Commit b8b87fd954b4 ("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@xxxxxxxxxx>
---
security/selinux/hooks.c | 202 ++++++++++-----------------------------
1 file changed, 53 insertions(+), 149 deletions(-)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index b60481192b38..e2a3b872c0f9 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -340,7 +340,6 @@ static void inode_free_security(struct inode *inode)
}
struct selinux_mnt_opts {
- const char *fscontext, *context, *rootcontext, *defcontext;
u32 fscontext_sid;
u32 context_sid;
u32 rootcontext_sid;
@@ -349,12 +348,7 @@ struct selinux_mnt_opts {
static void selinux_free_mnt_opts(void *mnt_opts)
{
- struct selinux_mnt_opts *opts = mnt_opts;
- kfree(opts->fscontext);
- kfree(opts->context);
- kfree(opts->rootcontext);
- kfree(opts->defcontext);
- kfree(opts);
+ kfree(mnt_opts);
}
enum {
@@ -601,17 +595,6 @@ static int bad_option(struct superblock_security_struct *sbsec, char flag,
return 0;
}
-static int parse_sid(struct super_block *sb, const char *s, u32 *sid)
-{
- int rc = security_context_str_to_sid(&selinux_state, s,
- sid, GFP_KERNEL);
- if (rc)
- pr_warn("SELinux: security_context_str_to_sid"
- "(%s) failed for (dev %s, type %s) errno=%d\n",
- s, sb ? sb->s_id : "?", sb ? sb->s_type->name : "?", rc);
- return rc;
-}
-
/*
* Allow filesystems with binary mount data to explicitly set mount point
* labeling information.
@@ -674,49 +657,29 @@ static int selinux_set_mnt_opts(struct super_block *sb,
* than once with different security options.
*/
if (opts) {
- if (opts->fscontext) {
- if (opts->fscontext_sid == SECSID_NULL) {
- rc = parse_sid(sb, opts->fscontext, &fscontext_sid);
- if (rc)
- goto out;
- } else
- fscontext_sid = opts->fscontext_sid;
+ if (opts->fscontext_sid) {
+ fscontext_sid = opts->fscontext_sid;
if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
fscontext_sid))
goto out_double_mount;
sbsec->flags |= FSCONTEXT_MNT;
}
- if (opts->context) {
- if (opts->context_sid == SECSID_NULL) {
- rc = parse_sid(sb, opts->context, &context_sid);
- if (rc)
- goto out;
- } else
- context_sid = opts->context_sid;
+ if (opts->context_sid) {
+ context_sid = opts->context_sid;
if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
context_sid))
goto out_double_mount;
sbsec->flags |= CONTEXT_MNT;
}
- if (opts->rootcontext) {
- if (opts->rootcontext_sid == SECSID_NULL) {
- rc = parse_sid(sb, opts->rootcontext, &rootcontext_sid);
- if (rc)
- goto out;
- } else
- rootcontext_sid = opts->rootcontext_sid;
+ if (opts->rootcontext_sid) {
+ rootcontext_sid = opts->rootcontext_sid;
if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
rootcontext_sid))
goto out_double_mount;
sbsec->flags |= ROOTCONTEXT_MNT;
}
- if (opts->defcontext) {
- if (opts->defcontext_sid == SECSID_NULL) {
- rc = parse_sid(sb, opts->defcontext, &defcontext_sid);
- if (rc)
- goto out;
- } else
- defcontext_sid = opts->defcontext_sid;
+ if (opts->defcontext_sid) {
+ defcontext_sid = opts->defcontext_sid;
if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
defcontext_sid))
goto out_double_mount;
@@ -986,6 +949,8 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts)
{
struct selinux_mnt_opts *opts = *mnt_opts;
bool is_alloc_opts = false;
+ u32 *dst_sid;
+ int rc;
if (token == Opt_seclabel)
/* eaten and completely ignored */
@@ -993,6 +958,11 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts)
if (!s)
return -ENOMEM;
+ if (!selinux_initialized(&selinux_state)) {
+ pr_warn("SELinux: Unable to set superblock options before the security server is initialized\n");
+ return -EINVAL;
+ }
+
if (!opts) {
opts = kzalloc(sizeof(*opts), GFP_KERNEL);
if (!opts)
@@ -1003,36 +973,34 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts)
switch (token) {
case Opt_context:
- if (opts->context || opts->defcontext)
+ if (opts->context_sid || opts->defcontext_sid)
goto err;
- opts->context = s;
- if (selinux_initialized(&selinux_state))
- parse_sid(NULL, s, &opts->context_sid);
+ dst_sid = &opts->context_sid;
break;
case Opt_fscontext:
- if (opts->fscontext)
+ if (opts->fscontext_sid)
goto err;
- opts->fscontext = s;
- if (selinux_initialized(&selinux_state))
- parse_sid(NULL, s, &opts->fscontext_sid);
+ dst_sid = &opts->fscontext_sid;
break;
case Opt_rootcontext:
- if (opts->rootcontext)
+ if (opts->rootcontext_sid)
goto err;
- opts->rootcontext = s;
- if (selinux_initialized(&selinux_state))
- parse_sid(NULL, s, &opts->rootcontext_sid);
+ dst_sid = &opts->rootcontext_sid;
break;
case Opt_defcontext:
- if (opts->context || opts->defcontext)
+ if (opts->context_sid || opts->defcontext_sid)
goto err;
- opts->defcontext = s;
- if (selinux_initialized(&selinux_state))
- parse_sid(NULL, s, &opts->defcontext_sid);
+ dst_sid = &opts->defcontext_sid;
break;
+ default:
+ WARN_ON(1);
+ return -EINVAL;
}
-
- return 0;
+ rc = security_context_str_to_sid(&selinux_state, s, dst_sid, GFP_KERNEL);
+ if (rc)
+ pr_warn("SELinux: security_context_str_to_sid (%s) failed with errno=%d\n",
+ s, rc);
+ return rc;
err:
if (is_alloc_opts) {
@@ -2681,37 +2649,27 @@ static int selinux_sb_mnt_opts_compat(struct super_block *sb, void *mnt_opts)
if (!opts)
return (sbsec->flags & SE_MNTMASK) ? 1 : 0;
- if (opts->fscontext) {
- if (opts->fscontext_sid == SECSID_NULL)
- return 1;
- else if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
- opts->fscontext_sid))
+ if (opts->fscontext_sid) {
+ if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
+ opts->fscontext_sid))
return 1;
}
- if (opts->context) {
- if (opts->context_sid == SECSID_NULL)
- return 1;
- else if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
- opts->context_sid))
+ if (opts->context_sid) {
+ if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
+ opts->context_sid))
return 1;
}
- if (opts->rootcontext) {
- if (opts->rootcontext_sid == SECSID_NULL)
- return 1;
- else {
- struct inode_security_struct *root_isec;
+ if (opts->rootcontext_sid) {
+ struct inode_security_struct *root_isec;
- root_isec = backing_inode_security(sb->s_root);
- if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
- opts->rootcontext_sid))
- return 1;
- }
- }
- if (opts->defcontext) {
- if (opts->defcontext_sid == SECSID_NULL)
+ root_isec = backing_inode_security(sb->s_root);
+ if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
+ opts->rootcontext_sid))
return 1;
- else if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
- opts->defcontext_sid))
+ }
+ if (opts->defcontext_sid) {
+ if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
+ opts->defcontext_sid))
return 1;
}
return 0;
@@ -2721,7 +2679,6 @@ static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)
{
struct selinux_mnt_opts *opts = mnt_opts;
struct superblock_security_struct *sbsec = selinux_superblock(sb);
- int rc;
if (!(sbsec->flags & SE_SBINITIALIZED))
return 0;
@@ -2729,47 +2686,24 @@ static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)
if (!opts)
return 0;
- if (opts->fscontext) {
- if (opts->fscontext_sid == SECSID_NULL) {
- rc = parse_sid(sb, opts->fscontext,
- &opts->fscontext_sid);
- if (rc)
- return rc;
- }
+ if (opts->fscontext_sid) {
if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
opts->fscontext_sid))
goto out_bad_option;
}
- if (opts->context) {
- if (opts->context_sid == SECSID_NULL) {
- rc = parse_sid(sb, opts->context, &opts->context_sid);
- if (rc)
- return rc;
- }
+ if (opts->context_sid) {
if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
opts->context_sid))
goto out_bad_option;
}
- if (opts->rootcontext) {
+ if (opts->rootcontext_sid) {
struct inode_security_struct *root_isec;
root_isec = backing_inode_security(sb->s_root);
- if (opts->rootcontext_sid == SECSID_NULL) {
- rc = parse_sid(sb, opts->rootcontext,
- &opts->rootcontext_sid);
- if (rc)
- return rc;
- }
if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
opts->rootcontext_sid))
goto out_bad_option;
}
- if (opts->defcontext) {
- if (opts->defcontext_sid == SECSID_NULL) {
- rc = parse_sid(sb, opts->defcontext,
- &opts->defcontext_sid);
- if (rc)
- return rc;
- }
+ if (opts->defcontext_sid) {
if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
opts->defcontext_sid))
goto out_bad_option;
@@ -2838,42 +2772,12 @@ static int selinux_fs_context_dup(struct fs_context *fc,
struct fs_context *src_fc)
{
const struct selinux_mnt_opts *src = src_fc->security;
- struct selinux_mnt_opts *opts;
if (!src)
return 0;
- fc->security = kzalloc(sizeof(struct selinux_mnt_opts), GFP_KERNEL);
- if (!fc->security)
- return -ENOMEM;
-
- opts = fc->security;
-
- if (src->fscontext) {
- opts->fscontext = kstrdup(src->fscontext, GFP_KERNEL);
- if (!opts->fscontext)
- return -ENOMEM;
- }
- if (src->context) {
- opts->context = kstrdup(src->context, GFP_KERNEL);
- if (!opts->context)
- return -ENOMEM;
- }
- if (src->rootcontext) {
- opts->rootcontext = kstrdup(src->rootcontext, GFP_KERNEL);
- if (!opts->rootcontext)
- return -ENOMEM;
- }
- if (src->defcontext) {
- opts->defcontext = kstrdup(src->defcontext, GFP_KERNEL);
- if (!opts->defcontext)
- return -ENOMEM;
- }
- opts->fscontext_sid = src->fscontext_sid;
- opts->context_sid = src->context_sid;
- opts->rootcontext_sid = src->rootcontext_sid;
- opts->defcontext_sid = src->defcontext_sid;
- return 0;
+ fc->security = kmemdup(src, sizeof(*src), GFP_KERNEL);
+ return fc->security ? 0 : -ENOMEM;
}
static const struct fs_parameter_spec selinux_fs_parameters[] = {
--
2.34.1
