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[PATCH openEuler-22.03-LTS-SP1] drm/amd/display: Check for NULL pointer
by Peng Zhang 23 Aug '24

23 Aug '24

From: Sung Joon Kim <sungjoon.kim(a)amd.com> mainline inclusion from mainline-v6.11-rc1 commit 4ab68e168ae1695f7c04fae98930740aaf7c50fa category: bugfix bugzilla: 190260 CVE: CVE-2024-42308 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- [why & how] Need to make sure plane_state is initialized before accessing its members. Cc: Mario Limonciello <mario.limonciello(a)amd.com> Cc: Alex Deucher <alexander.deucher(a)amd.com> Cc: stable(a)vger.kernel.org Reviewed-by: Xi (Alex) Liu <xi.liu(a)amd.com> Signed-off-by: Sung Joon Kim <sungjoon.kim(a)amd.com> Signed-off-by: Aurabindo Pillai <aurabindo.pillai(a)amd.com> Signed-off-by: Alex Deucher <alexander.deucher(a)amd.com> (cherry picked from commit 295d91cbc700651782a60572f83c24861607b648) Signed-off-by: ZhangPeng <zhangpeng362(a)huawei.com> --- drivers/gpu/drm/amd/display/dc/core/dc_surface.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_surface.c b/drivers/gpu/drm/amd/display/dc/core/dc_surface.c index 3d7d27435f15..98391ba103d6 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_surface.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_surface.c @@ -154,7 +154,8 @@ const struct dc_plane_status *dc_plane_get_status( if (pipe_ctx->plane_state != plane_state) continue; - pipe_ctx->plane_state->status.is_flip_pending = false; + if (pipe_ctx->plane_state) + pipe_ctx->plane_state->status.is_flip_pending = false; break; } -- 2.25.1

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[PATCH OLK-6.6 0/2] CVE-2024-43868
by Yuntao Liu 23 Aug '24

23 Aug '24

CVE-2024-43868 Clément Léger (1): riscv: Use SYM_*() assembly macros instead of deprecated ones Daniel Maslowski (1): riscv/purgatory: align riscv_kernel_entry arch/riscv/kernel/copy-unaligned.S | 8 ++++---- arch/riscv/kernel/fpu.S | 8 ++++---- arch/riscv/kernel/head.S | 12 +++++------ arch/riscv/kernel/hibernate-asm.S | 12 +++++------ arch/riscv/kernel/mcount-dyn.S | 20 ++++++++----------- arch/riscv/kernel/mcount.S | 8 ++++---- arch/riscv/kernel/probes/rethook_trampoline.S | 4 ++-- arch/riscv/kernel/suspend_entry.S | 4 ++-- arch/riscv/kernel/vdso/flush_icache.S | 4 ++-- arch/riscv/kernel/vdso/getcpu.S | 4 ++-- arch/riscv/kernel/vdso/rt_sigreturn.S | 4 ++-- arch/riscv/kernel/vdso/sys_hwprobe.S | 4 ++-- arch/riscv/lib/memcpy.S | 6 +++--- arch/riscv/lib/memmove.S | 3 +-- arch/riscv/lib/memset.S | 6 +++--- arch/riscv/lib/uaccess.S | 11 +++++----- arch/riscv/purgatory/entry.S | 18 ++++++----------- 17 files changed, 62 insertions(+), 74 deletions(-) -- 2.34.1

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[PATCH openEuler-1.0-LTS 0/2] fix hardlockup when cat /proc/slabinfo
by Jinjiang Tu 23 Aug '24

23 Aug '24

Jianfeng Wang (2): slub: introduce count_partial_free_approx() slub: use count_partial_free_approx() in slab_out_of_memory() mm/slub.c | 41 +++++++++++++++++++++++++++++++++++++++-- 1 file changed, 39 insertions(+), 2 deletions(-) -- 2.25.1

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[openEuler-1.0-LTS 0/2] fix hardlockup when cat /proc/slabinfo
by Jinjiang Tu 23 Aug '24

23 Aug '24

Jianfeng Wang (2): slub: introduce count_partial_free_approx() slub: use count_partial_free_approx() in slab_out_of_memory() mm/slub.c | 41 +++++++++++++++++++++++++++++++++++++++-- 1 file changed, 39 insertions(+), 2 deletions(-) -- 2.25.1

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[PATCH OLK-5.10] soc: qcom: pdr: protect locator_addr with the main mutex
by Li Nan 23 Aug '24

23 Aug '24

From: Dmitry Baryshkov <dmitry.baryshkov(a)linaro.org> stable inclusion from stable-v5.10.224 commit eab05737ee22216250fe20d27f5a596da5ea6eb7 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAKQ5M CVE: CVE-2024-43849 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit 107924c14e3ddd85119ca43c26a4ee1056fa9b84 ] If the service locator server is restarted fast enough, the PDR can rewrite locator_addr fields concurrently. Protect them by placing modification of those fields under the main pdr->lock. Fixes: fbe639b44a82 ("soc: qcom: Introduce Protection Domain Restart helpers") Tested-by: Neil Armstrong <neil.armstrong(a)linaro.org> # on SM8550-QRD Tested-by: Steev Klimaszewski <steev(a)kali.org> Tested-by: Alexey Minnekhanov <alexeymin(a)postmarketos.org> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov(a)linaro.org> Link: https://lore.kernel.org/r/20240622-qcom-pd-mapper-v9-1-a84ee3591c8e@linaro.… Signed-off-by: Bjorn Andersson <andersson(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Li Nan <linan122(a)huawei.com> --- drivers/soc/qcom/pdr_interface.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/soc/qcom/pdr_interface.c b/drivers/soc/qcom/pdr_interface.c index 205cc96823b7..373725b6d544 100644 --- a/drivers/soc/qcom/pdr_interface.c +++ b/drivers/soc/qcom/pdr_interface.c @@ -76,12 +76,12 @@ static int pdr_locator_new_server(struct qmi_handle *qmi, locator_hdl); struct pdr_service *pds; + mutex_lock(&pdr->lock); /* Create a local client port for QMI communication */ pdr->locator_addr.sq_family = AF_QIPCRTR; pdr->locator_addr.sq_node = svc->node; pdr->locator_addr.sq_port = svc->port; - mutex_lock(&pdr->lock); pdr->locator_init_complete = true; mutex_unlock(&pdr->lock); @@ -104,10 +104,10 @@ static void pdr_locator_del_server(struct qmi_handle *qmi, mutex_lock(&pdr->lock); pdr->locator_init_complete = false; - mutex_unlock(&pdr->lock); pdr->locator_addr.sq_node = 0; pdr->locator_addr.sq_port = 0; + mutex_unlock(&pdr->lock); } static struct qmi_ops pdr_locator_ops = { @@ -366,12 +366,14 @@ static int pdr_get_domain_list(struct servreg_get_domain_list_req *req, if (ret < 0) return ret; + mutex_lock(&pdr->lock); ret = qmi_send_request(&pdr->locator_hdl, &pdr->locator_addr, &txn, SERVREG_GET_DOMAIN_LIST_REQ, SERVREG_GET_DOMAIN_LIST_REQ_MAX_LEN, servreg_get_domain_list_req_ei, req); + mutex_unlock(&pdr->lock); if (ret < 0) { qmi_txn_cancel(&txn); return ret; -- 2.39.2

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[PATCH openEuler-22.03-LTS-SP1] soc: qcom: pdr: protect locator_addr with the main mutex
by Li Nan 23 Aug '24

23 Aug '24

From: Dmitry Baryshkov <dmitry.baryshkov(a)linaro.org> stable inclusion from stable-v5.10.224 commit eab05737ee22216250fe20d27f5a596da5ea6eb7 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAKQ5M CVE: CVE-2024-43849 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit 107924c14e3ddd85119ca43c26a4ee1056fa9b84 ] If the service locator server is restarted fast enough, the PDR can rewrite locator_addr fields concurrently. Protect them by placing modification of those fields under the main pdr->lock. Fixes: fbe639b44a82 ("soc: qcom: Introduce Protection Domain Restart helpers") Tested-by: Neil Armstrong <neil.armstrong(a)linaro.org> # on SM8550-QRD Tested-by: Steev Klimaszewski <steev(a)kali.org> Tested-by: Alexey Minnekhanov <alexeymin(a)postmarketos.org> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov(a)linaro.org> Link: https://lore.kernel.org/r/20240622-qcom-pd-mapper-v9-1-a84ee3591c8e@linaro.… Signed-off-by: Bjorn Andersson <andersson(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Li Nan <linan122(a)huawei.com> --- drivers/soc/qcom/pdr_interface.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/soc/qcom/pdr_interface.c b/drivers/soc/qcom/pdr_interface.c index 205cc96823b7..373725b6d544 100644 --- a/drivers/soc/qcom/pdr_interface.c +++ b/drivers/soc/qcom/pdr_interface.c @@ -76,12 +76,12 @@ static int pdr_locator_new_server(struct qmi_handle *qmi, locator_hdl); struct pdr_service *pds; + mutex_lock(&pdr->lock); /* Create a local client port for QMI communication */ pdr->locator_addr.sq_family = AF_QIPCRTR; pdr->locator_addr.sq_node = svc->node; pdr->locator_addr.sq_port = svc->port; - mutex_lock(&pdr->lock); pdr->locator_init_complete = true; mutex_unlock(&pdr->lock); @@ -104,10 +104,10 @@ static void pdr_locator_del_server(struct qmi_handle *qmi, mutex_lock(&pdr->lock); pdr->locator_init_complete = false; - mutex_unlock(&pdr->lock); pdr->locator_addr.sq_node = 0; pdr->locator_addr.sq_port = 0; + mutex_unlock(&pdr->lock); } static struct qmi_ops pdr_locator_ops = { @@ -366,12 +366,14 @@ static int pdr_get_domain_list(struct servreg_get_domain_list_req *req, if (ret < 0) return ret; + mutex_lock(&pdr->lock); ret = qmi_send_request(&pdr->locator_hdl, &pdr->locator_addr, &txn, SERVREG_GET_DOMAIN_LIST_REQ, SERVREG_GET_DOMAIN_LIST_REQ_MAX_LEN, servreg_get_domain_list_req_ei, req); + mutex_unlock(&pdr->lock); if (ret < 0) { qmi_txn_cancel(&txn); return ret; -- 2.39.2

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[PATCH OLK-6.6] perf: Fix event leak upon exec and file release
by Li Huafei 23 Aug '24

23 Aug '24

From: Frederic Weisbecker <frederic(a)kernel.org> stable inclusion from stable-v6.6.44 commit 104e258a004037bc7dba9f6085c71dad6af57ad4 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IALEPL CVE: CVE-2024-43869 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit 3a5465418f5fd970e86a86c7f4075be262682840 upstream. The perf pending task work is never waited upon the matching event release. In the case of a child event, released via free_event() directly, this can potentially result in a leaked event, such as in the following scenario that doesn't even require a weak IRQ work implementation to trigger: schedule() prepare_task_switch() =======> <NMI> perf_event_overflow() event->pending_sigtrap = ... irq_work_queue(&event->pending_irq) <======= </NMI> perf_event_task_sched_out() event_sched_out() event->pending_sigtrap = 0; atomic_long_inc_not_zero(&event->refcount) task_work_add(&event->pending_task) finish_lock_switch() =======> <IRQ> perf_pending_irq() //do nothing, rely on pending task work <======= </IRQ> begin_new_exec() perf_event_exit_task() perf_event_exit_event() // If is child event free_event() WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1) // event is leaked Similar scenarios can also happen with perf_event_remove_on_exec() or simply against concurrent perf_event_release(). Fix this with synchonizing against the possibly remaining pending task work while freeing the event, just like is done with remaining pending IRQ work. This means that the pending task callback neither need nor should hold a reference to the event, preventing it from ever beeing freed. Fixes: 517e6a301f34 ("perf: Fix perf_pending_task() UaF") Signed-off-by: Frederic Weisbecker <frederic(a)kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20240621091601.18227-5-frederic@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Li Huafei <lihuafei1(a)huawei.com> --- include/linux/perf_event.h | 1 + kernel/events/core.c | 38 ++++++++++++++++++++++++++++++++++---- 2 files changed, 35 insertions(+), 4 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 1601aa405669..618a729c9f9c 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -797,6 +797,7 @@ struct perf_event { struct irq_work pending_irq; struct callback_head pending_task; unsigned int pending_work; + struct rcuwait pending_work_wait; atomic_t event_limit; diff --git a/kernel/events/core.c b/kernel/events/core.c index e373f901ac20..b7c4b49411be 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2288,7 +2288,6 @@ event_sched_out(struct perf_event *event, struct perf_event_context *ctx) if (state != PERF_EVENT_STATE_OFF && !event->pending_work && !task_work_add(current, &event->pending_task, TWA_RESUME)) { - WARN_ON_ONCE(!atomic_long_inc_not_zero(&event->refcount)); event->pending_work = 1; } else { local_dec(&event->ctx->nr_pending); @@ -5172,9 +5171,35 @@ static bool exclusive_event_installable(struct perf_event *event, static void perf_addr_filters_splice(struct perf_event *event, struct list_head *head); +static void perf_pending_task_sync(struct perf_event *event) +{ + struct callback_head *head = &event->pending_task; + + if (!event->pending_work) + return; + /* + * If the task is queued to the current task's queue, we + * obviously can't wait for it to complete. Simply cancel it. + */ + if (task_work_cancel(current, head)) { + event->pending_work = 0; + local_dec(&event->ctx->nr_pending); + return; + } + + /* + * All accesses related to the event are within the same + * non-preemptible section in perf_pending_task(). The RCU + * grace period before the event is freed will make sure all + * those accesses are complete by then. + */ + rcuwait_wait_event(&event->pending_work_wait, !event->pending_work, TASK_UNINTERRUPTIBLE); +} + static void _free_event(struct perf_event *event) { irq_work_sync(&event->pending_irq); + perf_pending_task_sync(event); unaccount_event(event); @@ -6807,24 +6832,28 @@ static void perf_pending_task(struct callback_head *head) struct perf_event *event = container_of(head, struct perf_event, pending_task); int rctx; + /* + * All accesses to the event must belong to the same implicit RCU read-side + * critical section as the ->pending_work reset. See comment in + * perf_pending_task_sync(). + */ + preempt_disable_notrace(); /* * If we 'fail' here, that's OK, it means recursion is already disabled * and we won't recurse 'further'. */ - preempt_disable_notrace(); rctx = perf_swevent_get_recursion_context(); if (event->pending_work) { event->pending_work = 0; perf_sigtrap(event); local_dec(&event->ctx->nr_pending); + rcuwait_wake_up(&event->pending_work_wait); } if (rctx >= 0) perf_swevent_put_recursion_context(rctx); preempt_enable_notrace(); - - put_event(event); } #ifdef CONFIG_GUEST_PERF_EVENTS @@ -11934,6 +11963,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, init_waitqueue_head(&event->waitq); init_irq_work(&event->pending_irq, perf_pending_irq); init_task_work(&event->pending_task, perf_pending_task); + rcuwait_init(&event->pending_work_wait); mutex_init(&event->mmap_mutex); raw_spin_lock_init(&event->addr_filters.lock); -- 2.25.1

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[PATCH openEuler-22.03-LTS-SP1] wifi: mac80211: sdata can be NULL during AMPDU start
by Yue Haibing 23 Aug '24

23 Aug '24

From: Alexander Wetzel <alexander(a)wetzel-home.de> stable inclusion from stable-v5.10.165 commit 187523fa7c2d4c780f775cb869216865c4a909ef category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6IXN2 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit 69403bad97aa0162e3d7911b27e25abe774093df upstream. ieee80211_tx_ba_session_handle_start() may get NULL for sdata when a deauthentication is ongoing. Here a trace triggering the race with the hostapd test multi_ap_fronthaul_on_ap: (gdb) list *drv_ampdu_action+0x46 0x8b16 is in drv_ampdu_action (net/mac80211/driver-ops.c:396). 391 int ret = -EOPNOTSUPP; 392 393 might_sleep(); 394 395 sdata = get_bss_sdata(sdata); 396 if (!check_sdata_in_driver(sdata)) 397 return -EIO; 398 399 trace_drv_ampdu_action(local, sdata, params); 400 wlan0: moving STA 02:00:00:00:03:00 to state 3 wlan0: associated wlan0: deauthenticating from 02:00:00:00:03:00 by local choice (Reason: 3=DEAUTH_LEAVING) wlan3.sta1: Open BA session requested for 02:00:00:00:00:00 tid 0 wlan3.sta1: dropped frame to 02:00:00:00:00:00 (unauthorized port) wlan0: moving STA 02:00:00:00:03:00 to state 2 wlan0: moving STA 02:00:00:00:03:00 to state 1 wlan0: Removed STA 02:00:00:00:03:00 wlan0: Destroyed STA 02:00:00:00:03:00 BUG: unable to handle page fault for address: fffffffffffffb48 PGD 11814067 P4D 11814067 PUD 11816067 PMD 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 2 PID: 133397 Comm: kworker/u16:1 Tainted: G W 6.1.0-rc8-wt+ #59 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.0-20220807_005459-localhost 04/01/2014 Workqueue: phy3 ieee80211_ba_session_work [mac80211] RIP: 0010:drv_ampdu_action+0x46/0x280 [mac80211] Code: 53 48 89 f3 be 89 01 00 00 e8 d6 43 bf ef e8 21 46 81 f0 83 bb a0 1b 00 00 04 75 0e 48 8b 9b 28 0d 00 00 48 81 eb 10 0e 00 00 <8b> 93 58 09 00 00 f6 c2 20 0f 84 3b 01 00 00 8b 05 dd 1c 0f 00 85 RSP: 0018:ffffc900025ebd20 EFLAGS: 00010287 RAX: 0000000000000000 RBX: fffffffffffff1f0 RCX: ffff888102228240 RDX: 0000000080000000 RSI: ffffffff918c5de0 RDI: ffff888102228b40 RBP: ffffc900025ebd40 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000000 R12: ffff888118c18ec0 R13: 0000000000000000 R14: ffffc900025ebd60 R15: ffff888018b7efb8 FS: 0000000000000000(0000) GS:ffff88817a600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffffffffffb48 CR3: 0000000105228006 CR4: 0000000000170ee0 Call Trace: <TASK> ieee80211_tx_ba_session_handle_start+0xd0/0x190 [mac80211] ieee80211_ba_session_work+0xff/0x2e0 [mac80211] process_one_work+0x29f/0x620 worker_thread+0x4d/0x3d0 ? process_one_work+0x620/0x620 kthread+0xfb/0x120 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x22/0x30 </TASK> Signed-off-by: Alexander Wetzel <alexander(a)wetzel-home.de> Link: https://lore.kernel.org/r/20221230121850.218810-2-alexander@wetzel-home.de Cc: stable(a)vger.kernel.org Signed-off-by: Johannes Berg <johannes.berg(a)intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Wang Hai <wanghai38(a)huawei.com> --- net/mac80211/agg-tx.c | 6 +++++- net/mac80211/driver-ops.c | 3 +++ 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c index 4b4ab1961068..92e5812daf89 100644 --- a/net/mac80211/agg-tx.c +++ b/net/mac80211/agg-tx.c @@ -491,7 +491,7 @@ void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid) { struct tid_ampdu_tx *tid_tx; struct ieee80211_local *local = sta->local; - struct ieee80211_sub_if_data *sdata = sta->sdata; + struct ieee80211_sub_if_data *sdata; struct ieee80211_ampdu_params params = { .sta = &sta->sta, .action = IEEE80211_AMPDU_TX_START, @@ -521,6 +521,7 @@ void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid) */ synchronize_net(); + sdata = sta->sdata; params.ssn = sta->tid_seq[tid] >> 4; ret = drv_ampdu_action(local, sdata, &params); tid_tx->ssn = params.ssn; @@ -534,6 +535,9 @@ void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid) */ set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state); } else if (ret) { + if (!sdata) + return; + ht_dbg(sdata, "BA request denied - HW unavailable for %pM tid %d\n", sta->sta.addr, tid); diff --git a/net/mac80211/driver-ops.c b/net/mac80211/driver-ops.c index 48322e45e7dd..120bd9cdf7df 100644 --- a/net/mac80211/driver-ops.c +++ b/net/mac80211/driver-ops.c @@ -331,6 +331,9 @@ int drv_ampdu_action(struct ieee80211_local *local, might_sleep(); + if (!sdata) + return -EIO; + sdata = get_bss_sdata(sdata); if (!check_sdata_in_driver(sdata)) return -EIO; -- 2.34.1

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[PATCH OLK-6.6] exec: Fix ToCToU between perm check and set-uid/gid usage
by Zizhi Wo 23 Aug '24

23 Aug '24

From: Kees Cook <kees(a)kernel.org> stable inclusion from stable-v6.6.47 commit d2a2a4714d80d09b0f8eb6438ab4224690b7121e category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IALED4 CVE: CVE-2024-43882 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- commit f50733b45d865f91db90919f8311e2127ce5a0cb upstream. When opening a file for exec via do_filp_open(), permission checking is done against the file's metadata at that moment, and on success, a file pointer is passed back. Much later in the execve() code path, the file metadata (specifically mode, uid, and gid) is used to determine if/how to set the uid and gid. However, those values may have changed since the permissions check, meaning the execution may gain unintended privileges. For example, if a file could change permissions from executable and not set-id: ---------x 1 root root 16048 Aug 7 13:16 target to set-id and non-executable: ---S------ 1 root root 16048 Aug 7 13:16 target it is possible to gain root privileges when execution should have been disallowed. While this race condition is rare in real-world scenarios, it has been observed (and proven exploitable) when package managers are updating the setuid bits of installed programs. Such files start with being world-executable but then are adjusted to be group-exec with a set-uid bit. For example, "chmod o-x,u+s target" makes "target" executable only by uid "root" and gid "cdrom", while also becoming setuid-root: -rwxr-xr-x 1 root cdrom 16048 Aug 7 13:16 target becomes: -rwsr-xr-- 1 root cdrom 16048 Aug 7 13:16 target But racing the chmod means users without group "cdrom" membership can get the permission to execute "target" just before the chmod, and when the chmod finishes, the exec reaches brpm_fill_uid(), and performs the setuid to root, violating the expressed authorization of "only cdrom group members can setuid to root". Re-check that we still have execute permissions in case the metadata has changed. It would be better to keep a copy from the perm-check time, but until we can do that refactoring, the least-bad option is to do a full inode_permission() call (under inode lock). It is understood that this is safe against dead-locks, but hardly optimal. Reported-by: Marco Vanotti <mvanotti(a)google.com> Tested-by: Marco Vanotti <mvanotti(a)google.com> Suggested-by: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: stable(a)vger.kernel.org Cc: Eric Biederman <ebiederm(a)xmission.com> Cc: Alexander Viro <viro(a)zeniv.linux.org.uk> Cc: Christian Brauner <brauner(a)kernel.org> Signed-off-by: Kees Cook <kees(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Zizhi Wo <wozizhi(a)huawei.com> --- fs/exec.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/exec.c b/fs/exec.c index 04fb89656cc3..a4725461a443 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1589,6 +1589,7 @@ static void bprm_fill_uid(struct linux_binprm *bprm, struct file *file) unsigned int mode; vfsuid_t vfsuid; vfsgid_t vfsgid; + int err; if (!mnt_may_suid(file->f_path.mnt)) return; @@ -1605,12 +1606,17 @@ static void bprm_fill_uid(struct linux_binprm *bprm, struct file *file) /* Be careful if suid/sgid is set */ inode_lock(inode); - /* reload atomically mode/uid/gid now that lock held */ + /* Atomically reload and check mode/uid/gid now that lock held. */ mode = inode->i_mode; vfsuid = i_uid_into_vfsuid(idmap, inode); vfsgid = i_gid_into_vfsgid(idmap, inode); + err = inode_permission(idmap, inode, MAY_EXEC); inode_unlock(inode); + /* Did the exec bit vanish out from under us? Give up. */ + if (err) + return; + /* We ignore suid/sgid if there are no mappings for them in the ns */ if (!vfsuid_has_mapping(bprm->cred->user_ns, vfsuid) || !vfsgid_has_mapping(bprm->cred->user_ns, vfsgid)) -- 2.39.2

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[PATCH OLK-5.10] exec: Fix ToCToU between perm check and set-uid/gid usage
by Zizhi Wo 23 Aug '24

23 Aug '24

From: Kees Cook <kees(a)kernel.org> stable inclusion from stable-v5.10.224 commit 15469d46ba34559bfe7e3de6659115778c624759 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IALED4 CVE: CVE-2024-43882 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- commit f50733b45d865f91db90919f8311e2127ce5a0cb upstream. When opening a file for exec via do_filp_open(), permission checking is done against the file's metadata at that moment, and on success, a file pointer is passed back. Much later in the execve() code path, the file metadata (specifically mode, uid, and gid) is used to determine if/how to set the uid and gid. However, those values may have changed since the permissions check, meaning the execution may gain unintended privileges. For example, if a file could change permissions from executable and not set-id: ---------x 1 root root 16048 Aug 7 13:16 target to set-id and non-executable: ---S------ 1 root root 16048 Aug 7 13:16 target it is possible to gain root privileges when execution should have been disallowed. While this race condition is rare in real-world scenarios, it has been observed (and proven exploitable) when package managers are updating the setuid bits of installed programs. Such files start with being world-executable but then are adjusted to be group-exec with a set-uid bit. For example, "chmod o-x,u+s target" makes "target" executable only by uid "root" and gid "cdrom", while also becoming setuid-root: -rwxr-xr-x 1 root cdrom 16048 Aug 7 13:16 target becomes: -rwsr-xr-- 1 root cdrom 16048 Aug 7 13:16 target But racing the chmod means users without group "cdrom" membership can get the permission to execute "target" just before the chmod, and when the chmod finishes, the exec reaches brpm_fill_uid(), and performs the setuid to root, violating the expressed authorization of "only cdrom group members can setuid to root". Re-check that we still have execute permissions in case the metadata has changed. It would be better to keep a copy from the perm-check time, but until we can do that refactoring, the least-bad option is to do a full inode_permission() call (under inode lock). It is understood that this is safe against dead-locks, but hardly optimal. Reported-by: Marco Vanotti <mvanotti(a)google.com> Tested-by: Marco Vanotti <mvanotti(a)google.com> Suggested-by: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: stable(a)vger.kernel.org Cc: Eric Biederman <ebiederm(a)xmission.com> Cc: Alexander Viro <viro(a)zeniv.linux.org.uk> Cc: Christian Brauner <brauner(a)kernel.org> Signed-off-by: Kees Cook <kees(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Zizhi Wo <wozizhi(a)huawei.com> --- fs/exec.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/exec.c b/fs/exec.c index c8c5818ece9e..802566d81db7 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1584,6 +1584,7 @@ static void bprm_fill_uid(struct linux_binprm *bprm, struct file *file) unsigned int mode; kuid_t uid; kgid_t gid; + int err; if (!mnt_may_suid(file->f_path.mnt)) return; @@ -1599,12 +1600,17 @@ static void bprm_fill_uid(struct linux_binprm *bprm, struct file *file) /* Be careful if suid/sgid is set */ inode_lock(inode); - /* reload atomically mode/uid/gid now that lock held */ + /* Atomically reload and check mode/uid/gid now that lock held. */ mode = inode->i_mode; uid = inode->i_uid; gid = inode->i_gid; + err = inode_permission(inode, MAY_EXEC); inode_unlock(inode); + /* Did the exec bit vanish out from under us? Give up. */ + if (err) + return; + /* We ignore suid/sgid if there are no mappings for them in the ns */ if (!kuid_has_mapping(bprm->cred->user_ns, uid) || !kgid_has_mapping(bprm->cred->user_ns, gid)) -- 2.39.2

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