Messages in this thread | | | Date | Thu, 14 Dec 2006 17:02:29 -0800 | From | Randy Dunlap <> | Subject | Re: [patch 2/4] permission mapping for sys_syslog operations |
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On Thu, 14 Dec 2006 16:16:41 -0800 Zack Weinberg wrote:
> As suggested by Stephen Smalley: map the various sys_syslog operations > to a smaller set of privilege codes before calling security modules. > This patch changes the security module interface! There should be no > change in the actual security semantics enforced by dummy, capability, > nor SELinux (with one exception, clearly marked in sys_syslog). > > Change from previous version of patch: the privilege codes are now > in linux/security.h instead of linux/klog.h, and use the LSM_* naming > convention used for other such constants in that file. > > > Index: linux-2.6/kernel/printk.c > =================================================================== > --- linux-2.6.orig/kernel/printk.c 2006-12-13 16:06:22.000000000 -0800 > +++ linux-2.6/kernel/printk.c 2006-12-13 16:08:30.000000000 -0800 > @@ -164,6 +164,12 @@ > > __setup("log_buf_len=", log_buf_len_setup); > > +#define security_syslog_or_fail(type) do { \ > + int error = security_syslog(type); \ > + if (error) \ > + return error; \ > + } while (0) > +
From Documentation/CodingStyle:
Things to avoid when using macros:
1) macros that affect control flow: ...
> /* See linux/klog.h for the command numbers passed as the first argument. */ > int do_syslog(int type, char __user *buf, int len) > { > @@ -172,16 +178,15 @@ > char c; > int error = 0; > > - error = security_syslog(type); > - if (error) > - return error; > - > switch (type) { > case KLOG_CLOSE: > + security_syslog_or_fail(LSM_KLOG_READ); > break; > case KLOG_OPEN: > + security_syslog_or_fail(LSM_KLOG_READ); > break; > case KLOG_READ: > + security_syslog_or_fail(LSM_KLOG_READ); > error = -EINVAL; > if (!buf || len < 0) > goto out; > @@ -213,9 +218,11 @@ > error = i; > break; > case KLOG_READ_CLEAR_HIST: > + security_syslog_or_fail(LSM_KLOG_CLEARHIST); > do_clear = 1; > /* FALL THRU */ > case KLOG_READ_HIST: > + security_syslog_or_fail(LSM_KLOG_READHIST); > error = -EINVAL; > if (!buf || len < 0) > goto out; > @@ -269,15 +276,19 @@ > } > break; > case KLOG_CLEAR_HIST: > + security_syslog_or_fail(LSM_KLOG_CLEARHIST); > logged_chars = 0; > break; > case KLOG_DISABLE_CONSOLE: > + security_syslog_or_fail(LSM_KLOG_CONSOLE); > console_loglevel = minimum_console_loglevel; > break; > case KLOG_ENABLE_CONSOLE: > + security_syslog_or_fail(LSM_KLOG_CONSOLE); > console_loglevel = default_console_loglevel; > break; > case KLOG_SET_CONSOLE_LVL: > + security_syslog_or_fail(LSM_KLOG_CONSOLE); > error = -EINVAL; > if (len < 1 || len > 8) > goto out; > @@ -287,9 +298,18 @@ > error = 0; > break; > case KLOG_GET_UNREAD: > + security_syslog_or_fail(LSM_KLOG_READ); > error = log_end - log_start; > break;
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