Prink_emit use init_syslog_ns as a parameter of namespace,
but in some context, it will cause that logs generated
through printk_emit will be exported to host, for instance,
devkmsg_writev.
We add a new interface ns_printk_emit to pass an syslog_ns
parameter, and use it in devkmsg_writev.
Signed-off-by: Rui Xiang <rui.xiang@xxxxxxxxxx>
---
include/linux/printk.h | 6 ++++++
kernel/printk.c | 20 +++++++++++++++++++-
2 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/include/linux/printk.h b/include/linux/printk.h
index bf83ad9..4c7e2be 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -121,6 +121,12 @@ asmlinkage int printk_emit(int facility, int level,
const char *dict, size_t dictlen,
const char *fmt, ...);
+asmlinkage __printf(6, 7) __cold
+asmlinkage int ns_printk_emit(struct syslog_namespace *ns,
+ int facility, int level,
+ const char *dict, size_t dictlen,
+ const char *fmt, ...);
+
asmlinkage __printf(1, 2) __cold
int printk(const char *fmt, ...);
diff --git a/kernel/printk.c b/kernel/printk.c
index 38e8869..b60c1d4 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -420,6 +420,7 @@ static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv,
int facility = 1; /* LOG_USER */
size_t len = iov_length(iv, count);
ssize_t ret = len;
+ struct namespace *ns = current_user_ns()->syslog_ns;
if (len > LOG_LINE_MAX)
return -EINVAL;
@@ -461,7 +462,7 @@ static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv,
}
line[len] = '\0';
- printk_emit(facility, level, NULL, 0, "%s", line);
+ ns_printk_emit(ns, facility, level, NULL, 0, "%s", line);
out:
kfree(buf);
return ret;
@@ -1722,6 +1723,23 @@ asmlinkage int printk_emit(int facility, int level,
}
EXPORT_SYMBOL(printk_emit);
+asmlinkage int ns_printk_emit(struct syslog_namespace *ns,
+ int facility, int level,
+ const char *dict, size_t dictlen,
+ const char *fmt, ...)
+{
+ va_list args;
+ int r;
+
+ va_start(args, fmt);
+ r = ns_vprintk_emit(ns, facility, level, dict, dictlen, fmt,
+ args);
+ va_end(args);
+
+ return r;
+}
+EXPORT_SYMBOL(ns_printk_emit);
+
/**
* printk - print a kernel message
* @fmt: format string
--
1.8.2.2
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