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authorStephen Smalley <sds@tycho.nsa.gov>2017-03-10 12:14:18 -0500
committerPaul Moore <paul@paul-moore.com>2017-03-29 17:33:11 -0400
commit2a4c22426955d4fc04069811997b7390c0fb858e (patch)
tree5ca50881e92de4a8c25947b4adc2d8dd53bc01a5 /fs/namei.c
parent710a0647ba955abd25460c36a09d80fdbe878273 (diff)
fs: switch order of CAP_DAC_OVERRIDE and CAP_DAC_READ_SEARCH checks
generic_permission() presently checks CAP_DAC_OVERRIDE prior to CAP_DAC_READ_SEARCH. This can cause misleading audit messages when using a LSM such as SELinux or AppArmor, since CAP_DAC_OVERRIDE may not be required for the operation. Flip the order of the tests so that CAP_DAC_OVERRIDE is only checked when required for the operation. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: John Johansen <john.johansen@canonical.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Acked-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c20
1 files changed, 10 insertions, 10 deletions
diff --git a/fs/namei.c b/fs/namei.c
index d41fab78798b..482414aa558b 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -340,22 +340,14 @@ int generic_permission(struct inode *inode, int mask)
if (S_ISDIR(inode->i_mode)) {
/* DACs are overridable for directories */
- if (capable_wrt_inode_uidgid(inode, CAP_DAC_OVERRIDE))
- return 0;
if (!(mask & MAY_WRITE))
if (capable_wrt_inode_uidgid(inode,
CAP_DAC_READ_SEARCH))
return 0;
- return -EACCES;
- }
- /*
- * Read/write DACs are always overridable.
- * Executable DACs are overridable when there is
- * at least one exec bit set.
- */
- if (!(mask & MAY_EXEC) || (inode->i_mode & S_IXUGO))
if (capable_wrt_inode_uidgid(inode, CAP_DAC_OVERRIDE))
return 0;
+ return -EACCES;
+ }
/*
* Searching includes executable on directories, else just read.
@@ -364,6 +356,14 @@ int generic_permission(struct inode *inode, int mask)
if (mask == MAY_READ)
if (capable_wrt_inode_uidgid(inode, CAP_DAC_READ_SEARCH))
return 0;
+ /*
+ * Read/write DACs are always overridable.
+ * Executable DACs are overridable when there is
+ * at least one exec bit set.
+ */
+ if (!(mask & MAY_EXEC) || (inode->i_mode & S_IXUGO))
+ if (capable_wrt_inode_uidgid(inode, CAP_DAC_OVERRIDE))
+ return 0;
return -EACCES;
}