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authorStephen Smalley <sds@tycho.nsa.gov>2018-12-12 10:10:56 -0500
committerPaul Moore <paul@paul-moore.com>2019-01-10 20:34:37 -0500
commite46e01eebbbcf2ff6d28ee7cae9f117e9d1572c8 (patch)
tree21fb06603d0a98d0146053922e1a93ba5ded5817 /security/selinux
parentselinux: avoid silent denials in permissive mode under RCU walk (diff)
downloadlinux-dev-e46e01eebbbcf2ff6d28ee7cae9f117e9d1572c8.tar.xz
linux-dev-e46e01eebbbcf2ff6d28ee7cae9f117e9d1572c8.zip
selinux: stop passing MAY_NOT_BLOCK to the AVC upon follow_link
commit bda0be7ad9948 ("security: make inode_follow_link RCU-walk aware") switched selinux_inode_follow_link() to use avc_has_perm_flags() and pass down the MAY_NOT_BLOCK flag if called during RCU walk. However, the only test of MAY_NOT_BLOCK occurs during slow_avc_audit() and only if passing an inode as audit data (LSM_AUDIT_DATA_INODE). Since selinux_inode_follow_link() passes a dentry directly, passing MAY_NOT_BLOCK here serves no purpose. Switch selinux_inode_follow_link() to use avc_has_perm() and drop avc_has_perm_flags() since there are no other users. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'security/selinux')
-rw-r--r--security/selinux/avc.c24
-rw-r--r--security/selinux/hooks.c5
-rw-r--r--security/selinux/include/avc.h5
3 files changed, 4 insertions, 30 deletions
diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index 5de18a6d5c3f..9b63d8ee1687 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -867,9 +867,8 @@ static int avc_update_node(struct selinux_avc *avc,
* permissive mode that only appear when in enforcing mode.
*
* See the corresponding handling in slow_avc_audit(), and the
- * logic in selinux_inode_follow_link and selinux_inode_permission
- * for the VFS MAY_NOT_BLOCK flag, which is transliterated into
- * AVC_NONBLOCKING for avc_has_perm_noaudit().
+ * logic in selinux_inode_permission for the MAY_NOT_BLOCK flag,
+ * which is transliterated into AVC_NONBLOCKING.
*/
if (flags & AVC_NONBLOCKING)
return 0;
@@ -1209,25 +1208,6 @@ int avc_has_perm(struct selinux_state *state, u32 ssid, u32 tsid, u16 tclass,
return rc;
}
-int avc_has_perm_flags(struct selinux_state *state,
- u32 ssid, u32 tsid, u16 tclass, u32 requested,
- struct common_audit_data *auditdata,
- int flags)
-{
- struct av_decision avd;
- int rc, rc2;
-
- rc = avc_has_perm_noaudit(state, ssid, tsid, tclass, requested,
- (flags & MAY_NOT_BLOCK) ? AVC_NONBLOCKING : 0,
- &avd);
-
- rc2 = avc_audit(state, ssid, tsid, tclass, requested, &avd, rc,
- auditdata, flags);
- if (rc2)
- return rc2;
- return rc;
-}
-
u32 avc_policy_seqno(struct selinux_state *state)
{
return state->avc->avc_cache.latest_notif;
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 7f6068489a02..f08a0f201967 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2925,9 +2925,8 @@ static int selinux_inode_follow_link(struct dentry *dentry, struct inode *inode,
if (IS_ERR(isec))
return PTR_ERR(isec);
- return avc_has_perm_flags(&selinux_state,
- sid, isec->sid, isec->sclass, FILE__READ, &ad,
- rcu ? MAY_NOT_BLOCK : 0);
+ return avc_has_perm(&selinux_state,
+ sid, isec->sid, isec->sclass, FILE__READ, &ad);
}
static noinline int audit_inode_permission(struct inode *inode,
diff --git a/security/selinux/include/avc.h b/security/selinux/include/avc.h
index 74ea50977c20..7be0e1e90e8b 100644
--- a/security/selinux/include/avc.h
+++ b/security/selinux/include/avc.h
@@ -153,11 +153,6 @@ int avc_has_perm(struct selinux_state *state,
u32 ssid, u32 tsid,
u16 tclass, u32 requested,
struct common_audit_data *auditdata);
-int avc_has_perm_flags(struct selinux_state *state,
- u32 ssid, u32 tsid,
- u16 tclass, u32 requested,
- struct common_audit_data *auditdata,
- int flags);
int avc_has_extended_perms(struct selinux_state *state,
u32 ssid, u32 tsid, u16 tclass, u32 requested,