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jail: Clean up allprison_lock handing in kern_jail_set

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Keep explicit track of the allprison_lock state during the final part
of kern_jail_set, instead of deducing it from the JAIL_ATTACH flag.

Also properly clean up when the attachment fails, fixing a long-
standing (though minor) memory leak.
This commit is contained in:
Jamie Gritton 2020-12-31 15:18:43 -08:00
parent 942951ba46
commit b4e87a6329
1 changed files with 18 additions and 12 deletions
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30
sys/kern/kern_jail.c
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@ -526,7 +526,7 @@ kern_jail_set(struct thread *td, struct uio *optuio, int flags)
#endif
unsigned long hid;
size_t namelen, onamelen, pnamelen;
int born, created, cuflags, descend, enforce;
int born, created, cuflags, descend, enforce, slocked;
int error, errmsg_len, errmsg_pos;
int gotchildmax, gotenforce, gothid, gotrsnum, gotslevel;
int jid, jsys, len, level;
@ -1828,24 +1828,32 @@ kern_jail_set(struct thread *td, struct uio *optuio, int flags)
}
/* Attach this process to the prison if requested. */
slocked = PD_LIST_SLOCKED;
if (flags & JAIL_ATTACH) {
mtx_lock(&pr->pr_mtx);
error = do_jail_attach(td, pr);
slocked = 0;
if (error) {
vfs_opterror(opts, "attach failed");
if (!created)
prison_deref(pr, PD_DEREF);
if (born) {
sx_slock(&allprison_lock);
slocked = PD_LIST_SLOCKED;
(void)osd_jail_call(pr, PR_METHOD_REMOVE, NULL);
}
prison_deref(pr, created
? slocked
: PD_DEREF | slocked);
goto done_errmsg;
}
}
#ifdef RACCT
if (racct_enable && !created) {
if (!(flags & JAIL_ATTACH))
if (slocked) {
sx_sunlock(&allprison_lock);
slocked = 0;
}
prison_racct_modify(pr);
if (!(flags & JAIL_ATTACH))
sx_slock(&allprison_lock);
}
#endif
@ -1857,18 +1865,16 @@ kern_jail_set(struct thread *td, struct uio *optuio, int flags)
* (which was not done earlier so that the prison would not be publicly
* visible).
*/
if (!created) {
prison_deref(pr, (flags & JAIL_ATTACH)
? PD_DEREF
: PD_DEREF | PD_LIST_SLOCKED);
} else {
if (!created)
prison_deref(pr, PD_DEREF | slocked);
else {
if (pr_flags & PR_PERSIST) {
mtx_lock(&pr->pr_mtx);
pr->pr_ref++;
pr->pr_uref++;
mtx_unlock(&pr->pr_mtx);
}
if (!(flags & JAIL_ATTACH))
if (slocked)
sx_sunlock(&allprison_lock);
}