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authorOlga Kornievskaia <kolga@netapp.com>2021-02-27 06:37:55 +0300
committerPaul Moore <paul@paul-moore.com>2021-03-22 21:53:37 +0300
commit69c4a42d72eb9b41e1c6e4bc9ab7f3650bf35f62 (patch)
tree564b363284f41cce68ff9b55a2d0fa811bd8bfcf /security
parent431c3be16bd08728325814320e3603ec3284d542 (diff)
downloadlinux-69c4a42d72eb9b41e1c6e4bc9ab7f3650bf35f62.tar.xz
lsm,selinux: add new hook to compare new mount to an existing mount
Add a new hook that takes an existing super block and a new mount with new options and determines if new options confict with an existing mount or not. A filesystem can use this new hook to determine if it can share the an existing superblock with a new superblock for the new mount. Signed-off-by: Olga Kornievskaia <kolga@netapp.com> Acked-by: Anna Schumaker <Anna.Schumaker@Netapp.com> [PM: tweak the subject line, fix tab/space problems] Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'security')
-rw-r--r--security/security.c7
-rw-r--r--security/selinux/hooks.c56
2 files changed, 63 insertions, 0 deletions
diff --git a/security/security.c b/security/security.c
index 5ac96b16f8fa..a4e7d50c3e39 100644
--- a/security/security.c
+++ b/security/security.c
@@ -890,6 +890,13 @@ int security_sb_eat_lsm_opts(char *options, void **mnt_opts)
}
EXPORT_SYMBOL(security_sb_eat_lsm_opts);
+int security_sb_mnt_opts_compat(struct super_block *sb,
+ void *mnt_opts)
+{
+ return call_int_hook(sb_mnt_opts_compat, 0, sb, mnt_opts);
+}
+EXPORT_SYMBOL(security_sb_mnt_opts_compat);
+
int security_sb_remount(struct super_block *sb,
void *mnt_opts)
{
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index eca9fc0ba764..07ca2ebf979e 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2685,6 +2685,61 @@ free_opt:
return rc;
}
+static int selinux_sb_mnt_opts_compat(struct super_block *sb, void *mnt_opts)
+{
+ struct selinux_mnt_opts *opts = mnt_opts;
+ struct superblock_security_struct *sbsec = sb->s_security;
+ u32 sid;
+ int rc;
+
+ /*
+ * Superblock not initialized (i.e. no options) - reject if any
+ * options specified, otherwise accept.
+ */
+ if (!(sbsec->flags & SE_SBINITIALIZED))
+ return opts ? 1 : 0;
+
+ /*
+ * Superblock initialized and no options specified - reject if
+ * superblock has any options set, otherwise accept.
+ */
+ if (!opts)
+ return (sbsec->flags & SE_MNTMASK) ? 1 : 0;
+
+ if (opts->fscontext) {
+ rc = parse_sid(sb, opts->fscontext, &sid);
+ if (rc)
+ return 1;
+ if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, sid))
+ return 1;
+ }
+ if (opts->context) {
+ rc = parse_sid(sb, opts->context, &sid);
+ if (rc)
+ return 1;
+ if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, sid))
+ return 1;
+ }
+ if (opts->rootcontext) {
+ struct inode_security_struct *root_isec;
+
+ root_isec = backing_inode_security(sb->s_root);
+ rc = parse_sid(sb, opts->rootcontext, &sid);
+ if (rc)
+ return 1;
+ if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, sid))
+ return 1;
+ }
+ if (opts->defcontext) {
+ rc = parse_sid(sb, opts->defcontext, &sid);
+ if (rc)
+ return 1;
+ if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, sid))
+ return 1;
+ }
+ return 0;
+}
+
static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)
{
struct selinux_mnt_opts *opts = mnt_opts;
@@ -7078,6 +7133,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(sb_free_security, selinux_sb_free_security),
LSM_HOOK_INIT(sb_free_mnt_opts, selinux_free_mnt_opts),
+ LSM_HOOK_INIT(sb_mnt_opts_compat, selinux_sb_mnt_opts_compat),
LSM_HOOK_INIT(sb_remount, selinux_sb_remount),
LSM_HOOK_INIT(sb_kern_mount, selinux_sb_kern_mount),
LSM_HOOK_INIT(sb_show_options, selinux_sb_show_options),