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-rw-r--r--sys/dev/systrace.c208
-rw-r--r--sys/dev/systrace.h4
2 files changed, 156 insertions, 56 deletions
diff --git a/sys/dev/systrace.c b/sys/dev/systrace.c
index a2a51f42c17..c60bdcc0fe4 100644
--- a/sys/dev/systrace.c
+++ b/sys/dev/systrace.c
@@ -60,6 +60,8 @@ int systracewrite(dev_t, struct uio *, int);
int systraceioctl(dev_t, u_long, caddr_t, int, struct proc *);
int systraceselect(dev_t, int, struct proc *);
+uid_t systrace_seteuid(struct proc *, uid_t);
+gid_t systrace_setegid(struct proc *, gid_t);
int systracef_read(struct file *, off_t *, struct uio *, struct ucred *);
int systracef_write(struct file *, off_t *, struct uio *, struct ucred *);
int systracef_ioctl(struct file *, u_long, caddr_t, struct proc *p);
@@ -86,6 +88,8 @@ struct str_policy {
#define STR_PROC_SYSCALLRES 0x04
#define STR_PROC_REPORT 0x08 /* Report emulation */
#define STR_PROC_NEEDSEQNR 0x10 /* Answer must quote seqnr */
+#define STR_PROC_SETEUID 0x20 /* Elevate privileges */
+#define STR_PROC_SETEGID 0x40
struct str_process {
TAILQ_ENTRY(str_process) next;
@@ -104,6 +108,11 @@ struct str_process {
short error;
u_int16_t seqnr; /* expected reply sequence number */
+ uid_t seteuid;
+ uid_t saveuid;
+ gid_t setegid;
+ gid_t savegid;
+
struct str_message msg;
};
@@ -641,7 +650,11 @@ systrace_redirect(int code, struct proc *p, void *v, register_t *retval)
struct str_process *strp;
struct str_policy *strpolicy;
struct fsystrace *fst = NULL;
- int policy, error = 0, report = 0, maycontrol = 0;
+ struct emul *oldemul;
+ struct pcred *pc;
+ uid_t olduid;
+ gid_t oldgid;
+ int policy, error = 0, report = 0, maycontrol = 0, issuser = 0;
systrace_lock();
strp = p->p_systrace;
@@ -664,9 +677,10 @@ systrace_redirect(int code, struct proc *p, void *v, register_t *retval)
* real gid match the monitored process. Changing the
* uid or gid causes P_SUGID to be set.
*/
- if (fst->issuser)
+ if (fst->issuser) {
maycontrol = 1;
- else if (!(p->p_flag & P_SUGID)) {
+ issuser =1 ;
+ } else if (!(p->p_flag & P_SUGID)) {
maycontrol = fst->p_ruid == p->p_cred->p_ruid &&
fst->p_rgid == p->p_cred->p_rgid;
}
@@ -729,79 +743,150 @@ systrace_redirect(int code, struct proc *p, void *v, register_t *retval)
fst = NULL;
}
- if (!error) {
- struct emul *oldemul = p->p_emul;
- uid_t olduid = p->p_cred->p_ruid;
- gid_t oldgid = p->p_cred->p_rgid;
-
- error = (*callp->sy_call)(p, v, retval);
+ if (error)
+ return (error);
- if (p->p_flag & P_SUGID) {
- /* Stupid Locking not necessary */
- if ((strp = p->p_systrace) == NULL ||
- (fst = strp->parent) == NULL)
- return (error);
- if (!fst->issuser)
- return (error);
+ oldemul = p->p_emul;
+ pc = p->p_cred;
+ olduid = pc->p_ruid;
+ oldgid = pc->p_rgid;
+
+ /* Elevate privileges as desired */
+ if (issuser) {
+ systrace_lock();
+ if ((strp = p->p_systrace) != NULL) {
+ if (ISSET(strp->flags, STR_PROC_SETEUID))
+ strp->saveuid = systrace_seteuid(p, strp->seteuid);
+ if (ISSET(strp->flags, STR_PROC_SETEGID))
+ strp->savegid = systrace_setegid(p, strp->setegid);
}
+ systrace_unlock();
+ } else
+ CLR(strp->flags, STR_PROC_SETEUID|STR_PROC_SETEGID);
+
+ error = (*callp->sy_call)(p, v, retval);
- /* Report change in emulation */
+ /* Return to old privileges */
+ if (issuser) {
systrace_lock();
- strp = p->p_systrace;
-
- /* See if we should force a report */
- if (strp != NULL && ISSET(strp->flags, STR_PROC_REPORT)) {
- CLR(strp->flags, STR_PROC_REPORT);
- oldemul = NULL;
+ if ((strp = p->p_systrace) != NULL) {
+ if (ISSET(strp->flags, STR_PROC_SETEUID)) {
+ if (pc->pc_ucred->cr_uid == strp->seteuid)
+ systrace_seteuid(p, strp->saveuid);
+ CLR(strp->flags, STR_PROC_SETEUID);
+ }
+ if (ISSET(strp->flags, STR_PROC_SETEGID)) {
+ if (pc->pc_ucred->cr_gid == strp->setegid)
+ systrace_setegid(p, strp->savegid);
+ CLR(strp->flags, STR_PROC_SETEGID);
+ }
}
+ systrace_unlock();
+ }
- if (p->p_emul != oldemul && strp != NULL) {
- fst = strp->parent;
- lockmgr(&fst->lock, LK_EXCLUSIVE, NULL, p);
- systrace_unlock();
+ if (p->p_flag & P_SUGID) {
+ /* Stupid Locking not necessary */
+ if ((strp = p->p_systrace) == NULL ||
+ (fst = strp->parent) == NULL)
+ return (error);
+ if (!fst->issuser)
+ return (error);
+ }
- /* Old policy is without meaning now */
- if (strp->policy) {
- systrace_closepolicy(fst, strp->policy);
- strp->policy = NULL;
- }
- systrace_msg_emul(fst, strp);
- } else
- systrace_unlock();
+ /* Report change in emulation */
+ systrace_lock();
+ strp = p->p_systrace;
- /* Report if effective uid or gid changed */
- if (olduid != p->p_cred->p_ruid ||
- oldgid != p->p_cred->p_rgid) {
- systrace_lock();
- if ((strp = p->p_systrace) == NULL) {
- systrace_unlock();
- goto nougid;
- }
+ /* See if we should force a report */
+ if (strp != NULL && ISSET(strp->flags, STR_PROC_REPORT)) {
+ CLR(strp->flags, STR_PROC_REPORT);
+ oldemul = NULL;
+ }
- fst = strp->parent;
- lockmgr(&fst->lock, LK_EXCLUSIVE, NULL, p);
- systrace_unlock();
+ if (p->p_emul != oldemul && strp != NULL) {
+ fst = strp->parent;
+ lockmgr(&fst->lock, LK_EXCLUSIVE, NULL, p);
+ systrace_unlock();
- systrace_msg_ugid(fst, strp);
- nougid:
+ /* Old policy is without meaning now */
+ if (strp->policy) {
+ systrace_closepolicy(fst, strp->policy);
+ strp->policy = NULL;
}
+ systrace_msg_emul(fst, strp);
+ } else
+ systrace_unlock();
- /* Report result from system call */
+ /* Report if effective uid or gid changed */
+ if (olduid != p->p_cred->p_ruid ||
+ oldgid != p->p_cred->p_rgid) {
systrace_lock();
- if (report && (strp = p->p_systrace) != NULL) {
- fst = strp->parent;
- lockmgr(&fst->lock, LK_EXCLUSIVE, NULL, p);
+ if ((strp = p->p_systrace) == NULL) {
systrace_unlock();
+ goto nougid;
+ }
- systrace_msg_result(fst, strp, error, code,
- callp->sy_argsize, v, retval);
- } else
- systrace_unlock();
+ fst = strp->parent;
+ lockmgr(&fst->lock, LK_EXCLUSIVE, NULL, p);
+ systrace_unlock();
+
+ systrace_msg_ugid(fst, strp);
+ nougid:
}
+ /* Report result from system call */
+ systrace_lock();
+ if (report && (strp = p->p_systrace) != NULL) {
+ fst = strp->parent;
+ lockmgr(&fst->lock, LK_EXCLUSIVE, NULL, p);
+ systrace_unlock();
+
+ systrace_msg_result(fst, strp, error, code,
+ callp->sy_argsize, v, retval);
+ } else
+ systrace_unlock();
+
return (error);
}
+uid_t
+systrace_seteuid(struct proc *p, uid_t euid)
+{
+ struct pcred *pc = p->p_cred;
+ uid_t oeuid = pc->pc_ucred->cr_uid;
+
+ if (pc->pc_ucred->cr_uid == euid)
+ return (oeuid);
+
+ /*
+ * Copy credentials so other references do not see our changes.
+ */
+ pc->pc_ucred = crcopy(pc->pc_ucred);
+ pc->pc_ucred->cr_uid = euid;
+ p->p_flag |= P_SUGID;
+
+ return (oeuid);
+}
+
+gid_t
+systrace_setegid(struct proc *p, gid_t egid)
+{
+ struct pcred *pc = p->p_cred;
+ gid_t oegid = pc->pc_ucred->cr_gid;
+
+ if (pc->pc_ucred->cr_gid == egid)
+ return (oegid);
+
+ /*
+ * Copy credentials so other references do not see our changes.
+ */
+ pc->pc_ucred = crcopy(pc->pc_ucred);
+ pc->pc_ucred->cr_gid = egid;
+ p->p_flag |= P_SUGID;
+
+ return (oegid);
+}
+
/* Called with fst locked */
int
@@ -833,6 +918,17 @@ systrace_answer(struct str_process *strp, struct systrace_answer *ans)
if (ISSET(ans->stra_flags, SYSTR_FLAGS_RESULT))
SET(strp->flags, STR_PROC_SYSCALLRES);
+ /* See if we should elevate privileges for this system call */
+ if (ISSET(ans->stra_flags, SYSTR_FLAGS_SETEUID)) {
+ SET(strp->flags, STR_PROC_SETEUID);
+ strp->seteuid = ans->stra_seteuid;
+ }
+ if (ISSET(ans->stra_flags, SYSTR_FLAGS_SETEGID)) {
+ SET(strp->flags, STR_PROC_SETEGID);
+ strp->setegid = ans->stra_setegid;
+ }
+
+
/* Clearing the flag indicates to the process that it woke up */
CLR(strp->flags, STR_PROC_WAITANSWER);
wakeup(strp);
diff --git a/sys/dev/systrace.h b/sys/dev/systrace.h
index 6f5a13cda6e..1861dfed058 100644
--- a/sys/dev/systrace.h
+++ b/sys/dev/systrace.h
@@ -89,6 +89,8 @@ struct systrace_answer {
pid_t stra_pid;
u_int16_t stra_seqnr;
short reserved;
+ uid_t stra_seteuid; /* elevated privileges for system call */
+ uid_t stra_setegid;
int stra_policy;
int stra_error;
int stra_flags;
@@ -152,6 +154,8 @@ struct systrace_replace {
#define SYSTR_POLICY_NEVER 2
#define SYSTR_FLAGS_RESULT 0x001
+#define SYSTR_FLAGS_SETEUID 0x002
+#define SYSTR_FLAGS_SETEGID 0x004
#ifdef _KERNEL
struct str_process;
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-15 02:51:30 +0000