2022-11-02 17:03:32

by Roberto Sassu

Subject: [PATCH] ima: Fix memory leak in __ima_inode_hash()

From: Roberto Sassu <[email protected]>

Commit f3cc6b25dcc5 ("ima: always measure and audit files in policy") lets
measurement or audit happen even if the file digest cannot be calculated.

As a result, iint->ima_hash could have been allocated despite
ima_collect_measurement() returning an error.

Since ima_hash belongs to a temporary inode metadata structure, declared
at the beginning of __ima_inode_hash(), just add a kfree() call if
ima_collect_measurement() returns an error different from -ENOMEM (in that
case, ima_hash should not have been allocated).

Cc: [email protected]
Fixes: 280fe8367b0d ("ima: Always return a file measurement in ima_file_hash()")
Signed-off-by: Roberto Sassu <[email protected]>
---
security/integrity/ima/ima_main.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 040b03ddc1c7..4a207a3ef7ef 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -542,8 +542,13 @@ static int __ima_inode_hash(struct inode *inode, struct file *file, char *buf,

rc = ima_collect_measurement(&tmp_iint, file, NULL, 0,
ima_hash_algo, NULL);
- if (rc < 0)
+ if (rc < 0) {
+ /* ima_hash could be allocated in case of failure. */
+ if (rc != -ENOMEM)
+ kfree(tmp_iint.ima_hash);
+
return -EOPNOTSUPP;
+ }

iint = &tmp_iint;
mutex_lock(&iint->mutex);
--
2.25.1

2022-11-02 22:51:59

by Mimi Zohar

Subject: Re: [PATCH] ima: Fix memory leak in __ima_inode_hash()

Hi Roberto,

On Wed, 2022-11-02 at 17:30 +0100, Roberto Sassu wrote:
> From: Roberto Sassu <[email protected]>

Any chance you could fix your mailer?

>
> Commit f3cc6b25dcc5 ("ima: always measure and audit files in policy") lets
> measurement or audit happen even if the file digest cannot be calculated.
>
> As a result, iint->ima_hash could have been allocated despite
> ima_collect_measurement() returning an error.
>
> Since ima_hash belongs to a temporary inode metadata structure, declared
> at the beginning of __ima_inode_hash(), just add a kfree() call if
> ima_collect_measurement() returns an error different from -ENOMEM (in that
> case, ima_hash should not have been allocated).
>
> Cc: [email protected]
> Fixes: 280fe8367b0d ("ima: Always return a file measurement in ima_file_hash()")
> Signed-off-by: Roberto Sassu <[email protected]>

Thanks,

Reviewed-by: Mimi Zohar <[email protected]>

2022-11-03 08:06:23

by Roberto Sassu

Subject: Re: [PATCH] ima: Fix memory leak in __ima_inode_hash()

On Wed, 2022-11-02 at 18:04 -0400, Mimi Zohar wrote:
> Hi Roberto,
>
> On Wed, 2022-11-02 at 17:30 +0100, Roberto Sassu wrote:
> > From: Roberto Sassu <[email protected]>
>
> Any chance you could fix your mailer?

Hi Mimi

not sure how to fix this. I need to send from @huaweicloud.com because
some people didn't receive the patches from @huawei.com. But I still
prefer to have the original email in the patches.

Thanks

Roberto

> > Commit f3cc6b25dcc5 ("ima: always measure and audit files in
> > policy") lets
> > measurement or audit happen even if the file digest cannot be
> > calculated.
> >
> > As a result, iint->ima_hash could have been allocated despite
> > ima_collect_measurement() returning an error.
> >
> > Since ima_hash belongs to a temporary inode metadata structure,
> > declared
> > at the beginning of __ima_inode_hash(), just add a kfree() call if
> > ima_collect_measurement() returns an error different from -ENOMEM
> > (in that
> > case, ima_hash should not have been allocated).
> >
> > Cc: [email protected]
> > Fixes: 280fe8367b0d ("ima: Always return a file measurement in
> > ima_file_hash()")
> > Signed-off-by: Roberto Sassu <[email protected]>
>
> Thanks,
>
> Reviewed-by: Mimi Zohar <[email protected]>