diff options
| -rw-r--r-- | include/linux/printk.h | 2 | ||||
| -rw-r--r-- | kernel/printk/printk.c | 34 |
2 files changed, 24 insertions, 12 deletions
diff --git a/include/linux/printk.h b/include/linux/printk.h index 9b30871c9149..58b1fec40d37 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -30,6 +30,8 @@ static inline const char *printk_skip_level(const char *buffer) return buffer; } +#define CONSOLE_EXT_LOG_MAX 8192 + /* printk's without a loglevel use this.. */ #define MESSAGE_LOGLEVEL_DEFAULT CONFIG_MESSAGE_LOGLEVEL_DEFAULT diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index c099b082cd02..a11549034e07 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -505,6 +505,11 @@ int check_syslog_permissions(int type, bool from_file) return security_syslog(type); } +static void append_char(char **pp, char *e, char c) +{ + if (*pp < e) + *(*pp)++ = c; +} /* /dev/kmsg - userspace message inject/listen interface */ struct devkmsg_user { @@ -512,7 +517,7 @@ struct devkmsg_user { u32 idx; enum log_flags prev; struct mutex lock; - char buf[8192]; + char buf[CONSOLE_EXT_LOG_MAX]; }; static ssize_t devkmsg_write(struct kiocb *iocb, struct iov_iter *from) @@ -570,6 +575,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf, { struct devkmsg_user *user = file->private_data; struct printk_log *msg; + char *p, *e; u64 ts_usec; size_t i; char cont = '-'; @@ -579,6 +585,9 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf, if (!user) return -EBADF; + p = user->buf; + e = user->buf + sizeof(user->buf); + ret = mutex_lock_interruptible(&user->lock); if (ret) return ret; @@ -625,9 +634,9 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf, ((user->prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))) cont = '+'; - len = sprintf(user->buf, "%u,%llu,%llu,%c;", - (msg->facility << 3) | msg->level, - user->seq, ts_usec, cont); + p += scnprintf(p, e - p, "%u,%llu,%llu,%c;", + (msg->facility << 3) | msg->level, + user->seq, ts_usec, cont); user->prev = msg->flags; /* escape non-printable characters */ @@ -635,11 +644,11 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf, unsigned char c = log_text(msg)[i]; if (c < ' ' || c >= 127 || c == '\\') - len += sprintf(user->buf + len, "\\x%02x", c); + p += scnprintf(p, e - p, "\\x%02x", c); else - user->buf[len++] = c; + append_char(&p, e, c); } - user->buf[len++] = '\n'; + append_char(&p, e, '\n'); if (msg->dict_len) { bool line = true; @@ -648,30 +657,31 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf, unsigned char c = log_dict(msg)[i]; if (line) { - user->buf[len++] = ' '; + append_char(&p, e, ' '); line = false; } if (c == '\0') { - user->buf[len++] = '\n'; + append_char(&p, e, '\n'); line = true; continue; } if (c < ' ' || c >= 127 || c == '\\') { - len += sprintf(user->buf + len, "\\x%02x", c); + p += scnprintf(p, e - p, "\\x%02x", c); continue; } - user->buf[len++] = c; + append_char(&p, e, c); } - user->buf[len++] = '\n'; + append_char(&p, e, '\n'); } user->idx = log_next(user->idx); user->seq++; raw_spin_unlock_irq(&logbuf_lock); + len = p - user->buf; if (len > count) { ret = -EINVAL; goto out; |