diff --git a/include/linux/filter.h b/include/linux/filter.h index 259377723603..0b0144752d78 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -884,12 +884,12 @@ void bpf_jit_compile(struct bpf_prog *prog); bool bpf_jit_needs_zext(void); bool bpf_helper_changes_pkt_data(void *func); -static inline bool bpf_dump_raw_ok(void) +static inline bool bpf_dump_raw_ok(const struct cred *cred) { /* Reconstruction of call-sites is dependent on kallsyms, * thus make dump the same restriction. */ - return kallsyms_show_value() == 1; + return kallsyms_show_value(cred); } struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h index 98338dc6b5d2..481273f0c72d 100644 --- a/include/linux/kallsyms.h +++ b/include/linux/kallsyms.h @@ -18,6 +18,7 @@ #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s]") + (KSYM_NAME_LEN - 1) + \ 2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + 1) +struct cred; struct module; static inline int is_kernel_inittext(unsigned long addr) @@ -98,7 +99,7 @@ int lookup_symbol_name(unsigned long addr, char *symname); int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name); /* How and when do we show kallsyms values? */ -extern int kallsyms_show_value(void); +extern bool kallsyms_show_value(const struct cred *cred); #else /* !CONFIG_KALLSYMS */ @@ -158,7 +159,7 @@ static inline int lookup_symbol_attrs(unsigned long addr, unsigned long *size, u return -ERANGE; } -static inline int kallsyms_show_value(void) +static inline bool kallsyms_show_value(const struct cred *cred) { return false; } diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 8da159936bab..859053ddf05b 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3139,7 +3139,8 @@ static const struct bpf_map *bpf_map_from_imm(const struct bpf_prog *prog, return NULL; } -static struct bpf_insn *bpf_insn_prepare_dump(const struct bpf_prog *prog) +static struct bpf_insn *bpf_insn_prepare_dump(const struct bpf_prog *prog, + const struct cred *f_cred) { const struct bpf_map *map; struct bpf_insn *insns; @@ -3165,7 +3166,7 @@ static struct bpf_insn *bpf_insn_prepare_dump(const struct bpf_prog *prog) code == (BPF_JMP | BPF_CALL_ARGS)) { if (code == (BPF_JMP | BPF_CALL_ARGS)) insns[i].code = BPF_JMP | BPF_CALL; - if (!bpf_dump_raw_ok()) + if (!bpf_dump_raw_ok(f_cred)) insns[i].imm = 0; continue; } @@ -3221,7 +3222,8 @@ static int set_info_rec_size(struct bpf_prog_info *info) return 0; } -static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, +static int bpf_prog_get_info_by_fd(struct file *file, + struct bpf_prog *prog, const union bpf_attr *attr, union bpf_attr __user *uattr) { @@ -3290,11 +3292,11 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, struct bpf_insn *insns_sanitized; bool fault; - if (prog->blinded && !bpf_dump_raw_ok()) { + if (prog->blinded && !bpf_dump_raw_ok(file->f_cred)) { info.xlated_prog_insns = 0; goto done; } - insns_sanitized = bpf_insn_prepare_dump(prog); + insns_sanitized = bpf_insn_prepare_dump(prog, file->f_cred); if (!insns_sanitized) return -ENOMEM; uinsns = u64_to_user_ptr(info.xlated_prog_insns); @@ -3328,7 +3330,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, } if (info.jited_prog_len && ulen) { - if (bpf_dump_raw_ok()) { + if (bpf_dump_raw_ok(file->f_cred)) { uinsns = u64_to_user_ptr(info.jited_prog_insns); ulen = min_t(u32, info.jited_prog_len, ulen); @@ -3363,7 +3365,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, ulen = info.nr_jited_ksyms; info.nr_jited_ksyms = prog->aux->func_cnt ? : 1; if (ulen) { - if (bpf_dump_raw_ok()) { + if (bpf_dump_raw_ok(file->f_cred)) { unsigned long ksym_addr; u64 __user *user_ksyms; u32 i; @@ -3394,7 +3396,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, ulen = info.nr_jited_func_lens; info.nr_jited_func_lens = prog->aux->func_cnt ? : 1; if (ulen) { - if (bpf_dump_raw_ok()) { + if (bpf_dump_raw_ok(file->f_cred)) { u32 __user *user_lens; u32 func_len, i; @@ -3451,7 +3453,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, else info.nr_jited_line_info = 0; if (info.nr_jited_line_info && ulen) { - if (bpf_dump_raw_ok()) { + if (bpf_dump_raw_ok(file->f_cred)) { __u64 __user *user_linfo; u32 i; @@ -3497,7 +3499,8 @@ done: return 0; } -static int bpf_map_get_info_by_fd(struct bpf_map *map, +static int bpf_map_get_info_by_fd(struct file *file, + struct bpf_map *map, const union bpf_attr *attr, union bpf_attr __user *uattr) { @@ -3540,7 +3543,8 @@ static int bpf_map_get_info_by_fd(struct bpf_map *map, return 0; } -static int bpf_btf_get_info_by_fd(struct btf *btf, +static int bpf_btf_get_info_by_fd(struct file *file, + struct btf *btf, const union bpf_attr *attr, union bpf_attr __user *uattr) { @@ -3555,7 +3559,8 @@ static int bpf_btf_get_info_by_fd(struct btf *btf, return btf_get_info_by_fd(btf, attr, uattr); } -static int bpf_link_get_info_by_fd(struct bpf_link *link, +static int bpf_link_get_info_by_fd(struct file *file, + struct bpf_link *link, const union bpf_attr *attr, union bpf_attr __user *uattr) { @@ -3608,15 +3613,15 @@ static int bpf_obj_get_info_by_fd(const union bpf_attr *attr, return -EBADFD; if (f.file->f_op == &bpf_prog_fops) - err = bpf_prog_get_info_by_fd(f.file->private_data, attr, + err = bpf_prog_get_info_by_fd(f.file, f.file->private_data, attr, uattr); else if (f.file->f_op == &bpf_map_fops) - err = bpf_map_get_info_by_fd(f.file->private_data, attr, + err = bpf_map_get_info_by_fd(f.file, f.file->private_data, attr, uattr); else if (f.file->f_op == &btf_fops) - err = bpf_btf_get_info_by_fd(f.file->private_data, attr, uattr); + err = bpf_btf_get_info_by_fd(f.file, f.file->private_data, attr, uattr); else if (f.file->f_op == &bpf_link_fops) - err = bpf_link_get_info_by_fd(f.file->private_data, + err = bpf_link_get_info_by_fd(f.file, f.file->private_data, attr, uattr); else err = -EINVAL; diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 16c8c605f4b0..bb14e64f62a4 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -644,19 +644,20 @@ static inline int kallsyms_for_perf(void) * Otherwise, require CAP_SYSLOG (assuming kptr_restrict isn't set to * block even that). */ -int kallsyms_show_value(void) +bool kallsyms_show_value(const struct cred *cred) { switch (kptr_restrict) { case 0: if (kallsyms_for_perf()) - return 1; + return true; /* fallthrough */ case 1: - if (has_capability_noaudit(current, CAP_SYSLOG)) - return 1; + if (security_capable(cred, &init_user_ns, CAP_SYSLOG, + CAP_OPT_NOAUDIT) == 0) + return true; /* fallthrough */ default: - return 0; + return false; } } @@ -673,7 +674,11 @@ static int kallsyms_open(struct inode *inode, struct file *file) return -ENOMEM; reset_iter(iter, 0); - iter->show_value = kallsyms_show_value(); + /* + * Instead of checking this on every s_show() call, cache + * the result here at open time. + */ + iter->show_value = kallsyms_show_value(file->f_cred); return 0; } diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 4a904cc56d68..2e97febeef77 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2448,7 +2448,7 @@ static void report_probe(struct seq_file *pi, struct kprobe *p, else kprobe_type = "k"; - if (!kallsyms_show_value()) + if (!kallsyms_show_value(pi->file->f_cred)) addr = NULL; if (sym) @@ -2540,7 +2540,7 @@ static int kprobe_blacklist_seq_show(struct seq_file *m, void *v) * If /proc/kallsyms is not showing kernel address, we won't * show them here either. */ - if (!kallsyms_show_value()) + if (!kallsyms_show_value(m->file->f_cred)) seq_printf(m, "0x%px-0x%px\t%ps\n", NULL, NULL, (void *)ent->start_addr); else diff --git a/kernel/module.c b/kernel/module.c index bee1c25ca5c5..aa183c9ac0a2 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1510,8 +1510,7 @@ static inline bool sect_empty(const Elf_Shdr *sect) } struct module_sect_attr { - struct module_attribute mattr; - char *name; + struct bin_attribute battr; unsigned long address; }; @@ -1521,13 +1520,18 @@ struct module_sect_attrs { struct module_sect_attr attrs[]; }; -static ssize_t module_sect_show(struct module_attribute *mattr, - struct module_kobject *mk, char *buf) +static ssize_t module_sect_read(struct file *file, struct kobject *kobj, + struct bin_attribute *battr, + char *buf, loff_t pos, size_t count) { struct module_sect_attr *sattr = - container_of(mattr, struct module_sect_attr, mattr); - return sprintf(buf, "0x%px\n", kptr_restrict < 2 ? - (void *)sattr->address : NULL); + container_of(battr, struct module_sect_attr, battr); + + if (pos != 0) + return -EINVAL; + + return sprintf(buf, "0x%px\n", + kallsyms_show_value(file->f_cred) ? (void *)sattr->address : NULL); } static void free_sect_attrs(struct module_sect_attrs *sect_attrs) @@ -1535,7 +1539,7 @@ static void free_sect_attrs(struct module_sect_attrs *sect_attrs) unsigned int section; for (section = 0; section < sect_attrs->nsections; section++) - kfree(sect_attrs->attrs[section].name); + kfree(sect_attrs->attrs[section].battr.attr.name); kfree(sect_attrs); } @@ -1544,42 +1548,41 @@ static void add_sect_attrs(struct module *mod, const struct load_info *info) unsigned int nloaded = 0, i, size[2]; struct module_sect_attrs *sect_attrs; struct module_sect_attr *sattr; - struct attribute **gattr; + struct bin_attribute **gattr; /* Count loaded sections and allocate structures */ for (i = 0; i < info->hdr->e_shnum; i++) if (!sect_empty(&info->sechdrs[i])) nloaded++; size[0] = ALIGN(struct_size(sect_attrs, attrs, nloaded), - sizeof(sect_attrs->grp.attrs[0])); - size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.attrs[0]); + sizeof(sect_attrs->grp.bin_attrs[0])); + size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.bin_attrs[0]); sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL); if (sect_attrs == NULL) return; /* Setup section attributes. */ sect_attrs->grp.name = "sections"; - sect_attrs->grp.attrs = (void *)sect_attrs + size[0]; + sect_attrs->grp.bin_attrs = (void *)sect_attrs + size[0]; sect_attrs->nsections = 0; sattr = §_attrs->attrs[0]; - gattr = §_attrs->grp.attrs[0]; + gattr = §_attrs->grp.bin_attrs[0]; for (i = 0; i < info->hdr->e_shnum; i++) { Elf_Shdr *sec = &info->sechdrs[i]; if (sect_empty(sec)) continue; + sysfs_bin_attr_init(&sattr->battr); sattr->address = sec->sh_addr; - sattr->name = kstrdup(info->secstrings + sec->sh_name, - GFP_KERNEL); - if (sattr->name == NULL) + sattr->battr.attr.name = + kstrdup(info->secstrings + sec->sh_name, GFP_KERNEL); + if (sattr->battr.attr.name == NULL) goto out; sect_attrs->nsections++; - sysfs_attr_init(&sattr->mattr.attr); - sattr->mattr.show = module_sect_show; - sattr->mattr.store = NULL; - sattr->mattr.attr.name = sattr->name; - sattr->mattr.attr.mode = S_IRUSR; - *(gattr++) = &(sattr++)->mattr.attr; + sattr->battr.read = module_sect_read; + sattr->battr.size = 3 /* "0x", "\n" */ + (BITS_PER_LONG / 4); + sattr->battr.attr.mode = 0400; + *(gattr++) = &(sattr++)->battr; } *gattr = NULL; @@ -1669,7 +1672,7 @@ static void add_notes_attrs(struct module *mod, const struct load_info *info) continue; if (info->sechdrs[i].sh_type == SHT_NOTE) { sysfs_bin_attr_init(nattr); - nattr->attr.name = mod->sect_attrs->attrs[loaded].name; + nattr->attr.name = mod->sect_attrs->attrs[loaded].battr.attr.name; nattr->attr.mode = S_IRUGO; nattr->size = info->sechdrs[i].sh_size; nattr->private = (void *) info->sechdrs[i].sh_addr; @@ -4379,7 +4382,7 @@ static int modules_open(struct inode *inode, struct file *file) if (!err) { struct seq_file *m = file->private_data; - m->private = kallsyms_show_value() ? NULL : (void *)8ul; + m->private = kallsyms_show_value(file->f_cred) ? NULL : (void *)8ul; } return err; diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index f93f8ace6c56..6ada114bbcca 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -274,7 +274,7 @@ static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write, ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos); if (write && !ret) { if (jit_enable < 2 || - (jit_enable == 2 && bpf_dump_raw_ok())) { + (jit_enable == 2 && bpf_dump_raw_ok(current_cred()))) { *(int *)table->data = jit_enable; if (jit_enable == 2) pr_warn("bpf_jit_enable = 2 was set! NEVER use this in production, only for JIT debugging!\n"); diff --git a/tools/testing/selftests/kmod/kmod.sh b/tools/testing/selftests/kmod/kmod.sh index 3702dbcc90a7..c82aa77958e5 100755 --- a/tools/testing/selftests/kmod/kmod.sh +++ b/tools/testing/selftests/kmod/kmod.sh @@ -63,6 +63,8 @@ ALL_TESTS="$ALL_TESTS 0008:150:1" ALL_TESTS="$ALL_TESTS 0009:150:1" ALL_TESTS="$ALL_TESTS 0010:1:1" ALL_TESTS="$ALL_TESTS 0011:1:1" +ALL_TESTS="$ALL_TESTS 0012:1:1" +ALL_TESTS="$ALL_TESTS 0013:1:1" # Kselftest framework requirement - SKIP code is 4. ksft_skip=4 @@ -470,6 +472,38 @@ kmod_test_0011() echo "$MODPROBE" > /proc/sys/kernel/modprobe } +kmod_check_visibility() +{ + local name="$1" + local cmd="$2" + + modprobe $DEFAULT_KMOD_DRIVER + + local priv=$(eval $cmd) + local unpriv=$(capsh --drop=CAP_SYSLOG -- -c "$cmd") + + if [ "$priv" = "$unpriv" ] || \ + [ "${priv:0:3}" = "0x0" ] || \ + [ "${unpriv:0:3}" != "0x0" ] ; then + echo "${FUNCNAME[0]}: FAIL, $name visible to unpriv: '$priv' vs '$unpriv'" >&2 + exit 1 + else + echo "${FUNCNAME[0]}: OK!" + fi +} + +kmod_test_0012() +{ + kmod_check_visibility /proc/modules \ + "grep '^${DEFAULT_KMOD_DRIVER}\b' /proc/modules | awk '{print \$NF}'" +} + +kmod_test_0013() +{ + kmod_check_visibility '/sys/module/*/sections/*' \ + "cat /sys/module/${DEFAULT_KMOD_DRIVER}/sections/.*text | head -n1" +} + list_tests() { echo "Test ID list:" @@ -489,6 +523,8 @@ list_tests() echo "0009 x $(get_test_count 0009) - multithreaded - push kmod_concurrent over max_modprobes for get_fs_type()" echo "0010 x $(get_test_count 0010) - test nonexistent modprobe path" echo "0011 x $(get_test_count 0011) - test completely disabling module autoloading" + echo "0012 x $(get_test_count 0012) - test /proc/modules address visibility under CAP_SYSLOG" + echo "0013 x $(get_test_count 0013) - test /sys/module/*/sections/* visibility under CAP_SYSLOG" } usage()