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| author | Stephen Smalley <sds@tycho.nsa.gov> | 2017-03-10 12:14:18 -0500 |
|---|---|---|
| committer | Paul Moore <paul@paul-moore.com> | 2017-03-29 17:33:11 -0400 |
| commit | 2a4c22426955d4fc04069811997b7390c0fb858e (patch) | |
| tree | 5ca50881e92de4a8c25947b4adc2d8dd53bc01a5 /fs/namei.c | |
| parent | 710a0647ba955abd25460c36a09d80fdbe878273 (diff) | |
| download | lwn-2a4c22426955d4fc04069811997b7390c0fb858e.tar.gz lwn-2a4c22426955d4fc04069811997b7390c0fb858e.zip | |
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.c | 20 |
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; } |