mirror of
https://github.com/torvalds/linux.git
synced 2024-12-04 18:13:04 +00:00
staging: android: logger: Allow a UID to read it's own log entries
Modify the kernel logger to record the UID associated with the log entries. Always allow the same UID which generated a log message to read the log message. Allow anyone in the logs group, or anyone with CAP_SYSLOG, to read all log entries. In addition, allow the client to upgrade log formats, so they can get additional information from the kernel. Cc: Android Kernel Team <kernel-team@android.com> Cc: Nick Kralevich <nnk@google.com> Signed-off-by: Nick Kralevich <nnk@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nick Kralevich
Greg Kroah-Hartman
parent
99150f6a1a
commit
0441bcf4db
@ -68,6 +68,8 @@ static LIST_HEAD(log_list);
|
||||
* @log: The associated log
|
||||
* @list: The associated entry in @logger_log's list
|
||||
* @r_off: The current read head offset.
|
||||
* @r_all: Reader can read all entries
|
||||
* @r_ver: Reader ABI version
|
||||
*
|
||||
* This object lives from open to release, so we don't need additional
|
||||
* reference counting. The structure is protected by log->mutex.
|
||||
@ -76,6 +78,8 @@ struct logger_reader {
|
||||
struct logger_log *log;
|
||||
struct list_head list;
|
||||
size_t r_off;
|
||||
bool r_all;
|
||||
int r_ver;
|
||||
};
|
||||
|
||||
/* logger_offset - returns index 'n' into the log via (optimized) modulus */
|
||||
@ -109,8 +113,29 @@ static inline struct logger_log *file_get_log(struct file *file)
|
||||
}
|
||||
|
||||
/*
|
||||
* get_entry_len - Grabs the length of the payload of the next entry starting
|
||||
* from 'off'.
|
||||
* get_entry_header - returns a pointer to the logger_entry header within
|
||||
* 'log' starting at offset 'off'. A temporary logger_entry 'scratch' must
|
||||
* be provided. Typically the return value will be a pointer within
|
||||
* 'logger->buf'. However, a pointer to 'scratch' may be returned if
|
||||
* the log entry spans the end and beginning of the circular buffer.
|
||||
*/
|
||||
static struct logger_entry *get_entry_header(struct logger_log *log,
|
||||
size_t off, struct logger_entry *scratch)
|
||||
{
|
||||
size_t len = min(sizeof(struct logger_entry), log->size - off);
|
||||
if (len != sizeof(struct logger_entry)) {
|
||||
memcpy(((void *) scratch), log->buffer + off, len);
|
||||
memcpy(((void *) scratch) + len, log->buffer,
|
||||
sizeof(struct logger_entry) - len);
|
||||
return scratch;
|
||||
}
|
||||
|
||||
return (struct logger_entry *) (log->buffer + off);
|
||||
}
|
||||
|
||||
/*
|
||||
* get_entry_msg_len - Grabs the length of the message of the entry
|
||||
* starting from from 'off'.
|
||||
*
|
||||
* An entry length is 2 bytes (16 bits) in host endian order.
|
||||
* In the log, the length does not include the size of the log entry structure.
|
||||
@ -118,20 +143,45 @@ static inline struct logger_log *file_get_log(struct file *file)
|
||||
*
|
||||
* Caller needs to hold log->mutex.
|
||||
*/
|
||||
static __u32 get_entry_len(struct logger_log *log, size_t off)
|
||||
static __u32 get_entry_msg_len(struct logger_log *log, size_t off)
|
||||
{
|
||||
__u16 val;
|
||||
struct logger_entry scratch;
|
||||
struct logger_entry *entry;
|
||||
|
||||
/* copy 2 bytes from buffer, in memcpy order, */
|
||||
/* handling possible wrap at end of buffer */
|
||||
entry = get_entry_header(log, off, &scratch);
|
||||
return entry->len;
|
||||
}
|
||||
|
||||
((__u8 *)&val)[0] = log->buffer[off];
|
||||
if (likely(off+1 < log->size))
|
||||
((__u8 *)&val)[1] = log->buffer[off+1];
|
||||
static size_t get_user_hdr_len(int ver)
|
||||
{
|
||||
if (ver < 2)
|
||||
return sizeof(struct user_logger_entry_compat);
|
||||
else
|
||||
((__u8 *)&val)[1] = log->buffer[0];
|
||||
return sizeof(struct logger_entry);
|
||||
}
|
||||
|
||||
return sizeof(struct logger_entry) + val;
|
||||
static ssize_t copy_header_to_user(int ver, struct logger_entry *entry,
|
||||
char __user *buf)
|
||||
{
|
||||
void *hdr;
|
||||
size_t hdr_len;
|
||||
struct user_logger_entry_compat v1;
|
||||
|
||||
if (ver < 2) {
|
||||
v1.len = entry->len;
|
||||
v1.__pad = 0;
|
||||
v1.pid = entry->pid;
|
||||
v1.tid = entry->tid;
|
||||
v1.sec = entry->sec;
|
||||
v1.nsec = entry->nsec;
|
||||
hdr = &v1;
|
||||
hdr_len = sizeof(struct user_logger_entry_compat);
|
||||
} else {
|
||||
hdr = entry;
|
||||
hdr_len = sizeof(struct logger_entry);
|
||||
}
|
||||
|
||||
return copy_to_user(buf, hdr, hdr_len);
|
||||
}
|
||||
|
||||
/*
|
||||
@ -145,15 +195,31 @@ static ssize_t do_read_log_to_user(struct logger_log *log,
|
||||
char __user *buf,
|
||||
size_t count)
|
||||
{
|
||||
struct logger_entry scratch;
|
||||
struct logger_entry *entry;
|
||||
size_t len;
|
||||
size_t msg_start;
|
||||
|
||||
/*
|
||||
* We read from the log in two disjoint operations. First, we read from
|
||||
* the current read head offset up to 'count' bytes or to the end of
|
||||
* First, copy the header to userspace, using the version of
|
||||
* the header requested
|
||||
*/
|
||||
entry = get_entry_header(log, reader->r_off, &scratch);
|
||||
if (copy_header_to_user(reader->r_ver, entry, buf))
|
||||
return -EFAULT;
|
||||
|
||||
count -= get_user_hdr_len(reader->r_ver);
|
||||
buf += get_user_hdr_len(reader->r_ver);
|
||||
msg_start = logger_offset(log,
|
||||
reader->r_off + sizeof(struct logger_entry));
|
||||
|
||||
/*
|
||||
* We read from the msg in two disjoint operations. First, we read from
|
||||
* the current msg head offset up to 'count' bytes or to the end of
|
||||
* the log, whichever comes first.
|
||||
*/
|
||||
len = min(count, log->size - reader->r_off);
|
||||
if (copy_to_user(buf, log->buffer + reader->r_off, len))
|
||||
len = min(count, log->size - msg_start);
|
||||
if (copy_to_user(buf, log->buffer + msg_start, len))
|
||||
return -EFAULT;
|
||||
|
||||
/*
|
||||
@ -164,9 +230,34 @@ static ssize_t do_read_log_to_user(struct logger_log *log,
|
||||
if (copy_to_user(buf + len, log->buffer, count - len))
|
||||
return -EFAULT;
|
||||
|
||||
reader->r_off = logger_offset(log, reader->r_off + count);
|
||||
reader->r_off = logger_offset(log, reader->r_off +
|
||||
sizeof(struct logger_entry) + count);
|
||||
|
||||
return count;
|
||||
return count + get_user_hdr_len(reader->r_ver);
|
||||
}
|
||||
|
||||
/*
|
||||
* get_next_entry_by_uid - Starting at 'off', returns an offset into
|
||||
* 'log->buffer' which contains the first entry readable by 'euid'
|
||||
*/
|
||||
static size_t get_next_entry_by_uid(struct logger_log *log,
|
||||
size_t off, uid_t euid)
|
||||
{
|
||||
while (off != log->w_off) {
|
||||
struct logger_entry *entry;
|
||||
struct logger_entry scratch;
|
||||
size_t next_len;
|
||||
|
||||
entry = get_entry_header(log, off, &scratch);
|
||||
|
||||
if (entry->euid == euid)
|
||||
return off;
|
||||
|
||||
next_len = sizeof(struct logger_entry) + entry->len;
|
||||
off = logger_offset(log, off + next_len);
|
||||
}
|
||||
|
||||
return off;
|
||||
}
|
||||
|
||||
/*
|
||||
@ -178,7 +269,7 @@ static ssize_t do_read_log_to_user(struct logger_log *log,
|
||||
* - If there are no log entries to read, blocks until log is written to
|
||||
* - Atomically reads exactly one log entry
|
||||
*
|
||||
* Optimal read size is LOGGER_ENTRY_MAX_LEN. Will set errno to EINVAL if read
|
||||
* Will set errno to EINVAL if read
|
||||
* buffer is insufficient to hold next entry.
|
||||
*/
|
||||
static ssize_t logger_read(struct file *file, char __user *buf,
|
||||
@ -219,6 +310,10 @@ start:
|
||||
|
||||
mutex_lock(&log->mutex);
|
||||
|
||||
if (!reader->r_all)
|
||||
reader->r_off = get_next_entry_by_uid(log,
|
||||
reader->r_off, current_euid());
|
||||
|
||||
/* is there still something to read or did we race? */
|
||||
if (unlikely(log->w_off == reader->r_off)) {
|
||||
mutex_unlock(&log->mutex);
|
||||
@ -226,7 +321,8 @@ start:
|
||||
}
|
||||
|
||||
/* get the size of the next entry */
|
||||
ret = get_entry_len(log, reader->r_off);
|
||||
ret = get_user_hdr_len(reader->r_ver) +
|
||||
get_entry_msg_len(log, reader->r_off);
|
||||
if (count < ret) {
|
||||
ret = -EINVAL;
|
||||
goto out;
|
||||
@ -252,7 +348,8 @@ static size_t get_next_entry(struct logger_log *log, size_t off, size_t len)
|
||||
size_t count = 0;
|
||||
|
||||
do {
|
||||
size_t nr = get_entry_len(log, off);
|
||||
size_t nr = sizeof(struct logger_entry) +
|
||||
get_entry_msg_len(log, off);
|
||||
off = logger_offset(log, off + nr);
|
||||
count += nr;
|
||||
} while (count < len);
|
||||
@ -382,7 +479,9 @@ static ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov,
|
||||
header.tid = current->pid;
|
||||
header.sec = now.tv_sec;
|
||||
header.nsec = now.tv_nsec;
|
||||
header.euid = current_euid();
|
||||
header.len = min_t(size_t, iocb->ki_left, LOGGER_ENTRY_MAX_PAYLOAD);
|
||||
header.hdr_size = sizeof(struct logger_entry);
|
||||
|
||||
/* null writes succeed, return zero */
|
||||
if (unlikely(!header.len))
|
||||
@ -463,6 +562,10 @@ static int logger_open(struct inode *inode, struct file *file)
|
||||
return -ENOMEM;
|
||||
|
||||
reader->log = log;
|
||||
reader->r_ver = 1;
|
||||
reader->r_all = in_egroup_p(inode->i_gid) ||
|
||||
capable(CAP_SYSLOG);
|
||||
|
||||
INIT_LIST_HEAD(&reader->list);
|
||||
|
||||
mutex_lock(&log->mutex);
|
||||
@ -522,6 +625,10 @@ static unsigned int logger_poll(struct file *file, poll_table *wait)
|
||||
poll_wait(file, &log->wq, wait);
|
||||
|
||||
mutex_lock(&log->mutex);
|
||||
if (!reader->r_all)
|
||||
reader->r_off = get_next_entry_by_uid(log,
|
||||
reader->r_off, current_euid());
|
||||
|
||||
if (log->w_off != reader->r_off)
|
||||
ret |= POLLIN | POLLRDNORM;
|
||||
mutex_unlock(&log->mutex);
|
||||
@ -529,11 +636,25 @@ static unsigned int logger_poll(struct file *file, poll_table *wait)
|
||||
return ret;
|
||||
}
|
||||
|
||||
static long logger_set_version(struct logger_reader *reader, void __user *arg)
|
||||
{
|
||||
int version;
|
||||
if (copy_from_user(&version, arg, sizeof(int)))
|
||||
return -EFAULT;
|
||||
|
||||
if ((version < 1) || (version > 2))
|
||||
return -EINVAL;
|
||||
|
||||
reader->r_ver = version;
|
||||
return 0;
|
||||
}
|
||||
|
||||
static long logger_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
||||
{
|
||||
struct logger_log *log = file_get_log(file);
|
||||
struct logger_reader *reader;
|
||||
long ret = -ENOTTY;
|
||||
long ret = -EINVAL;
|
||||
void __user *argp = (void __user *) arg;
|
||||
|
||||
mutex_lock(&log->mutex);
|
||||
|
||||
@ -558,8 +679,14 @@ static long logger_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
||||
break;
|
||||
}
|
||||
reader = file->private_data;
|
||||
|
||||
if (!reader->r_all)
|
||||
reader->r_off = get_next_entry_by_uid(log,
|
||||
reader->r_off, current_euid());
|
||||
|
||||
if (log->w_off != reader->r_off)
|
||||
ret = get_entry_len(log, reader->r_off);
|
||||
ret = get_user_hdr_len(reader->r_ver) +
|
||||
get_entry_msg_len(log, reader->r_off);
|
||||
else
|
||||
ret = 0;
|
||||
break;
|
||||
@ -573,6 +700,22 @@ static long logger_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
||||
log->head = log->w_off;
|
||||
ret = 0;
|
||||
break;
|
||||
case LOGGER_GET_VERSION:
|
||||
if (!(file->f_mode & FMODE_READ)) {
|
||||
ret = -EBADF;
|
||||
break;
|
||||
}
|
||||
reader = file->private_data;
|
||||
ret = reader->r_ver;
|
||||
break;
|
||||
case LOGGER_SET_VERSION:
|
||||
if (!(file->f_mode & FMODE_READ)) {
|
||||
ret = -EBADF;
|
||||
break;
|
||||
}
|
||||
reader = file->private_data;
|
||||
ret = logger_set_version(reader, argp);
|
||||
break;
|
||||
}
|
||||
|
||||
mutex_unlock(&log->mutex);
|
||||
@ -592,8 +735,8 @@ static const struct file_operations logger_fops = {
|
||||
};
|
||||
|
||||
/*
|
||||
* Log size must be a power of two, greater than LOGGER_ENTRY_MAX_LEN,
|
||||
* and less than LONG_MAX minus LOGGER_ENTRY_MAX_LEN.
|
||||
* Log size must must be a power of two, and greater than
|
||||
* (LOGGER_ENTRY_MAX_PAYLOAD + sizeof(struct logger_entry)).
|
||||
*/
|
||||
static int __init create_log(char *log_name, int size)
|
||||
{
|
||||
|
||||
@ -21,7 +21,7 @@
|
||||
#include <linux/ioctl.h>
|
||||
|
||||
/**
|
||||
* struct logger_entry - defines a single entry that is given to a logger
|
||||
* struct user_logger_entry_compat - defines a single entry that is given to a logger
|
||||
* @len: The length of the payload
|
||||
* @__pad: Two bytes of padding that appear to be required
|
||||
* @pid: The generating process' process ID
|
||||
@ -29,8 +29,12 @@
|
||||
* @sec: The number of seconds that have elapsed since the Epoch
|
||||
* @nsec: The number of nanoseconds that have elapsed since @sec
|
||||
* @msg: The message that is to be logged
|
||||
*
|
||||
* The userspace structure for version 1 of the logger_entry ABI.
|
||||
* This structure is returned to userspace unless the caller requests
|
||||
* an upgrade to a newer ABI version.
|
||||
*/
|
||||
struct logger_entry {
|
||||
struct user_logger_entry_compat {
|
||||
__u16 len;
|
||||
__u16 __pad;
|
||||
__s32 pid;
|
||||
@ -40,14 +44,38 @@ struct logger_entry {
|
||||
char msg[0];
|
||||
};
|
||||
|
||||
/**
|
||||
* struct logger_entry - defines a single entry that is given to a logger
|
||||
* @len: The length of the payload
|
||||
* @hdr_size: sizeof(struct logger_entry_v2)
|
||||
* @pid: The generating process' process ID
|
||||
* @tid: The generating process' thread ID
|
||||
* @sec: The number of seconds that have elapsed since the Epoch
|
||||
* @nsec: The number of nanoseconds that have elapsed since @sec
|
||||
* @euid: Effective UID of logger
|
||||
* @msg: The message that is to be logged
|
||||
*
|
||||
* The structure for version 2 of the logger_entry ABI.
|
||||
* This structure is returned to userspace if ioctl(LOGGER_SET_VERSION)
|
||||
* is called with version >= 2
|
||||
*/
|
||||
struct logger_entry {
|
||||
__u16 len;
|
||||
__u16 hdr_size;
|
||||
__s32 pid;
|
||||
__s32 tid;
|
||||
__s32 sec;
|
||||
__s32 nsec;
|
||||
uid_t euid;
|
||||
char msg[0];
|
||||
};
|
||||
|
||||
#define LOGGER_LOG_RADIO "log_radio" /* radio-related messages */
|
||||
#define LOGGER_LOG_EVENTS "log_events" /* system/hardware events */
|
||||
#define LOGGER_LOG_SYSTEM "log_system" /* system/framework messages */
|
||||
#define LOGGER_LOG_MAIN "log_main" /* everything else */
|
||||
|
||||
#define LOGGER_ENTRY_MAX_LEN (4*1024)
|
||||
#define LOGGER_ENTRY_MAX_PAYLOAD \
|
||||
(LOGGER_ENTRY_MAX_LEN - sizeof(struct logger_entry))
|
||||
#define LOGGER_ENTRY_MAX_PAYLOAD 4076
|
||||
|
||||
#define __LOGGERIO 0xAE
|
||||
|
||||
@ -55,5 +83,7 @@ struct logger_entry {
|
||||
#define LOGGER_GET_LOG_LEN _IO(__LOGGERIO, 2) /* used log len */
|
||||
#define LOGGER_GET_NEXT_ENTRY_LEN _IO(__LOGGERIO, 3) /* next entry len */
|
||||
#define LOGGER_FLUSH_LOG _IO(__LOGGERIO, 4) /* flush log */
|
||||
#define LOGGER_GET_VERSION _IO(__LOGGERIO, 5) /* abi version */
|
||||
#define LOGGER_SET_VERSION _IO(__LOGGERIO, 6) /* abi version */
|
||||
|
||||
#endif /* _LINUX_LOGGER_H */
|
||||
|
||||
Loading…
Reference in New Issue
Block a user