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Date: Fri, 20 Nov 2009 11:01:19 -0800
From: ebiederm@...ssion.com (Eric W. Biederman)
To: <linux-kernel@...r.kernel.org>
Cc: James Morris <jmorris@...ei.org>,
linux-security-module@...r.kernel.org,
Stephen Smalley <sds@...ho.nsa.gov>
Subject: [RFC][PATCH] security/selinux: Simplify proc inode to security label mapping.
Currently selinux has incestuous knowledge of the implementation details
of procfs and sysctl that it uses to get a pathname from an inode. As it
happens the point we care is in the security_d_instantiate lsm hook so
we have a valid dentry that we can use to get the entire pathname on
the proc filesystem. With the recent change to sys_sysctl to go through
proc/sys all proc and sysctl accesses go through the vfs, which
means we no longer need a sysctl special case.
So get the path for the dentry, remove the incestuous knowledge
and simplify the code.
caveat: Because the dentry may not yet be hashed I think dentry_path will
append (deleted) and thus is not the right function to call.
Signed-off-by: Eric W. Biederman <ebiederm@...ssion.com>
---
security/selinux/hooks.c | 114 ++++-----------------------------------------
1 files changed, 11 insertions(+), 103 deletions(-)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index bb230d5..37ed36e 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -43,7 +43,6 @@
#include <linux/fdtable.h>
#include <linux/namei.h>
#include <linux/mount.h>
-#include <linux/proc_fs.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/tty.h>
@@ -70,7 +69,6 @@
#include <net/ipv6.h>
#include <linux/hugetlb.h>
#include <linux/personality.h>
-#include <linux/sysctl.h>
#include <linux/audit.h>
#include <linux/string.h>
#include <linux/selinux.h>
@@ -1178,39 +1176,27 @@ static inline u16 socket_type_to_security_class(int family, int type, int protoc
}
#ifdef CONFIG_PROC_FS
-static int selinux_proc_get_sid(struct proc_dir_entry *de,
+static int selinux_proc_get_sid(struct dentry *dentry,
u16 tclass,
u32 *sid)
{
- int buflen, rc;
- char *buffer, *path, *end;
+ int rc;
+ char *buffer, *path;
buffer = (char *)__get_free_page(GFP_KERNEL);
if (!buffer)
return -ENOMEM;
- buflen = PAGE_SIZE;
- end = buffer+buflen;
- *--end = '\0';
- buflen--;
- path = end-1;
- *path = '/';
- while (de && de != de->parent) {
- buflen -= de->namelen + 1;
- if (buflen < 0)
- break;
- end -= de->namelen;
- memcpy(end, de->name, de->namelen);
- *--end = '/';
- path = end;
- de = de->parent;
- }
- rc = security_genfs_sid("proc", path, tclass, sid);
+ path = dentry_path(dentry, buffer, PAGE_SIZE);
+ if (IS_ERR(path))
+ rc = PTR_ERR(path);
+ else
+ rc = security_genfs_sid("proc", path, tclass, sid);
free_page((unsigned long)buffer);
return rc;
}
#else
-static int selinux_proc_get_sid(struct proc_dir_entry *de,
+static int selinux_proc_get_sid(struct dentry *dentry,
u16 tclass,
u32 *sid)
{
@@ -1374,10 +1360,9 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
isec->sid = sbsec->sid;
if ((sbsec->flags & SE_SBPROC) && !S_ISLNK(inode->i_mode)) {
- struct proc_inode *proci = PROC_I(inode);
- if (proci->pde) {
+ if (opt_dentry) {
isec->sclass = inode_mode_to_security_class(inode->i_mode);
- rc = selinux_proc_get_sid(proci->pde,
+ rc = selinux_proc_get_sid(opt_dentry,
isec->sclass,
&sid);
if (rc)
@@ -1939,82 +1924,6 @@ static int selinux_capable(struct task_struct *tsk, const struct cred *cred,
return task_has_capability(tsk, cred, cap, audit);
}
-static int selinux_sysctl_get_sid(ctl_table *table, u16 tclass, u32 *sid)
-{
- int buflen, rc;
- char *buffer, *path, *end;
-
- 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:
- free_page((unsigned long)buffer);
-out:
- return rc;
-}
-
-static int selinux_sysctl(ctl_table *table, int op)
-{
- int error = 0;
- u32 av;
- u32 tsid, sid;
- int rc;
-
- sid = current_sid();
-
- rc = selinux_sysctl_get_sid(table, (op == 0001) ?
- SECCLASS_DIR : SECCLASS_FILE, &tsid);
- if (rc) {
- /* Default to the well-defined sysctl SID. */
- tsid = SECINITSID_SYSCTL;
- }
-
- /* The op values are "defined" in sysctl.c, thereby creating
- * a bad coupling between this module and sysctl.c */
- if (op == 001) {
- error = avc_has_perm(sid, tsid,
- SECCLASS_DIR, DIR__SEARCH, NULL);
- } else {
- av = 0;
- if (op & 004)
- av |= FILE__READ;
- if (op & 002)
- av |= FILE__WRITE;
- if (av)
- error = avc_has_perm(sid, tsid,
- SECCLASS_FILE, av, NULL);
- }
-
- return error;
-}
-
static int selinux_quotactl(int cmds, int type, int id, struct super_block *sb)
{
const struct cred *cred = current_cred();
@@ -5457,7 +5366,6 @@ static struct security_operations selinux_ops = {
.ptrace_traceme = selinux_ptrace_traceme,
.capget = selinux_capget,
.capset = selinux_capset,
- .sysctl = selinux_sysctl,
.capable = selinux_capable,
.quotactl = selinux_quotactl,
.quota_on = selinux_quota_on,
--
1.6.5.2.143.g8cc62
--
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