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authorLinus Torvalds <torvalds@linux-foundation.org>2018-06-30 11:15:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-30 11:15:12 -0700
commit34a484d58c1d0cdce4c5d63249ae89539dfad6b2 (patch)
tree92ba524b241b8866001ce07b78fe8ec4b202981e /security/selinux/selinuxfs.c
parente6e5bec43c0d5dec97355ebf9f6c9bbf4d4c29d5 (diff)
parent0da74120c5341389b97c4ee27487a97224999ee1 (diff)
Merge tag 'selinux-pr-20180629' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux fix from Paul Moore: "One fairly straightforward patch to fix a longstanding issue where a process could stall while accessing files in selinuxfs and block everyone else due to a held mutex. The patch passes all our tests and looks to apply cleanly to your current tree" * tag 'selinux-pr-20180629' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: selinux: move user accesses in selinuxfs out of locked regions
Diffstat (limited to 'security/selinux/selinuxfs.c')
-rw-r--r--security/selinux/selinuxfs.c78
1 files changed, 33 insertions, 45 deletions
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index f3d374d2ca04..79d3709b0671 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -441,22 +441,16 @@ static int sel_release_policy(struct inode *inode, struct file *filp)
static ssize_t sel_read_policy(struct file *filp, char __user *buf,
size_t count, loff_t *ppos)
{
- struct selinux_fs_info *fsi = file_inode(filp)->i_sb->s_fs_info;
struct policy_load_memory *plm = filp->private_data;
int ret;
- mutex_lock(&fsi->mutex);
-
ret = avc_has_perm(&selinux_state,
current_sid(), SECINITSID_SECURITY,
SECCLASS_SECURITY, SECURITY__READ_POLICY, NULL);
if (ret)
- goto out;
+ return ret;
- ret = simple_read_from_buffer(buf, count, ppos, plm->data, plm->len);
-out:
- mutex_unlock(&fsi->mutex);
- return ret;
+ return simple_read_from_buffer(buf, count, ppos, plm->data, plm->len);
}
static vm_fault_t sel_mmap_policy_fault(struct vm_fault *vmf)
@@ -1188,25 +1182,29 @@ static ssize_t sel_read_bool(struct file *filep, char __user *buf,
ret = -EINVAL;
if (index >= fsi->bool_num || strcmp(name,
fsi->bool_pending_names[index]))
- goto out;
+ goto out_unlock;
ret = -ENOMEM;
page = (char *)get_zeroed_page(GFP_KERNEL);
if (!page)
- goto out;
+ goto out_unlock;
cur_enforcing = security_get_bool_value(fsi->state, index);
if (cur_enforcing < 0) {
ret = cur_enforcing;
- goto out;
+ goto out_unlock;
}
length = scnprintf(page, PAGE_SIZE, "%d %d", cur_enforcing,
fsi->bool_pending_values[index]);
- ret = simple_read_from_buffer(buf, count, ppos, page, length);
-out:
mutex_unlock(&fsi->mutex);
+ ret = simple_read_from_buffer(buf, count, ppos, page, length);
+out_free:
free_page((unsigned long)page);
return ret;
+
+out_unlock:
+ mutex_unlock(&fsi->mutex);
+ goto out_free;
}
static ssize_t sel_write_bool(struct file *filep, const char __user *buf,
@@ -1219,6 +1217,17 @@ static ssize_t sel_write_bool(struct file *filep, const char __user *buf,
unsigned index = file_inode(filep)->i_ino & SEL_INO_MASK;
const char *name = filep->f_path.dentry->d_name.name;
+ if (count >= PAGE_SIZE)
+ return -ENOMEM;
+
+ /* No partial writes. */
+ if (*ppos != 0)
+ return -EINVAL;
+
+ page = memdup_user_nul(buf, count);
+ if (IS_ERR(page))
+ return PTR_ERR(page);
+
mutex_lock(&fsi->mutex);
length = avc_has_perm(&selinux_state,
@@ -1233,22 +1242,6 @@ static ssize_t sel_write_bool(struct file *filep, const char __user *buf,
fsi->bool_pending_names[index]))
goto out;
- length = -ENOMEM;
- if (count >= PAGE_SIZE)
- goto out;
-
- /* No partial writes. */
- length = -EINVAL;
- if (*ppos != 0)
- goto out;
-
- page = memdup_user_nul(buf, count);
- if (IS_ERR(page)) {
- length = PTR_ERR(page);
- page = NULL;
- goto out;
- }
-
length = -EINVAL;
if (sscanf(page, "%d", &new_value) != 1)
goto out;
@@ -1280,6 +1273,17 @@ static ssize_t sel_commit_bools_write(struct file *filep,
ssize_t length;
int new_value;
+ if (count >= PAGE_SIZE)
+ return -ENOMEM;
+
+ /* No partial writes. */
+ if (*ppos != 0)
+ return -EINVAL;
+
+ page = memdup_user_nul(buf, count);
+ if (IS_ERR(page))
+ return PTR_ERR(page);
+
mutex_lock(&fsi->mutex);
length = avc_has_perm(&selinux_state,
@@ -1289,22 +1293,6 @@ static ssize_t sel_commit_bools_write(struct file *filep,
if (length)
goto out;
- length = -ENOMEM;
- if (count >= PAGE_SIZE)
- goto out;
-
- /* No partial writes. */
- length = -EINVAL;
- if (*ppos != 0)
- goto out;
-
- page = memdup_user_nul(buf, count);
- if (IS_ERR(page)) {
- length = PTR_ERR(page);
- page = NULL;
- goto out;
- }
-
length = -EINVAL;
if (sscanf(page, "%d", &new_value) != 1)
goto out;