* [PATCH 0/3] ima_fs: Fine-tuning for ima_write_policy()
@ 2017-01-25 9:30 SF Markus Elfring
2017-01-25 9:31 ` [PATCH 1/3] ima_fs: One check less in ima_write_policy() after error detection SF Markus Elfring
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: SF Markus Elfring @ 2017-01-25 9:30 UTC (permalink / raw)
To: linux-ima-devel, linux-ima-user, linux-security-module,
Dmitry Kasatkin, James Morris, Mimi Zohar, Serge E. Hallyn
Cc: LKML, kernel-janitors
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Wed, 25 Jan 2017 10:20:30 +0100
A few update suggestions were taken into account
from static source code analysis.
Markus Elfring (3):
One check less after error detection
Reorder input parameter validation
Move three error code assignments
security/integrity/ima/ima_fs.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)
--
2.11.0
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH 1/3] ima_fs: One check less in ima_write_policy() after error detection
2017-01-25 9:30 [PATCH 0/3] ima_fs: Fine-tuning for ima_write_policy() SF Markus Elfring
@ 2017-01-25 9:31 ` SF Markus Elfring
2017-01-27 12:38 ` Mimi Zohar
2017-01-25 9:33 ` [PATCH 2/3] ima_fs: Reorder input parameter validation in ima_write_policy() SF Markus Elfring
2017-01-25 9:34 ` [PATCH 3/3] ima_fs: Move three error code assignments " SF Markus Elfring
2 siblings, 1 reply; 7+ messages in thread
From: SF Markus Elfring @ 2017-01-25 9:31 UTC (permalink / raw)
To: linux-ima-devel, linux-ima-user, linux-security-module,
Dmitry Kasatkin, James Morris, Mimi Zohar, Serge E. Hallyn
Cc: LKML, kernel-janitors
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Tue, 24 Jan 2017 20:30:55 +0100
Move the jump label directly before the desired assignment for the
variable "valid_policy" at the end so that the variable "result" will not
be checked once more after it was determined that a received input
parameter was not zero or a memory allocation failed.
Use the identifier "reset_validity" instead of the label "out".
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
security/integrity/ima/ima_fs.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index ca303e5d2b94..c1c8d34d111d 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -321,12 +321,12 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
/* No partial writes. */
result = -EINVAL;
if (*ppos != 0)
- goto out;
+ goto reset_validity;
result = -ENOMEM;
data = kmalloc(datalen + 1, GFP_KERNEL);
if (!data)
- goto out;
+ goto reset_validity;
*(data + datalen) = '\0';
@@ -353,8 +353,8 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
mutex_unlock(&ima_write_mutex);
out_free:
kfree(data);
-out:
if (result < 0)
+reset_validity:
valid_policy = 0;
return result;
--
2.11.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 2/3] ima_fs: Reorder input parameter validation in ima_write_policy()
2017-01-25 9:30 [PATCH 0/3] ima_fs: Fine-tuning for ima_write_policy() SF Markus Elfring
2017-01-25 9:31 ` [PATCH 1/3] ima_fs: One check less in ima_write_policy() after error detection SF Markus Elfring
@ 2017-01-25 9:33 ` SF Markus Elfring
2017-01-25 9:34 ` [PATCH 3/3] ima_fs: Move three error code assignments " SF Markus Elfring
2 siblings, 0 replies; 7+ messages in thread
From: SF Markus Elfring @ 2017-01-25 9:33 UTC (permalink / raw)
To: linux-ima-devel, linux-ima-user, linux-security-module,
Dmitry Kasatkin, James Morris, Mimi Zohar, Serge E. Hallyn
Cc: LKML, kernel-janitors
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Tue, 24 Jan 2017 22:38:00 +0100
Move validation for the input parameter "ppos" to the beginning in this
function so that a following check for the input parameter "datalen"
can be occasionally avoided earlier.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
security/integrity/ima/ima_fs.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index c1c8d34d111d..98304411915d 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -315,15 +315,14 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
char *data;
ssize_t result;
- if (datalen >= PAGE_SIZE)
- datalen = PAGE_SIZE - 1;
-
/* No partial writes. */
result = -EINVAL;
if (*ppos != 0)
goto reset_validity;
result = -ENOMEM;
+ if (datalen >= PAGE_SIZE)
+ datalen = PAGE_SIZE - 1;
data = kmalloc(datalen + 1, GFP_KERNEL);
if (!data)
goto reset_validity;
--
2.11.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 3/3] ima_fs: Move three error code assignments in ima_write_policy()
2017-01-25 9:30 [PATCH 0/3] ima_fs: Fine-tuning for ima_write_policy() SF Markus Elfring
2017-01-25 9:31 ` [PATCH 1/3] ima_fs: One check less in ima_write_policy() after error detection SF Markus Elfring
2017-01-25 9:33 ` [PATCH 2/3] ima_fs: Reorder input parameter validation in ima_write_policy() SF Markus Elfring
@ 2017-01-25 9:34 ` SF Markus Elfring
2017-01-27 12:39 ` Mimi Zohar
2 siblings, 1 reply; 7+ messages in thread
From: SF Markus Elfring @ 2017-01-25 9:34 UTC (permalink / raw)
To: linux-ima-devel, linux-ima-user, linux-security-module,
Dmitry Kasatkin, James Morris, Mimi Zohar, Serge E. Hallyn
Cc: LKML, kernel-janitors
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Tue, 24 Jan 2017 22:47:07 +0100
A local variable was set to an error code in three cases before a concrete
error situation was detected. Thus move the corresponding assignments into
if branches to indicate a software failure there.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
security/integrity/ima/ima_fs.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 98304411915d..a50c26f9772c 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -317,21 +317,24 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
/* No partial writes. */
result = -EINVAL;
- if (*ppos != 0)
+ if (*ppos != 0) {
+ result = -EINVAL;
goto reset_validity;
+ }
- result = -ENOMEM;
if (datalen >= PAGE_SIZE)
datalen = PAGE_SIZE - 1;
data = kmalloc(datalen + 1, GFP_KERNEL);
- if (!data)
+ if (!data) {
+ result = -ENOMEM;
goto reset_validity;
+ }
*(data + datalen) = '\0';
-
- result = -EFAULT;
- if (copy_from_user(data, buf, datalen))
+ if (copy_from_user(data, buf, datalen)) {
+ result = -EFAULT;
goto out_free;
+ }
result = mutex_lock_interruptible(&ima_write_mutex);
if (result < 0)
--
2.11.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 1/3] ima_fs: One check less in ima_write_policy() after error detection
2017-01-25 9:31 ` [PATCH 1/3] ima_fs: One check less in ima_write_policy() after error detection SF Markus Elfring
@ 2017-01-27 12:38 ` Mimi Zohar
0 siblings, 0 replies; 7+ messages in thread
From: Mimi Zohar @ 2017-01-27 12:38 UTC (permalink / raw)
To: SF Markus Elfring
Cc: linux-ima-devel, linux-ima-user, linux-security-module,
Dmitry Kasatkin, James Morris, Serge E. Hallyn, LKML,
kernel-janitors
On Wed, 2017-01-25 at 10:31 +0100, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Tue, 24 Jan 2017 20:30:55 +0100
>
> Move the jump label directly before the desired assignment for the
> variable "valid_policy" at the end so that the variable "result" will not
> be checked once more after it was determined that a received input
> parameter was not zero or a memory allocation failed.
> Use the identifier "reset_validity" instead of the label "out".
>
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
> security/integrity/ima/ima_fs.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
> index ca303e5d2b94..c1c8d34d111d 100644
> --- a/security/integrity/ima/ima_fs.c
> +++ b/security/integrity/ima/ima_fs.c
> @@ -321,12 +321,12 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
> /* No partial writes. */
> result = -EINVAL;
> if (*ppos != 0)
> - goto out;
> + goto reset_validity;
>
> result = -ENOMEM;
> data = kmalloc(datalen + 1, GFP_KERNEL);
> if (!data)
> - goto out;
> + goto reset_validity;
>
> *(data + datalen) = '\0';
>
> @@ -353,8 +353,8 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
> mutex_unlock(&ima_write_mutex);
> out_free:
> kfree(data);
> -out:
> if (result < 0)
> +reset_validity:
Really?! Do you really think this makes the code more readable? A
more common, readable approach is to have two exit points - a normal
exit and an error exit. Let's leave it to the compiler to do the
optimization.
Mimi
> valid_policy = 0;
>
> return result;
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 3/3] ima_fs: Move three error code assignments in ima_write_policy()
2017-01-25 9:34 ` [PATCH 3/3] ima_fs: Move three error code assignments " SF Markus Elfring
@ 2017-01-27 12:39 ` Mimi Zohar
2017-01-29 23:43 ` James Morris
0 siblings, 1 reply; 7+ messages in thread
From: Mimi Zohar @ 2017-01-27 12:39 UTC (permalink / raw)
To: SF Markus Elfring
Cc: linux-ima-devel, linux-ima-user, linux-security-module,
Dmitry Kasatkin, James Morris, Serge E. Hallyn, LKML,
kernel-janitors
On Wed, 2017-01-25 at 10:34 +0100, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Tue, 24 Jan 2017 22:47:07 +0100
>
> A local variable was set to an error code in three cases before a concrete
> error situation was detected. Thus move the corresponding assignments into
> if branches to indicate a software failure there.
>
> This issue was detected by using the Coccinelle software.
This coding style was pretty common. I assume the compiler is smart
enough to do the right thing. Is this a FYI, letting us know for the
future the preferred coding style, or are we really upstreaming these
sorts of coding style changes?
Mimi
>
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
> security/integrity/ima/ima_fs.c | 15 +++++++++------
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
> index 98304411915d..a50c26f9772c 100644
> --- a/security/integrity/ima/ima_fs.c
> +++ b/security/integrity/ima/ima_fs.c
> @@ -317,21 +317,24 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
>
> /* No partial writes. */
> result = -EINVAL;
> - if (*ppos != 0)
> + if (*ppos != 0) {
> + result = -EINVAL;
> goto reset_validity;
> + }
>
> - result = -ENOMEM;
> if (datalen >= PAGE_SIZE)
> datalen = PAGE_SIZE - 1;
> data = kmalloc(datalen + 1, GFP_KERNEL);
> - if (!data)
> + if (!data) {
> + result = -ENOMEM;
> goto reset_validity;
> + }
>
> *(data + datalen) = '\0';
> -
> - result = -EFAULT;
> - if (copy_from_user(data, buf, datalen))
> + if (copy_from_user(data, buf, datalen)) {
> + result = -EFAULT;
> goto out_free;
> + }
>
> result = mutex_lock_interruptible(&ima_write_mutex);
> if (result < 0)
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 3/3] ima_fs: Move three error code assignments in ima_write_policy()
2017-01-27 12:39 ` Mimi Zohar
@ 2017-01-29 23:43 ` James Morris
0 siblings, 0 replies; 7+ messages in thread
From: James Morris @ 2017-01-29 23:43 UTC (permalink / raw)
To: Mimi Zohar
Cc: SF Markus Elfring, linux-ima-devel, linux-ima-user,
linux-security-module, Dmitry Kasatkin, James Morris,
Serge E. Hallyn, LKML, kernel-janitors
On Fri, 27 Jan 2017, Mimi Zohar wrote:
> On Wed, 2017-01-25 at 10:34 +0100, SF Markus Elfring wrote:
> > From: Markus Elfring <elfring@users.sourceforge.net>
> > Date: Tue, 24 Jan 2017 22:47:07 +0100
> >
> > A local variable was set to an error code in three cases before a concrete
> > error situation was detected. Thus move the corresponding assignments into
> > if branches to indicate a software failure there.
> >
> > This issue was detected by using the Coccinelle software.
>
> This coding style was pretty common. I assume the compiler is smart
> enough to do the right thing. Is this a FYI, letting us know for the
> future the preferred coding style, or are we really upstreaming these
> sorts of coding style changes?
Nope, and I generally don't want cleanup patches from Markus going into
the security tree.
See also:
https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1254425.html
- James
--
James Morris
<jmorris@namei.org>
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2017-01-30 0:42 UTC | newest]
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2017-01-25 9:30 [PATCH 0/3] ima_fs: Fine-tuning for ima_write_policy() SF Markus Elfring
2017-01-25 9:31 ` [PATCH 1/3] ima_fs: One check less in ima_write_policy() after error detection SF Markus Elfring
2017-01-27 12:38 ` Mimi Zohar
2017-01-25 9:33 ` [PATCH 2/3] ima_fs: Reorder input parameter validation in ima_write_policy() SF Markus Elfring
2017-01-25 9:34 ` [PATCH 3/3] ima_fs: Move three error code assignments " SF Markus Elfring
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2017-01-29 23:43 ` James Morris
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