[PATCH] Smack: fix smack_new_inode bogosities

From: Casey Schaufler
Date: Wed May 23 2012 - 20:47:14 EST


From: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
Subject: [PATCH] Smack: fix smack_new_inode bogosities

In January of 2012 Al Viro pointed out three bits of code that
he titled "new_inode_smack bogosities". This patch repairs these
errors.

1. smack_sb_kern_mount() included a NULL check that is impossible.
The check and NULL case are removed.
2. smack_kb_kern_mount() included pointless locking. The locking is
removed. Since this is the only place that lock was used the lock
is removed from the superblock_smack structure.
3. smk_fill_super() incorrectly and unnecessarily set the Smack label
for the smackfs root inode. The assignment has been removed.

Targeted for git://gitorious.org/smack-next/kernel.git

Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>

---

security/smack/smack.h | 1 -
security/smack/smack_lsm.c | 8 ++------
security/smack/smackfs.c | 1 -
3 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index cc361b8..76feb31 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -43,7 +43,6 @@ struct superblock_smack {
char *smk_hat;
char *smk_default;
int smk_initialized;
- spinlock_t smk_sblock; /* for initialization */
};

struct socket_smack {
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index d583c05..5a4d52c 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -251,7 +251,6 @@ static int smack_sb_alloc_security(struct super_block *sb)
sbsp->smk_floor = smack_known_floor.smk_known;
sbsp->smk_hat = smack_known_hat.smk_known;
sbsp->smk_initialized = 0;
- spin_lock_init(&sbsp->smk_sblock);

sb->s_security = sbsp;

@@ -332,13 +331,10 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
char *commap;
char *nsp;

- spin_lock(&sp->smk_sblock);
- if (sp->smk_initialized != 0) {
- spin_unlock(&sp->smk_sblock);
+ if (sp->smk_initialized != 0)
return 0;
- }
+
sp->smk_initialized = 1;
- spin_unlock(&sp->smk_sblock);

for (op = data; op != NULL; op = commap) {
commap = strchr(op, ',');
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 1810c9a..3686db7 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -2051,7 +2051,6 @@ static int smk_fill_super(struct super_block *sb, void *data, int silent)
}

root_inode = sb->s_root->d_inode;
- root_inode->i_security = new_inode_smack(smack_known_floor.smk_known);

return 0;
}



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