4.9-stable review patch. If anyone has any objections, please let me know.
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From: Mimi Zohar zohar@linux.vnet.ibm.com
commit f5acb3dcba1ffb7f0b8cbb9dba61500eea5d610b upstream.
Userspace applications have been modified to write security xattrs, but they are not context aware. In the case of security.ima, the security xattr can be either a file hash or a file signature. Permitting writing one, but not the other requires the application to be context aware.
In addition, userspace applications might write files to a staging area, which might not be in policy, and then change some file metadata (eg. owner) making it in policy. As a result, these files are not labeled properly.
This reverts commit c68ed80c97d9720f51ef31fe91560fdd1e121533, which prevents writing file hashes as security.ima xattrs.
Requested-by: Patrick Ohly patrick.ohly@intel.com Cc: Dmitry Kasatkin dmitry.kasatkin@gmail.com Signed-off-by: Mimi Zohar zohar@linux.vnet.ibm.com Cc: Mike Rapoport rppt@linux.vnet.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- security/integrity/ima/ima_appraise.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)
--- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -389,14 +389,10 @@ int ima_inode_setxattr(struct dentry *de result = ima_protect_xattr(dentry, xattr_name, xattr_value, xattr_value_len); if (result == 1) { - bool digsig; - if (!xattr_value_len || (xvalue->type >= IMA_XATTR_LAST)) return -EINVAL; - digsig = (xvalue->type == EVM_IMA_XATTR_DIGSIG); - if (!digsig && (ima_appraise & IMA_APPRAISE_ENFORCE)) - return -EPERM; - ima_reset_appraise_flags(d_backing_inode(dentry), digsig); + ima_reset_appraise_flags(d_backing_inode(dentry), + (xvalue->type == EVM_IMA_XATTR_DIGSIG) ? 1 : 0); result = 0; } return result;