diff options
| -rw-r--r-- | include/linux/audit.h | 25 | ||||
| -rw-r--r-- | kernel/audit.c | 246 | ||||
| -rw-r--r-- | kernel/auditsc.c | 19 | ||||
| -rw-r--r-- | kernel/signal.c | 7 | ||||
| -rw-r--r-- | security/selinux/nlmsgtab.c | 1 |
5 files changed, 174 insertions, 124 deletions
diff --git a/include/linux/audit.h b/include/linux/audit.h index 19f04b049798..baa80760824c 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -28,14 +28,16 @@ #include <linux/elf.h> /* Request and reply types */ -#define AUDIT_GET 1000 /* Get status */ -#define AUDIT_SET 1001 /* Set status (enable/disable/auditd) */ -#define AUDIT_LIST 1002 /* List filtering rules */ -#define AUDIT_ADD 1003 /* Add filtering rule */ -#define AUDIT_DEL 1004 /* Delete filtering rule */ -#define AUDIT_USER 1005 /* Send a message from user-space */ -#define AUDIT_LOGIN 1006 /* Define the login id and informaiton */ -#define AUDIT_KERNEL 2000 /* Asynchronous audit record. NOT A REQUEST. */ +#define AUDIT_GET 1000 /* Get status */ +#define AUDIT_SET 1001 /* Set status (enable/disable/auditd) */ +#define AUDIT_LIST 1002 /* List filtering rules */ +#define AUDIT_ADD 1003 /* Add filtering rule */ +#define AUDIT_DEL 1004 /* Delete filtering rule */ +#define AUDIT_USER 1005 /* Send a message from user-space */ +#define AUDIT_LOGIN 1006 /* Define the login id and information */ +#define AUDIT_SIGNAL_INFO 1010 /* Get information about sender of signal*/ + +#define AUDIT_KERNEL 2000 /* Asynchronous audit record. NOT A REQUEST. */ /* Rule flags */ #define AUDIT_PER_TASK 0x01 /* Apply rule at task creation (not syscall) */ @@ -161,6 +163,11 @@ struct audit_rule { /* for AUDIT_LIST, AUDIT_ADD, and AUDIT_DEL */ #ifdef __KERNEL__ +struct audit_sig_info { + uid_t uid; + pid_t pid; +}; + struct audit_buffer; struct audit_context; struct inode; @@ -190,6 +197,7 @@ extern void audit_get_stamp(struct audit_context *ctx, extern int audit_set_loginuid(struct task_struct *task, uid_t loginuid); extern uid_t audit_get_loginuid(struct audit_context *ctx); extern int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode); +extern void audit_signal_info(int sig, struct task_struct *t); #else #define audit_alloc(t) ({ 0; }) #define audit_free(t) do { ; } while (0) @@ -200,6 +208,7 @@ extern int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mo #define audit_inode(n,i) do { ; } while (0) #define audit_get_loginuid(c) ({ -1; }) #define audit_ipc_perms(q,u,g,m) ({ 0; }) +#define audit_signal_info(s,t) do { ; } while (0) #endif #ifdef CONFIG_AUDIT diff --git a/kernel/audit.c b/kernel/audit.c index 9c4f1af0c794..b86007da8a3f 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -68,7 +68,7 @@ static int audit_failure = AUDIT_FAIL_PRINTK; /* If audit records are to be written to the netlink socket, audit_pid * contains the (non-zero) pid. */ -static int audit_pid; +int audit_pid; /* If audit_limit is non-zero, limit the rate of sending audit records * to that number per second. This prevents DoS attacks, but results in @@ -79,6 +79,10 @@ static int audit_rate_limit; static int audit_backlog_limit = 64; static atomic_t audit_backlog = ATOMIC_INIT(0); +/* The identity of the user shutting down the audit system. */ +uid_t audit_sig_uid = -1; +pid_t audit_sig_pid = -1; + /* Records can be lost in several ways: 0) [suppressed in audit_alloc] 1) out of memory in audit_log_start [kmalloc of struct audit_buffer] @@ -132,21 +136,20 @@ static DECLARE_MUTEX(audit_netlink_sem); * use simultaneously. */ struct audit_buffer { struct list_head list; - struct sk_buff_head sklist; /* formatted skbs ready to send */ + struct sk_buff *skb; /* formatted skb ready to send */ struct audit_context *ctx; /* NULL or associated context */ - int len; /* used area of tmp */ - char tmp[AUDIT_BUFSIZ]; - - /* Pointer to header and contents */ - struct nlmsghdr *nlh; - int total; - int type; - int pid; }; void audit_set_type(struct audit_buffer *ab, int type) { - ab->type = type; + struct nlmsghdr *nlh = (struct nlmsghdr *)ab->skb->data; + nlh->nlmsg_type = type; +} + +static void audit_set_pid(struct audit_buffer *ab, pid_t pid) +{ + struct nlmsghdr *nlh = (struct nlmsghdr *)ab->skb->data; + nlh->nlmsg_pid = pid; } struct audit_entry { @@ -321,6 +324,7 @@ static int audit_netlink_ok(kernel_cap_t eff_cap, u16 msg_type) case AUDIT_SET: case AUDIT_ADD: case AUDIT_DEL: + case AUDIT_SIGNAL_INFO: if (!cap_raised(eff_cap, CAP_AUDIT_CONTROL)) err = -EPERM; break; @@ -344,6 +348,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) struct audit_buffer *ab; u16 msg_type = nlh->nlmsg_type; uid_t loginuid; /* loginuid of sender */ + struct audit_sig_info sig_data; err = audit_netlink_ok(NETLINK_CB(skb).eff_cap, msg_type); if (err) @@ -402,8 +407,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) (int)(nlh->nlmsg_len - ((char *)data - (char *)nlh)), loginuid, (char *)data); - ab->type = AUDIT_USER; - ab->pid = pid; + audit_set_type(ab, AUDIT_USER); + audit_set_pid(ab, pid); audit_log_end(ab); break; case AUDIT_ADD: @@ -419,6 +424,12 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) err = -EOPNOTSUPP; #endif break; + case AUDIT_SIGNAL_INFO: + sig_data.uid = audit_sig_uid; + sig_data.pid = audit_sig_pid; + audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO, + 0, 0, &sig_data, sizeof(sig_data)); + break; default: err = -EINVAL; break; @@ -467,64 +478,23 @@ static void audit_receive(struct sock *sk, int length) up(&audit_netlink_sem); } -/* Move data from tmp buffer into an skb. This is an extra copy, and - * that is unfortunate. However, the copy will only occur when a record - * is being written to user space, which is already a high-overhead - * operation. (Elimination of the copy is possible, for example, by - * writing directly into a pre-allocated skb, at the cost of wasting - * memory. */ -static void audit_log_move(struct audit_buffer *ab) -{ - struct sk_buff *skb; - char *start; - int extra = ab->nlh ? 0 : NLMSG_SPACE(0); - - /* possible resubmission */ - if (ab->len == 0) - return; - - skb = skb_peek_tail(&ab->sklist); - if (!skb || skb_tailroom(skb) <= ab->len + extra) { - skb = alloc_skb(2 * ab->len + extra, GFP_ATOMIC); - if (!skb) { - ab->len = 0; /* Lose information in ab->tmp */ - audit_log_lost("out of memory in audit_log_move"); - return; - } - __skb_queue_tail(&ab->sklist, skb); - if (!ab->nlh) - ab->nlh = (struct nlmsghdr *)skb_put(skb, - NLMSG_SPACE(0)); - } - start = skb_put(skb, ab->len); - memcpy(start, ab->tmp, ab->len); - ab->len = 0; -} - -/* Iterate over the skbuff in the audit_buffer, sending their contents - * to user space. */ +/* Grab skbuff from the audit_buffer and send to user space. */ static inline int audit_log_drain(struct audit_buffer *ab) { - struct sk_buff *skb; + struct sk_buff *skb = ab->skb; - while ((skb = skb_dequeue(&ab->sklist))) { + if (skb) { int retval = 0; if (audit_pid) { - if (ab->nlh) { - ab->nlh->nlmsg_len = ab->total; - ab->nlh->nlmsg_type = ab->type; - ab->nlh->nlmsg_flags = 0; - ab->nlh->nlmsg_seq = 0; - ab->nlh->nlmsg_pid = ab->pid; - } + struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data; + nlh->nlmsg_len = skb->len; skb_get(skb); /* because netlink_* frees */ retval = netlink_unicast(audit_sock, skb, audit_pid, MSG_DONTWAIT); } if (retval == -EAGAIN && (atomic_read(&audit_backlog)) < audit_backlog_limit) { - skb_queue_head(&ab->sklist, skb); audit_log_end_irq(ab); return 1; } @@ -538,13 +508,11 @@ static inline int audit_log_drain(struct audit_buffer *ab) audit_log_lost("netlink socket too busy"); } if (!audit_pid) { /* No daemon */ - int offset = ab->nlh ? NLMSG_SPACE(0) : 0; + int offset = NLMSG_SPACE(0); int len = skb->len - offset; skb->data[offset + len] = '\0'; printk(KERN_ERR "%s\n", skb->data + offset); } - kfree_skb(skb); - ab->nlh = NULL; } return 0; } @@ -608,6 +576,62 @@ static int __init audit_enable(char *str) __setup("audit=", audit_enable); +static void audit_buffer_free(struct audit_buffer *ab) +{ + unsigned long flags; + + if (!ab) + return; + + if (ab->skb) + kfree_skb(ab->skb); + atomic_dec(&audit_backlog); + spin_lock_irqsave(&audit_freelist_lock, flags); + if (++audit_freelist_count > AUDIT_MAXFREE) + kfree(ab); + else + list_add(&ab->list, &audit_freelist); + spin_unlock_irqrestore(&audit_freelist_lock, flags); +} + +static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx, + int gfp_mask) +{ + unsigned long flags; + struct audit_buffer *ab = NULL; + struct nlmsghdr *nlh; + + spin_lock_irqsave(&audit_freelist_lock, flags); + if (!list_empty(&audit_freelist)) { + ab = list_entry(audit_freelist.next, + struct audit_buffer, list); + list_del(&ab->list); + --audit_freelist_count; + } + spin_unlock_irqrestore(&audit_freelist_lock, flags); + + if (!ab) { + ab = kmalloc(sizeof(*ab), gfp_mask); + if (!ab) + goto err; + } + atomic_inc(&audit_backlog); + + ab->skb = alloc_skb(AUDIT_BUFSIZ, gfp_mask); + if (!ab->skb) + goto err; + + ab->ctx = ctx; + nlh = (struct nlmsghdr *)skb_put(ab->skb, NLMSG_SPACE(0)); + nlh->nlmsg_type = AUDIT_KERNEL; + nlh->nlmsg_flags = 0; + nlh->nlmsg_pid = 0; + nlh->nlmsg_seq = 0; + return ab; +err: + audit_buffer_free(ab); + return NULL; +} /* Obtain an audit buffer. This routine does locking to obtain the * audit buffer, but then no locking is required for calls to @@ -618,7 +642,6 @@ __setup("audit=", audit_enable); struct audit_buffer *audit_log_start(struct audit_context *ctx) { struct audit_buffer *ab = NULL; - unsigned long flags; struct timespec t; unsigned int serial; @@ -637,32 +660,12 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx) return NULL; } - spin_lock_irqsave(&audit_freelist_lock, flags); - if (!list_empty(&audit_freelist)) { - ab = list_entry(audit_freelist.next, - struct audit_buffer, list); - list_del(&ab->list); - --audit_freelist_count; - } - spin_unlock_irqrestore(&audit_freelist_lock, flags); - - if (!ab) - ab = kmalloc(sizeof(*ab), GFP_ATOMIC); + ab = audit_buffer_alloc(ctx, GFP_ATOMIC); if (!ab) { audit_log_lost("out of memory in audit_log_start"); return NULL; } - atomic_inc(&audit_backlog); - skb_queue_head_init(&ab->sklist); - - ab->ctx = ctx; - ab->len = 0; - ab->nlh = NULL; - ab->total = 0; - ab->type = AUDIT_KERNEL; - ab->pid = 0; - #ifdef CONFIG_AUDITSYSCALL if (ab->ctx) audit_get_stamp(ab->ctx, &t, &serial); @@ -677,6 +680,24 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx) return ab; } +/** + * audit_expand - expand skb in the audit buffer + * @ab: audit_buffer + * + * Returns 0 (no space) on failed expansion, or available space if + * successful. + */ +static inline int audit_expand(struct audit_buffer *ab) +{ + struct sk_buff *skb = ab->skb; + int ret = pskb_expand_head(skb, skb_headroom(skb), AUDIT_BUFSIZ, + GFP_ATOMIC); + if (ret < 0) { + audit_log_lost("out of memory in audit_expand"); + return 0; + } + return skb_tailroom(skb); +} /* Format an audit message into the audit buffer. If there isn't enough * room in the audit buffer, more room will be allocated and vsnprint @@ -686,26 +707,32 @@ static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, va_list args) { int len, avail; + struct sk_buff *skb; if (!ab) return; - avail = sizeof(ab->tmp) - ab->len; - if (avail <= 0) { - audit_log_move(ab); - avail = sizeof(ab->tmp) - ab->len; + BUG_ON(!ab->skb); + skb = ab->skb; + avail = skb_tailroom(skb); + if (avail == 0) { + avail = audit_expand(ab); + if (!avail) + goto out; } - len = vsnprintf(ab->tmp + ab->len, avail, fmt, args); + len = vsnprintf(skb->tail, avail, fmt, args); if (len >= avail) { /* The printk buffer is 1024 bytes long, so if we get * here and AUDIT_BUFSIZ is at least 1024, then we can * log everything that printk could have logged. */ - audit_log_move(ab); - avail = sizeof(ab->tmp) - ab->len; - len = vsnprintf(ab->tmp + ab->len, avail, fmt, args); + avail = audit_expand(ab); + if (!avail) + goto out; + len = vsnprintf(skb->tail, avail, fmt, args); } - ab->len += (len < avail) ? len : avail; - ab->total += (len < avail) ? len : avail; + skb_put(skb, (len < avail) ? len : avail); +out: + return; } /* Format a message into the audit buffer. All the work is done in @@ -751,23 +778,22 @@ void audit_log_d_path(struct audit_buffer *ab, const char *prefix, struct dentry *dentry, struct vfsmount *vfsmnt) { char *p; + struct sk_buff *skb = ab->skb; int len, avail; - if (prefix) audit_log_format(ab, " %s", prefix); + if (prefix) + audit_log_format(ab, " %s", prefix); - if (ab->len > 128) - audit_log_move(ab); - avail = sizeof(ab->tmp) - ab->len; - p = d_path(dentry, vfsmnt, ab->tmp + ab->len, avail); + avail = skb_tailroom(skb); + p = d_path(dentry, vfsmnt, skb->tail, avail); if (IS_ERR(p)) { /* FIXME: can we save some information here? */ audit_log_format(ab, "<toolong>"); } else { - /* path isn't at start of buffer */ - len = (ab->tmp + sizeof(ab->tmp) - 1) - p; - memmove(ab->tmp + ab->len, p, len); - ab->len += len; - ab->total += len; + /* path isn't at start of buffer */ + len = ((char *)skb->tail + avail - 1) - p; + memmove(skb->tail, p, len); + skb_put(skb, len); } } @@ -812,26 +838,16 @@ static void audit_log_end_irq(struct audit_buffer *ab) * be called in an irq context. */ static void audit_log_end_fast(struct audit_buffer *ab) { - unsigned long flags; - BUG_ON(in_irq()); if (!ab) return; if (!audit_rate_check()) { audit_log_lost("rate limit exceeded"); } else { - audit_log_move(ab); if (audit_log_drain(ab)) return; } - - atomic_dec(&audit_backlog); - spin_lock_irqsave(&audit_freelist_lock, flags); - if (++audit_freelist_count > AUDIT_MAXFREE) - kfree(ab); - else - list_add(&ab->list, &audit_freelist); - spin_unlock_irqrestore(&audit_freelist_lock, flags); + audit_buffer_free(ab); } /* Send or queue the message in the audit buffer, depending on the diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 37b3ac94bc47..f1bf66510cd3 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -1056,3 +1056,22 @@ int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode) context->aux = (void *)ax; return 0; } + +void audit_signal_info(int sig, struct task_struct *t) +{ + extern pid_t audit_sig_pid; + extern uid_t audit_sig_uid; + extern int audit_pid; + + if (unlikely(audit_pid && t->pid == audit_pid)) { + if (sig == SIGTERM || sig == SIGHUP) { + struct audit_context *ctx = current->audit_context; + audit_sig_pid = current->pid; + if (ctx) + audit_sig_uid = ctx->loginuid; + else + audit_sig_uid = current->uid; + } + } +} + diff --git a/kernel/signal.c b/kernel/signal.c index 8f3debc77c5b..293e189d8bc3 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -24,6 +24,7 @@ #include <linux/ptrace.h> #include <linux/posix-timers.h> #include <linux/signal.h> +#include <linux/audit.h> #include <asm/param.h> #include <asm/uaccess.h> #include <asm/unistd.h> @@ -658,7 +659,11 @@ static int check_kill_permission(int sig, struct siginfo *info, && (current->uid ^ t->suid) && (current->uid ^ t->uid) && !capable(CAP_KILL)) return error; - return security_task_kill(t, info, sig); + + error = security_task_kill(t, info, sig); + if (!error) + audit_signal_info(sig, t); /* Let audit system see the signal */ + return error; } /* forward decl */ diff --git a/security/selinux/nlmsgtab.c b/security/selinux/nlmsgtab.c index b3adb481bc25..deac14367d43 100644 --- a/security/selinux/nlmsgtab.c +++ b/security/selinux/nlmsgtab.c @@ -97,6 +97,7 @@ static struct nlmsg_perm nlmsg_audit_perms[] = { AUDIT_ADD, NETLINK_AUDIT_SOCKET__NLMSG_WRITE }, { AUDIT_DEL, NETLINK_AUDIT_SOCKET__NLMSG_WRITE }, { AUDIT_USER, NETLINK_AUDIT_SOCKET__NLMSG_RELAY }, + { AUDIT_SIGNAL_INFO, NETLINK_AUDIT_SOCKET__NLMSG_READ }, }; |