| Message ID | 1467294433-3222-21-git-send-email-agruenba@redhat.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Thu, 2016-06-30 at 15:47 +0200, Andreas Gruenbacher wrote: > Hook the richacl permission checking function into the vfs. > > Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> > --- > fs/namei.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 52 insertions(+), 2 deletions(-) > > diff --git a/fs/namei.c b/fs/namei.c > index 7a822d0..48c9958 100644 > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -34,6 +34,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -256,7 +257,43 @@ void putname(struct filename *name) > __putname(name); > } > > -static int check_acl(struct inode *inode, int mask) > +static int check_richacl(struct inode *inode, int mask) > +{ > +#ifdef CONFIG_FS_RICHACL > + if (mask & MAY_NOT_BLOCK) { > + struct base_acl *base_acl; > + > + base_acl = rcu_dereference(inode->i_acl); > + if (!base_acl) > + goto no_acl; > + /* no ->get_richacl() calls in RCU mode... */ > + if (is_uncached_acl(base_acl)) > + return -ECHILD; > + return richacl_permission(inode, richacl(base_acl), > + mask & ~MAY_NOT_BLOCK); > + } else { > + struct richacl *acl; > + > + acl = get_richacl(inode); > + if (IS_ERR(acl)) > + return PTR_ERR(acl); > + if (acl) { > + int error = richacl_permission(inode, acl, mask); > + richacl_put(acl); > + return error; > + } > + } > +no_acl: > +#endif nit: Can you move the above to a static inline or something that becomes a noop when the config var is turned off? > + if (mask & (MAY_DELETE_SELF | MAY_TAKE_OWNERSHIP | > + MAY_CHMOD | MAY_SET_TIMES)) { > + /* File permission bits cannot grant this. */ > + return -EACCES; > + } > + return -EAGAIN; > +} > + > +static int check_posix_acl(struct inode *inode, int mask) > { > #ifdef CONFIG_FS_POSIX_ACL > if (mask & MAY_NOT_BLOCK) { > @@ -294,11 +331,24 @@ static int acl_permission_check(struct inode *inode, int mask) > { > unsigned int mode = inode->i_mode; > > + /* > + * With POSIX ACLs, the (mode & S_IRWXU) bits exactly match the owner > + * permissions, and we can skip checking posix acls for the owner. > + * With richacls, the owner may be granted fewer permissions than the > + * mode bits seem to suggest (for example, append but not write), and > + * we always need to check the richacl. > + */ > + > + if (IS_RICHACL(inode)) { > + int error = check_richacl(inode, mask); > + if (error != -EAGAIN) > + return error; > + } > if (likely(uid_eq(current_fsuid(), inode->i_uid))) > mode >>= 6; > else { > if (IS_POSIXACL(inode) && (mode & S_IRWXG)) { > - int error = check_acl(inode, mask); > + int error = check_posix_acl(inode, mask); > if (error != -EAGAIN) > return error; > } Looks fine other than the nit above: Reviewed-by: Jeff Layton <jlayton@redhat.com>
On Tue, Jul 12, 2016 at 2:13 PM, Jeff Layton <jlayton@redhat.com> wrote: > On Thu, 2016-06-30 at 15:47 +0200, Andreas Gruenbacher wrote: >> Hook the richacl permission checking function into the vfs. >> >> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> >> --- >> fs/namei.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- >> 1 file changed, 52 insertions(+), 2 deletions(-) >> >> diff --git a/fs/namei.c b/fs/namei.c >> index 7a822d0..48c9958 100644 >> --- a/fs/namei.c >> +++ b/fs/namei.c >> @@ -34,6 +34,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -256,7 +257,43 @@ void putname(struct filename *name) >> __putname(name); >> } >> >> -static int check_acl(struct inode *inode, int mask) >> +static int check_richacl(struct inode *inode, int mask) >> +{ >> +#ifdef CONFIG_FS_RICHACL >> + if (mask & MAY_NOT_BLOCK) { >> + struct base_acl *base_acl; >> + >> + base_acl = rcu_dereference(inode->i_acl); >> + if (!base_acl) >> + goto no_acl; >> + /* no ->get_richacl() calls in RCU mode... */ >> + if (is_uncached_acl(base_acl)) >> + return -ECHILD; >> + return richacl_permission(inode, richacl(base_acl), >> + mask & ~MAY_NOT_BLOCK); >> + } else { >> + struct richacl *acl; >> + >> + acl = get_richacl(inode); >> + if (IS_ERR(acl)) >> + return PTR_ERR(acl); >> + if (acl) { >> + int error = richacl_permission(inode, acl, mask); >> + richacl_put(acl); >> + return error; >> + } >> + } >> +no_acl: >> +#endif > > nit: Can you move the above to a static inline or something that becomes a noop when the config var is turned off? We could move check_richacl into richacl.c and check_posix_acl into posix_acl.c. Given that those functions are currently only called once in namei.c, that's a very small improvement at most though. >> + if (mask & (MAY_DELETE_SELF | MAY_TAKE_OWNERSHIP | >> + MAY_CHMOD | MAY_SET_TIMES)) { >> + /* File permission bits cannot grant this. */ >> + return -EACCES; >> + } >> + return -EAGAIN; >> +} >> + >> +static int check_posix_acl(struct inode *inode, int mask) >> { >> #ifdef CONFIG_FS_POSIX_ACL >> if (mask & MAY_NOT_BLOCK) { >> @@ -294,11 +331,24 @@ static int acl_permission_check(struct inode *inode, int mask) >> { >> unsigned int mode = inode->i_mode; >> >> + /* >> + * With POSIX ACLs, the (mode & S_IRWXU) bits exactly match the owner >> + * permissions, and we can skip checking posix acls for the owner. >> + * With richacls, the owner may be granted fewer permissions than the >> + * mode bits seem to suggest (for example, append but not write), and >> + * we always need to check the richacl. >> + */ >> + >> + if (IS_RICHACL(inode)) { >> + int error = check_richacl(inode, mask); >> + if (error != -EAGAIN) >> + return error; >> + } >> if (likely(uid_eq(current_fsuid(), inode->i_uid))) >> mode >>= 6; >> else { >> if (IS_POSIXACL(inode) && (mode & S_IRWXG)) { >> - int error = check_acl(inode, mask); >> + int error = check_posix_acl(inode, mask); >> if (error != -EAGAIN) >> return error; >> } > > Looks fine other than the nit above: > > Reviewed-by: Jeff Layton <jlayton@redhat.com> Thanks, Andreas
diff --git a/fs/namei.c b/fs/namei.c index 7a822d0..48c9958 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -34,6 +34,7 @@ #include <linux/device_cgroup.h> #include <linux/fs_struct.h> #include <linux/posix_acl.h> +#include <linux/richacl.h> #include <linux/hash.h> #include <linux/bitops.h> #include <asm/uaccess.h> @@ -256,7 +257,43 @@ void putname(struct filename *name) __putname(name); } -static int check_acl(struct inode *inode, int mask) +static int check_richacl(struct inode *inode, int mask) +{ +#ifdef CONFIG_FS_RICHACL + if (mask & MAY_NOT_BLOCK) { + struct base_acl *base_acl; + + base_acl = rcu_dereference(inode->i_acl); + if (!base_acl) + goto no_acl; + /* no ->get_richacl() calls in RCU mode... */ + if (is_uncached_acl(base_acl)) + return -ECHILD; + return richacl_permission(inode, richacl(base_acl), + mask & ~MAY_NOT_BLOCK); + } else { + struct richacl *acl; + + acl = get_richacl(inode); + if (IS_ERR(acl)) + return PTR_ERR(acl); + if (acl) { + int error = richacl_permission(inode, acl, mask); + richacl_put(acl); + return error; + } + } +no_acl: +#endif + if (mask & (MAY_DELETE_SELF | MAY_TAKE_OWNERSHIP | + MAY_CHMOD | MAY_SET_TIMES)) { + /* File permission bits cannot grant this. */ + return -EACCES; + } + return -EAGAIN; +} + +static int check_posix_acl(struct inode *inode, int mask) { #ifdef CONFIG_FS_POSIX_ACL if (mask & MAY_NOT_BLOCK) { @@ -294,11 +331,24 @@ static int acl_permission_check(struct inode *inode, int mask) { unsigned int mode = inode->i_mode; + /* + * With POSIX ACLs, the (mode & S_IRWXU) bits exactly match the owner + * permissions, and we can skip checking posix acls for the owner. + * With richacls, the owner may be granted fewer permissions than the + * mode bits seem to suggest (for example, append but not write), and + * we always need to check the richacl. + */ + + if (IS_RICHACL(inode)) { + int error = check_richacl(inode, mask); + if (error != -EAGAIN) + return error; + } if (likely(uid_eq(current_fsuid(), inode->i_uid))) mode >>= 6; else { if (IS_POSIXACL(inode) && (mode & S_IRWXG)) { - int error = check_acl(inode, mask); + int error = check_posix_acl(inode, mask); if (error != -EAGAIN) return error; }
Hook the richacl permission checking function into the vfs. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> --- fs/namei.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 52 insertions(+), 2 deletions(-)