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Message-id: <1434967566-11912-1-git-send-email-t.vivek@DO-T-VIVEK09.corp.samsungelectronics.net>
Date: Mon, 22 Jun 2015 15:36:06 +0530
From: "U-CORP\\t.vivek" <t.vivek@...T-VIVEK09.corp.samsungelectronics.net>
To: casey@...aufler-ca.com
Cc: james.l.morris@...cle.com, serge@...lyn.com,
linux-security-module@...r.kernel.org,
linux-kernel@...r.kernel.org, a.sahrawat@...sung.com,
pankaj.m@...sung.com, Vivek Trivedi <t.vivek@...sung.com>
Subject: [PATCH] smack: allow mount opts setting over filesystems with binary
mount data
From: Vivek Trivedi <t.vivek@...sung.com>
Add support for setting smack mount labels(using smackfsdef, smackfsroot,
smackfshat, smackfsfloor, smackfstransmute) for filesystems with binary
mount data like NFS.
To achieve this, implement sb_parse_opts_str and sb_set_mnt_opts security
operations in smack LSM similar to SELinux.
Signed-off-by: Vivek Trivedi <t.vivek@...sung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@...sung.com>
---
security/smack/smack.h | 18 ++++
security/smack/smack_lsm.c | 240 ++++++++++++++++++++++++++++++++++++--------
2 files changed, 218 insertions(+), 40 deletions(-)
diff --git a/security/smack/smack.h b/security/smack/smack.h
index 244e035..69ab9eb 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -143,6 +143,24 @@ struct smack_onlycap {
struct smack_known *smk_label;
};
+/* Super block security struct flags for mount options */
+#define FSDEFAULT_MNT 0x01
+#define FSFLOOR_MNT 0x02
+#define FSHAT_MNT 0x04
+#define FSROOT_MNT 0x08
+#define FSTRANS_MNT 0x10
+
+#define NUM_SMK_MNT_OPTS 5
+
+enum {
+ Opt_error = -1,
+ Opt_fsdefault = 1,
+ Opt_fsfloor = 2,
+ Opt_fshat = 3,
+ Opt_fsroot = 4,
+ Opt_fstransmute = 5,
+};
+
/*
* Mount options
*/
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index a143328..2d85f78 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -41,6 +41,7 @@
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/binfmts.h>
+#include <linux/parser.h>
#include "smack.h"
#define TRANS_TRUE "TRUE"
@@ -64,6 +65,15 @@ static char *smk_bu_mess[] = {
"Unconfined Object", /* SMACK_UNCONFINED_OBJECT */
};
+static const match_table_t tokens = {
+ {Opt_fsdefault, SMK_FSDEFAULT "%s"},
+ {Opt_fsfloor, SMK_FSFLOOR "%s"},
+ {Opt_fshat, SMK_FSHAT "%s"},
+ {Opt_fsroot, SMK_FSROOT "%s"},
+ {Opt_fstransmute, SMK_FSTRANS "%s"},
+ {Opt_error, NULL},
+};
+
static void smk_bu_mode(int mode, char *s)
{
int i = 0;
@@ -577,76 +587,192 @@ static int smack_sb_copy_data(char *orig, char *smackopts)
}
/**
- * smack_sb_kern_mount - Smack specific mount processing
+ * smack_parse_opts_str - parse Smack specific mount options
+ * @options: mount options string
+ * @opts: where to store converted mount opts
+ *
+ * Returns 0 on success or -ENOMEM on error.
+ *
+ * converts Smack specific mount options to generic security option format
+ */
+static int smack_parse_opts_str(char *options,
+ struct security_mnt_opts *opts)
+{
+ char *p;
+ char *fsdefault = NULL, *fsfloor = NULL;
+ char *fshat = NULL, *fsroot = NULL, *fstransmute = NULL;
+ int rc = -ENOMEM, num_mnt_opts = 0;
+
+ opts->num_mnt_opts = 0;
+
+ if (!options)
+ return 0;
+
+ while ((p = strsep(&options, ",")) != NULL) {
+ int token;
+ substring_t args[MAX_OPT_ARGS];
+
+ if (!*p)
+ continue;
+
+ token = match_token(p, tokens, args);
+
+ switch (token) {
+ case Opt_fsdefault:
+ if (fsdefault)
+ goto out_opt_err;
+ fsdefault = match_strdup(&args[0]);
+ if (!fsdefault)
+ goto out_err;
+ break;
+ case Opt_fsfloor:
+ if (fsfloor)
+ goto out_opt_err;
+ fsfloor = match_strdup(&args[0]);
+ if (!fsfloor)
+ goto out_err;
+ break;
+ case Opt_fshat:
+ if (fshat)
+ goto out_opt_err;
+ fshat = match_strdup(&args[0]);
+ if (!fshat)
+ goto out_err;
+ break;
+ case Opt_fsroot:
+ if (fsroot)
+ goto out_opt_err;
+ fsroot = match_strdup(&args[0]);
+ if (!fsroot)
+ goto out_err;
+ break;
+ case Opt_fstransmute:
+ if (fstransmute)
+ goto out_opt_err;
+ fstransmute = match_strdup(&args[0]);
+ if (!fstransmute)
+ goto out_err;
+ break;
+ default:
+ rc = -EINVAL;
+ pr_warn("Smack: unknown mount option\n");
+ goto out_err;
+ }
+ }
+
+ opts->mnt_opts = kcalloc(NUM_SMK_MNT_OPTS, sizeof(char *), GFP_ATOMIC);
+ if (!opts->mnt_opts)
+ goto out_err;
+
+ opts->mnt_opts_flags = kcalloc(NUM_SMK_MNT_OPTS, sizeof(int),
+ GFP_ATOMIC);
+ if (!opts->mnt_opts_flags) {
+ kfree(opts->mnt_opts);
+ goto out_err;
+ }
+
+ if (fsdefault) {
+ opts->mnt_opts[num_mnt_opts] = fsdefault;
+ opts->mnt_opts_flags[num_mnt_opts++] = FSDEFAULT_MNT;
+ }
+ if (fsfloor) {
+ opts->mnt_opts[num_mnt_opts] = fsfloor;
+ opts->mnt_opts_flags[num_mnt_opts++] = FSFLOOR_MNT;
+ }
+ if (fshat) {
+ opts->mnt_opts[num_mnt_opts] = fshat;
+ opts->mnt_opts_flags[num_mnt_opts++] = FSHAT_MNT;
+ }
+ if (fsroot) {
+ opts->mnt_opts[num_mnt_opts] = fsroot;
+ opts->mnt_opts_flags[num_mnt_opts++] = FSROOT_MNT;
+ }
+ if (fstransmute) {
+ opts->mnt_opts[num_mnt_opts] = fstransmute;
+ opts->mnt_opts_flags[num_mnt_opts++] = FSTRANS_MNT;
+ }
+
+ opts->num_mnt_opts = num_mnt_opts;
+ return 0;
+
+out_opt_err:
+ rc = -EINVAL;
+ pr_warn("Smack: duplicate mount options\n");
+
+out_err:
+ kfree(fsdefault);
+ kfree(fsfloor);
+ kfree(fshat);
+ kfree(fsroot);
+ kfree(fstransmute);
+ return rc;
+}
+
+/**
+ * smack_set_mnt_opts - set Smack specific mount options
* @sb: the file system superblock
- * @flags: the mount flags
- * @data: the smack mount options
+ * @opts: Smack mount options
+ * @kern_flags: mount option from kernel space or user space
+ * @set_kern_flags: where to store converted mount opts
*
* Returns 0 on success, an error code on failure
+ *
+ * Allow filesystems with binary mount data to explicitly set Smack mount
+ * labels.
*/
-static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
+static int smack_set_mnt_opts(struct super_block *sb,
+ struct security_mnt_opts *opts,
+ unsigned long kern_flags,
+ unsigned long *set_kern_flags)
{
struct dentry *root = sb->s_root;
struct inode *inode = d_backing_inode(root);
struct superblock_smack *sp = sb->s_security;
struct inode_smack *isp;
struct smack_known *skp;
- char *op;
- char *commap;
+ int i, num_opts = opts->num_mnt_opts;
int transmute = 0;
- int specified = 0;
if (sp->smk_initialized)
return 0;
sp->smk_initialized = 1;
- for (op = data; op != NULL; op = commap) {
- commap = strchr(op, ',');
- if (commap != NULL)
- *commap++ = '\0';
-
- if (strncmp(op, SMK_FSHAT, strlen(SMK_FSHAT)) == 0) {
- op += strlen(SMK_FSHAT);
- skp = smk_import_entry(op, 0);
+ for (i = 0; i < num_opts; i++) {
+ switch (opts->mnt_opts_flags[i]) {
+ case FSDEFAULT_MNT:
+ skp = smk_import_entry(opts->mnt_opts[i], 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
- sp->smk_hat = skp;
- specified = 1;
-
- } else if (strncmp(op, SMK_FSFLOOR, strlen(SMK_FSFLOOR)) == 0) {
- op += strlen(SMK_FSFLOOR);
- skp = smk_import_entry(op, 0);
+ sp->smk_default = skp;
+ break;
+ case FSFLOOR_MNT:
+ skp = smk_import_entry(opts->mnt_opts[i], 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
sp->smk_floor = skp;
- specified = 1;
-
- } else if (strncmp(op, SMK_FSDEFAULT,
- strlen(SMK_FSDEFAULT)) == 0) {
- op += strlen(SMK_FSDEFAULT);
- skp = smk_import_entry(op, 0);
+ break;
+ case FSHAT_MNT:
+ skp = smk_import_entry(opts->mnt_opts[i], 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
- sp->smk_default = skp;
- specified = 1;
-
- } else if (strncmp(op, SMK_FSROOT, strlen(SMK_FSROOT)) == 0) {
- op += strlen(SMK_FSROOT);
- skp = smk_import_entry(op, 0);
+ sp->smk_hat = skp;
+ break;
+ case FSROOT_MNT:
+ skp = smk_import_entry(opts->mnt_opts[i], 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
sp->smk_root = skp;
- specified = 1;
-
- } else if (strncmp(op, SMK_FSTRANS, strlen(SMK_FSTRANS)) == 0) {
- op += strlen(SMK_FSTRANS);
- skp = smk_import_entry(op, 0);
+ break;
+ case FSTRANS_MNT:
+ skp = smk_import_entry(opts->mnt_opts[i], 0);
if (IS_ERR(skp))
return PTR_ERR(skp);
sp->smk_root = skp;
transmute = 1;
- specified = 1;
+ break;
+ default:
+ break;
}
}
@@ -654,7 +780,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
/*
* Unprivileged mounts don't get to specify Smack values.
*/
- if (specified)
+ if (num_opts)
return -EPERM;
/*
* Unprivileged mounts get root and default from the caller.
@@ -663,6 +789,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
sp->smk_root = skp;
sp->smk_default = skp;
}
+
/*
* Initialize the root inode.
*/
@@ -682,6 +809,37 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
}
/**
+ * smack_sb_kern_mount - Smack specific mount processing
+ * @sb: the file system superblock
+ * @flags: the mount flags
+ * @data: the smack mount options
+ *
+ * Returns 0 on success, an error code on failure
+ */
+static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
+{
+ int rc = 0;
+ char *options = data;
+ struct security_mnt_opts opts;
+
+ security_init_mnt_opts(&opts);
+
+ if (!options)
+ goto out;
+
+ rc = smack_parse_opts_str(options, &opts);
+ if (rc)
+ goto out_err;
+
+out:
+ rc = smack_set_mnt_opts(sb, &opts, 0, NULL);
+
+out_err:
+ security_free_mnt_opts(&opts);
+ return rc;
+}
+
+/**
* smack_sb_statfs - Smack check on statfs
* @dentry: identifies the file system in question
*
@@ -4264,6 +4422,8 @@ struct security_hook_list smack_hooks[] = {
LSM_HOOK_INIT(sb_copy_data, smack_sb_copy_data),
LSM_HOOK_INIT(sb_kern_mount, smack_sb_kern_mount),
LSM_HOOK_INIT(sb_statfs, smack_sb_statfs),
+ LSM_HOOK_INIT(sb_set_mnt_opts, smack_set_mnt_opts),
+ LSM_HOOK_INIT(sb_parse_opts_str, smack_parse_opts_str),
LSM_HOOK_INIT(bprm_set_creds, smack_bprm_set_creds),
LSM_HOOK_INIT(bprm_committing_creds, smack_bprm_committing_creds),
--
1.7.9.5
--
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