6.17-stable review patch. If anyone has any objections, please let me know.
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From: Konstantin Andreev andreev@swemel.ru
[ Upstream commit 635a01da8385fc00a144ec24684100bd1aa9db11 ]
Signed-off-by: Konstantin Andreev andreev@swemel.ru Signed-off-by: Casey Schaufler casey@schaufler-ca.com Stable-dep-of: 78fc6a94be25 ("smack: fix bug: invalid label of unix socket file") Signed-off-by: Sasha Levin sashal@kernel.org --- security/smack/smack_lsm.c | 57 +++++++++++++++++++++----------------- 1 file changed, 32 insertions(+), 25 deletions(-)
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index fc340a6f0ddea..8629e58ea4fa1 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -962,6 +962,24 @@ static int smack_inode_alloc_security(struct inode *inode) return 0; }
+/** + * smk_rule_transmutes - does access rule for (subject,object) contain 't'? + * @subject: a pointer to the subject's Smack label entry + * @object: a pointer to the object's Smack label entry + */ +static bool +smk_rule_transmutes(struct smack_known *subject, + const struct smack_known *object) +{ + int may; + + rcu_read_lock(); + may = smk_access_entry(subject->smk_known, object->smk_known, + &subject->smk_rules); + rcu_read_unlock(); + return (may > 0) && (may & MAY_TRANSMUTE); +} + /** * smack_inode_init_security - copy out the smack from an inode * @inode: the newly created inode @@ -977,23 +995,19 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir, struct xattr *xattrs, int *xattr_count) { struct task_smack *tsp = smack_cred(current_cred()); - struct inode_smack *issp = smack_inode(inode); - struct smack_known *skp = smk_of_task(tsp); - struct smack_known *isp = smk_of_inode(inode); + struct inode_smack * const issp = smack_inode(inode); struct smack_known *dsp = smk_of_inode(dir); struct xattr *xattr = lsm_get_xattr_slot(xattrs, xattr_count); - int may; + bool trans_cred; + bool trans_rule;
/* * If equal, transmuting already occurred in * smack_dentry_create_files_as(). No need to check again. */ - if (tsp->smk_task != tsp->smk_transmuted) { - rcu_read_lock(); - may = smk_access_entry(skp->smk_known, dsp->smk_known, - &skp->smk_rules); - rcu_read_unlock(); - } + trans_cred = (tsp->smk_task == tsp->smk_transmuted); + if (!trans_cred) + trans_rule = smk_rule_transmutes(smk_of_task(tsp), dsp);
/* * In addition to having smk_task equal to smk_transmuted, @@ -1001,9 +1015,7 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir, * requests transmutation then by all means transmute. * Mark the inode as changed. */ - if ((tsp->smk_task == tsp->smk_transmuted) || - (may > 0 && ((may & MAY_TRANSMUTE) != 0) && - smk_inode_transmutable(dir))) { + if (trans_cred || (trans_rule && smk_inode_transmutable(dir))) { struct xattr *xattr_transmute;
/* @@ -1012,8 +1024,8 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir, * inode label was already set correctly in * smack_inode_alloc_security(). */ - if (tsp->smk_task != tsp->smk_transmuted) - isp = issp->smk_inode = dsp; + if (!trans_cred) + issp->smk_inode = dsp;
issp->smk_flags |= SMK_INODE_TRANSMUTE; xattr_transmute = lsm_get_xattr_slot(xattrs, @@ -1033,11 +1045,13 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir, issp->smk_flags |= SMK_INODE_INSTANT;
if (xattr) { - xattr->value = kstrdup(isp->smk_known, GFP_NOFS); + const char *inode_label = issp->smk_inode->smk_known; + + xattr->value = kstrdup(inode_label, GFP_NOFS); if (!xattr->value) return -ENOMEM;
- xattr->value_len = strlen(isp->smk_known); + xattr->value_len = strlen(inode_label); xattr->name = XATTR_SMACK_SUFFIX; }
@@ -4915,7 +4929,6 @@ static int smack_dentry_create_files_as(struct dentry *dentry, int mode, struct task_smack *otsp = smack_cred(old); struct task_smack *ntsp = smack_cred(new); struct inode_smack *isp; - int may;
/* * Use the process credential unless all of @@ -4929,18 +4942,12 @@ static int smack_dentry_create_files_as(struct dentry *dentry, int mode, isp = smack_inode(d_inode(dentry->d_parent));
if (isp->smk_flags & SMK_INODE_TRANSMUTE) { - rcu_read_lock(); - may = smk_access_entry(otsp->smk_task->smk_known, - isp->smk_inode->smk_known, - &otsp->smk_task->smk_rules); - rcu_read_unlock(); - /* * If the directory is transmuting and the rule * providing access is transmuting use the containing * directory label instead of the process label. */ - if (may > 0 && (may & MAY_TRANSMUTE)) { + if (smk_rule_transmutes(otsp->smk_task, isp->smk_inode)) { ntsp->smk_task = isp->smk_inode; ntsp->smk_transmuted = ntsp->smk_task; }