From 6c8f980c75185f8ba897814363d21882f7453f53 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Fri, 22 Apr 2016 14:43:48 +0200 Subject: [PATCH] jfs: Clean up xattr name mapping Instead of stripping "os2." prefixes in __jfs_setxattr, make callers strip them, as __jfs_getxattr already does. With that change, use the same name mapping function in jfs_{get,set,remove}xattr. Signed-off-by: Andreas Gruenbacher Signed-off-by: Al Viro --- fs/jfs/xattr.c | 80 ++++++++++++++++++---------------------------------------- 1 file changed, 25 insertions(+), 55 deletions(-) diff --git a/fs/jfs/xattr.c b/fs/jfs/xattr.c index 5becc6a3ff8c..9cdf7dc4d5cb 100644 --- a/fs/jfs/xattr.c +++ b/fs/jfs/xattr.c @@ -86,6 +86,14 @@ struct ea_buffer { #define EA_MALLOC 0x0008 +/* + * Mapping of on-disk attribute names: for on-disk attribute names with an + * unknown prefix (not "system.", "user.", "security.", or "trusted."), the + * prefix "os2." is prepended. On the way back to disk, "os2." prefixes are + * stripped and we make sure that the remaining name does not start with one + * of the know prefixes. + */ + static int is_known_namespace(const char *name) { if (strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) && @@ -97,29 +105,19 @@ static int is_known_namespace(const char *name) return true; } -/* - * These three routines are used to recognize on-disk extended attributes - * that are in a recognized namespace. If the attribute is not recognized, - * "os2." is prepended to the name - */ -static int is_os2_xattr(struct jfs_ea *ea) -{ - return !is_known_namespace(ea->name); -} - static inline int name_size(struct jfs_ea *ea) { - if (is_os2_xattr(ea)) - return ea->namelen + XATTR_OS2_PREFIX_LEN; - else + if (is_known_namespace(ea->name)) return ea->namelen; + else + return ea->namelen + XATTR_OS2_PREFIX_LEN; } static inline int copy_name(char *buffer, struct jfs_ea *ea) { int len = ea->namelen; - if (is_os2_xattr(ea)) { + if (!is_known_namespace(ea->name)) { memcpy(buffer, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN); buffer += XATTR_OS2_PREFIX_LEN; len += XATTR_OS2_PREFIX_LEN; @@ -669,29 +667,24 @@ static int ea_put(tid_t tid, struct inode *inode, struct ea_buffer *ea_buf, * Most of the permission checking is done by xattr_permission in the vfs. * We also need to verify that this is a namespace that we recognize. */ -static int can_set_xattr(struct inode *inode, const char *name, - const void *value, size_t value_len) +static bool map_name_to_disk(const char **name) { - if (!strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN)) { + if (!strncmp(*name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN)) { /* * This makes sure that we aren't trying to set an * attribute in a different namespace by prefixing it * with "os2." */ - if (is_known_namespace(name + XATTR_OS2_PREFIX_LEN)) - return -EOPNOTSUPP; - return 0; + if (is_known_namespace(*name + XATTR_OS2_PREFIX_LEN)) + return false; + *name += XATTR_OS2_PREFIX_LEN; + return true; } /* * Don't allow setting an attribute in an unknown namespace. */ - if (strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) && - strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) && - strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) - return -EOPNOTSUPP; - - return 0; + return is_known_namespace(*name); } int __jfs_setxattr(tid_t tid, struct inode *inode, const char *name, @@ -704,21 +697,10 @@ int __jfs_setxattr(tid_t tid, struct inode *inode, const char *name, int xattr_size; int new_size; int namelen = strlen(name); - char *os2name = NULL; int found = 0; int rc; int length; - if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) { - os2name = kmalloc(namelen - XATTR_OS2_PREFIX_LEN + 1, - GFP_KERNEL); - if (!os2name) - return -ENOMEM; - strcpy(os2name, name + XATTR_OS2_PREFIX_LEN); - name = os2name; - namelen -= XATTR_OS2_PREFIX_LEN; - } - down_write(&JFS_IP(inode)->xattr_sem); xattr_size = ea_get(inode, &ea_buf, 0); @@ -841,8 +823,6 @@ int __jfs_setxattr(tid_t tid, struct inode *inode, const char *name, out: up_write(&JFS_IP(inode)->xattr_sem); - kfree(os2name); - return rc; } @@ -862,8 +842,8 @@ int jfs_setxattr(struct dentry *dentry, const char *name, const void *value, if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) return generic_setxattr(dentry, name, value, value_len, flags); - if ((rc = can_set_xattr(inode, name, value, value_len))) - return rc; + if (!map_name_to_disk(&name)) + return -EOPNOTSUPP; if (value == NULL) { /* empty EA, do not remove */ value = ""; @@ -946,18 +926,8 @@ ssize_t jfs_getxattr(struct dentry *dentry, struct inode *inode, if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) return generic_getxattr(dentry, inode, name, data, buf_size); - if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) { - /* - * skip past "os2." prefix - */ - name += XATTR_OS2_PREFIX_LEN; - /* - * Don't allow retrieving properly prefixed attributes - * by prepending them with "os2." - */ - if (is_known_namespace(name)) - return -EOPNOTSUPP; - } + if (!map_name_to_disk(&name)) + return -EOPNOTSUPP; err = __jfs_getxattr(inode, name, data, buf_size); @@ -1042,8 +1012,8 @@ int jfs_removexattr(struct dentry *dentry, const char *name) if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) return generic_removexattr(dentry, name); - if ((rc = can_set_xattr(inode, name, NULL, 0))) - return rc; + if (!map_name_to_disk(&name)) + return -EOPNOTSUPP; tid = txBegin(inode->i_sb, 0); mutex_lock(&ji->commit_mutex); -- 2.11.0