[AppArmor 34/44] Factor out sysctl pathname code

jjohansen
2007-06-26T23:22:51Z

[-- Attachment #1: sysctl-pathname.diff --]
[-- Type: text/plain, Size: 2803 bytes --]

Convert the selinux sysctl pathname computation code into a standalone
function.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: John Johansen <jjohansen@suse.de>

---
include/linux/sysctl.h | 2 ++
kernel/sysctl.c | 27 +++++++++++++++++++++++++++
security/selinux/hooks.c | 35 +++++------------------------------
3 files changed, 34 insertions(+), 30 deletions(-)

--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -963,6 +963,8 @@ extern int proc_doulongvec_minmax(ctl_ta
extern int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int,
struct file *, void __user *, size_t *, loff_t *);

+extern char *sysctl_pathname(ctl_table *, char *, int);
+
extern int do_sysctl (int __user *name, int nlen,
void __user *oldval, size_t __user *oldlenp,
void __user *newval, size_t newlen);
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1110,6 +1110,33 @@ struct ctl_table_header *sysctl_head_nex
return NULL;
}

+char *sysctl_pathname(ctl_table *table, char *buffer, int buflen)
+{
+ if (buflen < 1)
+ return NULL;
+ buffer += --buflen;
+ *buffer = '\0';
+
+ while (table) {
+ int namelen = strlen(table->procname);
+
+ if (buflen < namelen + 1)
+ return NULL;
+ buflen -= namelen + 1;
+ buffer -= namelen;
+ memcpy(buffer, table->procname, namelen);
+ *--buffer = '/';
+ table = table->parent;
+ }
+ if (buflen < 4)
+ return NULL;
+ buffer -= 4;
+ memcpy(buffer, "/sys", 4);
+
+ return buffer;
+}
+EXPORT_SYMBOL(sysctl_pathname);
+
#ifdef CONFIG_SYSCTL_SYSCALL
int do_sysctl(int __user *name, int nlen, void __user *oldval, size_t __user *oldlenp,
void __user *newval, size_t newlen)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1427,40 +1427,15 @@ static int selinux_capable(struct task_s

static int selinux_sysctl_get_sid(ctl_table *table, u16 tclass, u32 *sid)
{
- int buflen, rc;
- char *buffer, *path, *end;
+ char *buffer, *path;
+ int rc = -ENOMEM;

- rc = -ENOMEM;
buffer = (char*)__get_free_page(GFP_KERNEL);
if (!buffer)
goto out;
-
- buflen = PAGE_SIZE;
- end = buffer+buflen;
- *--end = '\0';
- buflen--;
- path = end-1;
- *path = '/';
- while (table) {
- const char *name = table->procname;
- size_t namelen = strlen(name);
- buflen -= namelen + 1;
- if (buflen < 0)
- goto out_free;
- end -= namelen;
- memcpy(end, name, namelen);
- *--end = '/';
- path = end;
- table = table->parent;
- }
- buflen -= 4;
- if (buflen < 0)
- goto out_free;
- end -= 4;
- memcpy(end, "/sys", 4);
- path = end;
- rc = security_genfs_sid("proc", path, tclass, sid);
-out_free:
+ path = sysctl_pathname(table, buffer, PAGE_SIZE);
+ if (path)
+ rc = security_genfs_sid("proc", path, tclass, sid);
free_page((unsigned long)buffer);
out:
return rc;

--