diff options
Diffstat (limited to 'system/xen/xsa/xsa342-4.13.patch')
| -rw-r--r-- | system/xen/xsa/xsa342-4.13.patch | 145 |
1 files changed, 0 insertions, 145 deletions
diff --git a/system/xen/xsa/xsa342-4.13.patch b/system/xen/xsa/xsa342-4.13.patch deleted file mode 100644 index 334baf1b69..0000000000 --- a/system/xen/xsa/xsa342-4.13.patch +++ /dev/null @@ -1,145 +0,0 @@ -From: Jan Beulich <jbeulich@suse.com> -Subject: evtchn/x86: enforce correct upper limit for 32-bit guests - -The recording of d->max_evtchns in evtchn_2l_init(), in particular with -the limited set of callers of the function, is insufficient. Neither for -PV nor for HVM guests the bitness is known at domain_create() time, yet -the upper bound in 2-level mode depends upon guest bitness. Recording -too high a limit "allows" x86 32-bit domains to open not properly usable -event channels, management of which (inside Xen) would then result in -corruption of the shared info and vCPU info structures. - -Keep the upper limit dynamic for the 2-level case, introducing a helper -function to retrieve the effective limit. This helper is now supposed to -be private to the event channel code. The used in do_poll() and -domain_dump_evtchn_info() weren't consistent with port uses elsewhere -and hence get switched to port_is_valid(). - -Furthermore FIFO mode's setup_ports() gets adjusted to loop only up to -the prior ABI limit, rather than all the way up to the new one. - -Finally a word on the change to do_poll(): Accessing ->max_evtchns -without holding a suitable lock was never safe, as it as well as -->evtchn_port_ops may change behind do_poll()'s back. Using -port_is_valid() instead widens some the window for potential abuse, -until we've dealt with the race altogether (see XSA-343). - -This is XSA-342. - -Reported-by: Julien Grall <jgrall@amazon.com> -Fixes: 48974e6ce52e ("evtchn: use a per-domain variable for the max number of event channels") -Signed-off-by: Jan Beulich <jbeulich@suse.com> -Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> -Reviewed-by: Julien Grall <jgrall@amazon.com> - ---- a/xen/common/event_2l.c -+++ b/xen/common/event_2l.c -@@ -103,7 +103,6 @@ static const struct evtchn_port_ops evtc - void evtchn_2l_init(struct domain *d) - { - d->evtchn_port_ops = &evtchn_port_ops_2l; -- d->max_evtchns = BITS_PER_EVTCHN_WORD(d) * BITS_PER_EVTCHN_WORD(d); - } - - /* ---- a/xen/common/event_channel.c -+++ b/xen/common/event_channel.c -@@ -151,7 +151,7 @@ static void free_evtchn_bucket(struct do - - int evtchn_allocate_port(struct domain *d, evtchn_port_t port) - { -- if ( port > d->max_evtchn_port || port >= d->max_evtchns ) -+ if ( port > d->max_evtchn_port || port >= max_evtchns(d) ) - return -ENOSPC; - - if ( port_is_valid(d, port) ) -@@ -1396,13 +1396,11 @@ static void domain_dump_evtchn_info(stru - - spin_lock(&d->event_lock); - -- for ( port = 1; port < d->max_evtchns; ++port ) -+ for ( port = 1; port_is_valid(d, port); ++port ) - { - const struct evtchn *chn; - char *ssid; - -- if ( !port_is_valid(d, port) ) -- continue; - chn = evtchn_from_port(d, port); - if ( chn->state == ECS_FREE ) - continue; ---- a/xen/common/event_fifo.c -+++ b/xen/common/event_fifo.c -@@ -478,7 +478,7 @@ static void cleanup_event_array(struct d - d->evtchn_fifo = NULL; - } - --static void setup_ports(struct domain *d) -+static void setup_ports(struct domain *d, unsigned int prev_evtchns) - { - unsigned int port; - -@@ -488,7 +488,7 @@ static void setup_ports(struct domain *d - * - save its pending state. - * - set default priority. - */ -- for ( port = 1; port < d->max_evtchns; port++ ) -+ for ( port = 1; port < prev_evtchns; port++ ) - { - struct evtchn *evtchn; - -@@ -546,6 +546,8 @@ int evtchn_fifo_init_control(struct evtc - if ( !d->evtchn_fifo ) - { - struct vcpu *vcb; -+ /* Latch the value before it changes during setup_event_array(). */ -+ unsigned int prev_evtchns = max_evtchns(d); - - for_each_vcpu ( d, vcb ) { - rc = setup_control_block(vcb); -@@ -562,8 +564,7 @@ int evtchn_fifo_init_control(struct evtc - goto error; - - d->evtchn_port_ops = &evtchn_port_ops_fifo; -- d->max_evtchns = EVTCHN_FIFO_NR_CHANNELS; -- setup_ports(d); -+ setup_ports(d, prev_evtchns); - } - else - rc = map_control_block(v, gfn, offset); ---- a/xen/common/schedule.c -+++ b/xen/common/schedule.c -@@ -1434,7 +1434,7 @@ static long do_poll(struct sched_poll *s - goto out; - - rc = -EINVAL; -- if ( port >= d->max_evtchns ) -+ if ( !port_is_valid(d, port) ) - goto out; - - rc = 0; ---- a/xen/include/xen/event.h -+++ b/xen/include/xen/event.h -@@ -105,6 +105,12 @@ void notify_via_xen_event_channel(struct - #define bucket_from_port(d, p) \ - ((group_from_port(d, p))[((p) % EVTCHNS_PER_GROUP) / EVTCHNS_PER_BUCKET]) - -+static inline unsigned int max_evtchns(const struct domain *d) -+{ -+ return d->evtchn_fifo ? EVTCHN_FIFO_NR_CHANNELS -+ : BITS_PER_EVTCHN_WORD(d) * BITS_PER_EVTCHN_WORD(d); -+} -+ - static inline bool_t port_is_valid(struct domain *d, unsigned int p) - { - if ( p >= read_atomic(&d->valid_evtchns) ) ---- a/xen/include/xen/sched.h -+++ b/xen/include/xen/sched.h -@@ -382,7 +382,6 @@ struct domain - /* Event channel information. */ - struct evtchn *evtchn; /* first bucket only */ - struct evtchn **evtchn_group[NR_EVTCHN_GROUPS]; /* all other buckets */ -- unsigned int max_evtchns; /* number supported by ABI */ - unsigned int max_evtchn_port; /* max permitted port number */ - unsigned int valid_evtchns; /* number of allocated event channels */ - spinlock_t event_lock; |