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From: Konsta Karsisto <konsta.karsisto@gmail.com>
To: Tyler Hicks <tyhicks@linux.microsoft.com>,
	linux-integrity@vger.kernel.org
Cc: Mimi Zohar <zohar@linux.ibm.com>,
	Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
	James Morris <jmorris@namei.org>,
	"Serge E . Hallyn" <serge@hallyn.com>,
	Lakshmi Ramasubramanian <nramas@linux.microsoft.com>,
	Prakhar Srivastava <prsriva02@gmail.com>,
	linux-kernel@vger.kernel.org,
	linux-security-module@vger.kernel.org
Subject: Re: [PATCH v3 08/12] ima: Shallow copy the args_p member of ima_rule_entry.lsm elements
Date: Fri, 17 Jul 2020 18:35:03 +0300	[thread overview]
Message-ID: <CAAEqDhD-wCGY7ykjSsNgCri4ykWPi9cP3j1zoQPWddB4r92Kqw@mail.gmail.com> (raw)
In-Reply-To: <20200709061911.954326-9-tyhicks@linux.microsoft.com>

Hi,

Found one glitch with this change, see below:

On Thu, Jul 9, 2020 at 9:22 AM Tyler Hicks <tyhicks@linux.microsoft.com> wrote:
>
> The args_p member is a simple string that is allocated by
> ima_rule_init(). Shallow copy it like other non-LSM references in
> ima_rule_entry structs.
>
> There are no longer any necessary error path cleanups to do in
> ima_lsm_copy_rule().
>
> Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
> ---
>
> * v3
>   - No change
> * v2
>   - Adjusted context to account for ima_lsm_copy_rule() directly calling
>     ima_lsm_free_rule() and the lack of explicit reference ownership
>     transfers
>   - Added comment to ima_lsm_copy_rule() to document the args_p
>     reference ownership transfer
>
>  security/integrity/ima/ima_policy.c | 16 +++++++---------
>  1 file changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index 9842e2e0bc6d..b02e1ffd10c9 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -300,10 +300,13 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
>                         continue;
>
>                 nentry->lsm[i].type = entry->lsm[i].type;
> -               nentry->lsm[i].args_p = kstrdup(entry->lsm[i].args_p,
> -                                               GFP_KERNEL);
> -               if (!nentry->lsm[i].args_p)
> -                       goto out_err;
> +               nentry->lsm[i].args_p = entry->lsm[i].args_p;
> +               /*
> +                * Remove the reference from entry so that the associated
> +                * memory will not be freed during a later call to
> +                * ima_lsm_free_rule(entry).
> +                */
> +               entry->lsm[i].args_p = NULL;

This assignment necessitates a change in the code below...

>                 security_filter_rule_init(nentry->lsm[i].type,
>                                           Audit_equal,
> @@ -314,11 +317,6 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
>                                 (char *)entry->lsm[i].args_p);

... you should refer to nentry->lsm[i].args_p here!

Other than that,

Reviewed-by: Konsta Karsisto <konsta.karsisto@gmail.com>


Konsta

>         }
>         return nentry;
> -
> -out_err:
> -       ima_lsm_free_rule(nentry);
> -       kfree(nentry);
> -       return NULL;
>  }
>
>  static int ima_lsm_update_rule(struct ima_rule_entry *entry)
> --
> 2.25.1
>

  reply	other threads:[~2020-07-17 15:35 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-09  6:18 [PATCH v3 00/12] ima: Fix rule parsing bugs and extend KEXEC_CMDLINE rule support Tyler Hicks
2020-07-09  6:18 ` Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 01/12] ima: Have the LSM free its audit rule Tyler Hicks
2020-07-17 19:20   ` Nayna
2020-07-17 19:24     ` Tyler Hicks
2020-07-19 11:02       ` Mimi Zohar
2020-07-09  6:19 ` [PATCH v3 02/12] ima: Free the entire rule when deleting a list of rules Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 03/12] ima: Free the entire rule if it fails to parse Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 04/12] ima: Fail rule parsing when buffer hook functions have an invalid action Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 05/12] ima: Fail rule parsing when the KEXEC_CMDLINE hook is combined with an invalid cond Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 06/12] ima: Fail rule parsing when the KEY_CHECK " Tyler Hicks
2020-07-17 18:56   ` Nayna
2020-07-17 19:18     ` Tyler Hicks
2020-07-17 23:39       ` Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 07/12] ima: Fail rule parsing when appraise_flag=blacklist is unsupportable Tyler Hicks
2020-07-16 18:14   ` Mimi Zohar
2020-07-16 18:20     ` Tyler Hicks
     [not found]   ` <76d2b27b-3b59-1852-046a-b1718c62b167@linux.vnet.ibm.com>
2020-07-17 18:11     ` Tyler Hicks
2020-07-20 17:02       ` Nayna
2020-07-09  6:19 ` [PATCH v3 08/12] ima: Shallow copy the args_p member of ima_rule_entry.lsm elements Tyler Hicks
2020-07-17 15:35   ` Konsta Karsisto [this message]
2020-07-17 16:51     ` Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 09/12] ima: Use correct type for " Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 10/12] ima: Move comprehensive rule validation checks out of the token parser Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 11/12] ima: Use the common function to detect LSM conditionals in a rule Tyler Hicks
2020-07-09  6:19 ` [PATCH v3 12/12] ima: Support additional conditionals in the KEXEC_CMDLINE hook function Tyler Hicks
2020-07-09  6:19   ` Tyler Hicks
2020-07-17  4:31 ` [PATCH v3 00/12] ima: Fix rule parsing bugs and extend KEXEC_CMDLINE rule support Mimi Zohar
2020-07-17  4:34   ` Tyler Hicks
2020-07-17  4:34     ` Tyler Hicks
2020-07-20 21:38 ` Mimi Zohar
2020-07-20 21:38   ` Mimi Zohar

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