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Keep a copy of the credential used to mount filesystems around so

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we can check and use it later on.

Change the pieces of code which relied on mount->mnt_stat.f_owner
to check which user mounted the filesystem.

This became needed as the EA code needs to be able to allocate
blocks for "system" EA users like ACLs.

There seems to be some half-baked (probably only quarter- actually)
notion that the superuser for a given filesystem is the user who
mounted it, but this has far from been carried through.  It is
unclear if it should be.

Sponsored by: DARPA & NAI Labs.
This commit is contained in:
phk 2002-08-19 06:52:21 +00:00
parent 7a01faeb98
commit 8346c2fde3
3 changed files with 9 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
sys/kern/vfs_mount.c
View File

@ -527,7 +527,7 @@ vfs_nmount(td, fsflags, fsoptions)
* Only root, or the user that did the original mount is
* permitted to update it.
*/
if (mp->mnt_stat.f_owner != td->td_ucred->cr_uid) {
if (mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
error = suser(td);
if (error) {
vput(vp);
@ -643,6 +643,7 @@ vfs_nmount(td, fsflags, fsoptions)
mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
strncpy(mp->mnt_stat.f_fstypename, fstype, MFSNAMELEN);
mp->mnt_vnodecovered = vp;
mp->mnt_cred = crdup(td->td_ucred);
mp->mnt_stat.f_owner = td->td_ucred->cr_uid;
strncpy(mp->mnt_stat.f_mntonname, fspath, MNAMELEN);
mp->mnt_iosize_max = DFLTPHYS;
@ -901,7 +902,7 @@ vfs_mount(td, fstype, fspath, fsflags, fsdata)
* Only root, or the user that did the original mount is
* permitted to update it.
*/
if (mp->mnt_stat.f_owner != td->td_ucred->cr_uid) {
if (mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
error = suser(td);
if (error) {
vput(vp);
@ -1010,6 +1011,7 @@ vfs_mount(td, fstype, fspath, fsflags, fsdata)
mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
strncpy(mp->mnt_stat.f_fstypename, fstype, MFSNAMELEN);
mp->mnt_vnodecovered = vp;
mp->mnt_cred = crdup(td->td_ucred);
mp->mnt_stat.f_owner = td->td_ucred->cr_uid;
strncpy(mp->mnt_stat.f_mntonname, fspath, MNAMELEN);
mp->mnt_iosize_max = DFLTPHYS;
@ -1210,7 +1212,7 @@ unmount(td, uap)
* Only root, or the user that did the original mount is
* permitted to unmount this filesystem.
*/
if (mp->mnt_stat.f_owner != td->td_ucred->cr_uid) {
if (mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
error = suser(td);
if (error) {
vput(vp);
@ -1316,6 +1318,7 @@ dounmount(mp, flags, td)
wakeup(mp);
return (error);
}
crfree(mp->mnt_cred);
mtx_lock(&mountlist_mtx);
TAILQ_REMOVE(&mountlist, mp, mnt_list);
if ((coveredvp = mp->mnt_vnodecovered) != NULL)
@ -1370,6 +1373,7 @@ vfs_rootmountalloc(fstypename, devname, mpp)
mp->mnt_op = vfsp->vfc_vfsops;
mp->mnt_flag = MNT_RDONLY;
mp->mnt_vnodecovered = NULLVP;
mp->mnt_cred = crdup(td->td_ucred);
vfsp->vfc_refcount++;
mp->mnt_iosize_max = DFLTPHYS;
mp->mnt_stat.f_type = vfsp->vfc_typenum;

2
sys/security/lomac/kernel_util.c
View File

@ -383,7 +383,7 @@ unmount(td, uap)
*/
if (!mediate_subject_at_level("unmount", td->td_proc,
LOMAC_HIGHEST_LEVEL) ||
((mp->mnt_stat.f_owner != td->td_ucred->cr_uid) &&
((mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) &&
(error = suser(td)))) {
vput(vp);
return (error);

1
sys/sys/mount.h
View File

@ -146,6 +146,7 @@ struct mount {
int mnt_kern_flag; /* kernel only flags */
int mnt_maxsymlinklen; /* max size of short symlink */
struct statfs mnt_stat; /* cache of filesystem stats */
struct ucred *mnt_cred; /* credentials of mounter */
qaddr_t mnt_data; /* private data */
time_t mnt_time; /* last time written*/
u_int mnt_iosize_max; /* max IO request size */