Package: release.debian.org Severity: normal Tags: bookworm User: [email protected] Usertags: pu X-Debbugs-Cc: [email protected], [email protected] Control: affects -1 + src:libbpf
[ Reason ] As mentioned in #1101745, latest systemd versions will segfault if used with the libbpf packaged in bookworm. The systemd version present in bookworm is not affected, but if any user tries to update and install the latest systemd from upstream they will face the issue. The relevant systemd issue is https://github.com/systemd/systemd/issues/36903. The issue was reported for systemd, but it is possible that any user with a similar usecase will see the same segfault. [ Impact ] user applications using libbpf which triggers the same scenario as systemd issue will crash with a segfailt. [ Tests ] Manually tested by installing in a Bookworm system. 1. Confirmed that systemd still works and there is no issue seen in the basic usage of the system. 2. Used bpftrace and confirmed that it is still working and no issues seen in its basic usage. [ Risks ] There are total of 3 commits between 1.1.0 to 1.1.2. All 3 commits are only fixing bugs as documented in the [Changes] section below. There is no other change of code. All the 3 commits are backported by upstream from later release and they are part of v1.5.0 in Trixie and no issues has been reported yet. [ Checklist ] [x] *all* changes are documented in the d/changelog [x] I reviewed all changes and I approve them [x] attach debdiff against the package in (old)stable [x] the issue is verified as fixed in unstable [ Changes ] There are total of 3 commits as can be seen at: https://github.com/libbpf/libbpf/compare/v1.1.0...v1.1.2 The details of the commits: commit 6cbb1a25347de0c85cb91cdbed9912eb3c21e77b Author: Andrii Nakryiko <[email protected]> Date: Mon Jul 8 13:45:39 2024 -0700 libbpf: fix BPF skeleton forward/backward compat handling BPF skeleton was designed from day one to be extensible. Generated BPF skeleton code specifies actual sizes of map/prog/variable skeletons for that reason and libbpf is supposed to work with newer/older versions correctly. Unfortunately, it was missed that we implicitly embed hard-coded most up-to-date (according to libbpf's version of libbpf.h header used to compile BPF skeleton header) sizes of those structs, which can differ from the actual sizes at runtime when libbpf is used as a shared library. We have a few places were we just index array of maps/progs/vars, which implicitly uses these potentially invalid sizes of structs. This patch aims to fix this problem going forward. Once this lands, we'll backport these changes in Github repo to create patched releases for older libbpfs. commit 7696f8ada212798873295ef1ed837e5a5b7b0772 Author: Andrii Nakryiko <[email protected]> Date: Tue Aug 27 13:37:21 2024 -0700 libbpf: Fix bpf_object__open_skeleton()'s mishandling of options We do an ugly copying of options in bpf_object__open_skeleton() just to be able to set object name from skeleton's recorded name (while still allowing user to override it through opts->object_name). This is not just ugly, but it also is broken due to memcpy() that doesn't take into account potential skel_opts' and user-provided opts' sizes differences due to backward and forward compatibility. This leads to copying over extra bytes and then failing to validate options properly. It could, technically, lead also to SIGSEGV, if we are unlucky. So just get rid of that memory copy completely and instead pass default object name into bpf_object_open() directly, simplifying all this significantly. The rule now is that obj_name should be non-NULL for bpf_object_open() when called with in-memory buffer, so validate that explicitly as well. We adopt bpf_object__open_mem() to this as well and generate default name (based on buffer memory address and size) outside of bpf_object_open(). commit 5ba294c95a833505c815eec17d3afd0398c756b6 Author: Tony Ambardar <[email protected]> Date: Fri Aug 30 02:51:50 2024 -0700 libbpf: Ensure new BTF objects inherit input endianness New split BTF needs to preserve base's endianness. Similarly, when creating a distilled BTF, we need to preserve original endianness. Fix by updating libbpf's btf__distill_base() and btf_new_empty() to retain the byte order of any source BTF objects when creating new ones. [ Other info ] If updating the version is not acceptable, then I can try to find out the exact commit which fixes the segfault. But since the change only fixes reported bugs, I think it will be best to update libbpf to 1.1.2.
diff -Nru libbpf-1.1.0/debian/changelog libbpf-1.1.2/debian/changelog --- libbpf-1.1.0/debian/changelog 2023-01-06 20:31:46.000000000 +0000 +++ libbpf-1.1.2/debian/changelog 2025-04-04 21:06:45.000000000 +0100 @@ -1,3 +1,13 @@ +libbpf (1.1.2-1+deb12u1) bookworm; urgency=medium + + * New upstream version 1.1.2 (Closes: #1101745) + - Upstream changes: + - libbpf: fix BPF skeleton forward/backward compat handling. + - libbpf: Fix bpf_object__open_skeleton()'s mishandling of options. + - libbpf: Ensure new BTF objects inherit input endianness. + + -- Sudip Mukherjee <[email protected]> Fri, 04 Apr 2025 21:06:45 +0100 + libbpf (1.1.0-1) unstable; urgency=medium * New upstream version 1.1.0 diff -Nru libbpf-1.1.0/src/btf.c libbpf-1.1.2/src/btf.c --- libbpf-1.1.0/src/btf.c 2022-12-21 06:23:18.000000000 +0000 +++ libbpf-1.1.2/src/btf.c 2024-09-03 21:59:02.000000000 +0100 @@ -832,6 +832,7 @@ btf->base_btf = base_btf; btf->start_id = btf__type_cnt(base_btf); btf->start_str_off = base_btf->hdr->str_len; + btf->swapped_endian = base_btf->swapped_endian; } /* +1 for empty string at offset 0 */ diff -Nru libbpf-1.1.0/src/libbpf.c libbpf-1.1.2/src/libbpf.c --- libbpf-1.1.0/src/libbpf.c 2022-12-21 06:23:18.000000000 +0000 +++ libbpf-1.1.2/src/libbpf.c 2024-09-03 21:59:02.000000000 +0100 @@ -7214,16 +7214,19 @@ } static struct bpf_object *bpf_object_open(const char *path, const void *obj_buf, size_t obj_buf_sz, + const char *obj_name, const struct bpf_object_open_opts *opts) { - const char *obj_name, *kconfig, *btf_tmp_path; + const char *kconfig, *btf_tmp_path; struct bpf_object *obj; - char tmp_name[64]; int err; char *log_buf; size_t log_size; __u32 log_level; + if (obj_buf && !obj_name) + return ERR_PTR(-EINVAL); + if (elf_version(EV_CURRENT) == EV_NONE) { pr_warn("failed to init libelf for %s\n", path ? : "(mem buf)"); @@ -7233,16 +7236,12 @@ if (!OPTS_VALID(opts, bpf_object_open_opts)) return ERR_PTR(-EINVAL); - obj_name = OPTS_GET(opts, object_name, NULL); + obj_name = OPTS_GET(opts, object_name, NULL) ?: obj_name; if (obj_buf) { - if (!obj_name) { - snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx", - (unsigned long)obj_buf, - (unsigned long)obj_buf_sz); - obj_name = tmp_name; - } path = obj_name; pr_debug("loading object '%s' from buffer\n", obj_name); + } else { + pr_debug("loading object from %s\n", path); } log_buf = OPTS_GET(opts, kernel_log_buf, NULL); @@ -7308,9 +7307,7 @@ if (!path) return libbpf_err_ptr(-EINVAL); - pr_debug("loading %s\n", path); - - return libbpf_ptr(bpf_object_open(path, NULL, 0, opts)); + return libbpf_ptr(bpf_object_open(path, NULL, 0, NULL, opts)); } struct bpf_object *bpf_object__open(const char *path) @@ -7322,10 +7319,15 @@ bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz, const struct bpf_object_open_opts *opts) { + char tmp_name[64]; + if (!obj_buf || obj_buf_sz == 0) return libbpf_err_ptr(-EINVAL); - return libbpf_ptr(bpf_object_open(NULL, obj_buf, obj_buf_sz, opts)); + /* create a (quite useless) default "name" for this memory buffer object */ + snprintf(tmp_name, sizeof(tmp_name), "%lx-%zx", (unsigned long)obj_buf, obj_buf_sz); + + return libbpf_ptr(bpf_object_open(NULL, obj_buf, obj_buf_sz, tmp_name, opts)); } static int bpf_object_unload(struct bpf_object *obj) @@ -12213,14 +12215,15 @@ static int populate_skeleton_maps(const struct bpf_object *obj, struct bpf_map_skeleton *maps, - size_t map_cnt) + size_t map_cnt, size_t map_skel_sz) { int i; for (i = 0; i < map_cnt; i++) { - struct bpf_map **map = maps[i].map; - const char *name = maps[i].name; - void **mmaped = maps[i].mmaped; + struct bpf_map_skeleton *map_skel = (void *)maps + i * map_skel_sz; + struct bpf_map **map = map_skel->map; + const char *name = map_skel->name; + void **mmaped = map_skel->mmaped; *map = bpf_object__find_map_by_name(obj, name); if (!*map) { @@ -12237,13 +12240,14 @@ static int populate_skeleton_progs(const struct bpf_object *obj, struct bpf_prog_skeleton *progs, - size_t prog_cnt) + size_t prog_cnt, size_t prog_skel_sz) { int i; for (i = 0; i < prog_cnt; i++) { - struct bpf_program **prog = progs[i].prog; - const char *name = progs[i].name; + struct bpf_prog_skeleton *prog_skel = (void *)progs + i * prog_skel_sz; + struct bpf_program **prog = prog_skel->prog; + const char *name = prog_skel->name; *prog = bpf_object__find_program_by_name(obj, name); if (!*prog) { @@ -12257,40 +12261,24 @@ int bpf_object__open_skeleton(struct bpf_object_skeleton *s, const struct bpf_object_open_opts *opts) { - DECLARE_LIBBPF_OPTS(bpf_object_open_opts, skel_opts, - .object_name = s->name, - ); struct bpf_object *obj; int err; - /* Attempt to preserve opts->object_name, unless overriden by user - * explicitly. Overwriting object name for skeletons is discouraged, - * as it breaks global data maps, because they contain object name - * prefix as their own map name prefix. When skeleton is generated, - * bpftool is making an assumption that this name will stay the same. - */ - if (opts) { - memcpy(&skel_opts, opts, sizeof(*opts)); - if (!opts->object_name) - skel_opts.object_name = s->name; - } - - obj = bpf_object__open_mem(s->data, s->data_sz, &skel_opts); - err = libbpf_get_error(obj); - if (err) { - pr_warn("failed to initialize skeleton BPF object '%s': %d\n", - s->name, err); + obj = bpf_object_open(NULL, s->data, s->data_sz, s->name, opts); + if (IS_ERR(obj)) { + err = PTR_ERR(obj); + pr_warn("failed to initialize skeleton BPF object '%s': %d\n", s->name, err); return libbpf_err(err); } *s->obj = obj; - err = populate_skeleton_maps(obj, s->maps, s->map_cnt); + err = populate_skeleton_maps(obj, s->maps, s->map_cnt, s->map_skel_sz); if (err) { pr_warn("failed to populate skeleton maps for '%s': %d\n", s->name, err); return libbpf_err(err); } - err = populate_skeleton_progs(obj, s->progs, s->prog_cnt); + err = populate_skeleton_progs(obj, s->progs, s->prog_cnt, s->prog_skel_sz); if (err) { pr_warn("failed to populate skeleton progs for '%s': %d\n", s->name, err); return libbpf_err(err); @@ -12320,20 +12308,20 @@ return libbpf_err(-errno); } - err = populate_skeleton_maps(s->obj, s->maps, s->map_cnt); + err = populate_skeleton_maps(s->obj, s->maps, s->map_cnt, s->map_skel_sz); if (err) { pr_warn("failed to populate subskeleton maps: %d\n", err); return libbpf_err(err); } - err = populate_skeleton_progs(s->obj, s->progs, s->prog_cnt); + err = populate_skeleton_progs(s->obj, s->progs, s->prog_cnt, s->prog_skel_sz); if (err) { pr_warn("failed to populate subskeleton maps: %d\n", err); return libbpf_err(err); } for (var_idx = 0; var_idx < s->var_cnt; var_idx++) { - var_skel = &s->vars[var_idx]; + var_skel = (void *)s->vars + var_idx * s->var_skel_sz; map = *var_skel->map; map_type_id = bpf_map__btf_value_type_id(map); map_type = btf__type_by_id(btf, map_type_id); @@ -12380,10 +12368,11 @@ } for (i = 0; i < s->map_cnt; i++) { - struct bpf_map *map = *s->maps[i].map; + struct bpf_map_skeleton *map_skel = (void *)s->maps + i * s->map_skel_sz; + struct bpf_map *map = *map_skel->map; size_t mmap_sz = bpf_map_mmap_sz(map); - int prot, map_fd = bpf_map__fd(map); - void **mmaped = s->maps[i].mmaped; + int prot, map_fd = map->fd; + void **mmaped = map_skel->mmaped; if (!mmaped) continue; @@ -12427,8 +12416,9 @@ int i, err; for (i = 0; i < s->prog_cnt; i++) { - struct bpf_program *prog = *s->progs[i].prog; - struct bpf_link **link = s->progs[i].link; + struct bpf_prog_skeleton *prog_skel = (void *)s->progs + i * s->prog_skel_sz; + struct bpf_program *prog = *prog_skel->prog; + struct bpf_link **link = prog_skel->link; if (!prog->autoload || !prog->autoattach) continue; @@ -12468,7 +12458,8 @@ int i; for (i = 0; i < s->prog_cnt; i++) { - struct bpf_link **link = s->progs[i].link; + struct bpf_prog_skeleton *prog_skel = (void *)s->progs + i * s->prog_skel_sz; + struct bpf_link **link = prog_skel->link; bpf_link__destroy(*link); *link = NULL; diff -Nru libbpf-1.1.0/src/Makefile libbpf-1.1.2/src/Makefile --- libbpf-1.1.0/src/Makefile 2022-12-21 06:23:18.000000000 +0000 +++ libbpf-1.1.2/src/Makefile 2024-09-03 21:59:02.000000000 +0100 @@ -10,7 +10,7 @@ LIBBPF_MAJOR_VERSION := 1 LIBBPF_MINOR_VERSION := 1 -LIBBPF_PATCH_VERSION := 0 +LIBBPF_PATCH_VERSION := 2 LIBBPF_VERSION := $(LIBBPF_MAJOR_VERSION).$(LIBBPF_MINOR_VERSION).$(LIBBPF_PATCH_VERSION) LIBBPF_MAJMIN_VERSION := $(LIBBPF_MAJOR_VERSION).$(LIBBPF_MINOR_VERSION).0 LIBBPF_MAP_VERSION := $(shell grep -oE '^LIBBPF_([0-9.]+)' libbpf.map | sort -rV | head -n1 | cut -d'_' -f2)
