From 002345925e6c45861f60db6f4fc6236713fd8847 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 3 Feb 2010 15:36:43 -0800 Subject: syslog: distinguish between /proc/kmsg and syscalls This allows the LSM to distinguish between syslog functions originating from /proc/kmsg access and direct syscalls. By default, the commoncaps will now no longer require CAP_SYS_ADMIN to read an opened /proc/kmsg file descriptor. For example the kernel syslog reader can now drop privileges after opening /proc/kmsg, instead of staying privileged with CAP_SYS_ADMIN. MAC systems that implement security_syslog have unchanged behavior. Signed-off-by: Kees Cook Acked-by: Serge Hallyn Acked-by: John Johansen Signed-off-by: James Morris --- fs/proc/kmsg.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'fs/proc') diff --git a/fs/proc/kmsg.c b/fs/proc/kmsg.c index 7ca78346d3f0..6a3d843a1088 100644 --- a/fs/proc/kmsg.c +++ b/fs/proc/kmsg.c @@ -12,37 +12,37 @@ #include #include #include +#include #include #include extern wait_queue_head_t log_wait; -extern int do_syslog(int type, char __user *bug, int count); - static int kmsg_open(struct inode * inode, struct file * file) { - return do_syslog(1,NULL,0); + return do_syslog(1, NULL, 0, SYSLOG_FROM_FILE); } static int kmsg_release(struct inode * inode, struct file * file) { - (void) do_syslog(0,NULL,0); + (void) do_syslog(0, NULL, 0, SYSLOG_FROM_FILE); return 0; } static ssize_t kmsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { - if ((file->f_flags & O_NONBLOCK) && !do_syslog(9, NULL, 0)) + if ((file->f_flags & O_NONBLOCK) && + !do_syslog(9, NULL, 0, SYSLOG_FROM_FILE)) return -EAGAIN; - return do_syslog(2, buf, count); + return do_syslog(2, buf, count, SYSLOG_FROM_FILE); } static unsigned int kmsg_poll(struct file *file, poll_table *wait) { poll_wait(file, &log_wait, wait); - if (do_syslog(9, NULL, 0)) + if (do_syslog(9, NULL, 0, SYSLOG_FROM_FILE)) return POLLIN | POLLRDNORM; return 0; } -- cgit v1.2.3