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btrfs: don't accept bare namespace as a valid xattr
Due to insufficient check in btrfs_is_valid_xattr, this unexpectedly works: $ touch file $ setfattr -n user. -v 1 file $ getfattr -d file user.="1" ie. the missing attribute name after the namespace. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=94291 Reported-by: William Douglas <william.douglas@intel.com> CC: <stable@vger.kernel.org> # 2.6.29+ Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
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@ -364,22 +364,42 @@ const struct xattr_handler *btrfs_xattr_handlers[] = {
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/*
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* Check if the attribute is in a supported namespace.
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*
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* This applied after the check for the synthetic attributes in the system
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* This is applied after the check for the synthetic attributes in the system
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* namespace.
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*/
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static bool btrfs_is_valid_xattr(const char *name)
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static int btrfs_is_valid_xattr(const char *name)
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{
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return !strncmp(name, XATTR_SECURITY_PREFIX,
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XATTR_SECURITY_PREFIX_LEN) ||
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!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
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!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
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!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) ||
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!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN);
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int len = strlen(name);
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int prefixlen = 0;
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if (!strncmp(name, XATTR_SECURITY_PREFIX,
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XATTR_SECURITY_PREFIX_LEN))
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prefixlen = XATTR_SECURITY_PREFIX_LEN;
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else if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
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prefixlen = XATTR_SYSTEM_PREFIX_LEN;
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else if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
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prefixlen = XATTR_TRUSTED_PREFIX_LEN;
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else if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
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prefixlen = XATTR_USER_PREFIX_LEN;
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else if (!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN))
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prefixlen = XATTR_BTRFS_PREFIX_LEN;
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else
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return -EOPNOTSUPP;
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/*
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* The name cannot consist of just prefix
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*/
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if (len <= prefixlen)
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return -EINVAL;
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return 0;
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}
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ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
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void *buffer, size_t size)
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{
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int ret;
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/*
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* If this is a request for a synthetic attribute in the system.*
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* namespace use the generic infrastructure to resolve a handler
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@ -388,8 +408,9 @@ ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
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if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
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return generic_getxattr(dentry, name, buffer, size);
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if (!btrfs_is_valid_xattr(name))
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return -EOPNOTSUPP;
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ret = btrfs_is_valid_xattr(name);
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if (ret)
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return ret;
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return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
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}
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@ -397,6 +418,7 @@ int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
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size_t size, int flags)
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{
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struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
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int ret;
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/*
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* The permission on security.* and system.* is not checked
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@ -413,8 +435,9 @@ int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
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if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
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return generic_setxattr(dentry, name, value, size, flags);
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if (!btrfs_is_valid_xattr(name))
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return -EOPNOTSUPP;
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ret = btrfs_is_valid_xattr(name);
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if (ret)
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return ret;
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if (!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN))
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return btrfs_set_prop(dentry->d_inode, name,
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@ -430,6 +453,7 @@ int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
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int btrfs_removexattr(struct dentry *dentry, const char *name)
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{
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struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root;
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int ret;
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/*
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* The permission on security.* and system.* is not checked
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@ -446,8 +470,9 @@ int btrfs_removexattr(struct dentry *dentry, const char *name)
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if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
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return generic_removexattr(dentry, name);
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if (!btrfs_is_valid_xattr(name))
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return -EOPNOTSUPP;
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ret = btrfs_is_valid_xattr(name);
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if (ret)
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return ret;
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if (!strncmp(name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN))
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return btrfs_set_prop(dentry->d_inode, name,
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