On 4/28/2025 8:55 AM, Stephen Smalley wrote: > Update the security_inode_listsecurity() interface to allow > use of the xattr_list_one() helper and update the hook > implementations. > > Link: https://lore.kernel.org/selinux/20250424152822.2719-1-stephen.smalley.work@xxxxxxxxx/ > > Signed-off-by: Stephen Smalley <stephen.smalley.work@xxxxxxxxx> > --- > This patch is relative to the one linked above, which in theory is on > vfs.fixes but doesn't appear to have been pushed when I looked. > > fs/nfs/nfs4proc.c | 9 +++++---- > fs/xattr.c | 20 ++++++++------------ > include/linux/lsm_hook_defs.h | 4 ++-- > include/linux/security.h | 5 +++-- > net/socket.c | 8 +------- > security/security.c | 16 ++++++++-------- > security/selinux/hooks.c | 10 +++------- > security/smack/smack_lsm.c | 13 ++++--------- > 8 files changed, 34 insertions(+), 51 deletions(-) > > diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c > index 970f28dbf253..a1d7cb0acb5e 100644 > --- a/fs/nfs/nfs4proc.c > +++ b/fs/nfs/nfs4proc.c > @@ -8023,12 +8023,13 @@ static int nfs4_xattr_get_nfs4_label(const struct xattr_handler *handler, > static ssize_t > nfs4_listxattr_nfs4_label(struct inode *inode, char *list, size_t list_len) > { > - int len = 0; > + ssize_t len = 0; > + int err; > > if (nfs_server_capable(inode, NFS_CAP_SECURITY_LABEL)) { > - len = security_inode_listsecurity(inode, list, list_len); > - if (len >= 0 && list_len && len > list_len) > - return -ERANGE; > + err = security_inode_listsecurity(inode, &list, &len); > + if (err) > + len = err; > } > return len; > } > diff --git a/fs/xattr.c b/fs/xattr.c > index 2fc314b27120..fdd2f387bfd5 100644 > --- a/fs/xattr.c > +++ b/fs/xattr.c > @@ -492,9 +492,12 @@ vfs_listxattr(struct dentry *dentry, char *list, size_t size) > if (inode->i_op->listxattr) { > error = inode->i_op->listxattr(dentry, list, size); > } else { > - error = security_inode_listsecurity(inode, list, size); > - if (size && error > size) > - error = -ERANGE; > + char *buffer = list; > + ssize_t len = 0; > + > + error = security_inode_listsecurity(inode, &buffer, &len); > + if (!error) > + error = len; > } > return error; > } > @@ -1469,17 +1472,10 @@ ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, > if (err) > return err; > > - err = security_inode_listsecurity(inode, buffer, remaining_size); > - if (err < 0) > + err = security_inode_listsecurity(inode, &buffer, &remaining_size); > + if (err) > return err; > > - if (buffer) { > - if (remaining_size < err) > - return -ERANGE; > - buffer += err; > - } > - remaining_size -= err; > - > read_lock(&xattrs->lock); > for (rbp = rb_first(&xattrs->rb_root); rbp; rbp = rb_next(rbp)) { > xattr = rb_entry(rbp, struct simple_xattr, rb_node); > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h > index bf3bbac4e02a..3c3919dcdebc 100644 > --- a/include/linux/lsm_hook_defs.h > +++ b/include/linux/lsm_hook_defs.h > @@ -174,8 +174,8 @@ LSM_HOOK(int, -EOPNOTSUPP, inode_getsecurity, struct mnt_idmap *idmap, > struct inode *inode, const char *name, void **buffer, bool alloc) > LSM_HOOK(int, -EOPNOTSUPP, inode_setsecurity, struct inode *inode, > const char *name, const void *value, size_t size, int flags) > -LSM_HOOK(int, 0, inode_listsecurity, struct inode *inode, char *buffer, > - size_t buffer_size) > +LSM_HOOK(int, 0, inode_listsecurity, struct inode *inode, char **buffer, > + ssize_t *remaining_size) How about "rem", "rsize" or some other name instead of the overly long "remaining_size_"? > LSM_HOOK(void, LSM_RET_VOID, inode_getlsmprop, struct inode *inode, > struct lsm_prop *prop) > LSM_HOOK(int, 0, inode_copy_up, struct dentry *src, struct cred **new) > diff --git a/include/linux/security.h b/include/linux/security.h > index cc9b54d95d22..0efc6a0ab56d 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -457,7 +457,7 @@ int security_inode_getsecurity(struct mnt_idmap *idmap, > struct inode *inode, const char *name, > void **buffer, bool alloc); > int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags); > -int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size); > +int security_inode_listsecurity(struct inode *inode, char **buffer, ssize_t *remaining_size); > void security_inode_getlsmprop(struct inode *inode, struct lsm_prop *prop); > int security_inode_copy_up(struct dentry *src, struct cred **new); > int security_inode_copy_up_xattr(struct dentry *src, const char *name); > @@ -1077,7 +1077,8 @@ static inline int security_inode_setsecurity(struct inode *inode, const char *na > return -EOPNOTSUPP; > } > > -static inline int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size) > +static inline int security_inode_listsecurity(struct inode *inode, > + char **buffer, ssize_t *remaining_size) > { > return 0; > } > diff --git a/net/socket.c b/net/socket.c > index 9a0e720f0859..52e3670dc89b 100644 > --- a/net/socket.c > +++ b/net/socket.c > @@ -562,15 +562,9 @@ static ssize_t sockfs_listxattr(struct dentry *dentry, char *buffer, > ssize_t len; > ssize_t used = 0; > > - len = security_inode_listsecurity(d_inode(dentry), buffer, size); > + len = security_inode_listsecurity(d_inode(dentry), &buffer, &used); > if (len < 0) > return len; > - used += len; > - if (buffer) { > - if (size < used) > - return -ERANGE; > - buffer += len; > - } > > len = (XATTR_NAME_SOCKPROTONAME_LEN + 1); > used += len; > diff --git a/security/security.c b/security/security.c > index fb57e8fddd91..3985d040d5a9 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -2710,22 +2710,22 @@ int security_inode_setsecurity(struct inode *inode, const char *name, > /** > * security_inode_listsecurity() - List the xattr security label names > * @inode: inode > - * @buffer: buffer > - * @buffer_size: size of buffer > + * @buffer: pointer to buffer > + * @remaining_size: pointer to remaining size of buffer > * > * Copy the extended attribute names for the security labels associated with > - * @inode into @buffer. The maximum size of @buffer is specified by > - * @buffer_size. @buffer may be NULL to request the size of the buffer > - * required. > + * @inode into *(@buffer). The remaining size of @buffer is specified by > + * *(@remaining_size). *(@buffer) may be NULL to request the size of the > + * buffer required. Updates *(@buffer) and *(@remaining_size). > * > - * Return: Returns number of bytes used/required on success. > + * Return: Returns 0 on success, or -errno on failure. > */ > int security_inode_listsecurity(struct inode *inode, > - char *buffer, size_t buffer_size) > + char **buffer, ssize_t *remaining_size) > { > if (unlikely(IS_PRIVATE(inode))) > return 0; > - return call_int_hook(inode_listsecurity, inode, buffer, buffer_size); > + return call_int_hook(inode_listsecurity, inode, buffer, remaining_size); > } > EXPORT_SYMBOL(security_inode_listsecurity); > > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > index b8115df536ab..e6c98ebbf7bc 100644 > --- a/security/selinux/hooks.c > +++ b/security/selinux/hooks.c > @@ -3612,16 +3612,12 @@ static int selinux_inode_setsecurity(struct inode *inode, const char *name, > return 0; > } > > -static int selinux_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size) > +static int selinux_inode_listsecurity(struct inode *inode, char **buffer, > + ssize_t *remaining_size) > { > - const int len = sizeof(XATTR_NAME_SELINUX); > - > if (!selinux_initialized()) > return 0; > - > - if (buffer && len <= buffer_size) > - memcpy(buffer, XATTR_NAME_SELINUX, len); > - return len; > + return xattr_list_one(buffer, remaining_size, XATTR_NAME_SELINUX); > } > > static void selinux_inode_getlsmprop(struct inode *inode, struct lsm_prop *prop) > diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c > index 99833168604e..3f7ac865532e 100644 > --- a/security/smack/smack_lsm.c > +++ b/security/smack/smack_lsm.c > @@ -1619,17 +1619,12 @@ static int smack_inode_getsecurity(struct mnt_idmap *idmap, > * smack_inode_listsecurity - list the Smack attributes > * @inode: the object > * @buffer: where they go > - * @buffer_size: size of buffer > + * @remaining_size: size of buffer > */ > -static int smack_inode_listsecurity(struct inode *inode, char *buffer, > - size_t buffer_size) > +static int smack_inode_listsecurity(struct inode *inode, char **buffer, > + ssize_t *remaining_size) > { > - int len = sizeof(XATTR_NAME_SMACK); > - > - if (buffer != NULL && len <= buffer_size) > - memcpy(buffer, XATTR_NAME_SMACK, len); > - > - return len; > + return xattr_list_one(buffer, remaining_size, XATTR_NAME_SMACK); > } > > /**
