On Wed, 2025-01-22 at 18:24 +0100, Roberto Sassu wrote:
> From: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
>
> Commit 11c60f23ed13 ("integrity: Remove unused macro
> IMA_ACTION_RULE_FLAGS") removed the IMA_ACTION_RULE_FLAGS mask, due to it
> not being used after commit 0d73a55208e9 ("ima: re-introduce own integrity
> cache lock").
>
> However, it seems that the latter commit mistakenly used the wrong mask
> when moving the code from ima_inode_post_setattr() to process_measurement(). There
> is no mention in the commit message about this
> change and it looks quite important, since changing from IMA_ACTIONS_FLAGS
> (later renamed to IMA_NONACTION_FLAGS) to IMA_ACTION_RULE_FLAGS was done by
> commit 42a4c603198f0 ("ima: fix ima_inode_post_setattr").
Roberto, thank you for the detailed explanation. Could we summarize the problem as:
Commit 0d73a55208e9 ("ima: re-introduce own integrity cache lock") mistakenly
reverted the performance improvement introduced in commit 42a4c603198f0 ("ima: fix
ima_inode_post_setattr"). The unused bit mask was subsequently removed by commit
11c60f23ed13 ("integrity: Remove unused macro IMA_ACTION_RULE_FLAGS").
>
> Restore the original change of resetting only the policy-specific flags and
> not the new file status, but with new mask 0xfb000000 since the
> policy-specific flags changed meanwhile. Also rename IMA_ACTION_RULE_FLAGS
> to IMA_NONACTION_RULE_FLAGS, to be consistent with IMA_NONACTION_FLAGS.
Instead of restoring the bit mask that is used only once, consider inlining the
correct bit mask (e.g. IMA_NONACTION_FLAGS & ~IMA_NEW_FILE) and expanding the
existing comment.
>
> Cc: stable@xxxxxxxxxxxxxxx # v4.16.x
> Fixes: 11c60f23ed13 ("integrity: Remove unused macro IMA_ACTION_RULE_FLAGS")
Please update the Fixes tag to refer to commit 0d73a55208e9.
> Reviewed-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
> Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
> ---
> security/integrity/ima/ima.h | 1 +
> security/integrity/ima/ima_main.c | 2 +-
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index e1a3d1239bee..615900d4150d 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -141,6 +141,7 @@ struct ima_kexec_hdr {
>
> /* IMA iint policy rule cache flags */
> #define IMA_NONACTION_FLAGS 0xff000000
> +#define IMA_NONACTION_RULE_FLAGS 0xfb000000
> #define IMA_DIGSIG_REQUIRED 0x01000000
> #define IMA_PERMIT_DIRECTIO 0x02000000
> #define IMA_NEW_FILE 0x04000000
> diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> index 46adfd524dd8..7173dca20c23 100644
> --- a/security/integrity/ima/ima_main.c
> +++ b/security/integrity/ima/ima_main.c
> @@ -275,7 +275,7 @@ static int process_measurement(struct file *file, const struct
> cred *cred,
> /* reset appraisal flags if ima_inode_post_setattr was called */
Update the comment based on the original commit 42a4c603198f ("ima: fix
ima_inode_post_setattr") patch description.
thanks,
Mimi
> iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED |
> IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK |
> - IMA_NONACTION_FLAGS);
> + IMA_NONACTION_RULE_FLAGS);
> /*
> * Re-evaulate the file if either the xattr has changed or the
