4.15-stable review patch. If anyone has any objections, please let me know.
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From: Mimi Zohar zohar@linux.vnet.ibm.com
[ Upstream commit b7e27bc1d42e8e0cc58b602b529c25cd0071b336 ]
Custom policies can require file signatures based on LSM labels. These files are normally created and only afterwards labeled, requiring them to be signed.
Instead of requiring file signatures based on LSM labels, entire filesystems could require file signatures. In this case, we need the ability of writing new files without requiring file signatures.
The definition of a "new" file was originally defined as any file with a length of zero. Subsequent patches redefined a "new" file to be based on the FILE_CREATE open flag. By combining the open flag with a file size of zero, this patch relaxes the file signature requirement.
Fixes: 1ac202e978e1 ima: accept previously set IMA_NEW_FILE Signed-off-by: Mimi Zohar zohar@linux.vnet.ibm.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- security/integrity/ima/ima_appraise.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -223,7 +223,8 @@ int ima_appraise_measurement(enum ima_ho if (opened & FILE_CREATED) iint->flags |= IMA_NEW_FILE; if ((iint->flags & IMA_NEW_FILE) && - !(iint->flags & IMA_DIGSIG_REQUIRED)) + (!(iint->flags & IMA_DIGSIG_REQUIRED) || + (inode->i_size == 0))) status = INTEGRITY_PASS; goto out; }