From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
stable@vger.kernel.org,
"Demi Marie Obenour" <demi@invisiblethingslab.com>,
"Juergen Gross" <jgross@suse.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: [PATCH 5.15 49/58] xen/blkfront: dont use gnttab_query_foreign_access() for mapped status
Date: Thu, 10 Mar 2022 15:19:38 +0100 [thread overview]
Message-ID: <20220310140814.377286177@linuxfoundation.org> (raw)
In-Reply-To: <20220310140812.983088611@linuxfoundation.org>
From: Juergen Gross <jgross@suse.com>
Commit abf1fd5919d6238ee3bc5eb4a9b6c3947caa6638 upstream.
It isn't enough to check whether a grant is still being in use by
calling gnttab_query_foreign_access(), as a mapping could be realized
by the other side just after having called that function.
In case the call was done in preparation of revoking a grant it is
better to do so via gnttab_end_foreign_access_ref() and check the
success of that operation instead.
For the ring allocation use alloc_pages_exact() in order to avoid
high order pages in case of a multi-page ring.
If a grant wasn't unmapped by the backend without persistent grants
being used, set the device state to "error".
This is CVE-2022-23036 / part of XSA-396.
Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/block/xen-blkfront.c | 63 +++++++++++++++++++++++++------------------
1 file changed, 37 insertions(+), 26 deletions(-)
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1290,7 +1290,8 @@ free_shadow:
rinfo->ring_ref[i] = GRANT_INVALID_REF;
}
}
- free_pages((unsigned long)rinfo->ring.sring, get_order(info->nr_ring_pages * XEN_PAGE_SIZE));
+ free_pages_exact(rinfo->ring.sring,
+ info->nr_ring_pages * XEN_PAGE_SIZE);
rinfo->ring.sring = NULL;
if (rinfo->irq)
@@ -1374,9 +1375,15 @@ static int blkif_get_final_status(enum b
return BLKIF_RSP_OKAY;
}
-static bool blkif_completion(unsigned long *id,
- struct blkfront_ring_info *rinfo,
- struct blkif_response *bret)
+/*
+ * Return values:
+ * 1 response processed.
+ * 0 missing further responses.
+ * -1 error while processing.
+ */
+static int blkif_completion(unsigned long *id,
+ struct blkfront_ring_info *rinfo,
+ struct blkif_response *bret)
{
int i = 0;
struct scatterlist *sg;
@@ -1399,7 +1406,7 @@ static bool blkif_completion(unsigned lo
/* Wait the second response if not yet here. */
if (s2->status < REQ_DONE)
- return false;
+ return 0;
bret->status = blkif_get_final_status(s->status,
s2->status);
@@ -1450,42 +1457,43 @@ static bool blkif_completion(unsigned lo
}
/* Add the persistent grant into the list of free grants */
for (i = 0; i < num_grant; i++) {
- if (gnttab_query_foreign_access(s->grants_used[i]->gref)) {
+ if (!gnttab_try_end_foreign_access(s->grants_used[i]->gref)) {
/*
* If the grant is still mapped by the backend (the
* backend has chosen to make this grant persistent)
* we add it at the head of the list, so it will be
* reused first.
*/
- if (!info->feature_persistent)
- pr_alert_ratelimited("backed has not unmapped grant: %u\n",
- s->grants_used[i]->gref);
+ if (!info->feature_persistent) {
+ pr_alert("backed has not unmapped grant: %u\n",
+ s->grants_used[i]->gref);
+ return -1;
+ }
list_add(&s->grants_used[i]->node, &rinfo->grants);
rinfo->persistent_gnts_c++;
} else {
/*
- * If the grant is not mapped by the backend we end the
- * foreign access and add it to the tail of the list,
- * so it will not be picked again unless we run out of
- * persistent grants.
+ * If the grant is not mapped by the backend we add it
+ * to the tail of the list, so it will not be picked
+ * again unless we run out of persistent grants.
*/
- gnttab_end_foreign_access(s->grants_used[i]->gref, 0, 0UL);
s->grants_used[i]->gref = GRANT_INVALID_REF;
list_add_tail(&s->grants_used[i]->node, &rinfo->grants);
}
}
if (s->req.operation == BLKIF_OP_INDIRECT) {
for (i = 0; i < INDIRECT_GREFS(num_grant); i++) {
- if (gnttab_query_foreign_access(s->indirect_grants[i]->gref)) {
- if (!info->feature_persistent)
- pr_alert_ratelimited("backed has not unmapped grant: %u\n",
- s->indirect_grants[i]->gref);
+ if (!gnttab_try_end_foreign_access(s->indirect_grants[i]->gref)) {
+ if (!info->feature_persistent) {
+ pr_alert("backed has not unmapped grant: %u\n",
+ s->indirect_grants[i]->gref);
+ return -1;
+ }
list_add(&s->indirect_grants[i]->node, &rinfo->grants);
rinfo->persistent_gnts_c++;
} else {
struct page *indirect_page;
- gnttab_end_foreign_access(s->indirect_grants[i]->gref, 0, 0UL);
/*
* Add the used indirect page back to the list of
* available pages for indirect grefs.
@@ -1500,7 +1508,7 @@ static bool blkif_completion(unsigned lo
}
}
- return true;
+ return 1;
}
static irqreturn_t blkif_interrupt(int irq, void *dev_id)
@@ -1566,12 +1574,17 @@ static irqreturn_t blkif_interrupt(int i
}
if (bret.operation != BLKIF_OP_DISCARD) {
+ int ret;
+
/*
* We may need to wait for an extra response if the
* I/O request is split in 2
*/
- if (!blkif_completion(&id, rinfo, &bret))
+ ret = blkif_completion(&id, rinfo, &bret);
+ if (!ret)
continue;
+ if (unlikely(ret < 0))
+ goto err;
}
if (add_id_to_freelist(rinfo, id)) {
@@ -1678,8 +1691,7 @@ static int setup_blkring(struct xenbus_d
for (i = 0; i < info->nr_ring_pages; i++)
rinfo->ring_ref[i] = GRANT_INVALID_REF;
- sring = (struct blkif_sring *)__get_free_pages(GFP_NOIO | __GFP_HIGH,
- get_order(ring_size));
+ sring = alloc_pages_exact(ring_size, GFP_NOIO);
if (!sring) {
xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
return -ENOMEM;
@@ -1689,7 +1701,7 @@ static int setup_blkring(struct xenbus_d
err = xenbus_grant_ring(dev, rinfo->ring.sring, info->nr_ring_pages, gref);
if (err < 0) {
- free_pages((unsigned long)sring, get_order(ring_size));
+ free_pages_exact(sring, ring_size);
rinfo->ring.sring = NULL;
goto fail;
}
@@ -2529,11 +2541,10 @@ static void purge_persistent_grants(stru
list_for_each_entry_safe(gnt_list_entry, tmp, &rinfo->grants,
node) {
if (gnt_list_entry->gref == GRANT_INVALID_REF ||
- gnttab_query_foreign_access(gnt_list_entry->gref))
+ !gnttab_try_end_foreign_access(gnt_list_entry->gref))
continue;
list_del(&gnt_list_entry->node);
- gnttab_end_foreign_access(gnt_list_entry->gref, 0, 0UL);
rinfo->persistent_gnts_c--;
gnt_list_entry->gref = GRANT_INVALID_REF;
list_add_tail(&gnt_list_entry->node, &rinfo->grants);
next prev parent reply other threads:[~2022-03-10 14:35 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-10 14:18 [PATCH 5.15 00/58] 5.15.28-rc2 review Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 01/58] slip: fix macro redefine warning Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 02/58] x86,bugs: Unconditionally allow spectre_v2=retpoline,amd Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 03/58] x86/speculation: Rename RETPOLINE_AMD to RETPOLINE_LFENCE Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 04/58] x86/speculation: Add eIBRS + Retpoline options Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 05/58] Documentation/hw-vuln: Update spectre doc Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 06/58] x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 07/58] x86/speculation: Use generic retpoline by default on AMD Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 08/58] x86/speculation: Update link to AMD speculation whitepaper Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 09/58] x86/speculation: Warn about Spectre v2 LFENCE mitigation Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 5.15 10/58] x86/speculation: Warn about eIBRS + LFENCE + Unprivileged eBPF + SMT Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 11/58] ARM: report Spectre v2 status through sysfs Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 12/58] ARM: early traps initialisation Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 13/58] ARM: use LOADADDR() to get load address of sections Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 14/58] ARM: Spectre-BHB workaround Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 15/58] ARM: include unprivileged BPF status in Spectre V2 reporting Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 16/58] arm64: Add Neoverse-N2, Cortex-A710 CPU part definition Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 17/58] arm64: Add HWCAP for self-synchronising virtual counter Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 18/58] arm64: Add Cortex-X2 CPU part definition Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 19/58] arm64: add ID_AA64ISAR2_EL1 sys register Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 20/58] arm64: cpufeature: add HWCAP for FEAT_AFP Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 21/58] arm64: cpufeature: add HWCAP for FEAT_RPRES Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 22/58] arm64: entry.S: Add ventry overflow sanity checks Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 23/58] arm64: spectre: Rename spectre_v4_patch_fw_mitigation_conduit Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 24/58] KVM: arm64: Allow indirect vectors to be used without SPECTRE_V3A Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 25/58] arm64: entry: Make the trampoline cleanup optional Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 26/58] arm64: entry: Free up another register on kptis tramp_exit path Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 27/58] arm64: entry: Move the trampoline data page before the text page Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 28/58] arm64: entry: Allow tramp_alias to access symbols after the 4K boundary Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 29/58] arm64: entry: Dont assume tramp_vectors is the start of the vectors Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 30/58] arm64: entry: Move trampoline macros out of ifdefd section Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 31/58] arm64: entry: Make the kpti trampolines kpti sequence optional Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 32/58] arm64: entry: Allow the trampoline text to occupy multiple pages Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 33/58] arm64: entry: Add non-kpti __bp_harden_el1_vectors for mitigations Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 34/58] arm64: entry: Add vectors that have the bhb mitigation sequences Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 35/58] arm64: entry: Add macro for reading symbol addresses from the trampoline Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 36/58] arm64: Add percpu vectors for EL1 Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 37/58] arm64: proton-pack: Report Spectre-BHB vulnerabilities as part of Spectre-v2 Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 38/58] arm64: Mitigate spectre style branch history side channels Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 39/58] KVM: arm64: Allow SMCCC_ARCH_WORKAROUND_3 to be discovered and migrated Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 40/58] arm64: Use the clearbhb instruction in mitigations Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 41/58] arm64: proton-pack: Include unprivileged eBPF status in Spectre v2 mitigation reporting Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 42/58] ARM: fix build error when BPF_SYSCALL is disabled Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 43/58] ARM: fix co-processor register typo Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 44/58] ARM: Do not use NOCROSSREFS directive with ld.lld Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 45/58] arm64: Do not include __READ_ONCE() block in assembly files Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 46/58] ARM: fix build warning in proc-v7-bugs.c Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 47/58] xen/xenbus: dont let xenbus_grant_ring() remove grants in error case Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 48/58] xen/grant-table: add gnttab_try_end_foreign_access() Greg Kroah-Hartman
2022-03-10 14:19 ` Greg Kroah-Hartman [this message]
2022-03-10 14:19 ` [PATCH 5.15 50/58] xen/netfront: dont use gnttab_query_foreign_access() for mapped status Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 51/58] xen/scsifront: " Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 52/58] xen/gntalloc: dont use gnttab_query_foreign_access() Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 53/58] xen: remove gnttab_query_foreign_access() Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 54/58] xen/9p: use alloc/free_pages_exact() Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 55/58] xen/pvcalls: " Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 56/58] xen/gnttab: fix gnttab_end_foreign_access() without page specified Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 57/58] xen/netfront: react properly to failing gnttab_end_foreign_access_ref() Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 5.15 58/58] Revert "ACPI: PM: s2idle: Cancel wakeup before dispatching EC GPE" Greg Kroah-Hartman
2022-03-10 18:48 ` [PATCH 5.15 00/58] 5.15.28-rc2 review Jon Hunter
2022-03-10 19:04 ` Fox Chen
2022-03-10 19:32 ` Shuah Khan
2022-03-10 22:12 ` Florian Fainelli
2022-03-11 1:03 ` Guenter Roeck
2022-03-11 7:34 ` Ron Economos
2022-03-11 8:27 ` Bagas Sanjaya
2022-03-11 10:08 ` Sudip Mukherjee
2022-03-11 10:26 ` Anders Roxell
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