diff options
Diffstat (limited to 'kernel/printk.c')
-rw-r--r-- | kernel/printk.c | 92 |
1 files changed, 48 insertions, 44 deletions
diff --git a/kernel/printk.c b/kernel/printk.c index 59d354e95763..a1bdf61d38ba 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -32,6 +32,7 @@ #include <linux/security.h> #include <linux/bootmem.h> #include <linux/memblock.h> +#include <linux/aio.h> #include <linux/syscalls.h> #include <linux/kexec.h> #include <linux/kdb.h> @@ -362,6 +363,46 @@ static void log_store(int facility, int level, log_next_seq++; } +#ifdef CONFIG_SECURITY_DMESG_RESTRICT +int dmesg_restrict = 1; +#else +int dmesg_restrict; +#endif + +static int syslog_action_restricted(int type) +{ + if (dmesg_restrict) + return 1; + /* Unless restricted, we allow "read all" and "get buffer size" for everybody */ + return type != SYSLOG_ACTION_READ_ALL && type != SYSLOG_ACTION_SIZE_BUFFER; +} + +static int check_syslog_permissions(int type, bool from_file) +{ + /* + * If this is from /proc/kmsg and we've already opened it, then we've + * already done the capabilities checks at open time. + */ + if (from_file && type != SYSLOG_ACTION_OPEN) + goto ok; + + if (syslog_action_restricted(type)) { + if (capable(CAP_SYSLOG)) + goto ok; + /* For historical reasons, accept CAP_SYS_ADMIN too, with a warning */ + if (capable(CAP_SYS_ADMIN)) { + printk_once(KERN_WARNING "%s (%d): " + "Attempt to access syslog with CAP_SYS_ADMIN " + "but no CAP_SYSLOG (deprecated).\n", + current->comm, task_pid_nr(current)); + goto ok; + } + return -EPERM; + } +ok: + return security_syslog(type); +} + /* /dev/kmsg - userspace message inject/listen interface */ struct devkmsg_user { u64 seq; @@ -437,10 +478,16 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf, char cont = '-'; size_t len; ssize_t ret; + int err; if (!user) return -EBADF; + err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL, + SYSLOG_FROM_FILE); + if (err) + return err; + ret = mutex_lock_interruptible(&user->lock); if (ret) return ret; @@ -619,7 +666,7 @@ static int devkmsg_open(struct inode *inode, struct file *file) if ((file->f_flags & O_ACCMODE) == O_WRONLY) return 0; - err = security_syslog(SYSLOG_ACTION_READ_ALL); + err = check_syslog_permissions(SYSLOG_ACTION_OPEN, SYSLOG_FROM_FILE); if (err) return err; @@ -812,45 +859,6 @@ static inline void boot_delay_msec(int level) } #endif -#ifdef CONFIG_SECURITY_DMESG_RESTRICT -int dmesg_restrict = 1; -#else -int dmesg_restrict; -#endif - -static int syslog_action_restricted(int type) -{ - if (dmesg_restrict) - return 1; - /* Unless restricted, we allow "read all" and "get buffer size" for everybody */ - return type != SYSLOG_ACTION_READ_ALL && type != SYSLOG_ACTION_SIZE_BUFFER; -} - -static int check_syslog_permissions(int type, bool from_file) -{ - /* - * If this is from /proc/kmsg and we've already opened it, then we've - * already done the capabilities checks at open time. - */ - if (from_file && type != SYSLOG_ACTION_OPEN) - return 0; - - if (syslog_action_restricted(type)) { - if (capable(CAP_SYSLOG)) - return 0; - /* For historical reasons, accept CAP_SYS_ADMIN too, with a warning */ - if (capable(CAP_SYS_ADMIN)) { - printk_once(KERN_WARNING "%s (%d): " - "Attempt to access syslog with CAP_SYS_ADMIN " - "but no CAP_SYSLOG (deprecated).\n", - current->comm, task_pid_nr(current)); - return 0; - } - return -EPERM; - } - return 0; -} - #if defined(CONFIG_PRINTK_TIME) static bool printk_time = 1; #else @@ -1126,10 +1134,6 @@ int do_syslog(int type, char __user *buf, int len, bool from_file) if (error) goto out; - error = security_syslog(type); - if (error) - return error; - switch (type) { case SYSLOG_ACTION_CLOSE: /* Close log */ break; |