From e43a18206ff7a4eb7473d47fe82c4c5091c38d1c Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Tue, 13 Mar 2012 19:14:19 -0700 Subject: [PATCH] Smack: recursive tramsmute The transmuting directory feature of Smack requires that the transmuting attribute be explicitly set in all cases. It seems the users of this facility would expect that the transmuting attribute be inherited by subdirectories that are created in a transmuting directory. This does not seem to add any additional complexity to the understanding of how the system works. Signed-off-by: Casey Schaufler --- security/smack/smack.h | 1 + security/smack/smack_lsm.c | 44 ++++++++++++++++++++++++++++++-------- 2 files changed, 36 insertions(+), 9 deletions(-) diff --git a/security/smack/smack.h b/security/smack/smack.h index 2ad00657b801..49e6ee215d5b 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -66,6 +66,7 @@ struct task_smack { #define SMK_INODE_INSTANT 0x01 /* inode is instantiated */ #define SMK_INODE_TRANSMUTE 0x02 /* directory is transmuting */ +#define SMK_INODE_CHANGED 0x04 /* smack was transmuted */ /* * A label access rule. diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index cd667b4089a5..c9d2fd99ff0b 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -556,6 +556,7 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir, void **value, size_t *len) { struct smack_known *skp; + struct inode_smack *issp = inode->i_security; char *csp = smk_of_current(); char *isp = smk_of_inode(inode); char *dsp = smk_of_inode(dir); @@ -577,10 +578,13 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir, * If the access rule allows transmutation and * the directory requests transmutation then * by all means transmute. + * Mark the inode as changed. */ if (may > 0 && ((may & MAY_TRANSMUTE) != 0) && - smk_inode_transmutable(dir)) + smk_inode_transmutable(dir)) { isp = dsp; + issp->smk_flags |= SMK_INODE_CHANGED; + } *value = kstrdup(isp, GFP_KERNEL); if (*value == NULL) @@ -2550,6 +2554,7 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) char *final; char trattr[TRANS_TRUE_SIZE]; int transflag = 0; + int rc; struct dentry *dp; if (inode == NULL) @@ -2668,17 +2673,38 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) */ dp = dget(opt_dentry); fetched = smk_fetch(XATTR_NAME_SMACK, inode, dp); - if (fetched != NULL) { + if (fetched != NULL) final = fetched; - if (S_ISDIR(inode->i_mode)) { - trattr[0] = '\0'; - inode->i_op->getxattr(dp, + + /* + * Transmuting directory + */ + if (S_ISDIR(inode->i_mode)) { + /* + * If this is a new directory and the label was + * transmuted when the inode was initialized + * set the transmute attribute on the directory + * and mark the inode. + * + * If there is a transmute attribute on the + * directory mark the inode. + */ + if (isp->smk_flags & SMK_INODE_CHANGED) { + isp->smk_flags &= ~SMK_INODE_CHANGED; + rc = inode->i_op->setxattr(dp, XATTR_NAME_SMACKTRANSMUTE, - trattr, TRANS_TRUE_SIZE); - if (strncmp(trattr, TRANS_TRUE, - TRANS_TRUE_SIZE) == 0) - transflag = SMK_INODE_TRANSMUTE; + TRANS_TRUE, TRANS_TRUE_SIZE, + 0); + } else { + rc = inode->i_op->getxattr(dp, + XATTR_NAME_SMACKTRANSMUTE, trattr, + TRANS_TRUE_SIZE); + if (rc >= 0 && strncmp(trattr, TRANS_TRUE, + TRANS_TRUE_SIZE) != 0) + rc = -EINVAL; } + if (rc >= 0) + transflag = SMK_INODE_TRANSMUTE; } isp->smk_task = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp); isp->smk_mmap = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp); -- 2.39.5