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| author | Olga Kornievskaia <kolga@netapp.com> | 2021-02-26 22:37:55 -0500 |
|---|---|---|
| committer | Paul Moore <paul@paul-moore.com> | 2021-03-22 14:53:37 -0400 |
| commit | 69c4a42d72eb9b41e1c6e4bc9ab7f3650bf35f62 (patch) | |
| tree | 564b363284f41cce68ff9b55a2d0fa811bd8bfcf /security/selinux | |
| parent | 431c3be16bd08728325814320e3603ec3284d542 (diff) | |
| download | lwn-69c4a42d72eb9b41e1c6e4bc9ab7f3650bf35f62.tar.gz lwn-69c4a42d72eb9b41e1c6e4bc9ab7f3650bf35f62.zip | |
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/selinux')
| -rw-r--r-- | security/selinux/hooks.c | 56 |
1 files changed, 56 insertions, 0 deletions
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), |