Dave Chinner <david@xxxxxxxxxxxxx> writes: > On Sun, Apr 27, 2014 at 09:44:39PM +0530, Aneesh Kumar K.V wrote: >> From: Andreas Gruenbacher <agruen@xxxxxxxxxx> >> >> Some permission models can allow processes to take ownership of a file, >> change the file permissions, and set the file timestamps. Introduce new >> permission mask flags and check for those permissions in >> inode_change_ok(). >> >> Signed-off-by: Andreas Gruenbacher <agruen@xxxxxxxxxx> >> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> >> --- >> fs/attr.c | 68 ++++++++++++++++++++++++++++++++++++++++++++---------- >> fs/namei.c | 2 +- >> include/linux/fs.h | 4 ++++ >> 3 files changed, 61 insertions(+), 13 deletions(-) >> >> diff --git a/fs/attr.c b/fs/attr.c >> index 1d158c972442..e468d4f2dca8 100644 >> --- a/fs/attr.c >> +++ b/fs/attr.c >> @@ -16,6 +16,54 @@ >> #include <linux/evm.h> >> #include <linux/ima.h> >> >> +static int richacl_change_ok(struct inode *inode, int mask) >> +{ > > acl_change_ok() Will update. > >> + if (!IS_RICHACL(inode)) >> + return -EPERM; >> + >> + if (inode->i_op->permission) >> + return inode->i_op->permission(inode, mask); >> + >> + return check_acl(inode, mask); >> +} >> + >> +static bool inode_uid_change_ok(struct inode *inode, kuid_t ia_uid) >> +{ >> + if (uid_eq(current_fsuid(), inode->i_uid) && >> + uid_eq(ia_uid, inode->i_uid)) >> + return true; >> + if (uid_eq(current_fsuid(), ia_uid) && >> + richacl_change_ok(inode, MAY_TAKE_OWNERSHIP) == 0) >> + return true; >> + if (capable(CAP_CHOWN)) >> + return true; >> + return false; >> +} >> + >> +static bool inode_gid_change_ok(struct inode *inode, kgid_t ia_gid) >> +{ >> + int in_group = in_group_p(ia_gid); >> + if (uid_eq(current_fsuid(), inode->i_uid) && >> + (in_group || gid_eq(ia_gid, inode->i_gid))) >> + return true; >> + if (in_group && richacl_change_ok(inode, MAY_TAKE_OWNERSHIP) == 0) >> + return true; >> + if (capable(CAP_CHOWN)) >> + return true; >> + return false; >> +} >> + >> +static bool inode_owner_permitted_or_capable(struct inode *inode, int mask) >> +{ >> + if (uid_eq(current_fsuid(), inode->i_uid)) >> + return true; >> + if (richacl_change_ok(inode, mask) == 0) >> + return true; >> + if (inode_capable(inode, CAP_FOWNER)) >> + return true; >> + return false; >> +} > > Some comments on when and why these need to be used instead of > inode_owner_or_capable() would be useful. I can see people getting > this wrong in future. > Ok. -aneesh -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html