This patch will display selinux mount options in /proc/mounts. It does
so by building a complete string and then writing it to the seq_file. I
could cut a fair bit of this patch out by just writing things piecemeal
to the seq_file but when I did that none of the code looked like it
could ever be used again. Do we think we'll ever have another need to
turn a superblock back into an option string? Should I just make this
patch as small as possible?
Anyway, lightly tested and never looked at since I wrote it so it could
very likely have bad error handling or memory leaks or major flaws....
comments?
-Eric
---
fs/namespace.c | 4 +
include/linux/security.h | 9 +++
security/dummy.c | 6 ++
security/security.c | 5 ++
security/selinux/hooks.c | 121 ++++++++++++++++++++++++++++++++---
security/selinux/include/security.h | 5 ++
6 files changed, 141 insertions(+), 9 deletions(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index 94f026e..a9748d3 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -426,8 +426,12 @@ static int show_vfsmnt(struct seq_file *m, void *v)
if (mnt->mnt_flags & fs_infop->flag)
seq_puts(m, fs_infop->str);
}
+ err = security_sb_show_options(m, mnt->mnt_sb);
+ if (err)
+ goto out;
if (mnt->mnt_sb->s_op->show_options)
err = mnt->mnt_sb->s_op->show_options(m, mnt);
+out:
seq_puts(m, " 0 0\n");
return err;
}
diff --git a/include/linux/security.h b/include/linux/security.h
index c673dfd..2743bf2 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -74,6 +74,7 @@ struct xfrm_selector;
struct xfrm_policy;
struct xfrm_state;
struct xfrm_user_sec_ctx;
+struct seq_file;
extern int cap_netlink_send(struct sock *sk, struct sk_buff *skb);
extern int cap_netlink_recv(struct sk_buff *skb, int cap);
@@ -1259,6 +1260,7 @@ struct security_operations {
void (*sb_free_security) (struct super_block * sb);
int (*sb_copy_data)(char *orig, char *copy);
int (*sb_kern_mount) (struct super_block *sb, void *data);
+ int (*sb_show_options) (struct seq_file *m, struct super_block *sb);
int (*sb_statfs) (struct dentry *dentry);
int (*sb_mount) (char *dev_name, struct nameidata * nd,
char *type, unsigned long flags, void *data);
@@ -1527,6 +1529,7 @@ int security_sb_alloc(struct super_block *sb);
void security_sb_free(struct super_block *sb);
int security_sb_copy_data(char *orig, char *copy);
int security_sb_kern_mount(struct super_block *sb, void *data);
+int security_sb_show_options(struct seq_file *m, struct super_block *sb);
int security_sb_statfs(struct dentry *dentry);
int security_sb_mount(char *dev_name, struct nameidata *nd,
char *type, unsigned long flags, void *data);
@@ -1800,6 +1803,12 @@ static inline int security_sb_kern_mount (struct super_block *sb, void *data)
return 0;
}
+static inline int security_sb_show_options (struct seq_file *m,
+ struct super_block *sb)
+{
+ return 0;
+}
+
static inline int security_sb_statfs (struct dentry *dentry)
{
return 0;
diff --git a/security/dummy.c b/security/dummy.c
index 78d8f92..7f8ac13 100644
--- a/security/dummy.c
+++ b/security/dummy.c
@@ -191,6 +191,11 @@ static int dummy_sb_kern_mount (struct super_block *sb, void *data)
return 0;
}
+static int dummy_sb_show_options (struct seq_file *m, struct super_block *sb)
+{
+ return 0;
+}
+
static int dummy_sb_statfs (struct dentry *dentry)
{
return 0;
@@ -1017,6 +1022,7 @@ void security_fixup_ops (struct security_operations *ops)
set_to_dummy_if_null(ops, sb_free_security);
set_to_dummy_if_null(ops, sb_copy_data);
set_to_dummy_if_null(ops, sb_kern_mount);
+ set_to_dummy_if_null(ops, sb_show_options);
set_to_dummy_if_null(ops, sb_statfs);
set_to_dummy_if_null(ops, sb_mount);
set_to_dummy_if_null(ops, sb_check_sb);
diff --git a/security/security.c b/security/security.c
index b1387a6..93e6309 100644
--- a/security/security.c
+++ b/security/security.c
@@ -255,6 +255,11 @@ int security_sb_kern_mount(struct super_block *sb, void *data)
return security_ops->sb_kern_mount(sb, data);
}
+int security_sb_show_options (struct seq_file *m, struct super_block *sb)
+{
+ return security_ops->sb_show_options(m, sb);
+}
+
int security_sb_statfs(struct dentry *dentry)
{
return security_ops->sb_statfs(dentry);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 41a049f..1bdc7b7 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -16,10 +16,11 @@
* Paul Moore <paul.moore@xxxxxx>
* Copyright (C) 2007 Hitachi Software Engineering Co., Ltd.
* Yuichi Nakamura <ynakam@xxxxxxxxxxxxxx>
+ * Copyright (C) 2006-2008 Red Hat, Inc., Eric Paris <eparis@xxxxxxxxxx>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2,
- * as published by the Free Software Foundation.
+ * as published by the Free Software Foundation.
*/
#include <linux/init.h>
@@ -324,10 +325,10 @@ enum {
};
static match_table_t tokens = {
- {Opt_context, "context=%s"},
- {Opt_fscontext, "fscontext=%s"},
- {Opt_defcontext, "defcontext=%s"},
- {Opt_rootcontext, "rootcontext=%s"},
+ {Opt_context, CONTEXT_STR "%s"},
+ {Opt_fscontext, FSCONTEXT_STR "%s"},
+ {Opt_defcontext, DEFCONTEXT_STR "%s"},
+ {Opt_rootcontext, ROOTCONTEXT_STR "%s"},
{Opt_error, NULL},
};
@@ -947,6 +948,107 @@ out_err:
return rc;
}
+int selinux_get_opts_str(char **ret_str, struct security_mnt_opts *opts)
+{
+ size_t total_len = 0;
+ char *new_string;
+ int i;
+
+ if (opts->num_mnt_opts == 0) {
+ *ret_str = NULL;
+ return 0;
+ }
+
+ /* determine size of the new string */
+ for(i = 0; i < opts->num_mnt_opts; i++) {
+ total_len += strlen(opts->mnt_opts[i]);
+ switch (opts->mnt_opts_flags[i]) {
+ case CONTEXT_MNT:
+ total_len += strlen(CONTEXT_STR);
+ break;
+ case FSCONTEXT_MNT:
+ total_len += strlen(FSCONTEXT_STR);
+ break;
+ case ROOTCONTEXT_MNT:
+ total_len += strlen(ROOTCONTEXT_STR);
+ break;
+ case DEFCONTEXT_MNT:
+ total_len += strlen(DEFCONTEXT_STR);
+ break;
+ default:
+ BUG();
+ };
+ /* comma between options */
+ total_len += 1;
+ }
+
+ *ret_str = new_string = kmalloc((total_len + 1) * sizeof(char), GFP_KERNEL);
+ if (!new_string)
+ return -ENOMEM;
+
+ /* build new string */
+ new_string[0] = '\0';
+ for(i = 0; i < opts->num_mnt_opts; i++) {
+ /* we need a comma before each option */
+ strcat(new_string, ",");
+ switch (opts->mnt_opts_flags[i]) {
+ case CONTEXT_MNT:
+ strcat(new_string, CONTEXT_STR);
+ break;
+ case FSCONTEXT_MNT:
+ strcat(new_string, FSCONTEXT_STR);
+ break;
+ case ROOTCONTEXT_MNT:
+ strcat(new_string, ROOTCONTEXT_STR);
+ break;
+ case DEFCONTEXT_MNT:
+ strcat(new_string, DEFCONTEXT_STR);
+ break;
+ default:
+ BUG();
+ };
+ strcat(new_string, opts->mnt_opts[i]);
+ }
+ return 0;
+}
+
+static char *selinux_sb_to_opts_str(struct super_block *sb)
+{
+ struct security_mnt_opts opts;
+ char *opts_str = NULL;
+
+ int rc;
+
+ rc = selinux_get_mnt_opts(sb, &opts);
+ if (rc)
+ return ERR_PTR(rc);
+
+ rc = selinux_get_opts_str(&opts_str, &opts);
+ if (rc)
+ return ERR_PTR(rc);
+
+ security_free_mnt_opts(&opts);
+
+ return opts_str;
+}
+
+
+static int selinux_sb_show_options(struct seq_file *m, struct super_block *sb)
+{
+ char *opts_str;
+ int rc = 0;
+
+ opts_str = selinux_sb_to_opts_str(sb);
+
+ if (IS_ERR(opts_str))
+ return PTR_ERR(opts_str);
+
+ rc = seq_puts(m, opts_str);
+
+ kfree(opts_str);
+ return rc;
+}
+
static inline u16 inode_mode_to_security_class(umode_t mode)
{
switch (mode & S_IFMT) {
@@ -2232,10 +2334,10 @@ static inline int match_prefix(char *prefix, int plen, char *option, int olen)
static inline int selinux_option(char *option, int len)
{
- return (match_prefix("context=", sizeof("context=")-1, option, len) ||
- match_prefix("fscontext=", sizeof("fscontext=")-1, option, len) ||
- match_prefix("defcontext=", sizeof("defcontext=")-1, option, len) ||
- match_prefix("rootcontext=", sizeof("rootcontext=")-1, option, len));
+ return (match_prefix(CONTEXT_STR, sizeof(CONTEXT_STR)-1, option, len) ||
+ match_prefix(FSCONTEXT_STR, sizeof(FSCONTEXT_STR)-1, option, len) ||
+ match_prefix(DEFCONTEXT_STR, sizeof(DEFCONTEXT_STR)-1, option, len) ||
+ match_prefix(ROOTCONTEXT_STR, sizeof(ROOTCONTEXT_STR)-1, option, len));
}
static inline void take_option(char **to, char *from, int *first, int len)
@@ -5257,6 +5359,7 @@ static struct security_operations selinux_ops = {
.sb_free_security = selinux_sb_free_security,
.sb_copy_data = selinux_sb_copy_data,
.sb_kern_mount = selinux_sb_kern_mount,
+ .sb_show_options = selinux_sb_show_options,
.sb_statfs = selinux_sb_statfs,
.sb_mount = selinux_mount,
.sb_umount = selinux_umount,
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index f7d2f03..63e0171 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -40,6 +40,11 @@
#define ROOTCONTEXT_MNT 0x04
#define DEFCONTEXT_MNT 0x08
+#define CONTEXT_STR "context="
+#define FSCONTEXT_STR "fscontext="
+#define ROOTCONTEXT_STR "rootcontext="
+#define DEFCONTEXT_STR "defcontext="
+
struct netlbl_lsm_secattr;
extern int selinux_enabled;
--
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