i + 1, cs_temp.rel_data);
534 if (ret) return ret;
535 ALOGD("Loaded relo section %d (%s)", i, name.c_str());
536 }
537 }
538
539 if (cs_temp.data.size() > 0) {
540 cs.push_back(std::move(cs_temp));
541 ALOGD("Adding section %d to cs list", i);
542 }
543 }
544 return 0;
545}
546
547static int getSymNameByIdx(ifstream& elfFile, int index, string& name) {
548 vector<Elf64_Sym> symtab;
549 int ret = 0;
550
551 ret = readSymTab(elfFile, 0 /* !sort */, symtab);
552 if (ret) return ret;
553
554 if (index >= (int)symtab.size()) return -1;
555
556 return getSymName(elfFile, symtab[index].st_name, name);
557}
558
559static bool mapMatchesExpectations(const unique_fd& fd, const string& mapName,
560 const struct bpf_map_def& mapDef, const enum bpf_map_type type) {
Maciej Żenczykowski7e5b09a2024-03-11 12:40:06 +0000561 // bpfGetFd... family of functions require at minimum a 4.14 kernel,
562 // so on 4.9-T kernels just pretend the map matches our expectations.
563 // Additionally we'll get almost equivalent test coverage on newer devices/kernels.
564 // This is because the primary failure mode we're trying to detect here
565 // is either a source code misconfiguration (which is likely kernel independent)
566 // or a newly introduced kernel feature/bug (which is unlikely to get backported to 4.9).
567 if (!isAtLeastKernelVersion(4, 14, 0)) return true;
568
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700569 // Assuming fd is a valid Bpf Map file descriptor then
570 // all the following should always succeed on a 4.14+ kernel.
571 // If they somehow do fail, they'll return -1 (and set errno),
572 // which should then cause (among others) a key_size mismatch.
573 int fd_type = bpfGetFdMapType(fd);
574 int fd_key_size = bpfGetFdKeySize(fd);
575 int fd_value_size = bpfGetFdValueSize(fd);
576 int fd_max_entries = bpfGetFdMaxEntries(fd);
577 int fd_map_flags = bpfGetFdMapFlags(fd);
578
579 // DEVMAPs are readonly from the bpf program side's point of view, as such
580 // the kernel in kernel/bpf/devmap.c dev_map_init_map() will set the flag
581 int desired_map_flags = (int)mapDef.map_flags;
582 if (type == BPF_MAP_TYPE_DEVMAP || type == BPF_MAP_TYPE_DEVMAP_HASH)
583 desired_map_flags |= BPF_F_RDONLY_PROG;
584
585 // The .h file enforces that this is a power of two, and page size will
586 // also always be a power of two, so this logic is actually enough to
587 // force it to be a multiple of the page size, as required by the kernel.
588 unsigned int desired_max_entries = mapDef.max_entries;
589 if (type == BPF_MAP_TYPE_RINGBUF) {
590 if (desired_max_entries < page_size) desired_max_entries = page_size;
591 }
592
593 // The following checks should *never* trigger, if one of them somehow does,
594 // it probably means a bpf .o file has been changed/replaced at runtime
595 // and bpfloader was manually rerun (normally it should only run *once*
596 // early during the boot process).
597 // Another possibility is that something is misconfigured in the code:
598 // most likely a shared map is declared twice differently.
599 // But such a change should never be checked into the source tree...
600 if ((fd_type == type) &&
601 (fd_key_size == (int)mapDef.key_size) &&
602 (fd_value_size == (int)mapDef.value_size) &&
603 (fd_max_entries == (int)desired_max_entries) &&
604 (fd_map_flags == desired_map_flags)) {
605 return true;
606 }
607
608 ALOGE("bpf map name %s mismatch: desired/found: "
609 "type:%d/%d key:%u/%d value:%u/%d entries:%u/%d flags:%u/%d",
610 mapName.c_str(), type, fd_type, mapDef.key_size, fd_key_size, mapDef.value_size,
611 fd_value_size, mapDef.max_entries, fd_max_entries, desired_map_flags, fd_map_flags);
612 return false;
613}
614
615static int createMaps(const char* elfPath, ifstream& elfFile, vector<unique_fd>& mapFds,
Maciej Żenczykowski221b2482024-03-18 14:33:10 -0700616 const char* prefix, const size_t sizeOfBpfMapDef,
617 const unsigned int bpfloader_ver) {
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700618 int ret;
619 vector<char> mdData;
620 vector<struct bpf_map_def> md;
621 vector<string> mapNames;
622 string objName = pathToObjName(string(elfPath));
623
624 ret = readSectionByName("maps", elfFile, mdData);
625 if (ret == -2) return 0; // no maps to read
626 if (ret) return ret;
627
628 if (mdData.size() % sizeOfBpfMapDef) {
629 ALOGE("createMaps failed due to improper sized maps section, %zu %% %zu != 0",
630 mdData.size(), sizeOfBpfMapDef);
631 return -1;
632 };
633
634 int mapCount = mdData.size() / sizeOfBpfMapDef;
635 md.resize(mapCount);
636 size_t trimmedSize = std::min(sizeOfBpfMapDef, sizeof(struct bpf_map_def));
637
638 const char* dataPtr = mdData.data();
639 for (auto& m : md) {
640 // First we zero initialize
641 memset(&m, 0, sizeof(m));
642 // Then we set non-zero defaults
643 m.bpfloader_max_ver = DEFAULT_BPFLOADER_MAX_VER; // v1.0
644 m.max_kver = 0xFFFFFFFFu; // matches KVER_INF from bpf_helpers.h
645 // Then we copy over the structure prefix from the ELF file.
646 memcpy(&m, dataPtr, trimmedSize);
647 // Move to next struct in the ELF file
648 dataPtr += sizeOfBpfMapDef;
649 }
650
651 ret = getSectionSymNames(elfFile, "maps", mapNames);
652 if (ret) return ret;
653
654 unsigned kvers = kernelVersion();
655
656 for (int i = 0; i < (int)mapNames.size(); i++) {
657 if (md[i].zero != 0) abort();
658
Maciej Żenczykowski221b2482024-03-18 14:33:10 -0700659 if (bpfloader_ver < md[i].bpfloader_min_ver) {
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700660 ALOGI("skipping map %s which requires bpfloader min ver 0x%05x", mapNames[i].c_str(),
661 md[i].bpfloader_min_ver);
662 mapFds.push_back(unique_fd());
663 continue;
664 }
665
Maciej Żenczykowski221b2482024-03-18 14:33:10 -0700666 if (bpfloader_ver >= md[i].bpfloader_max_ver) {
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700667 ALOGI("skipping map %s which requires bpfloader max ver 0x%05x", mapNames[i].c_str(),
668 md[i].bpfloader_max_ver);
669 mapFds.push_back(unique_fd());
670 continue;
671 }
672
673 if (kvers < md[i].min_kver) {
674 ALOGI("skipping map %s which requires kernel version 0x%x >= 0x%x",
675 mapNames[i].c_str(), kvers, md[i].min_kver);
676 mapFds.push_back(unique_fd());
677 continue;
678 }
679
680 if (kvers >= md[i].max_kver) {
681 ALOGI("skipping map %s which requires kernel version 0x%x < 0x%x",
682 mapNames[i].c_str(), kvers, md[i].max_kver);
683 mapFds.push_back(unique_fd());
684 continue;
685 }
686
687 if ((md[i].ignore_on_eng && isEng()) || (md[i].ignore_on_user && isUser()) ||
688 (md[i].ignore_on_userdebug && isUserdebug())) {
689 ALOGI("skipping map %s which is ignored on %s builds", mapNames[i].c_str(),
690 getBuildType().c_str());
691 mapFds.push_back(unique_fd());
692 continue;
693 }
694
695 if ((isArm() && isKernel32Bit() && md[i].ignore_on_arm32) ||
696 (isArm() && isKernel64Bit() && md[i].ignore_on_aarch64) ||
697 (isX86() && isKernel32Bit() && md[i].ignore_on_x86_32) ||
698 (isX86() && isKernel64Bit() && md[i].ignore_on_x86_64) ||
699 (isRiscV() && md[i].ignore_on_riscv64)) {
700 ALOGI("skipping map %s which is ignored on %s", mapNames[i].c_str(),
701 describeArch());
702 mapFds.push_back(unique_fd());
703 continue;
704 }
705
706 enum bpf_map_type type = md[i].type;
Maciej Żenczykowski7e5b09a2024-03-11 12:40:06 +0000707 if (type == BPF_MAP_TYPE_DEVMAP && !isAtLeastKernelVersion(4, 14, 0)) {
708 // On Linux Kernels older than 4.14 this map type doesn't exist, but it can kind
709 // of be approximated: ARRAY has the same userspace api, though it is not usable
710 // by the same ebpf programs. However, that's okay because the bpf_redirect_map()
711 // helper doesn't exist on 4.9-T anyway (so the bpf program would fail to load,
712 // and thus needs to be tagged as 4.14+ either way), so there's nothing useful you
713 // could do with a DEVMAP anyway (that isn't already provided by an ARRAY)...
714 // Hence using an ARRAY instead of a DEVMAP simply makes life easier for userspace.
715 type = BPF_MAP_TYPE_ARRAY;
716 }
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700717 if (type == BPF_MAP_TYPE_DEVMAP_HASH && !isAtLeastKernelVersion(5, 4, 0)) {
718 // On Linux Kernels older than 5.4 this map type doesn't exist, but it can kind
719 // of be approximated: HASH has the same userspace visible api.
720 // However it cannot be used by ebpf programs in the same way.
721 // Since bpf_redirect_map() only requires 4.14, a program using a DEVMAP_HASH map
722 // would fail to load (due to trying to redirect to a HASH instead of DEVMAP_HASH).
723 // One must thus tag any BPF_MAP_TYPE_DEVMAP_HASH + bpf_redirect_map() using
724 // programs as being 5.4+...
725 type = BPF_MAP_TYPE_HASH;
726 }
727
728 // The .h file enforces that this is a power of two, and page size will
729 // also always be a power of two, so this logic is actually enough to
730 // force it to be a multiple of the page size, as required by the kernel.
731 unsigned int max_entries = md[i].max_entries;
732 if (type == BPF_MAP_TYPE_RINGBUF) {
733 if (max_entries < page_size) max_entries = page_size;
734 }
735
736 domain selinux_context = getDomainFromSelinuxContext(md[i].selinux_context);
737 if (specified(selinux_context)) {
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700738 ALOGI("map %s selinux_context [%-32s] -> %d -> '%s' (%s)", mapNames[i].c_str(),
739 md[i].selinux_context, selinux_context, lookupSelinuxContext(selinux_context),
740 lookupPinSubdir(selinux_context));
741 }
742
743 domain pin_subdir = getDomainFromPinSubdir(md[i].pin_subdir);
744 if (unrecognized(pin_subdir)) return -ENOTDIR;
745 if (specified(pin_subdir)) {
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700746 ALOGI("map %s pin_subdir [%-32s] -> %d -> '%s'", mapNames[i].c_str(), md[i].pin_subdir,
747 pin_subdir, lookupPinSubdir(pin_subdir));
748 }
749
750 // Format of pin location is /sys/fs/bpf/<pin_subdir|prefix>map_<objName>_<mapName>
751 // except that maps shared across .o's have empty <objName>
752 // Note: <objName> refers to the extension-less basename of the .o file (without @ suffix).
753 string mapPinLoc = string(BPF_FS_PATH) + lookupPinSubdir(pin_subdir, prefix) + "map_" +
754 (md[i].shared ? "" : objName) + "_" + mapNames[i];
755 bool reuse = false;
756 unique_fd fd;
757 int saved_errno;
758
759 if (access(mapPinLoc.c_str(), F_OK) == 0) {
760 fd.reset(mapRetrieveRO(mapPinLoc.c_str()));
761 saved_errno = errno;
762 ALOGD("bpf_create_map reusing map %s, ret: %d", mapNames[i].c_str(), fd.get());
763 reuse = true;
764 } else {
765 union bpf_attr req = {
766 .map_type = type,
767 .key_size = md[i].key_size,
768 .value_size = md[i].value_size,
769 .max_entries = max_entries,
770 .map_flags = md[i].map_flags,
771 };
Maciej Żenczykowskid0bb1722024-04-22 23:30:42 +0000772 if (isAtLeastKernelVersion(4, 15, 0))
Maciej Żenczykowski22836352024-03-15 19:03:13 +0000773 strlcpy(req.map_name, mapNames[i].c_str(), sizeof(req.map_name));
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700774 fd.reset(bpf(BPF_MAP_CREATE, req));
775 saved_errno = errno;
776 ALOGD("bpf_create_map name %s, ret: %d", mapNames[i].c_str(), fd.get());
777 }
778
779 if (!fd.ok()) return -saved_errno;
780
781 // When reusing a pinned map, we need to check the map type/sizes/etc match, but for
782 // safety (since reuse code path is rare) run these checks even if we just created it.
783 // We assume failure is due to pinned map mismatch, hence the 'NOT UNIQUE' return code.
784 if (!mapMatchesExpectations(fd, mapNames[i], md[i], type)) return -ENOTUNIQ;
785
786 if (!reuse) {
787 if (specified(selinux_context)) {
788 string createLoc = string(BPF_FS_PATH) + lookupPinSubdir(selinux_context) +
789 "tmp_map_" + objName + "_" + mapNames[i];
790 ret = bpfFdPin(fd, createLoc.c_str());
791 if (ret) {
792 int err = errno;
793 ALOGE("create %s -> %d [%d:%s]", createLoc.c_str(), ret, err, strerror(err));
794 return -err;
795 }
796 ret = renameat2(AT_FDCWD, createLoc.c_str(),
797 AT_FDCWD, mapPinLoc.c_str(), RENAME_NOREPLACE);
798 if (ret) {
799 int err = errno;
800 ALOGE("rename %s %s -> %d [%d:%s]", createLoc.c_str(), mapPinLoc.c_str(), ret,
801 err, strerror(err));
802 return -err;
803 }
804 } else {
805 ret = bpfFdPin(fd, mapPinLoc.c_str());
806 if (ret) {
807 int err = errno;
808 ALOGE("pin %s -> %d [%d:%s]", mapPinLoc.c_str(), ret, err, strerror(err));
809 return -err;
810 }
811 }
812 ret = chmod(mapPinLoc.c_str(), md[i].mode);
813 if (ret) {
814 int err = errno;
815 ALOGE("chmod(%s, 0%o) = %d [%d:%s]", mapPinLoc.c_str(), md[i].mode, ret, err,
816 strerror(err));
817 return -err;
818 }
819 ret = chown(mapPinLoc.c_str(), (uid_t)md[i].uid, (gid_t)md[i].gid);
820 if (ret) {
821 int err = errno;
822 ALOGE("chown(%s, %u, %u) = %d [%d:%s]", mapPinLoc.c_str(), md[i].uid, md[i].gid,
823 ret, err, strerror(err));
824 return -err;
825 }
826 }
827
828 int mapId = bpfGetFdMapId(fd);
829 if (mapId == -1) {
830 ALOGE("bpfGetFdMapId failed, ret: %d [%d]", mapId, errno);
831 } else {
832 ALOGI("map %s id %d", mapPinLoc.c_str(), mapId);
833 }
834
835 mapFds.push_back(std::move(fd));
836 }
837
838 return ret;
839}
840
841/* For debugging, dump all instructions */
842static void dumpIns(char* ins, int size) {
843 for (int row = 0; row < size / 8; row++) {
844 ALOGE("%d: ", row);
845 for (int j = 0; j < 8; j++) {
846 ALOGE("%3x ", ins[(row * 8) + j]);
847 }
848 ALOGE("\n");
849 }
850}
851
852/* For debugging, dump all code sections from cs list */
853static void dumpAllCs(vector<codeSection>& cs) {
854 for (int i = 0; i < (int)cs.size(); i++) {
855 ALOGE("Dumping cs %d, name %s", int(i), cs[i].name.c_str());
856 dumpIns((char*)cs[i].data.data(), cs[i].data.size());
857 ALOGE("-----------");
858 }
859}
860
861static void applyRelo(void* insnsPtr, Elf64_Addr offset, int fd) {
862 int insnIndex;
863 struct bpf_insn *insn, *insns;
864
865 insns = (struct bpf_insn*)(insnsPtr);
866
867 insnIndex = offset / sizeof(struct bpf_insn);
868 insn = &insns[insnIndex];
869
870 // Occasionally might be useful for relocation debugging, but pretty spammy
871 if (0) {
872 ALOGD("applying relo to instruction at byte offset: %llu, "
873 "insn offset %d, insn %llx",
874 (unsigned long long)offset, insnIndex, *(unsigned long long*)insn);
875 }
876
877 if (insn->code != (BPF_LD | BPF_IMM | BPF_DW)) {
878 ALOGE("Dumping all instructions till ins %d", insnIndex);
879 ALOGE("invalid relo for insn %d: code 0x%x", insnIndex, insn->code);
880 dumpIns((char*)insnsPtr, (insnIndex + 3) * 8);
881 return;
882 }
883
884 insn->imm = fd;
885 insn->src_reg = BPF_PSEUDO_MAP_FD;
886}
887
888static void applyMapRelo(ifstream& elfFile, vector<unique_fd> &mapFds, vector<codeSection>& cs) {
889 vector<string> mapNames;
890
891 int ret = getSectionSymNames(elfFile, "maps", mapNames);
892 if (ret) return;
893
894 for (int k = 0; k != (int)cs.size(); k++) {
895 Elf64_Rel* rel = (Elf64_Rel*)(cs[k].rel_data.data());
896 int n_rel = cs[k].rel_data.size() / sizeof(*rel);
897
898 for (int i = 0; i < n_rel; i++) {
899 int symIndex = ELF64_R_SYM(rel[i].r_info);
900 string symName;
901
902 ret = getSymNameByIdx(elfFile, symIndex, symName);
903 if (ret) return;
904
905 /* Find the map fd and apply relo */
906 for (int j = 0; j < (int)mapNames.size(); j++) {
907 if (!mapNames[j].compare(symName)) {
908 applyRelo(cs[k].data.data(), rel[i].r_offset, mapFds[j]);
909 break;
910 }
911 }
912 }
913 }
914}
915
916static int loadCodeSections(const char* elfPath, vector<codeSection>& cs, const string& license,
Maciej Żenczykowski221b2482024-03-18 14:33:10 -0700917 const char* prefix, const unsigned int bpfloader_ver) {
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700918 unsigned kvers = kernelVersion();
919
920 if (!kvers) {
921 ALOGE("unable to get kernel version");
922 return -EINVAL;
923 }
924
925 string objName = pathToObjName(string(elfPath));
926
927 for (int i = 0; i < (int)cs.size(); i++) {
928 unique_fd& fd = cs[i].prog_fd;
929 int ret;
930 string name = cs[i].name;
931
932 if (!cs[i].prog_def.has_value()) {
933 ALOGE("[%d] '%s' missing program definition! bad bpf.o build?", i, name.c_str());
934 return -EINVAL;
935 }
936
937 unsigned min_kver = cs[i].prog_def->min_kver;
938 unsigned max_kver = cs[i].prog_def->max_kver;
939 ALOGD("cs[%d].name:%s min_kver:%x .max_kver:%x (kvers:%x)", i, name.c_str(), min_kver,
940 max_kver, kvers);
941 if (kvers < min_kver) continue;
942 if (kvers >= max_kver) continue;
943
944 unsigned bpfMinVer = cs[i].prog_def->bpfloader_min_ver;
945 unsigned bpfMaxVer = cs[i].prog_def->bpfloader_max_ver;
946 domain selinux_context = getDomainFromSelinuxContext(cs[i].prog_def->selinux_context);
947 domain pin_subdir = getDomainFromPinSubdir(cs[i].prog_def->pin_subdir);
948 // Note: make sure to only check for unrecognized *after* verifying bpfloader
949 // version limits include this bpfloader's version.
950
951 ALOGD("cs[%d].name:%s requires bpfloader version [0x%05x,0x%05x)", i, name.c_str(),
952 bpfMinVer, bpfMaxVer);
Maciej Żenczykowski221b2482024-03-18 14:33:10 -0700953 if (bpfloader_ver < bpfMinVer) continue;
954 if (bpfloader_ver >= bpfMaxVer) continue;
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700955
956 if ((cs[i].prog_def->ignore_on_eng && isEng()) ||
957 (cs[i].prog_def->ignore_on_user && isUser()) ||
958 (cs[i].prog_def->ignore_on_userdebug && isUserdebug())) {
959 ALOGD("cs[%d].name:%s is ignored on %s builds", i, name.c_str(),
960 getBuildType().c_str());
961 continue;
962 }
963
964 if ((isArm() && isKernel32Bit() && cs[i].prog_def->ignore_on_arm32) ||
965 (isArm() && isKernel64Bit() && cs[i].prog_def->ignore_on_aarch64) ||
966 (isX86() && isKernel32Bit() && cs[i].prog_def->ignore_on_x86_32) ||
967 (isX86() && isKernel64Bit() && cs[i].prog_def->ignore_on_x86_64) ||
968 (isRiscV() && cs[i].prog_def->ignore_on_riscv64)) {
969 ALOGD("cs[%d].name:%s is ignored on %s", i, name.c_str(), describeArch());
970 continue;
971 }
972
973 if (unrecognized(pin_subdir)) return -ENOTDIR;
974
975 if (specified(selinux_context)) {
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700976 ALOGI("prog %s selinux_context [%-32s] -> %d -> '%s' (%s)", name.c_str(),
977 cs[i].prog_def->selinux_context, selinux_context,
978 lookupSelinuxContext(selinux_context), lookupPinSubdir(selinux_context));
979 }
980
981 if (specified(pin_subdir)) {
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -0700982 ALOGI("prog %s pin_subdir [%-32s] -> %d -> '%s'", name.c_str(),
983 cs[i].prog_def->pin_subdir, pin_subdir, lookupPinSubdir(pin_subdir));
984 }
985
986 // strip any potential $foo suffix
987 // this can be used to provide duplicate programs
988 // conditionally loaded based on running kernel version
989 name = name.substr(0, name.find_last_of('$'));
990
991 bool reuse = false;
992 // Format of pin location is
993 // /sys/fs/bpf/<prefix>prog_<objName>_<progName>
994 string progPinLoc = string(BPF_FS_PATH) + lookupPinSubdir(pin_subdir, prefix) + "prog_" +
995 objName + '_' + string(name);
996 if (access(progPinLoc.c_str(), F_OK) == 0) {
997 fd.reset(retrieveProgram(progPinLoc.c_str()));
998 ALOGD("New bpf prog load reusing prog %s, ret: %d (%s)", progPinLoc.c_str(), fd.get(),
999 (!fd.ok() ? std::strerror(errno) : "no error"));
1000 reuse = true;
1001 } else {
1002 vector<char> log_buf(BPF_LOAD_LOG_SZ, 0);
1003
1004 union bpf_attr req = {
1005 .prog_type = cs[i].type,
1006 .kern_version = kvers,
1007 .license = ptr_to_u64(license.c_str()),
1008 .insns = ptr_to_u64(cs[i].data.data()),
1009 .insn_cnt = static_cast<__u32>(cs[i].data.size() / sizeof(struct bpf_insn)),
1010 .log_level = 1,
1011 .log_buf = ptr_to_u64(log_buf.data()),
1012 .log_size = static_cast<__u32>(log_buf.size()),
1013 .expected_attach_type = cs[i].expected_attach_type,
1014 };
Maciej Żenczykowski22836352024-03-15 19:03:13 +00001015 if (isAtLeastKernelVersion(4, 14, 0))
1016 strlcpy(req.prog_name, cs[i].name.c_str(), sizeof(req.prog_name));
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -07001017 fd.reset(bpf(BPF_PROG_LOAD, req));
1018
1019 ALOGD("BPF_PROG_LOAD call for %s (%s) returned fd: %d (%s)", elfPath,
1020 cs[i].name.c_str(), fd.get(), (!fd.ok() ? std::strerror(errno) : "no error"));
1021
1022 if (!fd.ok()) {
1023 vector<string> lines = android::base::Split(log_buf.data(), "\n");
1024
1025 ALOGW("BPF_PROG_LOAD - BEGIN log_buf contents:");
1026 for (const auto& line : lines) ALOGW("%s", line.c_str());
1027 ALOGW("BPF_PROG_LOAD - END log_buf contents.");
1028
1029 if (cs[i].prog_def->optional) {
1030 ALOGW("failed program is marked optional - continuing...");
1031 continue;
1032 }
1033 ALOGE("non-optional program failed to load.");
1034 }
1035 }
1036
1037 if (!fd.ok()) return fd.get();
1038
1039 if (!reuse) {
1040 if (specified(selinux_context)) {
1041 string createLoc = string(BPF_FS_PATH) + lookupPinSubdir(selinux_context) +
1042 "tmp_prog_" + objName + '_' + string(name);
1043 ret = bpfFdPin(fd, createLoc.c_str());
1044 if (ret) {
1045 int err = errno;
1046 ALOGE("create %s -> %d [%d:%s]", createLoc.c_str(), ret, err, strerror(err));
1047 return -err;
1048 }
1049 ret = renameat2(AT_FDCWD, createLoc.c_str(),
1050 AT_FDCWD, progPinLoc.c_str(), RENAME_NOREPLACE);
1051 if (ret) {
1052 int err = errno;
1053 ALOGE("rename %s %s -> %d [%d:%s]", createLoc.c_str(), progPinLoc.c_str(), ret,
1054 err, strerror(err));
1055 return -err;
1056 }
1057 } else {
1058 ret = bpfFdPin(fd, progPinLoc.c_str());
1059 if (ret) {
1060 int err = errno;
1061 ALOGE("create %s -> %d [%d:%s]", progPinLoc.c_str(), ret, err, strerror(err));
1062 return -err;
1063 }
1064 }
1065 if (chmod(progPinLoc.c_str(), 0440)) {
1066 int err = errno;
1067 ALOGE("chmod %s 0440 -> [%d:%s]", progPinLoc.c_str(), err, strerror(err));
1068 return -err;
1069 }
1070 if (chown(progPinLoc.c_str(), (uid_t)cs[i].prog_def->uid,
1071 (gid_t)cs[i].prog_def->gid)) {
1072 int err = errno;
1073 ALOGE("chown %s %d %d -> [%d:%s]", progPinLoc.c_str(), cs[i].prog_def->uid,
1074 cs[i].prog_def->gid, err, strerror(err));
1075 return -err;
1076 }
1077 }
1078
1079 int progId = bpfGetFdProgId(fd);
1080 if (progId == -1) {
1081 ALOGE("bpfGetFdProgId failed, ret: %d [%d]", progId, errno);
1082 } else {
1083 ALOGI("prog %s id %d", progPinLoc.c_str(), progId);
1084 }
1085 }
1086
1087 return 0;
1088}
1089
Maciej Żenczykowskia2706bf2024-03-18 22:27:22 -07001090int loadProg(const char* const elfPath, bool* const isCritical, const unsigned int bpfloader_ver,
Maciej Żenczykowski221b2482024-03-18 14:33:10 -07001091 const Location& location) {
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -07001092 vector<char> license;
1093 vector<char> critical;
1094 vector<codeSection> cs;
1095 vector<unique_fd> mapFds;
1096 int ret;
1097
1098 if (!isCritical) return -1;
1099 *isCritical = false;
1100
1101 ifstream elfFile(elfPath, ios::in | ios::binary);
1102 if (!elfFile.is_open()) return -1;
1103
1104 ret = readSectionByName("critical", elfFile, critical);
1105 *isCritical = !ret;
1106
1107 ret = readSectionByName("license", elfFile, license);
1108 if (ret) {
1109 ALOGE("Couldn't find license in %s", elfPath);
1110 return ret;
1111 } else {
1112 ALOGD("Loading %s%s ELF object %s with license %s",
1113 *isCritical ? "critical for " : "optional", *isCritical ? (char*)critical.data() : "",
1114 elfPath, (char*)license.data());
1115 }
1116
1117 // the following default values are for bpfloader V0.0 format which does not include them
1118 unsigned int bpfLoaderMinVer =
1119 readSectionUint("bpfloader_min_ver", elfFile, DEFAULT_BPFLOADER_MIN_VER);
1120 unsigned int bpfLoaderMaxVer =
1121 readSectionUint("bpfloader_max_ver", elfFile, DEFAULT_BPFLOADER_MAX_VER);
1122 unsigned int bpfLoaderMinRequiredVer =
1123 readSectionUint("bpfloader_min_required_ver", elfFile, 0);
1124 size_t sizeOfBpfMapDef =
1125 readSectionUint("size_of_bpf_map_def", elfFile, DEFAULT_SIZEOF_BPF_MAP_DEF);
1126 size_t sizeOfBpfProgDef =
1127 readSectionUint("size_of_bpf_prog_def", elfFile, DEFAULT_SIZEOF_BPF_PROG_DEF);
1128
1129 // inclusive lower bound check
Maciej Żenczykowski221b2482024-03-18 14:33:10 -07001130 if (bpfloader_ver < bpfLoaderMinVer) {
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -07001131 ALOGI("BpfLoader version 0x%05x ignoring ELF object %s with min ver 0x%05x",
Maciej Żenczykowski221b2482024-03-18 14:33:10 -07001132 bpfloader_ver, elfPath, bpfLoaderMinVer);
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -07001133 return 0;
1134 }
1135
1136 // exclusive upper bound check
Maciej Żenczykowski221b2482024-03-18 14:33:10 -07001137 if (bpfloader_ver >= bpfLoaderMaxVer) {
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -07001138 ALOGI("BpfLoader version 0x%05x ignoring ELF object %s with max ver 0x%05x",
Maciej Żenczykowski221b2482024-03-18 14:33:10 -07001139 bpfloader_ver, elfPath, bpfLoaderMaxVer);
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -07001140 return 0;
1141 }
1142
Maciej Żenczykowski221b2482024-03-18 14:33:10 -07001143 if (bpfloader_ver < bpfLoaderMinRequiredVer) {
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -07001144 ALOGI("BpfLoader version 0x%05x failing due to ELF object %s with required min ver 0x%05x",
Maciej Żenczykowski221b2482024-03-18 14:33:10 -07001145 bpfloader_ver, elfPath, bpfLoaderMinRequiredVer);
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -07001146 return -1;
1147 }
1148
1149 ALOGI("BpfLoader version 0x%05x processing ELF object %s with ver [0x%05x,0x%05x)",
Maciej Żenczykowski221b2482024-03-18 14:33:10 -07001150 bpfloader_ver, elfPath, bpfLoaderMinVer, bpfLoaderMaxVer);
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -07001151
1152 if (sizeOfBpfMapDef < DEFAULT_SIZEOF_BPF_MAP_DEF) {
1153 ALOGE("sizeof(bpf_map_def) of %zu is too small (< %d)", sizeOfBpfMapDef,
1154 DEFAULT_SIZEOF_BPF_MAP_DEF);
1155 return -1;
1156 }
1157
1158 if (sizeOfBpfProgDef < DEFAULT_SIZEOF_BPF_PROG_DEF) {
1159 ALOGE("sizeof(bpf_prog_def) of %zu is too small (< %d)", sizeOfBpfProgDef,
1160 DEFAULT_SIZEOF_BPF_PROG_DEF);
1161 return -1;
1162 }
1163
Maciej Żenczykowskifcea70f2023-10-08 23:35:00 -07001164 ret = readCodeSections(elfFile, cs, sizeOfBpfProgDef);
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -07001165 if (ret) {
1166 ALOGE("Couldn't read all code sections in %s", elfPath);
1167 return ret;
1168 }
1169
1170 /* Just for future debugging */
1171 if (0) dumpAllCs(cs);
1172
Maciej Żenczykowski221b2482024-03-18 14:33:10 -07001173 ret = createMaps(elfPath, elfFile, mapFds, location.prefix, sizeOfBpfMapDef, bpfloader_ver);
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -07001174 if (ret) {
1175 ALOGE("Failed to create maps: (ret=%d) in %s", ret, elfPath);
1176 return ret;
1177 }
1178
1179 for (int i = 0; i < (int)mapFds.size(); i++)
1180 ALOGD("map_fd found at %d is %d in %s", i, mapFds[i].get(), elfPath);
1181
1182 applyMapRelo(elfFile, mapFds, cs);
1183
Maciej Żenczykowski221b2482024-03-18 14:33:10 -07001184 ret = loadCodeSections(elfPath, cs, string(license.data()), location.prefix, bpfloader_ver);
Maciej Żenczykowski60c159f2023-10-02 14:54:48 -07001185 if (ret) ALOGE("Failed to load programs, loadCodeSections ret=%d", ret);
1186
1187 return ret;
1188}
1189
1190} // namespace bpf
1191} // namespace android