diff options
Diffstat (limited to 'drivers/char/mem.c')
| -rw-r--r-- | drivers/char/mem.c | 55 |
1 files changed, 38 insertions, 17 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index d6e9d081c8b1..cf56614479ef 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -810,33 +810,54 @@ static const struct file_operations oldmem_fops = { static ssize_t kmsg_writev(struct kiocb *iocb, const struct iovec *iv, unsigned long count, loff_t pos) { - char *line, *p; + char *buf, *line; int i; - ssize_t ret = -EFAULT; + int level = default_message_loglevel; + int facility = 1; /* LOG_USER */ size_t len = iov_length(iv, count); + ssize_t ret = len; - line = kmalloc(len + 1, GFP_KERNEL); - if (line == NULL) + if (len > 1024) + return -EINVAL; + buf = kmalloc(len+1, GFP_KERNEL); + if (buf == NULL) return -ENOMEM; - /* - * copy all vectors into a single string, to ensure we do - * not interleave our log line with other printk calls - */ - p = line; + line = buf; for (i = 0; i < count; i++) { - if (copy_from_user(p, iv[i].iov_base, iv[i].iov_len)) + if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len)) goto out; - p += iv[i].iov_len; + line += iv[i].iov_len; + } + + /* + * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace + * the decimal value represents 32bit, the lower 3 bit are the log + * level, the rest are the log facility. + * + * If no prefix or no userspace facility is specified, we + * enforce LOG_USER, to be able to reliably distinguish + * kernel-generated messages from userspace-injected ones. + */ + line = buf; + if (line[0] == '<') { + char *endp = NULL; + + i = simple_strtoul(line+1, &endp, 10); + if (endp && endp[0] == '>') { + level = i & 7; + if (i >> 3) + facility = i >> 3; + endp++; + len -= endp - line; + line = endp; + } } - p[0] = '\0'; + line[len] = '\0'; - ret = printk("%s", line); - /* printk can add a prefix */ - if (ret > len) - ret = len; + printk_emit(facility, level, NULL, 0, "%s", line); out: - kfree(line); + kfree(buf); return ret; } |