![Andrey Ryabinin](/assets/img/avatar_default.png)
We hit use after free on dereferncing pointer to task_smack struct in smk_of_task() called from smack_task_to_inode(). task_security() macro uses task_cred_xxx() to get pointer to the task_smack. task_cred_xxx() could be used only for non-pointer members of task's credentials. It cannot be used for pointer members since what they point to may disapper after dropping RCU read lock. Mainly task_security() used this way: smk_of_task(task_security(p)) Intead of this introduce function smk_of_task_struct() which takes task_struct as argument and returns pointer to smk_known struct and do this under RCU read lock. Bogus task_security() macro is not used anymore, so remove it. KASan's report for this: AddressSanitizer: use after free in smack_task_to_inode+0x50/0x70 at addr c4635600 ============================================================================= BUG kmalloc-64 (Tainted: PO): kasan error ----------------------------------------------------------------------------- Disabling lock debugging due to kernel taint INFO: Allocated in new_task_smack+0x44/0xd8 age=39 cpu=0 pid=1866 kmem_cache_alloc_trace+0x88/0x1bc new_task_smack+0x44/0xd8 smack_cred_prepare+0x48/0x21c security_prepare_creds+0x44/0x4c prepare_creds+0xdc/0x110 smack_setprocattr+0x104/0x150 security_setprocattr+0x4c/0x54 proc_pid_attr_write+0x12c/0x194 vfs_write+0x1b0/0x370 SyS_write+0x5c/0x94 ret_fast_syscall+0x0/0x48 INFO: Freed in smack_cred_free+0xc4/0xd0 age=27 cpu=0 pid=1564 kfree+0x270/0x290 smack_cred_free+0xc4/0xd0 security_cred_free+0x34/0x3c put_cred_rcu+0x58/0xcc rcu_process_callbacks+0x738/0x998 __do_softirq+0x264/0x4cc do_softirq+0x94/0xf4 irq_exit+0xbc/0x120 handle_IRQ+0x104/0x134 gic_handle_irq+0x70/0xac __irq_svc+0x44/0x78 _raw_spin_unlock+0x18/0x48 sync_inodes_sb+0x17c/0x1d8 sync_filesystem+0xac/0xfc vdfs_file_fsync+0x90/0xc0 vfs_fsync_range+0x74/0x7c INFO: Slab 0xd3b23f50 objects=32 used=31 fp=0xc4635600 flags=0x4080 INFO: Object 0xc4635600 @offset=5632 fp=0x (null) Bytes b4 c46355f0: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ Object c4635600: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object c4635610: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object c4635620: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object c4635630: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkkkkkkkkkk. Redzone c4635640: bb bb bb bb .... Padding c46356e8: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ Padding c46356f8: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ CPU: 5 PID: 834 Comm: launchpad_prelo Tainted: PBO 3.10.30 #1 Backtrace: [<c00233a4>] (dump_backtrace+0x0/0x158) from [<c0023dec>] (show_stack+0x20/0x24) r7:c4634010 r6:d3b23f50 r5:c4635600 r4:d1002140 [<c0023dcc>] (show_stack+0x0/0x24) from [<c06d6d7c>] (dump_stack+0x20/0x28) [<c06d6d5c>] (dump_stack+0x0/0x28) from [<c01c1d50>] (print_trailer+0x124/0x144) [<c01c1c2c>] (print_trailer+0x0/0x144) from [<c01c1e88>] (object_err+0x3c/0x44) r7:c4635600 r6:d1002140 r5:d3b23f50 r4:c4635600 [<c01c1e4c>] (object_err+0x0/0x44) from [<c01cac18>] (kasan_report_error+0x2b8/0x538) r6:d1002140 r5:d3b23f50 r4:c6429cf8 r3:c09e1aa7 [<c01ca960>] (kasan_report_error+0x0/0x538) from [<c01c9430>] (__asan_load4+0xd4/0xf8) [<c01c935c>] (__asan_load4+0x0/0xf8) from [<c031e168>] (smack_task_to_inode+0x50/0x70) r5:c4635600 r4:ca9da000 [<c031e118>] (smack_task_to_inode+0x0/0x70) from [<c031af64>] (security_task_to_inode+0x3c/0x44) r5:cca25e80 r4:c0ba9780 [<c031af28>] (security_task_to_inode+0x0/0x44) from [<c023d614>] (pid_revalidate+0x124/0x178) r6:00000000 r5:cca25e80 r4:cbabe3c0 r3:00008124 [<c023d4f0>] (pid_revalidate+0x0/0x178) from [<c01db98c>] (lookup_fast+0x35c/0x43y4) r9:c6429efc r8:00000101 r7:c079d940 r6:c6429e90 r5:c6429ed8 r4:c83c4148 [<c01db630>] (lookup_fast+0x0/0x434) from [<c01deec8>] (do_last.isra.24+0x1c0/0x1108) [<c01ded08>] (do_last.isra.24+0x0/0x1108) from [<c01dff04>] (path_openat.isra.25+0xf4/0x648) [<c01dfe10>] (path_openat.isra.25+0x0/0x648) from [<c01e1458>] (do_filp_open+0x3c/0x88) [<c01e141c>] (do_filp_open+0x0/0x88) from [<c01ccb28>] (do_sys_open+0xf0/0x198) r7:00000001 r6:c0ea2180 r5:0000000b r4:00000000 [<c01cca38>] (do_sys_open+0x0/0x198) from [<c01ccc00>] (SyS_open+0x30/0x34) [<c01ccbd0>] (SyS_open+0x0/0x34) from [<c001db80>] (ret_fast_syscall+0x0/0x48) Read of size 4 by thread T834: Memory state around the buggy address: c4635380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc c4635400: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc c4635480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc c4635500: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc c4635580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >c4635600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ c4635680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb c4635700: 00 00 00 00 04 fc fc fc fc fc fc fc fc fc fc fc c4635780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc c4635800: 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc fc c4635880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: <stable@vger.kernel.org>
437 lines
11 KiB
C
437 lines
11 KiB
C
/*
|
|
* Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, version 2.
|
|
*
|
|
* Author:
|
|
* Casey Schaufler <casey@schaufler-ca.com>
|
|
*
|
|
*/
|
|
|
|
#ifndef _SECURITY_SMACK_H
|
|
#define _SECURITY_SMACK_H
|
|
|
|
#include <linux/capability.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/security.h>
|
|
#include <linux/in.h>
|
|
#include <net/netlabel.h>
|
|
#include <linux/list.h>
|
|
#include <linux/rculist.h>
|
|
#include <linux/lsm_audit.h>
|
|
|
|
/*
|
|
* Smack labels were limited to 23 characters for a long time.
|
|
*/
|
|
#define SMK_LABELLEN 24
|
|
#define SMK_LONGLABEL 256
|
|
|
|
/*
|
|
* This is the repository for labels seen so that it is
|
|
* not necessary to keep allocating tiny chuncks of memory
|
|
* and so that they can be shared.
|
|
*
|
|
* Labels are never modified in place. Anytime a label
|
|
* is imported (e.g. xattrset on a file) the list is checked
|
|
* for it and it is added if it doesn't exist. The address
|
|
* is passed out in either case. Entries are added, but
|
|
* never deleted.
|
|
*
|
|
* Since labels are hanging around anyway it doesn't
|
|
* hurt to maintain a secid for those awkward situations
|
|
* where kernel components that ought to use LSM independent
|
|
* interfaces don't. The secid should go away when all of
|
|
* these components have been repaired.
|
|
*
|
|
* The cipso value associated with the label gets stored here, too.
|
|
*
|
|
* Keep the access rules for this subject label here so that
|
|
* the entire set of rules does not need to be examined every
|
|
* time.
|
|
*/
|
|
struct smack_known {
|
|
struct list_head list;
|
|
struct hlist_node smk_hashed;
|
|
char *smk_known;
|
|
u32 smk_secid;
|
|
struct netlbl_lsm_secattr smk_netlabel; /* on wire labels */
|
|
struct list_head smk_rules; /* access rules */
|
|
struct mutex smk_rules_lock; /* lock for rules */
|
|
};
|
|
|
|
/*
|
|
* Maximum number of bytes for the levels in a CIPSO IP option.
|
|
* Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
|
|
* bigger than can be used, and 24 is the next lower multiple
|
|
* of 8, and there are too many issues if there isn't space set
|
|
* aside for the terminating null byte.
|
|
*/
|
|
#define SMK_CIPSOLEN 24
|
|
|
|
struct superblock_smack {
|
|
struct smack_known *smk_root;
|
|
struct smack_known *smk_floor;
|
|
struct smack_known *smk_hat;
|
|
struct smack_known *smk_default;
|
|
int smk_initialized;
|
|
};
|
|
|
|
struct socket_smack {
|
|
struct smack_known *smk_out; /* outbound label */
|
|
struct smack_known *smk_in; /* inbound label */
|
|
struct smack_known *smk_packet; /* TCP peer label */
|
|
};
|
|
|
|
/*
|
|
* Inode smack data
|
|
*/
|
|
struct inode_smack {
|
|
struct smack_known *smk_inode; /* label of the fso */
|
|
struct smack_known *smk_task; /* label of the task */
|
|
struct smack_known *smk_mmap; /* label of the mmap domain */
|
|
struct mutex smk_lock; /* initialization lock */
|
|
int smk_flags; /* smack inode flags */
|
|
};
|
|
|
|
struct task_smack {
|
|
struct smack_known *smk_task; /* label for access control */
|
|
struct smack_known *smk_forked; /* label when forked */
|
|
struct list_head smk_rules; /* per task access rules */
|
|
struct mutex smk_rules_lock; /* lock for the rules */
|
|
};
|
|
|
|
#define SMK_INODE_INSTANT 0x01 /* inode is instantiated */
|
|
#define SMK_INODE_TRANSMUTE 0x02 /* directory is transmuting */
|
|
#define SMK_INODE_CHANGED 0x04 /* smack was transmuted */
|
|
|
|
/*
|
|
* A label access rule.
|
|
*/
|
|
struct smack_rule {
|
|
struct list_head list;
|
|
struct smack_known *smk_subject;
|
|
struct smack_known *smk_object;
|
|
int smk_access;
|
|
};
|
|
|
|
/*
|
|
* An entry in the table identifying hosts.
|
|
*/
|
|
struct smk_netlbladdr {
|
|
struct list_head list;
|
|
struct sockaddr_in smk_host; /* network address */
|
|
struct in_addr smk_mask; /* network mask */
|
|
struct smack_known *smk_label; /* label */
|
|
};
|
|
|
|
/*
|
|
* An entry in the table identifying ports.
|
|
*/
|
|
struct smk_port_label {
|
|
struct list_head list;
|
|
struct sock *smk_sock; /* socket initialized on */
|
|
unsigned short smk_port; /* the port number */
|
|
struct smack_known *smk_in; /* inbound label */
|
|
struct smack_known *smk_out; /* outgoing label */
|
|
};
|
|
|
|
/*
|
|
* Mount options
|
|
*/
|
|
#define SMK_FSDEFAULT "smackfsdef="
|
|
#define SMK_FSFLOOR "smackfsfloor="
|
|
#define SMK_FSHAT "smackfshat="
|
|
#define SMK_FSROOT "smackfsroot="
|
|
#define SMK_FSTRANS "smackfstransmute="
|
|
|
|
#define SMACK_CIPSO_OPTION "-CIPSO"
|
|
|
|
/*
|
|
* How communications on this socket are treated.
|
|
* Usually it's determined by the underlying netlabel code
|
|
* but there are certain cases, including single label hosts
|
|
* and potentially single label interfaces for which the
|
|
* treatment can not be known in advance.
|
|
*
|
|
* The possibility of additional labeling schemes being
|
|
* introduced in the future exists as well.
|
|
*/
|
|
#define SMACK_UNLABELED_SOCKET 0
|
|
#define SMACK_CIPSO_SOCKET 1
|
|
|
|
/*
|
|
* CIPSO defaults.
|
|
*/
|
|
#define SMACK_CIPSO_DOI_DEFAULT 3 /* Historical */
|
|
#define SMACK_CIPSO_DOI_INVALID -1 /* Not a DOI */
|
|
#define SMACK_CIPSO_DIRECT_DEFAULT 250 /* Arbitrary */
|
|
#define SMACK_CIPSO_MAPPED_DEFAULT 251 /* Also arbitrary */
|
|
#define SMACK_CIPSO_MAXLEVEL 255 /* CIPSO 2.2 standard */
|
|
/*
|
|
* CIPSO 2.2 standard is 239, but Smack wants to use the
|
|
* categories in a structured way that limits the value to
|
|
* the bits in 23 bytes, hence the unusual number.
|
|
*/
|
|
#define SMACK_CIPSO_MAXCATNUM 184 /* 23 * 8 */
|
|
|
|
/*
|
|
* Ptrace rules
|
|
*/
|
|
#define SMACK_PTRACE_DEFAULT 0
|
|
#define SMACK_PTRACE_EXACT 1
|
|
#define SMACK_PTRACE_DRACONIAN 2
|
|
#define SMACK_PTRACE_MAX SMACK_PTRACE_DRACONIAN
|
|
|
|
/*
|
|
* Flags for untraditional access modes.
|
|
* It shouldn't be necessary to avoid conflicts with definitions
|
|
* in fs.h, but do so anyway.
|
|
*/
|
|
#define MAY_TRANSMUTE 0x00001000 /* Controls directory labeling */
|
|
#define MAY_LOCK 0x00002000 /* Locks should be writes, but ... */
|
|
#define MAY_BRINGUP 0x00004000 /* Report use of this rule */
|
|
|
|
/*
|
|
* Just to make the common cases easier to deal with
|
|
*/
|
|
#define MAY_ANYREAD (MAY_READ | MAY_EXEC)
|
|
#define MAY_READWRITE (MAY_READ | MAY_WRITE)
|
|
#define MAY_NOT 0
|
|
|
|
/*
|
|
* Number of access types used by Smack (rwxatlb)
|
|
*/
|
|
#define SMK_NUM_ACCESS_TYPE 7
|
|
|
|
/* SMACK data */
|
|
struct smack_audit_data {
|
|
const char *function;
|
|
char *subject;
|
|
char *object;
|
|
char *request;
|
|
int result;
|
|
};
|
|
|
|
/*
|
|
* Smack audit data; is empty if CONFIG_AUDIT not set
|
|
* to save some stack
|
|
*/
|
|
struct smk_audit_info {
|
|
#ifdef CONFIG_AUDIT
|
|
struct common_audit_data a;
|
|
struct smack_audit_data sad;
|
|
#endif
|
|
};
|
|
/*
|
|
* These functions are in smack_lsm.c
|
|
*/
|
|
struct inode_smack *new_inode_smack(struct smack_known *);
|
|
|
|
/*
|
|
* These functions are in smack_access.c
|
|
*/
|
|
int smk_access_entry(char *, char *, struct list_head *);
|
|
int smk_access(struct smack_known *, struct smack_known *,
|
|
int, struct smk_audit_info *);
|
|
int smk_tskacc(struct task_smack *, struct smack_known *,
|
|
u32, struct smk_audit_info *);
|
|
int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
|
|
struct smack_known *smack_from_secid(const u32);
|
|
char *smk_parse_smack(const char *string, int len);
|
|
int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
|
|
struct smack_known *smk_import_entry(const char *, int);
|
|
void smk_insert_entry(struct smack_known *skp);
|
|
struct smack_known *smk_find_entry(const char *);
|
|
|
|
/*
|
|
* Shared data.
|
|
*/
|
|
extern int smack_enabled;
|
|
extern int smack_cipso_direct;
|
|
extern int smack_cipso_mapped;
|
|
extern struct smack_known *smack_net_ambient;
|
|
extern struct smack_known *smack_onlycap;
|
|
extern struct smack_known *smack_syslog_label;
|
|
extern struct smack_known smack_cipso_option;
|
|
extern int smack_ptrace_rule;
|
|
|
|
extern struct smack_known smack_known_floor;
|
|
extern struct smack_known smack_known_hat;
|
|
extern struct smack_known smack_known_huh;
|
|
extern struct smack_known smack_known_invalid;
|
|
extern struct smack_known smack_known_star;
|
|
extern struct smack_known smack_known_web;
|
|
|
|
extern struct mutex smack_known_lock;
|
|
extern struct list_head smack_known_list;
|
|
extern struct list_head smk_netlbladdr_list;
|
|
|
|
extern struct security_operations smack_ops;
|
|
|
|
#define SMACK_HASH_SLOTS 16
|
|
extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
|
|
|
|
/*
|
|
* Is the directory transmuting?
|
|
*/
|
|
static inline int smk_inode_transmutable(const struct inode *isp)
|
|
{
|
|
struct inode_smack *sip = isp->i_security;
|
|
return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
|
|
}
|
|
|
|
/*
|
|
* Present a pointer to the smack label entry in an inode blob.
|
|
*/
|
|
static inline struct smack_known *smk_of_inode(const struct inode *isp)
|
|
{
|
|
struct inode_smack *sip = isp->i_security;
|
|
return sip->smk_inode;
|
|
}
|
|
|
|
/*
|
|
* Present a pointer to the smack label entry in an task blob.
|
|
*/
|
|
static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
|
|
{
|
|
return tsp->smk_task;
|
|
}
|
|
|
|
static inline struct smack_known *smk_of_task_struct(const struct task_struct *t)
|
|
{
|
|
struct smack_known *skp;
|
|
|
|
rcu_read_lock();
|
|
skp = smk_of_task(__task_cred(t)->security);
|
|
rcu_read_unlock();
|
|
return skp;
|
|
}
|
|
|
|
/*
|
|
* Present a pointer to the forked smack label entry in an task blob.
|
|
*/
|
|
static inline struct smack_known *smk_of_forked(const struct task_smack *tsp)
|
|
{
|
|
return tsp->smk_forked;
|
|
}
|
|
|
|
/*
|
|
* Present a pointer to the smack label in the current task blob.
|
|
*/
|
|
static inline struct smack_known *smk_of_current(void)
|
|
{
|
|
return smk_of_task(current_security());
|
|
}
|
|
|
|
/*
|
|
* Is the task privileged and allowed to be privileged
|
|
* by the onlycap rule.
|
|
*/
|
|
static inline int smack_privileged(int cap)
|
|
{
|
|
struct smack_known *skp = smk_of_current();
|
|
|
|
if (!capable(cap))
|
|
return 0;
|
|
if (smack_onlycap == NULL || smack_onlycap == skp)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* logging functions
|
|
*/
|
|
#define SMACK_AUDIT_DENIED 0x1
|
|
#define SMACK_AUDIT_ACCEPT 0x2
|
|
extern int log_policy;
|
|
|
|
void smack_log(char *subject_label, char *object_label,
|
|
int request,
|
|
int result, struct smk_audit_info *auditdata);
|
|
|
|
#ifdef CONFIG_AUDIT
|
|
|
|
/*
|
|
* some inline functions to set up audit data
|
|
* they do nothing if CONFIG_AUDIT is not set
|
|
*
|
|
*/
|
|
static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
|
|
char type)
|
|
{
|
|
memset(&a->sad, 0, sizeof(a->sad));
|
|
a->a.type = type;
|
|
a->a.smack_audit_data = &a->sad;
|
|
a->a.smack_audit_data->function = func;
|
|
}
|
|
|
|
static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
|
|
char type, struct lsm_network_audit *net)
|
|
{
|
|
smk_ad_init(a, func, type);
|
|
memset(net, 0, sizeof(*net));
|
|
a->a.u.net = net;
|
|
}
|
|
|
|
static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
|
|
struct task_struct *t)
|
|
{
|
|
a->a.u.tsk = t;
|
|
}
|
|
static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
|
|
struct dentry *d)
|
|
{
|
|
a->a.u.dentry = d;
|
|
}
|
|
static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
|
|
struct inode *i)
|
|
{
|
|
a->a.u.inode = i;
|
|
}
|
|
static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
|
|
struct path p)
|
|
{
|
|
a->a.u.path = p;
|
|
}
|
|
static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
|
|
struct sock *sk)
|
|
{
|
|
a->a.u.net->sk = sk;
|
|
}
|
|
|
|
#else /* no AUDIT */
|
|
|
|
static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
|
|
char type)
|
|
{
|
|
}
|
|
static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
|
|
struct task_struct *t)
|
|
{
|
|
}
|
|
static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
|
|
struct dentry *d)
|
|
{
|
|
}
|
|
static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
|
|
struct vfsmount *m)
|
|
{
|
|
}
|
|
static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
|
|
struct inode *i)
|
|
{
|
|
}
|
|
static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
|
|
struct path p)
|
|
{
|
|
}
|
|
static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
|
|
struct sock *sk)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
#endif /* _SECURITY_SMACK_H */
|