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-rw-r--r--security/commoncap.c10
-rw-r--r--security/integrity/evm/evm_crypto.c4
-rw-r--r--security/selinux/hooks.c25
-rw-r--r--security/smack/smack.h8
-rw-r--r--security/smack/smack_lsm.c34
5 files changed, 73 insertions, 8 deletions
diff --git a/security/commoncap.c b/security/commoncap.c
index e7fadde737f4..14540bd78561 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -453,7 +453,15 @@ static int get_file_caps(struct linux_binprm *bprm, bool *effective, bool *has_c
if (!file_caps_enabled)
return 0;
- if (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)
+ if (!mnt_may_suid(bprm->file->f_path.mnt))
+ return 0;
+
+ /*
+ * This check is redundant with mnt_may_suid() but is kept to make
+ * explicit that capability bits are limited to s_user_ns and its
+ * descendants.
+ */
+ if (!current_in_userns(bprm->file->f_path.mnt->mnt_sb->s_user_ns))
return 0;
rc = get_vfs_caps_from_disk(bprm->file->f_path.dentry, &vcaps);
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index 30b6b7d0429f..11c1d30bd705 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -151,8 +151,8 @@ static void hmac_add_misc(struct shash_desc *desc, struct inode *inode,
memset(&hmac_misc, 0, sizeof(hmac_misc));
hmac_misc.ino = inode->i_ino;
hmac_misc.generation = inode->i_generation;
- hmac_misc.uid = from_kuid(&init_user_ns, inode->i_uid);
- hmac_misc.gid = from_kgid(&init_user_ns, inode->i_gid);
+ hmac_misc.uid = from_kuid(inode->i_sb->s_user_ns, inode->i_uid);
+ hmac_misc.gid = from_kgid(inode->i_sb->s_user_ns, inode->i_gid);
hmac_misc.mode = inode->i_mode;
crypto_shash_update(desc, (const u8 *)&hmac_misc, sizeof(hmac_misc));
if (evm_hmac_attrs & EVM_ATTR_FSUUID)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index a86d537eb79b..19be9d39c742 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -830,6 +830,28 @@ static int selinux_set_mnt_opts(struct super_block *sb,
goto out;
}
}
+
+ /*
+ * If this is a user namespace mount, no contexts are allowed
+ * on the command line and security labels must be ignored.
+ */
+ if (sb->s_user_ns != &init_user_ns) {
+ if (context_sid || fscontext_sid || rootcontext_sid ||
+ defcontext_sid) {
+ rc = -EACCES;
+ goto out;
+ }
+ if (sbsec->behavior == SECURITY_FS_USE_XATTR) {
+ sbsec->behavior = SECURITY_FS_USE_MNTPOINT;
+ rc = security_transition_sid(current_sid(), current_sid(),
+ SECCLASS_FILE, NULL,
+ &sbsec->mntpoint_sid);
+ if (rc)
+ goto out;
+ }
+ goto out_set_opts;
+ }
+
/* sets the context of the superblock for the fs being mounted. */
if (fscontext_sid) {
rc = may_context_mount_sb_relabel(fscontext_sid, sbsec, cred);
@@ -898,6 +920,7 @@ static int selinux_set_mnt_opts(struct super_block *sb,
sbsec->def_sid = defcontext_sid;
}
+out_set_opts:
rc = sb_finish_set_opts(sb);
out:
mutex_unlock(&sbsec->lock);
@@ -2259,7 +2282,7 @@ static int check_nnp_nosuid(const struct linux_binprm *bprm,
const struct task_security_struct *new_tsec)
{
int nnp = (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS);
- int nosuid = (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID);
+ int nosuid = !mnt_may_suid(bprm->file->f_path.mnt);
int rc;
if (!nnp && !nosuid)
diff --git a/security/smack/smack.h b/security/smack/smack.h
index 6c91156ae225..26e58f1804b1 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -90,9 +90,15 @@ struct superblock_smack {
struct smack_known *smk_floor;
struct smack_known *smk_hat;
struct smack_known *smk_default;
- int smk_initialized;
+ int smk_flags;
};
+/*
+ * Superblock flags
+ */
+#define SMK_SB_INITIALIZED 0x01
+#define SMK_SB_UNTRUSTED 0x02
+
struct socket_smack {
struct smack_known *smk_out; /* outbound label */
struct smack_known *smk_in; /* inbound label */
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 6777295f4b2b..b75634dbf53b 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -549,7 +549,7 @@ static int smack_sb_alloc_security(struct super_block *sb)
sbsp->smk_floor = &smack_known_floor;
sbsp->smk_hat = &smack_known_hat;
/*
- * smk_initialized will be zero from kzalloc.
+ * SMK_SB_INITIALIZED will be zero from kzalloc.
*/
sb->s_security = sbsp;
@@ -766,10 +766,10 @@ static int smack_set_mnt_opts(struct super_block *sb,
int num_opts = opts->num_mnt_opts;
int transmute = 0;
- if (sp->smk_initialized)
+ if (sp->smk_flags & SMK_SB_INITIALIZED)
return 0;
- sp->smk_initialized = 1;
+ sp->smk_flags |= SMK_SB_INITIALIZED;
for (i = 0; i < num_opts; i++) {
switch (opts->mnt_opts_flags[i]) {
@@ -821,6 +821,17 @@ static int smack_set_mnt_opts(struct super_block *sb,
skp = smk_of_current();
sp->smk_root = skp;
sp->smk_default = skp;
+ /*
+ * For a handful of fs types with no user-controlled
+ * backing store it's okay to trust security labels
+ * in the filesystem. The rest are untrusted.
+ */
+ if (sb->s_user_ns != &init_user_ns &&
+ sb->s_magic != SYSFS_MAGIC && sb->s_magic != TMPFS_MAGIC &&
+ sb->s_magic != RAMFS_MAGIC) {
+ transmute = 1;
+ sp->smk_flags |= SMK_SB_UNTRUSTED;
+ }
}
/*
@@ -908,6 +919,7 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm)
struct inode *inode = file_inode(bprm->file);
struct task_smack *bsp = bprm->cred->security;
struct inode_smack *isp;
+ struct superblock_smack *sbsp;
int rc;
if (bprm->cred_prepared)
@@ -917,6 +929,11 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm)
if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task)
return 0;
+ sbsp = inode->i_sb->s_security;
+ if ((sbsp->smk_flags & SMK_SB_UNTRUSTED) &&
+ isp->smk_task != sbsp->smk_root)
+ return 0;
+
if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
struct task_struct *tracer;
rc = 0;
@@ -1203,6 +1220,7 @@ static int smack_inode_rename(struct inode *old_inode,
*/
static int smack_inode_permission(struct inode *inode, int mask)
{
+ struct superblock_smack *sbsp = inode->i_sb->s_security;
struct smk_audit_info ad;
int no_block = mask & MAY_NOT_BLOCK;
int rc;
@@ -1214,6 +1232,11 @@ static int smack_inode_permission(struct inode *inode, int mask)
if (mask == 0)
return 0;
+ if (sbsp->smk_flags & SMK_SB_UNTRUSTED) {
+ if (smk_of_inode(inode) != sbsp->smk_root)
+ return -EACCES;
+ }
+
/* May be droppable after audit */
if (no_block)
return -ECHILD;
@@ -1708,6 +1731,7 @@ static int smack_mmap_file(struct file *file,
struct task_smack *tsp;
struct smack_known *okp;
struct inode_smack *isp;
+ struct superblock_smack *sbsp;
int may;
int mmay;
int tmay;
@@ -1719,6 +1743,10 @@ static int smack_mmap_file(struct file *file,
isp = file_inode(file)->i_security;
if (isp->smk_mmap == NULL)
return 0;
+ sbsp = file_inode(file)->i_sb->s_security;
+ if (sbsp->smk_flags & SMK_SB_UNTRUSTED &&
+ isp->smk_mmap != sbsp->smk_root)
+ return -EACCES;
mkp = isp->smk_mmap;
tsp = current_security();
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.