diff options
author | Daniel Borkmann <daniel@iogearbox.net> | 2023-12-20 16:38:05 +0300 |
---|---|---|
committer | Daniel Borkmann <daniel@iogearbox.net> | 2023-12-21 16:24:30 +0300 |
commit | b08c8fc0411dce0fc44b78ce4d67f1b67c35c196 (patch) | |
tree | 4939fe5cb33dab0c69fcb62808f63cc982ce6d7b | |
parent | fc3a5534e2a8855427403113cbeb54af5837bbe0 (diff) | |
download | linux-b08c8fc0411dce0fc44b78ce4d67f1b67c35c196.tar.xz |
bpf: Re-support uid and gid when mounting bpffs
For a clean, conflict-free revert of the token-related patches in commit
d17aff807f84 ("Revert BPF token-related functionality"), the bpf fs commit
750e785796bb ("bpf: Support uid and gid when mounting bpffs") was undone
temporarily as well.
This patch manually re-adds the functionality from the original one back
in 750e785796bb, no other functional changes intended.
Testing:
# mount -t bpf -o uid=65534,gid=65534 bpffs ./foo
# ls -la . | grep foo
drwxrwxrwt 2 nobody nogroup 0 Dec 20 13:16 foo
# mount -t bpf
bpffs on /root/foo type bpf (rw,relatime,uid=65534,gid=65534)
Also, passing invalid arguments for uid/gid are properly rejected as expected.
Fixes: d17aff807f84 ("Revert BPF token-related functionality")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Cc: Jie Jiang <jiejiang@chromium.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/bpf/20231220133805.20953-1-daniel@iogearbox.net
-rw-r--r-- | kernel/bpf/inode.c | 53 |
1 files changed, 51 insertions, 2 deletions
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c index 1aafb2ff2e95..41e0a55c35f5 100644 --- a/kernel/bpf/inode.c +++ b/kernel/bpf/inode.c @@ -599,8 +599,15 @@ EXPORT_SYMBOL(bpf_prog_get_type_path); */ static int bpf_show_options(struct seq_file *m, struct dentry *root) { - umode_t mode = d_inode(root)->i_mode & S_IALLUGO & ~S_ISVTX; - + struct inode *inode = d_inode(root); + umode_t mode = inode->i_mode & S_IALLUGO & ~S_ISVTX; + + 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)); if (mode != S_IRWXUGO) seq_printf(m, ",mode=%o", mode); return 0; @@ -625,15 +632,21 @@ static const struct super_operations bpf_super_ops = { }; enum { + OPT_UID, + OPT_GID, OPT_MODE, }; static const struct fs_parameter_spec bpf_fs_parameters[] = { + fsparam_u32 ("uid", OPT_UID), + fsparam_u32 ("gid", OPT_GID), fsparam_u32oct ("mode", OPT_MODE), {} }; struct bpf_mount_opts { + kuid_t uid; + kgid_t gid; umode_t mode; }; @@ -641,6 +654,8 @@ static int bpf_parse_param(struct fs_context *fc, struct fs_parameter *param) { struct bpf_mount_opts *opts = fc->fs_private; struct fs_parse_result result; + kuid_t uid; + kgid_t gid; int opt; opt = fs_parse(fc, bpf_fs_parameters, param, &result); @@ -662,12 +677,42 @@ 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; } return 0; +bad_value: + return invalfc(fc, "Bad value for '%s'", param->key); } struct bpf_preload_ops *bpf_preload_ops; @@ -750,6 +795,8 @@ 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); @@ -785,6 +832,8 @@ static int bpf_init_fs_context(struct fs_context *fc) return -ENOMEM; opts->mode = S_IRWXUGO; + opts->uid = current_fsuid(); + opts->gid = current_fsgid(); fc->fs_private = opts; fc->ops = &bpf_context_ops; |