selinux: parse contexts for mount options early
Commit b8b87fd954 ("selinux: Fix selinux_sb_mnt_opts_compat()")
started to parse mount options into SIDs in selinux_add_opt() if policy
has already been loaded. Since it's extremely unlikely that anyone would
depend on the ability to set SELinux contexts on fs_context before
loading the policy and then mounting that context after simplify the
logic by always parsing the options early.
Note that the multi-step mounting is only possible with the new
fscontext mount API and wasn't possible before its introduction.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This commit is contained in:
Ondrej Mosnacek
Paul Moore
Родитель
0e326df069
Коммит
70f4169ab4
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@ -340,7 +340,6 @@ static void inode_free_security(struct inode *inode)
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}
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struct selinux_mnt_opts {
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const char *fscontext, *context, *rootcontext, *defcontext;
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u32 fscontext_sid;
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u32 context_sid;
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u32 rootcontext_sid;
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@ -349,12 +348,7 @@ struct selinux_mnt_opts {
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static void selinux_free_mnt_opts(void *mnt_opts)
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{
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struct selinux_mnt_opts *opts = mnt_opts;
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kfree(opts->fscontext);
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kfree(opts->context);
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kfree(opts->rootcontext);
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kfree(opts->defcontext);
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kfree(opts);
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kfree(mnt_opts);
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}
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enum {
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@ -601,17 +595,6 @@ static int bad_option(struct superblock_security_struct *sbsec, char flag,
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return 0;
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}
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static int parse_sid(struct super_block *sb, const char *s, u32 *sid)
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{
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int rc = security_context_str_to_sid(&selinux_state, s,
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sid, GFP_KERNEL);
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if (rc)
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pr_warn("SELinux: security_context_str_to_sid"
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"(%s) failed for (dev %s, type %s) errno=%d\n",
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s, sb ? sb->s_id : "?", sb ? sb->s_type->name : "?", rc);
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return rc;
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}
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/*
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* Allow filesystems with binary mount data to explicitly set mount point
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* labeling information.
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@ -674,49 +657,29 @@ static int selinux_set_mnt_opts(struct super_block *sb,
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* than once with different security options.
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*/
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if (opts) {
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if (opts->fscontext) {
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if (opts->fscontext_sid == SECSID_NULL) {
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rc = parse_sid(sb, opts->fscontext, &fscontext_sid);
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if (rc)
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goto out;
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} else
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fscontext_sid = opts->fscontext_sid;
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if (opts->fscontext_sid) {
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fscontext_sid = opts->fscontext_sid;
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if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
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fscontext_sid))
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goto out_double_mount;
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sbsec->flags |= FSCONTEXT_MNT;
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}
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if (opts->context) {
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if (opts->context_sid == SECSID_NULL) {
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rc = parse_sid(sb, opts->context, &context_sid);
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if (rc)
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goto out;
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} else
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context_sid = opts->context_sid;
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if (opts->context_sid) {
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context_sid = opts->context_sid;
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if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
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context_sid))
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goto out_double_mount;
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sbsec->flags |= CONTEXT_MNT;
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}
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if (opts->rootcontext) {
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if (opts->rootcontext_sid == SECSID_NULL) {
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rc = parse_sid(sb, opts->rootcontext, &rootcontext_sid);
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if (rc)
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goto out;
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} else
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rootcontext_sid = opts->rootcontext_sid;
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if (opts->rootcontext_sid) {
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rootcontext_sid = opts->rootcontext_sid;
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if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
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rootcontext_sid))
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goto out_double_mount;
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sbsec->flags |= ROOTCONTEXT_MNT;
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}
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if (opts->defcontext) {
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if (opts->defcontext_sid == SECSID_NULL) {
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rc = parse_sid(sb, opts->defcontext, &defcontext_sid);
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if (rc)
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goto out;
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} else
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defcontext_sid = opts->defcontext_sid;
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if (opts->defcontext_sid) {
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defcontext_sid = opts->defcontext_sid;
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if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
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defcontext_sid))
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goto out_double_mount;
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@ -986,6 +949,8 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts)
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{
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struct selinux_mnt_opts *opts = *mnt_opts;
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bool is_alloc_opts = false;
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u32 *dst_sid;
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int rc;
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if (token == Opt_seclabel)
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/* eaten and completely ignored */
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@ -993,6 +958,11 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts)
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if (!s)
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return -ENOMEM;
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if (!selinux_initialized(&selinux_state)) {
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pr_warn("SELinux: Unable to set superblock options before the security server is initialized\n");
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return -EINVAL;
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}
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if (!opts) {
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opts = kzalloc(sizeof(*opts), GFP_KERNEL);
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if (!opts)
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@ -1003,36 +973,34 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts)
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switch (token) {
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case Opt_context:
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if (opts->context || opts->defcontext)
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if (opts->context_sid || opts->defcontext_sid)
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goto err;
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opts->context = s;
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if (selinux_initialized(&selinux_state))
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parse_sid(NULL, s, &opts->context_sid);
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dst_sid = &opts->context_sid;
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break;
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case Opt_fscontext:
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if (opts->fscontext)
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if (opts->fscontext_sid)
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goto err;
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opts->fscontext = s;
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if (selinux_initialized(&selinux_state))
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parse_sid(NULL, s, &opts->fscontext_sid);
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dst_sid = &opts->fscontext_sid;
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break;
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case Opt_rootcontext:
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if (opts->rootcontext)
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if (opts->rootcontext_sid)
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goto err;
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opts->rootcontext = s;
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if (selinux_initialized(&selinux_state))
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parse_sid(NULL, s, &opts->rootcontext_sid);
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dst_sid = &opts->rootcontext_sid;
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break;
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case Opt_defcontext:
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if (opts->context || opts->defcontext)
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if (opts->context_sid || opts->defcontext_sid)
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goto err;
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opts->defcontext = s;
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if (selinux_initialized(&selinux_state))
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parse_sid(NULL, s, &opts->defcontext_sid);
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dst_sid = &opts->defcontext_sid;
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break;
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default:
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WARN_ON(1);
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return -EINVAL;
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}
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return 0;
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rc = security_context_str_to_sid(&selinux_state, s, dst_sid, GFP_KERNEL);
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if (rc)
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pr_warn("SELinux: security_context_str_to_sid (%s) failed with errno=%d\n",
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s, rc);
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return rc;
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err:
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if (is_alloc_opts) {
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@ -2681,37 +2649,27 @@ static int selinux_sb_mnt_opts_compat(struct super_block *sb, void *mnt_opts)
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if (!opts)
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return (sbsec->flags & SE_MNTMASK) ? 1 : 0;
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if (opts->fscontext) {
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if (opts->fscontext_sid == SECSID_NULL)
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return 1;
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else if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
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opts->fscontext_sid))
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if (opts->fscontext_sid) {
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if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
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opts->fscontext_sid))
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return 1;
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}
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if (opts->context) {
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if (opts->context_sid == SECSID_NULL)
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return 1;
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else if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
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opts->context_sid))
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if (opts->context_sid) {
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if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
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opts->context_sid))
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return 1;
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}
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if (opts->rootcontext) {
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if (opts->rootcontext_sid == SECSID_NULL)
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return 1;
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else {
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struct inode_security_struct *root_isec;
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if (opts->rootcontext_sid) {
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struct inode_security_struct *root_isec;
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root_isec = backing_inode_security(sb->s_root);
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if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
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opts->rootcontext_sid))
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return 1;
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}
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}
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if (opts->defcontext) {
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if (opts->defcontext_sid == SECSID_NULL)
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root_isec = backing_inode_security(sb->s_root);
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if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
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opts->rootcontext_sid))
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return 1;
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else if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
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opts->defcontext_sid))
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}
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if (opts->defcontext_sid) {
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if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
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opts->defcontext_sid))
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return 1;
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}
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return 0;
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@ -2721,7 +2679,6 @@ static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)
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{
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struct selinux_mnt_opts *opts = mnt_opts;
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struct superblock_security_struct *sbsec = selinux_superblock(sb);
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int rc;
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if (!(sbsec->flags & SE_SBINITIALIZED))
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return 0;
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@ -2729,47 +2686,24 @@ static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)
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if (!opts)
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return 0;
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if (opts->fscontext) {
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if (opts->fscontext_sid == SECSID_NULL) {
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rc = parse_sid(sb, opts->fscontext,
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&opts->fscontext_sid);
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if (rc)
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return rc;
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}
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if (opts->fscontext_sid) {
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if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
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opts->fscontext_sid))
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goto out_bad_option;
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}
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if (opts->context) {
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if (opts->context_sid == SECSID_NULL) {
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rc = parse_sid(sb, opts->context, &opts->context_sid);
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if (rc)
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return rc;
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}
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if (opts->context_sid) {
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if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
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opts->context_sid))
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goto out_bad_option;
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}
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if (opts->rootcontext) {
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if (opts->rootcontext_sid) {
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struct inode_security_struct *root_isec;
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root_isec = backing_inode_security(sb->s_root);
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if (opts->rootcontext_sid == SECSID_NULL) {
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rc = parse_sid(sb, opts->rootcontext,
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&opts->rootcontext_sid);
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if (rc)
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return rc;
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}
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if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
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opts->rootcontext_sid))
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goto out_bad_option;
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}
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if (opts->defcontext) {
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if (opts->defcontext_sid == SECSID_NULL) {
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rc = parse_sid(sb, opts->defcontext,
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&opts->defcontext_sid);
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if (rc)
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return rc;
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}
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if (opts->defcontext_sid) {
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if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
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opts->defcontext_sid))
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goto out_bad_option;
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@ -2838,42 +2772,12 @@ static int selinux_fs_context_dup(struct fs_context *fc,
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struct fs_context *src_fc)
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{
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const struct selinux_mnt_opts *src = src_fc->security;
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struct selinux_mnt_opts *opts;
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if (!src)
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return 0;
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fc->security = kzalloc(sizeof(struct selinux_mnt_opts), GFP_KERNEL);
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if (!fc->security)
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return -ENOMEM;
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opts = fc->security;
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if (src->fscontext) {
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opts->fscontext = kstrdup(src->fscontext, GFP_KERNEL);
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if (!opts->fscontext)
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return -ENOMEM;
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}
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if (src->context) {
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opts->context = kstrdup(src->context, GFP_KERNEL);
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if (!opts->context)
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return -ENOMEM;
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}
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if (src->rootcontext) {
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opts->rootcontext = kstrdup(src->rootcontext, GFP_KERNEL);
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if (!opts->rootcontext)
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return -ENOMEM;
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}
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if (src->defcontext) {
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opts->defcontext = kstrdup(src->defcontext, GFP_KERNEL);
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if (!opts->defcontext)
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return -ENOMEM;
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}
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opts->fscontext_sid = src->fscontext_sid;
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opts->context_sid = src->context_sid;
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opts->rootcontext_sid = src->rootcontext_sid;
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opts->defcontext_sid = src->defcontext_sid;
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return 0;
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fc->security = kmemdup(src, sizeof(*src), GFP_KERNEL);
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return fc->security ? 0 : -ENOMEM;
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}
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static const struct fs_parameter_spec selinux_fs_parameters[] = {
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