Revert BPF token-related functionality

This patch includes the following revert (one  conflicting BPF FS
patch and three token patch sets, represented by merge commits):
  - revert 0f5d5454c723 "Merge branch 'bpf-fs-mount-options-parsing-follow-ups'";
  - revert 750e785796bb "bpf: Support uid and gid when mounting bpffs";
  - revert 733763285acf "Merge branch 'bpf-token-support-in-libbpf-s-bpf-object'";
  - revert c35919dcce28 "Merge branch 'bpf-token-and-bpf-fs-based-delegation'".

Link: https://lore.kernel.org/bpf/CAHk-=wg7JuFYwGy=GOMbRCtOL+jwSQsdUaBsRWkDVYbxipbM5A@mail.gmail.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

1 files changed, 16 insertions, 310 deletions

diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index 4383b3d13a55..1aafb2ff2e95 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -20,7 +20,6 @@
 #include <linux/filter.h>
 #include <linux/bpf.h>
 #include <linux/bpf_trace.h>
-#include <linux/kstrtox.h>
 #include "preload/bpf_preload.h"
 
 enum bpf_type {
@@ -99,9 +98,9 @@ static const struct inode_operations bpf_prog_iops = { };
 static const struct inode_operations bpf_map_iops  = { };
 static const struct inode_operations bpf_link_iops  = { };
 
-struct inode *bpf_get_inode(struct super_block *sb,
-			    const struct inode *dir,
-			    umode_t mode)
+static struct inode *bpf_get_inode(struct super_block *sb,
+				   const struct inode *dir,
+				   umode_t mode)
 {
 	struct inode *inode;
 
@@ -595,183 +594,15 @@ struct bpf_prog *bpf_prog_get_type_path(const char *name, enum bpf_prog_type typ
 }
 EXPORT_SYMBOL(bpf_prog_get_type_path);
 
-struct bpffs_btf_enums {
-	const struct btf *btf;
-	const struct btf_type *cmd_t;
-	const struct btf_type *map_t;
-	const struct btf_type *prog_t;
-	const struct btf_type *attach_t;
-};
-
-static int find_bpffs_btf_enums(struct bpffs_btf_enums *info)
-{
-	const struct btf *btf;
-	const struct btf_type *t;
-	const char *name;
-	int i, n;
-
-	memset(info, 0, sizeof(*info));
-
-	btf = bpf_get_btf_vmlinux();
-	if (IS_ERR(btf))
-		return PTR_ERR(btf);
-	if (!btf)
-		return -ENOENT;
-
-	info->btf = btf;
-
-	for (i = 1, n = btf_nr_types(btf); i < n; i++) {
-		t = btf_type_by_id(btf, i);
-		if (!btf_type_is_enum(t))
-			continue;
-
-		name = btf_name_by_offset(btf, t->name_off);
-		if (!name)
-			continue;
-
-		if (strcmp(name, "bpf_cmd") == 0)
-			info->cmd_t = t;
-		else if (strcmp(name, "bpf_map_type") == 0)
-			info->map_t = t;
-		else if (strcmp(name, "bpf_prog_type") == 0)
-			info->prog_t = t;
-		else if (strcmp(name, "bpf_attach_type") == 0)
-			info->attach_t = t;
-		else
-			continue;
-
-		if (info->cmd_t && info->map_t && info->prog_t && info->attach_t)
-			return 0;
-	}
-
-	return -ESRCH;
-}
-
-static bool find_btf_enum_const(const struct btf *btf, const struct btf_type *enum_t,
-				const char *prefix, const char *str, int *value)
-{
-	const struct btf_enum *e;
-	const char *name;
-	int i, n, pfx_len = strlen(prefix);
-
-	*value = 0;
-
-	if (!btf || !enum_t)
-		return false;
-
-	for (i = 0, n = btf_vlen(enum_t); i < n; i++) {
-		e = &btf_enum(enum_t)[i];
-
-		name = btf_name_by_offset(btf, e->name_off);
-		if (!name || strncasecmp(name, prefix, pfx_len) != 0)
-			continue;
-
-		/* match symbolic name case insensitive and ignoring prefix */
-		if (strcasecmp(name + pfx_len, str) == 0) {
-			*value = e->val;
-			return true;
-		}
-	}
-
-	return false;
-}
-
-static void seq_print_delegate_opts(struct seq_file *m,
-				    const char *opt_name,
-				    const struct btf *btf,
-				    const struct btf_type *enum_t,
-				    const char *prefix,
-				    u64 delegate_msk, u64 any_msk)
-{
-	const struct btf_enum *e;
-	bool first = true;
-	const char *name;
-	u64 msk;
-	int i, n, pfx_len = strlen(prefix);
-
-	delegate_msk &= any_msk; /* clear unknown bits */
-
-	if (delegate_msk == 0)
-		return;
-
-	seq_printf(m, ",%s", opt_name);
-	if (delegate_msk == any_msk) {
-		seq_printf(m, "=any");
-		return;
-	}
-
-	if (btf && enum_t) {
-		for (i = 0, n = btf_vlen(enum_t); i < n; i++) {
-			e = &btf_enum(enum_t)[i];
-			name = btf_name_by_offset(btf, e->name_off);
-			if (!name || strncasecmp(name, prefix, pfx_len) != 0)
-				continue;
-			msk = 1ULL << e->val;
-			if (delegate_msk & msk) {
-				/* emit lower-case name without prefix */
-				seq_printf(m, "%c", first ? '=' : ':');
-				name += pfx_len;
-				while (*name) {
-					seq_printf(m, "%c", tolower(*name));
-					name++;
-				}
-
-				delegate_msk &= ~msk;
-				first = false;
-			}
-		}
-	}
-	if (delegate_msk)
-		seq_printf(m, "%c0x%llx", first ? '=' : ':', delegate_msk);
-}
-
 /*
  * Display the mount options in /proc/mounts.
  */
 static int bpf_show_options(struct seq_file *m, struct dentry *root)
 {
-	struct bpf_mount_opts *opts = root->d_sb->s_fs_info;
-	struct inode *inode = d_inode(root);
-	umode_t mode = inode->i_mode & S_IALLUGO & ~S_ISVTX;
-	u64 mask;
-
-	if (!uid_eq(inode->i_uid, GLOBAL_ROOT_UID))
-		seq_printf(m, ",uid=%u",
-			   from_kuid_munged(&init_user_ns, inode->i_uid));
-	if (!gid_eq(inode->i_gid, GLOBAL_ROOT_GID))
-		seq_printf(m, ",gid=%u",
-			   from_kgid_munged(&init_user_ns, inode->i_gid));
+	umode_t mode = d_inode(root)->i_mode & S_IALLUGO & ~S_ISVTX;
+
 	if (mode != S_IRWXUGO)
 		seq_printf(m, ",mode=%o", mode);
-
-	if (opts->delegate_cmds || opts->delegate_maps ||
-	    opts->delegate_progs || opts->delegate_attachs) {
-		struct bpffs_btf_enums info;
-
-		/* ignore errors, fallback to hex */
-		(void)find_bpffs_btf_enums(&info);
-
-		mask = (1ULL << __MAX_BPF_CMD) - 1;
-		seq_print_delegate_opts(m, "delegate_cmds",
-					info.btf, info.cmd_t, "BPF_",
-					opts->delegate_cmds, mask);
-
-		mask = (1ULL << __MAX_BPF_MAP_TYPE) - 1;
-		seq_print_delegate_opts(m, "delegate_maps",
-					info.btf, info.map_t, "BPF_MAP_TYPE_",
-					opts->delegate_maps, mask);
-
-		mask = (1ULL << __MAX_BPF_PROG_TYPE) - 1;
-		seq_print_delegate_opts(m, "delegate_progs",
-					info.btf, info.prog_t, "BPF_PROG_TYPE_",
-					opts->delegate_progs, mask);
-
-		mask = (1ULL << __MAX_BPF_ATTACH_TYPE) - 1;
-		seq_print_delegate_opts(m, "delegate_attachs",
-					info.btf, info.attach_t, "BPF_",
-					opts->delegate_attachs, mask);
-	}
-
 	return 0;
 }
 
@@ -786,7 +617,7 @@ static void bpf_free_inode(struct inode *inode)
 	free_inode_nonrcu(inode);
 }
 
-const struct super_operations bpf_super_ops = {
+static const struct super_operations bpf_super_ops = {
 	.statfs		= simple_statfs,
 	.drop_inode	= generic_delete_inode,
 	.show_options	= bpf_show_options,
@@ -794,33 +625,23 @@ const struct super_operations bpf_super_ops = {
 };
 
 enum {
-	OPT_UID,
-	OPT_GID,
 	OPT_MODE,
-	OPT_DELEGATE_CMDS,
-	OPT_DELEGATE_MAPS,
-	OPT_DELEGATE_PROGS,
-	OPT_DELEGATE_ATTACHS,
 };
 
 static const struct fs_parameter_spec bpf_fs_parameters[] = {
-	fsparam_u32	("uid",				OPT_UID),
-	fsparam_u32	("gid",				OPT_GID),
 	fsparam_u32oct	("mode",			OPT_MODE),
-	fsparam_string	("delegate_cmds",		OPT_DELEGATE_CMDS),
-	fsparam_string	("delegate_maps",		OPT_DELEGATE_MAPS),
-	fsparam_string	("delegate_progs",		OPT_DELEGATE_PROGS),
-	fsparam_string	("delegate_attachs",		OPT_DELEGATE_ATTACHS),
 	{}
 };
 
+struct bpf_mount_opts {
+	umode_t mode;
+};
+
 static int bpf_parse_param(struct fs_context *fc, struct fs_parameter *param)
 {
-	struct bpf_mount_opts *opts = fc->s_fs_info;
+	struct bpf_mount_opts *opts = fc->fs_private;
 	struct fs_parse_result result;
-	kuid_t uid;
-	kgid_t gid;
-	int opt, err;
+	int opt;
 
 	opt = fs_parse(fc, bpf_fs_parameters, param, &result);
 	if (opt < 0) {
@@ -841,104 +662,12 @@ static int bpf_parse_param(struct fs_context *fc, struct fs_parameter *param)
 	}
 
 	switch (opt) {
-	case OPT_UID:
-		uid = make_kuid(current_user_ns(), result.uint_32);
-		if (!uid_valid(uid))
-			goto bad_value;
-
-		/*
-		 * The requested uid must be representable in the
-		 * filesystem's idmapping.
-		 */
-		if (!kuid_has_mapping(fc->user_ns, uid))
-			goto bad_value;
-
-		opts->uid = uid;
-		break;
-	case OPT_GID:
-		gid = make_kgid(current_user_ns(), result.uint_32);
-		if (!gid_valid(gid))
-			goto bad_value;
-
-		/*
-		 * The requested gid must be representable in the
-		 * filesystem's idmapping.
-		 */
-		if (!kgid_has_mapping(fc->user_ns, gid))
-			goto bad_value;
-
-		opts->gid = gid;
-		break;
 	case OPT_MODE:
 		opts->mode = result.uint_32 & S_IALLUGO;
 		break;
-	case OPT_DELEGATE_CMDS:
-	case OPT_DELEGATE_MAPS:
-	case OPT_DELEGATE_PROGS:
-	case OPT_DELEGATE_ATTACHS: {
-		struct bpffs_btf_enums info;
-		const struct btf_type *enum_t;
-		const char *enum_pfx;
-		u64 *delegate_msk, msk = 0;
-		char *p;
-		int val;
-
-		/* ignore errors, fallback to hex */
-		(void)find_bpffs_btf_enums(&info);
-
-		switch (opt) {
-		case OPT_DELEGATE_CMDS:
-			delegate_msk = &opts->delegate_cmds;
-			enum_t = info.cmd_t;
-			enum_pfx = "BPF_";
-			break;
-		case OPT_DELEGATE_MAPS:
-			delegate_msk = &opts->delegate_maps;
-			enum_t = info.map_t;
-			enum_pfx = "BPF_MAP_TYPE_";
-			break;
-		case OPT_DELEGATE_PROGS:
-			delegate_msk = &opts->delegate_progs;
-			enum_t = info.prog_t;
-			enum_pfx = "BPF_PROG_TYPE_";
-			break;
-		case OPT_DELEGATE_ATTACHS:
-			delegate_msk = &opts->delegate_attachs;
-			enum_t = info.attach_t;
-			enum_pfx = "BPF_";
-			break;
-		default:
-			return -EINVAL;
-		}
-
-		while ((p = strsep(&param->string, ":"))) {
-			if (strcmp(p, "any") == 0) {
-				msk |= ~0ULL;
-			} else if (find_btf_enum_const(info.btf, enum_t, enum_pfx, p, &val)) {
-				msk |= 1ULL << val;
-			} else {
-				err = kstrtou64(p, 0, &msk);
-				if (err)
-					return err;
-			}
-		}
-
-		/* Setting delegation mount options requires privileges */
-		if (msk && !capable(CAP_SYS_ADMIN))
-			return -EPERM;
-
-		*delegate_msk |= msk;
-		break;
-	}
-	default:
-		/* ignore unknown mount options */
-		break;
 	}
 
 	return 0;
-
-bad_value:
-	return invalfc(fc, "Bad value for '%s'", param->key);
 }
 
 struct bpf_preload_ops *bpf_preload_ops;
@@ -1010,14 +739,10 @@ out:
 static int bpf_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	static const struct tree_descr bpf_rfiles[] = { { "" } };
-	struct bpf_mount_opts *opts = sb->s_fs_info;
+	struct bpf_mount_opts *opts = fc->fs_private;
 	struct inode *inode;
 	int ret;
 
-	/* Mounting an instance of BPF FS requires privileges */
-	if (fc->user_ns != &init_user_ns && !capable(CAP_SYS_ADMIN))
-		return -EPERM;
-
 	ret = simple_fill_super(sb, BPF_FS_MAGIC, bpf_rfiles);
 	if (ret)
 		return ret;
@@ -1025,8 +750,6 @@ static int bpf_fill_super(struct super_block *sb, struct fs_context *fc)
 	sb->s_op = &bpf_super_ops;
 
 	inode = sb->s_root->d_inode;
-	inode->i_uid = opts->uid;
-	inode->i_gid = opts->gid;
 	inode->i_op = &bpf_dir_iops;
 	inode->i_mode &= ~S_IALLUGO;
 	populate_bpffs(sb->s_root);
@@ -1041,7 +764,7 @@ static int bpf_get_tree(struct fs_context *fc)
 
 static void bpf_free_fc(struct fs_context *fc)
 {
-	kfree(fc->s_fs_info);
+	kfree(fc->fs_private);
 }
 
 static const struct fs_context_operations bpf_context_ops = {
@@ -1062,35 +785,18 @@ static int bpf_init_fs_context(struct fs_context *fc)
 		return -ENOMEM;
 
 	opts->mode = S_IRWXUGO;
-	opts->uid = current_fsuid();
-	opts->gid = current_fsgid();
-
-	/* start out with no BPF token delegation enabled */
-	opts->delegate_cmds = 0;
-	opts->delegate_maps = 0;
-	opts->delegate_progs = 0;
-	opts->delegate_attachs = 0;
 
-	fc->s_fs_info = opts;
+	fc->fs_private = opts;
 	fc->ops = &bpf_context_ops;
 	return 0;
 }
 
-static void bpf_kill_super(struct super_block *sb)
-{
-	struct bpf_mount_opts *opts = sb->s_fs_info;
-
-	kill_litter_super(sb);
-	kfree(opts);
-}
-
 static struct file_system_type bpf_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "bpf",
 	.init_fs_context = bpf_init_fs_context,
 	.parameters	= bpf_fs_parameters,
-	.kill_sb	= bpf_kill_super,
-	.fs_flags	= FS_USERNS_MOUNT,
+	.kill_sb	= kill_litter_super,
 };
 
 static int __init bpf_init(void)