kernel: smack security backport from kernel 4

Here is the backport of all patches relating to smack support
on kernel side. For more details, see file:

  meta-rcar-gen2/recipes-kernel/linux/linux-renesas/smack/README

Please note that patches are applied only if "smack" is in the
ditro features. Here are the 2 lines to add in the local.conf

OVERRIDES .= ":smack"
DISTRO_FEATURES_append = " smack"

Change-Id: I147a3532aec531f977d6ec34c576261835711f1e
Signed-off-by: Yannick GICQUEL <yannick.gicquel@iot.bzh>
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

1 files changed, 62 insertions, 0 deletions

diff --git a/meta-rcar-gen2/recipes-kernel/linux/linux-renesas/smack/0035-Smack-handle-zero-length-security-labels-without-pan.patch b/meta-rcar-gen2/recipes-kernel/linux/linux-renesas/smack/0035-Smack-handle-zero-length-security-labels-without-pan.patch
new file mode 100644
index 0000000..b22dbed
--- /dev/null
+++ b/meta-rcar-gen2/recipes-kernel/linux/linux-renesas/smack/0035-Smack-handle-zero-length-security-labels-without-pan.patch
@@ -0,0 +1,62 @@
+From 725aece63ff35520dbd369079dd2f6430f795a5f Mon Sep 17 00:00:00 2001
+From: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
+Date: Thu, 7 Aug 2014 20:52:43 +0400
+Subject: [PATCH 35/54] Smack: handle zero-length security labels without panic
+
+Zero-length security labels are invalid but kernel should handle them.
+
+This patch fixes kernel panic after setting zero-length security labels:
+# attr -S -s "SMACK64" -V "" file
+
+And after writing zero-length string into smackfs files syslog and onlycp:
+# python -c 'import os; os.write(1, "")' > /smack/syslog
+
+The problem is caused by brain-damaged logic in function smk_parse_smack()
+which takes pointer to buffer and its length but if length below or equal zero
+it thinks that the buffer is zero-terminated. Unfortunately callers of this
+function are widely used and proper fix requires serious refactoring.
+
+Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
+---
+ security/smack/smack_lsm.c | 2 +-
+ security/smack/smackfs.c   | 4 ++--
+ 2 files changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
+index f72d17c..8d23c23 100644
+--- a/security/smack/smack_lsm.c
++++ b/security/smack/smack_lsm.c
+@@ -923,7 +923,7 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
+ 		rc = -EPERM;
+ 
+ 	if (rc == 0 && check_import) {
+-		skp = smk_import_entry(value, size);
++		skp = size ? smk_import_entry(value, size) : NULL;
+ 		if (skp == NULL || (check_star &&
+ 		    (skp == &smack_known_star || skp == &smack_known_web)))
+ 			rc = -EINVAL;
+diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
+index 32b2488..585bea0 100644
+--- a/security/smack/smackfs.c
++++ b/security/smack/smackfs.c
+@@ -1677,7 +1677,7 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
+ 	if (smack_onlycap != NULL && smack_onlycap != skp)
+ 		return -EPERM;
+ 
+-	data = kzalloc(count, GFP_KERNEL);
++	data = kzalloc(count + 1, GFP_KERNEL);
+ 	if (data == NULL)
+ 		return -ENOMEM;
+ 
+@@ -2228,7 +2228,7 @@ static ssize_t smk_write_syslog(struct file *file, const char __user *buf,
+ 	if (!smack_privileged(CAP_MAC_ADMIN))
+ 		return -EPERM;
+ 
+-	data = kzalloc(count, GFP_KERNEL);
++	data = kzalloc(count + 1, GFP_KERNEL);
+ 	if (data == NULL)
+ 		return -ENOMEM;
+ 
+-- 
+2.1.4
+