diff options
| -rw-r--r-- | security/smack/smack.h | 8 | ||||
| -rw-r--r-- | security/smack/smack_lsm.c | 41 |
2 files changed, 37 insertions, 12 deletions
diff --git a/security/smack/smack.h b/security/smack/smack.h index 6c91156..26e58f1 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -90,9 +90,15 @@ struct superblock_smack { struct smack_known *smk_floor; struct smack_known *smk_hat; struct smack_known *smk_default; - int smk_initialized; + int smk_flags; }; +/* + * Superblock flags + */ +#define SMK_SB_INITIALIZED 0x01 +#define SMK_SB_UNTRUSTED 0x02 + struct socket_smack { struct smack_known *smk_out; /* outbound label */ struct smack_known *smk_in; /* inbound label */ diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 6777295..a799b7a 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -549,7 +549,7 @@ static int smack_sb_alloc_security(struct super_block *sb) sbsp->smk_floor = &smack_known_floor; sbsp->smk_hat = &smack_known_hat; /* - * smk_initialized will be zero from kzalloc. + * SMK_SB_INITIALIZED will be zero from kzalloc. */ sb->s_security = sbsp; @@ -766,10 +766,10 @@ static int smack_set_mnt_opts(struct super_block *sb, int num_opts = opts->num_mnt_opts; int transmute = 0; - if (sp->smk_initialized) + if (sp->smk_flags & SMK_SB_INITIALIZED) return 0; - sp->smk_initialized = 1; + sp->smk_flags |= SMK_SB_INITIALIZED; for (i = 0; i < num_opts; i++) { switch (opts->mnt_opts_flags[i]) { @@ -821,6 +821,17 @@ static int smack_set_mnt_opts(struct super_block *sb, skp = smk_of_current(); sp->smk_root = skp; sp->smk_default = skp; + /* + * For a handful of fs types with no user-controlled + * backing store it's okay to trust security labels + * in the filesystem. The rest are untrusted. + */ + if (sb->s_user_ns != &init_user_ns && + sb->s_magic != SYSFS_MAGIC && sb->s_magic != TMPFS_MAGIC && + sb->s_magic != RAMFS_MAGIC) { + transmute = 1; + sp->smk_flags |= SMK_SB_UNTRUSTED; + } } /* @@ -1203,6 +1214,7 @@ static int smack_inode_rename(struct inode *old_inode, */ static int smack_inode_permission(struct inode *inode, int mask) { + struct superblock_smack *sbsp = inode->i_sb->s_security; struct smk_audit_info ad; int no_block = mask & MAY_NOT_BLOCK; int rc; @@ -1214,6 +1226,11 @@ static int smack_inode_permission(struct inode *inode, int mask) if (mask == 0) return 0; + if (sbsp->smk_flags & SMK_SB_UNTRUSTED) { + if (smk_of_inode(inode) != sbsp->smk_root) + return -EACCES; + } + /* May be droppable after audit */ if (no_block) return -ECHILD; @@ -3529,14 +3546,16 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) if (rc >= 0) transflag = SMK_INODE_TRANSMUTE; } - /* - * Don't let the exec or mmap label be "*" or "@". - */ - skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp); - if (IS_ERR(skp) || skp == &smack_known_star || - skp == &smack_known_web) - skp = NULL; - isp->smk_task = skp; + if (!(sbsp->smk_flags & SMK_SB_UNTRUSTED)) { + /* + * Don't let the exec or mmap label be "*" or "@". + */ + skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp); + if (IS_ERR(skp) || skp == &smack_known_star || + skp == &smack_known_web) + skp = NULL; + isp->smk_task = skp; + } skp = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp); if (IS_ERR(skp) || skp == &smack_known_star || |
