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SubjectRe: [PATCH v1 2/3] evm: skip integrity verification for newly created files
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On Fri, 2014-07-11 at 14:47 +0300, Dmitry Kasatkin wrote: 
> Newly created files do not get initial security.ima until close.
> Setting xattr value before close fails because EVM fails to verify
> integrity due to missing xattrs. Following is the example when it
> happens:
> fd = open("foo", O_CREAT | O_WRONLY, 0644);
> setxattr("foo", "security.SMACK64", value, sizeof(value), 0);
> close(fd);
>
> This patch skips integrity verification if IMA_NEW_FILE flag is set.

Right, unless the LSM initially created the security xattr at
d_instantiate(), security.evm will not have been created.

Mimi

>
> Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
> ---
> security/integrity/evm/evm_main.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
> index 3bcb80d..682e640 100644
> --- a/security/integrity/evm/evm_main.c
> +++ b/security/integrity/evm/evm_main.c
> @@ -248,10 +248,14 @@ EXPORT_SYMBOL_GPL(evm_verifyxattr);
> static enum integrity_status evm_verify_current_integrity(struct dentry *dentry)
> {
> struct inode *inode = dentry->d_inode;
> + struct integrity_iint_cache *iint;
>
> if (!evm_initialized || !S_ISREG(inode->i_mode) || evm_fixmode)
> return 0;
> - return evm_verify_hmac(dentry, NULL, NULL, 0, NULL);
> + iint = integrity_iint_find(inode);
> + if (iint && (iint->flags & IMA_NEW_FILE))
> + return 0;
> + return evm_verify_hmac(dentry, NULL, NULL, 0, iint);
> }
>
> /*




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