From 420a62dde6ebca7bc22e6c57c9cb25d7967ff1ea Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Tue, 10 Oct 2023 14:17:59 +0300 Subject: ovl: Move xattr support to new xattrs.c file This moves the code from super.c and inode.c, and makes ovl_xattr_get/set() static. This is in preparation for doing more work on xattrs support. Signed-off-by: Alexander Larsson Reviewed-by: Amir Goldstein Signed-off-by: Amir Goldstein --- fs/overlayfs/Makefile | 2 +- fs/overlayfs/inode.c | 122 ----------------------------- fs/overlayfs/overlayfs.h | 18 ++--- fs/overlayfs/super.c | 65 +--------------- fs/overlayfs/xattrs.c | 196 +++++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 207 insertions(+), 196 deletions(-) create mode 100644 fs/overlayfs/xattrs.c (limited to 'fs/overlayfs') diff --git a/fs/overlayfs/Makefile b/fs/overlayfs/Makefile index 4e173d56b11f..5648954f8588 100644 --- a/fs/overlayfs/Makefile +++ b/fs/overlayfs/Makefile @@ -6,4 +6,4 @@ obj-$(CONFIG_OVERLAY_FS) += overlay.o overlay-objs := super.o namei.o util.o inode.o file.o dir.o readdir.o \ - copy_up.o export.o params.o + copy_up.o export.o params.o xattrs.o diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 9e9192aa6e07..345b8f161ca4 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -339,128 +339,6 @@ static const char *ovl_get_link(struct dentry *dentry, return p; } -bool ovl_is_private_xattr(struct super_block *sb, const char *name) -{ - struct ovl_fs *ofs = OVL_FS(sb); - - if (ofs->config.userxattr) - return strncmp(name, OVL_XATTR_USER_PREFIX, - sizeof(OVL_XATTR_USER_PREFIX) - 1) == 0; - else - return strncmp(name, OVL_XATTR_TRUSTED_PREFIX, - sizeof(OVL_XATTR_TRUSTED_PREFIX) - 1) == 0; -} - -int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, - const void *value, size_t size, int flags) -{ - int err; - struct ovl_fs *ofs = OVL_FS(dentry->d_sb); - struct dentry *upperdentry = ovl_i_dentry_upper(inode); - struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry); - struct path realpath; - const struct cred *old_cred; - - if (!value && !upperdentry) { - ovl_path_lower(dentry, &realpath); - old_cred = ovl_override_creds(dentry->d_sb); - err = vfs_getxattr(mnt_idmap(realpath.mnt), realdentry, name, NULL, 0); - revert_creds(old_cred); - if (err < 0) - goto out; - } - - if (!upperdentry) { - err = ovl_copy_up(dentry); - if (err) - goto out; - - realdentry = ovl_dentry_upper(dentry); - } - - err = ovl_want_write(dentry); - if (err) - goto out; - - old_cred = ovl_override_creds(dentry->d_sb); - if (value) { - err = ovl_do_setxattr(ofs, realdentry, name, value, size, - flags); - } else { - WARN_ON(flags != XATTR_REPLACE); - err = ovl_do_removexattr(ofs, realdentry, name); - } - revert_creds(old_cred); - ovl_drop_write(dentry); - - /* copy c/mtime */ - ovl_copyattr(inode); -out: - return err; -} - -int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, - void *value, size_t size) -{ - ssize_t res; - const struct cred *old_cred; - struct path realpath; - - ovl_i_path_real(inode, &realpath); - old_cred = ovl_override_creds(dentry->d_sb); - res = vfs_getxattr(mnt_idmap(realpath.mnt), realpath.dentry, name, value, size); - revert_creds(old_cred); - return res; -} - -static bool ovl_can_list(struct super_block *sb, const char *s) -{ - /* Never list private (.overlay) */ - if (ovl_is_private_xattr(sb, s)) - return false; - - /* List all non-trusted xattrs */ - if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0) - return true; - - /* list other trusted for superuser only */ - return ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN); -} - -ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) -{ - struct dentry *realdentry = ovl_dentry_real(dentry); - ssize_t res; - size_t len; - char *s; - const struct cred *old_cred; - - old_cred = ovl_override_creds(dentry->d_sb); - res = vfs_listxattr(realdentry, list, size); - revert_creds(old_cred); - if (res <= 0 || size == 0) - return res; - - /* filter out private xattrs */ - for (s = list, len = res; len;) { - size_t slen = strnlen(s, len) + 1; - - /* underlying fs providing us with an broken xattr list? */ - if (WARN_ON(slen > len)) - return -EIO; - - len -= slen; - if (!ovl_can_list(dentry->d_sb, s)) { - res -= slen; - memmove(s, s + slen, len); - } else { - s += slen; - } - } - - return res; -} - #ifdef CONFIG_FS_POSIX_ACL /* * Apply the idmapping of the layer to POSIX ACLs. The caller must pass a clone diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 26e4fc4e44c8..59ee6ba79ee8 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -699,17 +699,8 @@ int ovl_set_nlink_lower(struct dentry *dentry); unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry, struct dentry *upperdentry, unsigned int fallback); -int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry, - struct iattr *attr); -int ovl_getattr(struct mnt_idmap *idmap, const struct path *path, - struct kstat *stat, u32 request_mask, unsigned int flags); int ovl_permission(struct mnt_idmap *idmap, struct inode *inode, int mask); -int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, - const void *value, size_t size, int flags); -int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, - void *value, size_t size); -ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); #ifdef CONFIG_FS_POSIX_ACL struct posix_acl *do_ovl_get_acl(struct mnt_idmap *idmap, @@ -846,3 +837,12 @@ static inline bool ovl_force_readonly(struct ovl_fs *ofs) { return (!ovl_upper_mnt(ofs) || !ofs->workdir); } + +/* xattr.c */ + +const struct xattr_handler * const *ovl_xattr_handlers(struct ovl_fs *ofs); +int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry, + struct iattr *attr); +int ovl_getattr(struct mnt_idmap *idmap, const struct path *path, + struct kstat *stat, u32 request_mask, unsigned int flags); +ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 5476dbfef6e5..0a42a25656fa 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -445,68 +445,6 @@ static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) return ok; } -static int ovl_own_xattr_get(const struct xattr_handler *handler, - struct dentry *dentry, struct inode *inode, - const char *name, void *buffer, size_t size) -{ - return -EOPNOTSUPP; -} - -static int ovl_own_xattr_set(const struct xattr_handler *handler, - struct mnt_idmap *idmap, - struct dentry *dentry, struct inode *inode, - const char *name, const void *value, - size_t size, int flags) -{ - return -EOPNOTSUPP; -} - -static int ovl_other_xattr_get(const struct xattr_handler *handler, - struct dentry *dentry, struct inode *inode, - const char *name, void *buffer, size_t size) -{ - return ovl_xattr_get(dentry, inode, name, buffer, size); -} - -static int ovl_other_xattr_set(const struct xattr_handler *handler, - struct mnt_idmap *idmap, - struct dentry *dentry, struct inode *inode, - const char *name, const void *value, - size_t size, int flags) -{ - return ovl_xattr_set(dentry, inode, name, value, size, flags); -} - -static const struct xattr_handler ovl_own_trusted_xattr_handler = { - .prefix = OVL_XATTR_TRUSTED_PREFIX, - .get = ovl_own_xattr_get, - .set = ovl_own_xattr_set, -}; - -static const struct xattr_handler ovl_own_user_xattr_handler = { - .prefix = OVL_XATTR_USER_PREFIX, - .get = ovl_own_xattr_get, - .set = ovl_own_xattr_set, -}; - -static const struct xattr_handler ovl_other_xattr_handler = { - .prefix = "", /* catch all */ - .get = ovl_other_xattr_get, - .set = ovl_other_xattr_set, -}; - -static const struct xattr_handler * const ovl_trusted_xattr_handlers[] = { - &ovl_own_trusted_xattr_handler, - &ovl_other_xattr_handler, - NULL -}; - -static const struct xattr_handler * const ovl_user_xattr_handlers[] = { - &ovl_own_user_xattr_handler, - &ovl_other_xattr_handler, - NULL -}; - static int ovl_setup_trap(struct super_block *sb, struct dentry *dir, struct inode **ptrap, const char *name) { @@ -1501,8 +1439,7 @@ int ovl_fill_super(struct super_block *sb, struct fs_context *fc) cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); sb->s_magic = OVERLAYFS_SUPER_MAGIC; - sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers : - ovl_trusted_xattr_handlers; + sb->s_xattr = ovl_xattr_handlers(ofs); sb->s_fs_info = ofs; #ifdef CONFIG_FS_POSIX_ACL sb->s_flags |= SB_POSIXACL; diff --git a/fs/overlayfs/xattrs.c b/fs/overlayfs/xattrs.c new file mode 100644 index 000000000000..8e7e4ca62448 --- /dev/null +++ b/fs/overlayfs/xattrs.c @@ -0,0 +1,196 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include +#include +#include "overlayfs.h" + +bool ovl_is_private_xattr(struct super_block *sb, const char *name) +{ + struct ovl_fs *ofs = OVL_FS(sb); + + if (ofs->config.userxattr) + return strncmp(name, OVL_XATTR_USER_PREFIX, + sizeof(OVL_XATTR_USER_PREFIX) - 1) == 0; + else + return strncmp(name, OVL_XATTR_TRUSTED_PREFIX, + sizeof(OVL_XATTR_TRUSTED_PREFIX) - 1) == 0; +} + +static int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, + const void *value, size_t size, int flags) +{ + int err; + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + struct dentry *upperdentry = ovl_i_dentry_upper(inode); + struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry); + struct path realpath; + const struct cred *old_cred; + + if (!value && !upperdentry) { + ovl_path_lower(dentry, &realpath); + old_cred = ovl_override_creds(dentry->d_sb); + err = vfs_getxattr(mnt_idmap(realpath.mnt), realdentry, name, NULL, 0); + revert_creds(old_cred); + if (err < 0) + goto out; + } + + if (!upperdentry) { + err = ovl_copy_up(dentry); + if (err) + goto out; + + realdentry = ovl_dentry_upper(dentry); + } + + err = ovl_want_write(dentry); + if (err) + goto out; + + old_cred = ovl_override_creds(dentry->d_sb); + if (value) { + err = ovl_do_setxattr(ofs, realdentry, name, value, size, + flags); + } else { + WARN_ON(flags != XATTR_REPLACE); + err = ovl_do_removexattr(ofs, realdentry, name); + } + revert_creds(old_cred); + ovl_drop_write(dentry); + + /* copy c/mtime */ + ovl_copyattr(inode); +out: + return err; +} + +static int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, + void *value, size_t size) +{ + ssize_t res; + const struct cred *old_cred; + struct path realpath; + + ovl_i_path_real(inode, &realpath); + old_cred = ovl_override_creds(dentry->d_sb); + res = vfs_getxattr(mnt_idmap(realpath.mnt), realpath.dentry, name, value, size); + revert_creds(old_cred); + return res; +} + +static bool ovl_can_list(struct super_block *sb, const char *s) +{ + /* Never list private (.overlay) */ + if (ovl_is_private_xattr(sb, s)) + return false; + + /* List all non-trusted xattrs */ + if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0) + return true; + + /* list other trusted for superuser only */ + return ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN); +} + +ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) +{ + struct dentry *realdentry = ovl_dentry_real(dentry); + ssize_t res; + size_t len; + char *s; + const struct cred *old_cred; + + old_cred = ovl_override_creds(dentry->d_sb); + res = vfs_listxattr(realdentry, list, size); + revert_creds(old_cred); + if (res <= 0 || size == 0) + return res; + + /* filter out private xattrs */ + for (s = list, len = res; len;) { + size_t slen = strnlen(s, len) + 1; + + /* underlying fs providing us with an broken xattr list? */ + if (WARN_ON(slen > len)) + return -EIO; + + len -= slen; + if (!ovl_can_list(dentry->d_sb, s)) { + res -= slen; + memmove(s, s + slen, len); + } else { + s += slen; + } + } + + return res; +} + +static int ovl_own_xattr_get(const struct xattr_handler *handler, + struct dentry *dentry, struct inode *inode, + const char *name, void *buffer, size_t size) +{ + return -EOPNOTSUPP; +} + +static int ovl_own_xattr_set(const struct xattr_handler *handler, + struct mnt_idmap *idmap, + struct dentry *dentry, struct inode *inode, + const char *name, const void *value, + size_t size, int flags) +{ + return -EOPNOTSUPP; +} + +static int ovl_other_xattr_get(const struct xattr_handler *handler, + struct dentry *dentry, struct inode *inode, + const char *name, void *buffer, size_t size) +{ + return ovl_xattr_get(dentry, inode, name, buffer, size); +} + +static int ovl_other_xattr_set(const struct xattr_handler *handler, + struct mnt_idmap *idmap, + struct dentry *dentry, struct inode *inode, + const char *name, const void *value, + size_t size, int flags) +{ + return ovl_xattr_set(dentry, inode, name, value, size, flags); +} + +static const struct xattr_handler ovl_own_trusted_xattr_handler = { + .prefix = OVL_XATTR_TRUSTED_PREFIX, + .get = ovl_own_xattr_get, + .set = ovl_own_xattr_set, +}; + +static const struct xattr_handler ovl_own_user_xattr_handler = { + .prefix = OVL_XATTR_USER_PREFIX, + .get = ovl_own_xattr_get, + .set = ovl_own_xattr_set, +}; + +static const struct xattr_handler ovl_other_xattr_handler = { + .prefix = "", /* catch all */ + .get = ovl_other_xattr_get, + .set = ovl_other_xattr_set, +}; + +static const struct xattr_handler * const ovl_trusted_xattr_handlers[] = { + &ovl_own_trusted_xattr_handler, + &ovl_other_xattr_handler, + NULL +}; + +static const struct xattr_handler * const ovl_user_xattr_handlers[] = { + &ovl_own_user_xattr_handler, + &ovl_other_xattr_handler, + NULL +}; + +const struct xattr_handler * const *ovl_xattr_handlers(struct ovl_fs *ofs) +{ + return ofs->config.userxattr ? ovl_user_xattr_handlers : + ovl_trusted_xattr_handlers; +} + -- cgit