[PATCH 0/2] tun: Fine-tuning for update_filter()

From: Markus Elfring <redacted>
Date: Sat, 20 Aug 2016 09:16:16 +0200

A few update suggestions were taken into account
from static source code analysis.

Markus Elfring (2):
  Use memdup_user()
  Rename a jump label

 drivers/net/tun.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

-- 
2.9.3

From: Markus Elfring <redacted>
Date: Sat, 20 Aug 2016 08:54:15 +0200

Reuse existing functionality from memdup_user() instead of keeping
duplicate source code.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <redacted>
---
 drivers/net/tun.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 9c8b5bc..a1aeccb 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c

@@ -731,14 +731,9 @@ static int update_filter(struct tap_filter *filter, void __user *arg)
 	}
 
 	alen = ETH_ALEN * uf.count;
-	addr = kmalloc(alen, GFP_KERNEL);
-	if (!addr)
-		return -ENOMEM;
-
-	if (copy_from_user(addr, arg + sizeof(uf), alen)) {
-		err = -EFAULT;
-		goto done;
-	}
+	addr = memdup_user(arg + sizeof(uf), alen);
+	if (IS_ERR(addr))
+		return PTR_ERR(addr);
 
 	/* The filter is updated without holding any locks. Which is
 	 * perfectly safe. We disable it first and in the worst

-- 
2.9.3

From: Markus Elfring <redacted>
Date: Sat, 20 Aug 2016 09:00:34 +0200

Adjust a jump target according to the Linux coding style convention.

Signed-off-by: Markus Elfring <redacted>
---
 drivers/net/tun.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index a1aeccb..e249428 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c

@@ -753,7 +753,7 @@ static int update_filter(struct tap_filter *filter, void __user *arg)
 	for (; n < uf.count; n++) {
 		if (!is_multicast_ether_addr(addr[n].u)) {
 			err = 0; /* no filter */
-			goto done;
+			goto free_addr;
 		}
 		addr_hash_set(filter->mask, addr[n].u);
 	}

@@ -769,8 +769,7 @@ static int update_filter(struct tap_filter *filter, void __user *arg)
 
 	/* Return the number of exact filters */
 	err = nexact;
-
-done:
+free_addr:
 	kfree(addr);
 	return err;
 }

-- 
2.9.3

Hi,

On Sat, 20 Aug 2016 09:34:56 +0200 SF Markus Elfring [off-list ref] wrote:

From: Markus Elfring <redacted>
Date: Sat, 20 Aug 2016 08:54:15 +0200

Reuse existing functionality from memdup_user() instead of keeping
duplicate source code.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <redacted>

Reviewed-by: Shmulik Ladkani <redacted>

From: SF Markus Elfring <redacted>
Date: Sat, 20 Aug 2016 09:27:39 +0200

A few update suggestions were taken into account
from static source code analysis.

Series applied.

On Sat, Aug 20, 2016 at 09:37:16AM +0200, SF Markus Elfring wrote:

From: Markus Elfring <redacted>
Date: Sat, 20 Aug 2016 09:00:34 +0200

Adjust a jump target according to the Linux coding style convention.

Signed-off-by: Markus Elfring <redacted>

I don't have an opinion of this one. Which convention do you refer to?

On Sat, Aug 20, 2016 at 09:34:56AM +0200, SF Markus Elfring wrote:

From: Markus Elfring <redacted>
Date: Sat, 20 Aug 2016 08:54:15 +0200

Reuse existing functionality from memdup_user() instead of keeping
duplicate source code.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <redacted>

Acked-by: Michael S. Tsirkin <mst@redhat.com>

On Mon, Aug 22, 2016 at 04:41:11AM +0300, Michael S. Tsirkin wrote:

On Sat, Aug 20, 2016 at 09:37:16AM +0200, SF Markus Elfring wrote:

quoted

From: Markus Elfring <redacted>
Date: Sat, 20 Aug 2016 09:00:34 +0200

Adjust a jump target according to the Linux coding style convention.

Signed-off-by: Markus Elfring <redacted>

I don't have an opinion of this one. Which convention do you refer to?

Citing Documentation/CodingStyle:

Choose label names which say what the goto does or why the goto exists.  An
example of a good name could be "out_buffer:" if the goto frees "buffer".
Avoid using GW-BASIC names like "err1:" and "err2:".  Also don't name them after
the goto location like "err_kmalloc_failed:"

quoted

---
 drivers/net/tun.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index a1aeccb..e249428 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c

@@ -753,7 +753,7 @@ static int update_filter(struct tap_filter *filter, void __user *arg)
 	for (; n < uf.count; n++) {
 		if (!is_multicast_ether_addr(addr[n].u)) {
 			err = 0; /* no filter */
-			goto done;
+			goto free_addr;
 		}
 		addr_hash_set(filter->mask, addr[n].u);
 	}

@@ -769,8 +769,7 @@ static int update_filter(struct tap_filter *filter, void __user *arg)
 
 	/* Return the number of exact filters */
 	err = nexact;
-
-done:
+free_addr:
 	kfree(addr);
 	return err;
 }

-- 
2.9.3