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authorOndrej Mosnacek <omosnace@redhat.com>2019-04-03 09:29:41 +0200
committerPaul Moore <paul@paul-moore.com>2019-04-04 09:00:27 -0400
commit1537ad15c9c59ce852748578eb5633139053e86b (patch)
treea5ac0a90e8e376d1442fbc83a1d18e713717d551 /security
parent593854c05210fccf92a5883ab8a8505837b82199 (diff)
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kernfs: fix xattr name handling in LSM helpers
The implementation of kernfs_security_xattr_*() helpers reuses the kernfs_node_xattr_*() functions, which take the suffix of the xattr name and extract full xattr name from it using xattr_full_name(). However, this function relies on the fact that the suffix passed to xattr handlers from VFS is always constructed from the full name by just incerementing the pointer. This doesn't necessarily hold for the callers of kernfs_security_xattr_*(), so their usage will easily lead to out-of-bounds access. Fix this by moving the xattr name reconstruction to the VFS xattr handlers and replacing the kernfs_security_xattr_*() helpers with more general kernfs_xattr_*() helpers that take full xattr name and allow accessing all kernfs node's xattrs. Reported-by: kernel test robot <rong.a.chen@intel.com> Fixes: b230d5aba2d1 ("LSM: add new hook for kernfs node initialization") Fixes: ec882da5cda9 ("selinux: implement the kernfs_init_security hook") Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'security')
-rw-r--r--security/selinux/hooks.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index b6e61524d68d..d5fdcb0d26fe 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3394,7 +3394,7 @@ static int selinux_kernfs_init_security(struct kernfs_node *kn_dir,
int rc;
char *context;
- rc = kernfs_security_xattr_get(kn_dir, XATTR_SELINUX_SUFFIX, NULL, 0);
+ rc = kernfs_xattr_get(kn_dir, XATTR_NAME_SELINUX, NULL, 0);
if (rc == -ENODATA)
return 0;
else if (rc < 0)
@@ -3405,8 +3405,7 @@ static int selinux_kernfs_init_security(struct kernfs_node *kn_dir,
if (!context)
return -ENOMEM;
- rc = kernfs_security_xattr_get(kn_dir, XATTR_SELINUX_SUFFIX, context,
- clen);
+ rc = kernfs_xattr_get(kn_dir, XATTR_NAME_SELINUX, context, clen);
if (rc < 0) {
kfree(context);
return rc;
@@ -3439,8 +3438,8 @@ static int selinux_kernfs_init_security(struct kernfs_node *kn_dir,
if (rc)
return rc;
- rc = kernfs_security_xattr_set(kn, XATTR_SELINUX_SUFFIX, context, clen,
- XATTR_CREATE);
+ rc = kernfs_xattr_set(kn, XATTR_NAME_SELINUX, context, clen,
+ XATTR_CREATE);
kfree(context);
return rc;
}