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ktrace: use the limit of the trace initiator for file size limit on writes

Browse Source 
Reviewed by:	markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D30257
This commit is contained in:
Konstantin Belousov 2021-05-15 02:51:01 +03:00
parent 1762f674cc
commit 02645b886b
3 changed files with 17 additions and 8 deletions
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6
sys/kern/kern_ktrace.c
View File

@ -51,6 +51,7 @@ __FBSDID("$FreeBSD$");
#include <sys/namei.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
#include <sys/socket.h>
@ -148,6 +149,7 @@ static struct sx ktrace_sx;
struct ktr_io_params {
struct vnode *vp;
struct ucred *cr;
off_t lim;
u_int refs;
};
@ -465,6 +467,7 @@ ktr_io_params_alloc(struct thread *td, struct vnode *vp)
res = malloc(sizeof(struct ktr_io_params), M_KTRACE, M_WAITOK);
res->vp = vp;
res->cr = crhold(td->td_ucred);
res->lim = lim_cur(td, RLIMIT_FSIZE);
res->refs = 1;
return (res);
}
@ -1255,6 +1258,7 @@ ktr_writerequest(struct thread *td, struct ktr_request *req)
struct uio auio;
struct iovec aiov[3];
struct mount *mp;
off_t lim;
int datalen, buflen;
int error;
@ -1282,6 +1286,7 @@ ktr_writerequest(struct thread *td, struct ktr_request *req)
vp = kiop->vp;
cred = kiop->cr;
lim = kiop->lim;
vrefact(vp);
KASSERT(cred != NULL, ("ktr_writerequest: cred == NULL"));
@ -1319,6 +1324,7 @@ ktr_writerequest(struct thread *td, struct ktr_request *req)
vn_start_write(vp, &mp, V_WAIT);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
td->td_ktr_io_lim = lim;
#ifdef MAC
error = mac_vnode_check_write(cred, NOCRED, vp);
if (error == 0)

18
sys/kern/vfs_vnops.c
View File

@ -2359,18 +2359,20 @@ int
vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio,
struct thread *td)
{
off_t lim;
if (vp->v_type != VREG || td == NULL ||
(td->td_pflags2 & TDP2_ACCT) != 0)
return (0);
if ((uoff_t)uio->uio_offset + uio->uio_resid >
lim_cur(td, RLIMIT_FSIZE)) {
PROC_LOCK(td->td_proc);
kern_psignal(td->td_proc, SIGXFSZ);
PROC_UNLOCK(td->td_proc);
return (EFBIG);
}
return (0);
ktr_write = (td->td_pflags & TDP_INKTRACE) != 0;
lim = ktr_write ? td->td_ktr_io_lim : lim_cur(td, RLIMIT_FSIZE);
if ((uoff_t)uio->uio_offset + uio->uio_resid < lim)
return (0);
PROC_LOCK(td->td_proc);
kern_psignal(td->td_proc, SIGXFSZ);
PROC_UNLOCK(td->td_proc);
return (EFBIG);
}
int

1
sys/sys/proc.h
View File

@ -378,6 +378,7 @@ struct thread {
void *td_lkpi_task; /* LinuxKPI task struct pointer */
int td_pmcpend;
void *td_coredump; /* (c) coredump request. */
off_t td_ktr_io_lim; /* (k) limit for ktrace file size */
#ifdef EPOCH_TRACE
SLIST_HEAD(, epoch_tracker) td_epochs;
#endif