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[PATCH RFC v3 00/10] extensible syscalls: CHECK_FIELDS to allow for easier feature detection

by Aleksa Sarai

This is something that I've been thinking about for a while. We had a discussion at LPC 2020 about this[1] but the proposals suggested there never materialised. In short, it is quite difficult for userspace to detect the feature capability of syscalls at runtime. This is something a lot of programs want to do, but they are forced to create elaborate scenarios to try to figure out if a feature is supported without causing damage to the system. For the vast majority of cases, each individual feature also needs to be tested individually (because syscall results are all-or-nothing), so testing even a single syscall's feature set can easily inflate the startup time of programs. This patchset implements the fairly minimal design I proposed in this talk[2] and in some old LKML threads (though I can't find the exact references ATM). The general flow looks like: 1. Userspace will indicate to the kernel that a syscall should a be no-op by setting the top bit of the extensible struct size argument. We will almost certainly never support exabyte sized structs, so the top bits are free for us to use as makeshift flag bits. This is preferable to using the per-syscall flag field inside the structure because seccomp can easily detect the bit in the flag and allow the probe or forcefully return -EEXTSYS_NOOP. 2. The kernel will then fill the provided structure with every valid bit pattern that the current kernel understands. For flags or other bitflag-like fields, this is the set of valid flags or bits. For pointer fields or fields that take an arbitrary value, the field has every bit set (0xFF... to fill the field) to indicate that any value is valid in the field. 3. The syscall then returns -EEXTSYS_NOOP which is an errno that will only ever be used for this purpose (so userspace can be sure that the request succeeded). On older kernels, the syscall will return a different error (usually -E2BIG or -EFAULT) and userspace can do their old-fashioned checks. 4. Userspace can then check which flags and fields are supported by looking at the fields in the returned structure. Flags are checked by doing an AND with the flags field, and field support can checked by comparing to 0. In principle you could just AND the entire structure if you wanted to do this check generically without caring about the structure contents (this is what libraries might consider doing). Userspace can even find out the internal kernel structure size by passing a PAGE_SIZE buffer and seeing how many bytes are non-zero. As with copy_struct_from_user(), this is designed to be forward- and backwards- compatible. This allows programas to get a one-shot understanding of what features a syscall supports without having to do any elaborate setups or tricks to detect support for destructive features. Flags can simply be ANDed to check if they are in the supported set, and fields can just be checked to see if they are non-zero. This patchset is IMHO the simplest way we can add the ability to introspect the feature set of extensible struct (copy_struct_from_user) syscalls. It doesn't preclude the chance of a more generic mechanism being added later. The intended way of using this interface to get feature information looks something like the following (imagine that openat2 has gained a new field and a new flag in the future): static bool openat2_no_automount_supported; static bool openat2_cwd_fd_supported; int check_openat2_support(void) { int err; struct open_how how = {}; err = openat2(AT_FDCWD, ".", &how, CHECK_FIELDS | sizeof(how)); assert(err < 0); switch (errno) { case EFAULT: case E2BIG: /* Old kernel... */ check_support_the_old_way(); break; case EEXTSYS_NOOP: openat2_no_automount_supported = (how.flags & RESOLVE_NO_AUTOMOUNT); openat2_cwd_fd_supported = (how.cwd_fd != 0); break; } } This series adds CHECK_FIELDS support for the following extensible struct syscalls, as they are quite likely to grow flags in the near future: * openat2 * clone3 * mount_setattr [1]: https://lwn.net/Articles/830666/ [2]: https://youtu.be/ggD-eb3yPVs Signed-off-by: Aleksa Sarai <cyphar(a)cyphar.com> --- Changes in v3: - Fix copy_struct_to_user() return values in case of clear_user() failure. - v2: <https://lore.kernel.org/r/20240906-extensible-structs-check_fields-v2-0-0f4…> Changes in v2: - Add CHECK_FIELDS support to mount_setattr(2). - Fix build failure on architectures with custom errno values. - Rework selftests to use the tools/ uAPI headers rather than custom defining EEXTSYS_NOOP. - Make sure we return -EINVAL and -E2BIG for invalid sizes even if CHECK_FIELDS is set, and add some tests for that. - v1: <https://lore.kernel.org/r/20240902-extensible-structs-check_fields-v1-0-545…> --- Aleksa Sarai (10): uaccess: add copy_struct_to_user helper sched_getattr: port to copy_struct_to_user openat2: explicitly return -E2BIG for (usize > PAGE_SIZE) openat2: add CHECK_FIELDS flag to usize argument selftests: openat2: add 0xFF poisoned data after misaligned struct selftests: openat2: add CHECK_FIELDS selftests clone3: add CHECK_FIELDS flag to usize argument selftests: clone3: add CHECK_FIELDS selftests mount_setattr: add CHECK_FIELDS flag to usize argument selftests: mount_setattr: add CHECK_FIELDS selftest arch/alpha/include/uapi/asm/errno.h | 3 + arch/mips/include/uapi/asm/errno.h | 3 + arch/parisc/include/uapi/asm/errno.h | 3 + arch/sparc/include/uapi/asm/errno.h | 3 + fs/namespace.c | 17 ++ fs/open.c | 18 ++ include/linux/uaccess.h | 97 ++++++++ include/uapi/asm-generic/errno.h | 3 + include/uapi/linux/openat2.h | 2 + kernel/fork.c | 30 ++- kernel/sched/syscalls.c | 42 +--- tools/arch/alpha/include/uapi/asm/errno.h | 3 + tools/arch/mips/include/uapi/asm/errno.h | 3 + tools/arch/parisc/include/uapi/asm/errno.h | 3 + tools/arch/sparc/include/uapi/asm/errno.h | 3 + tools/include/uapi/asm-generic/errno.h | 3 + tools/include/uapi/asm-generic/posix_types.h | 101 ++++++++ tools/testing/selftests/clone3/.gitignore | 1 + tools/testing/selftests/clone3/Makefile | 4 +- .../testing/selftests/clone3/clone3_check_fields.c | 264 +++++++++++++++++++++ tools/testing/selftests/mount_setattr/Makefile | 2 +- .../selftests/mount_setattr/mount_setattr_test.c | 53 ++++- tools/testing/selftests/openat2/Makefile | 2 + tools/testing/selftests/openat2/openat2_test.c | 165 ++++++++++++- 24 files changed, 777 insertions(+), 51 deletions(-) --- base-commit: 98f7e32f20d28ec452afb208f9cffc08448a2652 change-id: 20240803-extensible-structs-check_fields-a47e94cef691 Best regards, -- Aleksa Sarai <cyphar(a)cyphar.com>

1 week, 3 days

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[PATCH] leds: lp55xx: Fix check for invalid channel number

by Michal Vokáč

Prior to commit 92a81562e695 ("leds: lp55xx: Add multicolor framework support to lp55xx") the reg property (chan_nr) was parsed and stored as it was. Then, in lp55xx_init_led() function, it was checked if it is within valid range. In case it was not, an error message was printed and the driver probe failed. With the mentioned commit the reg property is checked right after it is read from the device tree. Comparison to the upper range is not correct though. Valid reg values are 0 to (max_channel - 1). So in case the parsed value is out of this (wrong) range the probe just fails and no error message is shown. Fix it by using proper comparison and print a message in case of an error. The check that is done in lp55xx_init_led() function is now redundant and can be removed. Fixes: 92a81562e695 ("leds: lp55xx: Add multicolor framework support to lp55xx") Cc: <stable(a)vger.kernel.org> Signed-off-by: Michal Vokáč <michal.vokac(a)ysoft.com> --- drivers/leds/leds-lp55xx-common.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/drivers/leds/leds-lp55xx-common.c b/drivers/leds/leds-lp55xx-common.c index 5a2e259679cf..055ee77455f9 100644 --- a/drivers/leds/leds-lp55xx-common.c +++ b/drivers/leds/leds-lp55xx-common.c @@ -512,12 +512,6 @@ static int lp55xx_init_led(struct lp55xx_led *led, led->max_current = pdata->led_config[chan].max_current; led->chan_nr = pdata->led_config[chan].chan_nr; - if (led->chan_nr >= max_channel) { - dev_err(dev, "Use channel numbers between 0 and %d\n", - max_channel - 1); - return -EINVAL; - } - if (pdata->led_config[chan].num_colors > 1) ret = devm_led_classdev_multicolor_register(dev, &led->mc_cdev); else @@ -1132,8 +1126,11 @@ static int lp55xx_parse_common_child(struct device_node *np, if (ret) return ret; - if (*chan_nr < 0 || *chan_nr > cfg->max_channel) + if (*chan_nr < 0 || *chan_nr >= cfg->max_channel) { + dev_err(dev, "Use channel numbers between 0 and %d\n", + cfg->max_channel - 1); return -EINVAL; + } return 0; } -- 2.1.4

1 week, 3 days

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[PATCH 6.1] net/mlx5: Always drain health in shutdown callback

by Xiangyu Chen

From: Shay Drory <shayd(a)nvidia.com> [ Upstream commit 1b75da22ed1e6171e261bc9265370162553d5393 ] There is no point in recovery during device shutdown. if health work started need to wait for it to avoid races and NULL pointer access. Hence, drain health WQ on shutdown callback. Fixes: 1958fc2f0712 ("net/mlx5: SF, Add auxiliary device driver") Fixes: d2aa060d40fa ("net/mlx5: Cancel health poll before sending panic teardown command") Signed-off-by: Shay Drory <shayd(a)nvidia.com> Reviewed-by: Moshe Shemesh <moshe(a)nvidia.com> Signed-off-by: Tariq Toukan <tariqt(a)nvidia.com> Reviewed-by: Wojciech Drewek <wojciech.drewek(a)intel.com> Link: https://patch.msgid.link/20240730061638.1831002-2-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> [Xiangyu: Modified to apply on 6.1.y to fix CVE-2024-43866] Signed-off-by: Xiangyu Chen <xiangyu.chen(a)windriver.com> --- drivers/net/ethernet/mellanox/mlx5/core/main.c | 2 +- drivers/net/ethernet/mellanox/mlx5/core/sf/dev/driver.c | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c index 76af59cfdd0e..825ad7663fa4 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c @@ -1950,7 +1950,6 @@ static int mlx5_try_fast_unload(struct mlx5_core_dev *dev) /* Panic tear down fw command will stop the PCI bus communication * with the HCA, so the health poll is no longer needed. */ - mlx5_drain_health_wq(dev); mlx5_stop_health_poll(dev, false); ret = mlx5_cmd_fast_teardown_hca(dev); @@ -1985,6 +1984,7 @@ static void shutdown(struct pci_dev *pdev) mlx5_core_info(dev, "Shutdown was called\n"); set_bit(MLX5_BREAK_FW_WAIT, &dev->intf_state); + mlx5_drain_health_wq(dev); err = mlx5_try_fast_unload(dev); if (err) mlx5_unload_one(dev, false); diff --git a/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/driver.c b/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/driver.c index 2424cdf9cca9..d6850eb0ed7f 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/driver.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/driver.c @@ -75,6 +75,7 @@ static void mlx5_sf_dev_shutdown(struct auxiliary_device *adev) { struct mlx5_sf_dev *sf_dev = container_of(adev, struct mlx5_sf_dev, adev); + mlx5_drain_health_wq(sf_dev->mdev); mlx5_unload_one(sf_dev->mdev, false); } -- 2.43.0

1 week, 3 days

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[PATCH v3 6.1/6.6] wifi: mac80211: Avoid address calculations via out of bounds array indexing

by Xiangyu Chen

From: Kenton Groombridge <concord(a)gentoo.org> [ Upstream commit 2663d0462eb32ae7c9b035300ab6b1523886c718 ] req->n_channels must be set before req->channels[] can be used. This patch fixes one of the issues encountered in [1]. [ 83.964255] UBSAN: array-index-out-of-bounds in net/mac80211/scan.c:364:4 [ 83.964258] index 0 is out of range for type 'struct ieee80211_channel *[]' [...] [ 83.964264] Call Trace: [ 83.964267] <TASK> [ 83.964269] dump_stack_lvl+0x3f/0xc0 [ 83.964274] __ubsan_handle_out_of_bounds+0xec/0x110 [ 83.964278] ieee80211_prep_hw_scan+0x2db/0x4b0 [ 83.964281] __ieee80211_start_scan+0x601/0x990 [ 83.964291] nl80211_trigger_scan+0x874/0x980 [ 83.964295] genl_family_rcv_msg_doit+0xe8/0x160 [ 83.964298] genl_rcv_msg+0x240/0x270 [...] [1] https://bugzilla.kernel.org/show_bug.cgi?id=218810 Co-authored-by: Kees Cook <keescook(a)chromium.org> Signed-off-by: Kees Cook <kees(a)kernel.org> Signed-off-by: Kenton Groombridge <concord(a)gentoo.org> Link: https://msgid.link/20240605152218.236061-1-concord@gentoo.org Signed-off-by: Johannes Berg <johannes.berg(a)intel.com> [Xiangyu: Modified to apply on 6.1.y and 6.6.y] Signed-off-by: Xiangyu Chen <xiangyu.chen(a)windriver.com> --- V1 -> V2: add v6.6 support V2 -> V3: add commit id from Linus's code tree --- net/mac80211/scan.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c index 62c22ff329ad..d81b49fb6458 100644 --- a/net/mac80211/scan.c +++ b/net/mac80211/scan.c @@ -357,7 +357,8 @@ static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata) struct cfg80211_scan_request *req; struct cfg80211_chan_def chandef; u8 bands_used = 0; - int i, ielen, n_chans; + int i, ielen; + u32 *n_chans; u32 flags = 0; req = rcu_dereference_protected(local->scan_req, @@ -367,34 +368,34 @@ static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata) return false; if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) { + local->hw_scan_req->req.n_channels = req->n_channels; + for (i = 0; i < req->n_channels; i++) { local->hw_scan_req->req.channels[i] = req->channels[i]; bands_used |= BIT(req->channels[i]->band); } - - n_chans = req->n_channels; } else { do { if (local->hw_scan_band == NUM_NL80211_BANDS) return false; - n_chans = 0; + n_chans = &local->hw_scan_req->req.n_channels; + *n_chans = 0; for (i = 0; i < req->n_channels; i++) { if (req->channels[i]->band != local->hw_scan_band) continue; - local->hw_scan_req->req.channels[n_chans] = + local->hw_scan_req->req.channels[(*n_chans)++] = req->channels[i]; - n_chans++; + bands_used |= BIT(req->channels[i]->band); } local->hw_scan_band++; - } while (!n_chans); + } while (!*n_chans); } - local->hw_scan_req->req.n_channels = n_chans; ieee80211_prepare_scan_chandef(&chandef, req->scan_width); if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT) -- 2.43.0

1 week, 3 days

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[PATCH v1 1/1] ufs: core: set SDEV_OFFLINE when ufs shutdown.

by Seunghwan Baek

There is a history of dead lock as reboot is performed at the beginning of booting. SDEV_QUIESCE was set for all lu's scsi_devices by ufs shutdown, and at that time the audio driver was waiting on blk_mq_submit_bio holding a mutex_lock while reading the fw binary. After that, a deadlock issue occurred while audio driver shutdown was waiting for mutex_unlock of blk_mq_submit_bio. To solve this, set SDEV_OFFLINE for all lus except wlun, so that any i/o that comes down after a ufs shutdown will return an error. [ 31.907781]I[0: swapper/0: 0] 1 130705007 1651079834 11289729804 0 D( 2) 3 ffffff882e208000 * init [device_shutdown] [ 31.907793]I[0: swapper/0: 0] Mutex: 0xffffff8849a2b8b0: owner[0xffffff882e28cb00 kworker/6:0 :49] [ 31.907806]I[0: swapper/0: 0] Call trace: [ 31.907810]I[0: swapper/0: 0] __switch_to+0x174/0x338 [ 31.907819]I[0: swapper/0: 0] __schedule+0x5ec/0x9cc [ 31.907826]I[0: swapper/0: 0] schedule+0x7c/0xe8 [ 31.907834]I[0: swapper/0: 0] schedule_preempt_disabled+0x24/0x40 [ 31.907842]I[0: swapper/0: 0] __mutex_lock+0x408/0xdac [ 31.907849]I[0: swapper/0: 0] __mutex_lock_slowpath+0x14/0x24 [ 31.907858]I[0: swapper/0: 0] mutex_lock+0x40/0xec [ 31.907866]I[0: swapper/0: 0] device_shutdown+0x108/0x280 [ 31.907875]I[0: swapper/0: 0] kernel_restart+0x4c/0x11c [ 31.907883]I[0: swapper/0: 0] __arm64_sys_reboot+0x15c/0x280 [ 31.907890]I[0: swapper/0: 0] invoke_syscall+0x70/0x158 [ 31.907899]I[0: swapper/0: 0] el0_svc_common+0xb4/0xf4 [ 31.907909]I[0: swapper/0: 0] do_el0_svc+0x2c/0xb0 [ 31.907918]I[0: swapper/0: 0] el0_svc+0x34/0xe0 [ 31.907928]I[0: swapper/0: 0] el0t_64_sync_handler+0x68/0xb4 [ 31.907937]I[0: swapper/0: 0] el0t_64_sync+0x1a0/0x1a4 [ 31.908774]I[0: swapper/0: 0] 49 0 11960702 11236868007 0 D( 2) 6 ffffff882e28cb00 * kworker/6:0 [__bio_queue_enter] [ 31.908783]I[0: swapper/0: 0] Call trace: [ 31.908788]I[0: swapper/0: 0] __switch_to+0x174/0x338 [ 31.908796]I[0: swapper/0: 0] __schedule+0x5ec/0x9cc [ 31.908803]I[0: swapper/0: 0] schedule+0x7c/0xe8 [ 31.908811]I[0: swapper/0: 0] __bio_queue_enter+0xb8/0x178 [ 31.908818]I[0: swapper/0: 0] blk_mq_submit_bio+0x194/0x67c [ 31.908827]I[0: swapper/0: 0] __submit_bio+0xb8/0x19c Fixes: b294ff3e3449 ("scsi: ufs: core: Enable power management for wlun") Cc: stable(a)vger.kernel.org Signed-off-by: Seunghwan Baek <sh8267.baek(a)samsung.com> --- drivers/ufs/core/ufshcd.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index a6f818cdef0e..4ac1492787c2 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -10215,7 +10215,9 @@ static void ufshcd_wl_shutdown(struct device *dev) shost_for_each_device(sdev, hba->host) { if (sdev == hba->ufs_device_wlun) continue; - scsi_device_quiesce(sdev); + mutex_lock(&sdev->state_mutex); + scsi_device_set_state(sdev, SDEV_OFFLINE); + mutex_unlock(&sdev->state_mutex); } __ufshcd_wl_suspend(hba, UFS_SHUTDOWN_PM); -- 2.17.1

1 week, 3 days

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FAILED: patch "[PATCH] resource: fix region_intersects() vs" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x b4afe4183ec77f230851ea139d91e5cf2644c68b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024100733-tiara-detective-885e@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: b4afe4183ec7 ("resource: fix region_intersects() vs add_memory_driver_managed()") 14b80582c43e ("resource: Introduce alloc_free_mem_region()") 27674ef6c73f ("mm: remove the extra ZONE_DEVICE struct page refcount") dc90f0846df4 ("mm: don't include <linux/memremap.h> in <linux/mm.h>") 895749455f60 ("mm: simplify freeing of devmap managed pages") 75e55d8a107e ("mm: move free_devmap_managed_page to memremap.c") 730ff52194cd ("mm: remove pointless includes from <linux/hmm.h>") f56caedaf94f ("Merge branch 'akpm' (patches from Andrew)") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From b4afe4183ec77f230851ea139d91e5cf2644c68b Mon Sep 17 00:00:00 2001 From: Huang Ying <ying.huang(a)intel.com> Date: Fri, 6 Sep 2024 11:07:11 +0800 Subject: [PATCH] resource: fix region_intersects() vs add_memory_driver_managed() On a system with CXL memory, the resource tree (/proc/iomem) related to CXL memory may look like something as follows. 490000000-50fffffff : CXL Window 0 490000000-50fffffff : region0 490000000-50fffffff : dax0.0 490000000-50fffffff : System RAM (kmem) Because drivers/dax/kmem.c calls add_memory_driver_managed() during onlining CXL memory, which makes "System RAM (kmem)" a descendant of "CXL Window X". This confuses region_intersects(), which expects all "System RAM" resources to be at the top level of iomem_resource. This can lead to bugs. For example, when the following command line is executed to write some memory in CXL memory range via /dev/mem, $ dd if=data of=/dev/mem bs=$((1 << 10)) seek=$((0x490000000 >> 10)) count=1 dd: error writing '/dev/mem': Bad address 1+0 records in 0+0 records out 0 bytes copied, 0.0283507 s, 0.0 kB/s the command fails as expected. However, the error code is wrong. It should be "Operation not permitted" instead of "Bad address". More seriously, the /dev/mem permission checking in devmem_is_allowed() passes incorrectly. Although the accessing is prevented later because ioremap() isn't allowed to map system RAM, it is a potential security issue. During command executing, the following warning is reported in the kernel log for calling ioremap() on system RAM. ioremap on RAM at 0x0000000490000000 - 0x0000000490000fff WARNING: CPU: 2 PID: 416 at arch/x86/mm/ioremap.c:216 __ioremap_caller.constprop.0+0x131/0x35d Call Trace: memremap+0xcb/0x184 xlate_dev_mem_ptr+0x25/0x2f write_mem+0x94/0xfb vfs_write+0x128/0x26d ksys_write+0xac/0xfe do_syscall_64+0x9a/0xfd entry_SYSCALL_64_after_hwframe+0x4b/0x53 The details of command execution process are as follows. In the above resource tree, "System RAM" is a descendant of "CXL Window 0" instead of a top level resource. So, region_intersects() will report no System RAM resources in the CXL memory region incorrectly, because it only checks the top level resources. Consequently, devmem_is_allowed() will return 1 (allow access via /dev/mem) for CXL memory region incorrectly. Fortunately, ioremap() doesn't allow to map System RAM and reject the access. So, region_intersects() needs to be fixed to work correctly with the resource tree with "System RAM" not at top level as above. To fix it, if we found a unmatched resource in the top level, we will continue to search matched resources in its descendant resources. So, we will not miss any matched resources in resource tree anymore. In the new implementation, an example resource tree |------------- "CXL Window 0" ------------| |-- "System RAM" --| will behave similar as the following fake resource tree for region_intersects(, IORESOURCE_SYSTEM_RAM, ), |-- "System RAM" --||-- "CXL Window 0a" --| Where "CXL Window 0a" is part of the original "CXL Window 0" that isn't covered by "System RAM". Link: https://lkml.kernel.org/r/20240906030713.204292-2-ying.huang@intel.com Fixes: c221c0b0308f ("device-dax: "Hotplug" persistent memory for use like normal RAM") Signed-off-by: "Huang, Ying" <ying.huang(a)intel.com> Cc: Dan Williams <dan.j.williams(a)intel.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: Davidlohr Bueso <dave(a)stgolabs.net> Cc: Jonathan Cameron <jonathan.cameron(a)huawei.com> Cc: Dave Jiang <dave.jiang(a)intel.com> Cc: Alison Schofield <alison.schofield(a)intel.com> Cc: Vishal Verma <vishal.l.verma(a)intel.com> Cc: Ira Weiny <ira.weiny(a)intel.com> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: Andy Shevchenko <andriy.shevchenko(a)linux.intel.com> Cc: Bjorn Helgaas <bhelgaas(a)google.com> Cc: Baoquan He <bhe(a)redhat.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/kernel/resource.c b/kernel/resource.c index 14777afb0a99..235dc77f8add 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -540,20 +540,62 @@ static int __region_intersects(struct resource *parent, resource_size_t start, size_t size, unsigned long flags, unsigned long desc) { - struct resource res; + resource_size_t ostart, oend; int type = 0; int other = 0; - struct resource *p; + struct resource *p, *dp; + bool is_type, covered; + struct resource res; res.start = start; res.end = start + size - 1; for (p = parent->child; p ; p = p->sibling) { - bool is_type = (((p->flags & flags) == flags) && - ((desc == IORES_DESC_NONE) || - (desc == p->desc))); - - if (resource_overlaps(p, &res)) - is_type ? type++ : other++; + if (!resource_overlaps(p, &res)) + continue; + is_type = (p->flags & flags) == flags && + (desc == IORES_DESC_NONE || desc == p->desc); + if (is_type) { + type++; + continue; + } + /* + * Continue to search in descendant resources as if the + * matched descendant resources cover some ranges of 'p'. + * + * |------------- "CXL Window 0" ------------| + * |-- "System RAM" --| + * + * will behave similar as the following fake resource + * tree when searching "System RAM". + * + * |-- "System RAM" --||-- "CXL Window 0a" --| + */ + covered = false; + ostart = max(res.start, p->start); + oend = min(res.end, p->end); + for_each_resource(p, dp, false) { + if (!resource_overlaps(dp, &res)) + continue; + is_type = (dp->flags & flags) == flags && + (desc == IORES_DESC_NONE || desc == dp->desc); + if (is_type) { + type++; + /* + * Range from 'ostart' to 'dp->start' + * isn't covered by matched resource. + */ + if (dp->start > ostart) + break; + if (dp->end >= oend) { + covered = true; + break; + } + /* Remove covered range */ + ostart = max(ostart, dp->end + 1); + } + } + if (!covered) + other++; } if (type == 0)

1 week, 3 days

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FAILED: patch "[PATCH] resource: fix region_intersects() vs" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x b4afe4183ec77f230851ea139d91e5cf2644c68b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024100732-disinfect-spied-83fc@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: b4afe4183ec7 ("resource: fix region_intersects() vs add_memory_driver_managed()") 14b80582c43e ("resource: Introduce alloc_free_mem_region()") 27674ef6c73f ("mm: remove the extra ZONE_DEVICE struct page refcount") dc90f0846df4 ("mm: don't include <linux/memremap.h> in <linux/mm.h>") 895749455f60 ("mm: simplify freeing of devmap managed pages") 75e55d8a107e ("mm: move free_devmap_managed_page to memremap.c") 730ff52194cd ("mm: remove pointless includes from <linux/hmm.h>") f56caedaf94f ("Merge branch 'akpm' (patches from Andrew)") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From b4afe4183ec77f230851ea139d91e5cf2644c68b Mon Sep 17 00:00:00 2001 From: Huang Ying <ying.huang(a)intel.com> Date: Fri, 6 Sep 2024 11:07:11 +0800 Subject: [PATCH] resource: fix region_intersects() vs add_memory_driver_managed() On a system with CXL memory, the resource tree (/proc/iomem) related to CXL memory may look like something as follows. 490000000-50fffffff : CXL Window 0 490000000-50fffffff : region0 490000000-50fffffff : dax0.0 490000000-50fffffff : System RAM (kmem) Because drivers/dax/kmem.c calls add_memory_driver_managed() during onlining CXL memory, which makes "System RAM (kmem)" a descendant of "CXL Window X". This confuses region_intersects(), which expects all "System RAM" resources to be at the top level of iomem_resource. This can lead to bugs. For example, when the following command line is executed to write some memory in CXL memory range via /dev/mem, $ dd if=data of=/dev/mem bs=$((1 << 10)) seek=$((0x490000000 >> 10)) count=1 dd: error writing '/dev/mem': Bad address 1+0 records in 0+0 records out 0 bytes copied, 0.0283507 s, 0.0 kB/s the command fails as expected. However, the error code is wrong. It should be "Operation not permitted" instead of "Bad address". More seriously, the /dev/mem permission checking in devmem_is_allowed() passes incorrectly. Although the accessing is prevented later because ioremap() isn't allowed to map system RAM, it is a potential security issue. During command executing, the following warning is reported in the kernel log for calling ioremap() on system RAM. ioremap on RAM at 0x0000000490000000 - 0x0000000490000fff WARNING: CPU: 2 PID: 416 at arch/x86/mm/ioremap.c:216 __ioremap_caller.constprop.0+0x131/0x35d Call Trace: memremap+0xcb/0x184 xlate_dev_mem_ptr+0x25/0x2f write_mem+0x94/0xfb vfs_write+0x128/0x26d ksys_write+0xac/0xfe do_syscall_64+0x9a/0xfd entry_SYSCALL_64_after_hwframe+0x4b/0x53 The details of command execution process are as follows. In the above resource tree, "System RAM" is a descendant of "CXL Window 0" instead of a top level resource. So, region_intersects() will report no System RAM resources in the CXL memory region incorrectly, because it only checks the top level resources. Consequently, devmem_is_allowed() will return 1 (allow access via /dev/mem) for CXL memory region incorrectly. Fortunately, ioremap() doesn't allow to map System RAM and reject the access. So, region_intersects() needs to be fixed to work correctly with the resource tree with "System RAM" not at top level as above. To fix it, if we found a unmatched resource in the top level, we will continue to search matched resources in its descendant resources. So, we will not miss any matched resources in resource tree anymore. In the new implementation, an example resource tree |------------- "CXL Window 0" ------------| |-- "System RAM" --| will behave similar as the following fake resource tree for region_intersects(, IORESOURCE_SYSTEM_RAM, ), |-- "System RAM" --||-- "CXL Window 0a" --| Where "CXL Window 0a" is part of the original "CXL Window 0" that isn't covered by "System RAM". Link: https://lkml.kernel.org/r/20240906030713.204292-2-ying.huang@intel.com Fixes: c221c0b0308f ("device-dax: "Hotplug" persistent memory for use like normal RAM") Signed-off-by: "Huang, Ying" <ying.huang(a)intel.com> Cc: Dan Williams <dan.j.williams(a)intel.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: Davidlohr Bueso <dave(a)stgolabs.net> Cc: Jonathan Cameron <jonathan.cameron(a)huawei.com> Cc: Dave Jiang <dave.jiang(a)intel.com> Cc: Alison Schofield <alison.schofield(a)intel.com> Cc: Vishal Verma <vishal.l.verma(a)intel.com> Cc: Ira Weiny <ira.weiny(a)intel.com> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: Andy Shevchenko <andriy.shevchenko(a)linux.intel.com> Cc: Bjorn Helgaas <bhelgaas(a)google.com> Cc: Baoquan He <bhe(a)redhat.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/kernel/resource.c b/kernel/resource.c index 14777afb0a99..235dc77f8add 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -540,20 +540,62 @@ static int __region_intersects(struct resource *parent, resource_size_t start, size_t size, unsigned long flags, unsigned long desc) { - struct resource res; + resource_size_t ostart, oend; int type = 0; int other = 0; - struct resource *p; + struct resource *p, *dp; + bool is_type, covered; + struct resource res; res.start = start; res.end = start + size - 1; for (p = parent->child; p ; p = p->sibling) { - bool is_type = (((p->flags & flags) == flags) && - ((desc == IORES_DESC_NONE) || - (desc == p->desc))); - - if (resource_overlaps(p, &res)) - is_type ? type++ : other++; + if (!resource_overlaps(p, &res)) + continue; + is_type = (p->flags & flags) == flags && + (desc == IORES_DESC_NONE || desc == p->desc); + if (is_type) { + type++; + continue; + } + /* + * Continue to search in descendant resources as if the + * matched descendant resources cover some ranges of 'p'. + * + * |------------- "CXL Window 0" ------------| + * |-- "System RAM" --| + * + * will behave similar as the following fake resource + * tree when searching "System RAM". + * + * |-- "System RAM" --||-- "CXL Window 0a" --| + */ + covered = false; + ostart = max(res.start, p->start); + oend = min(res.end, p->end); + for_each_resource(p, dp, false) { + if (!resource_overlaps(dp, &res)) + continue; + is_type = (dp->flags & flags) == flags && + (desc == IORES_DESC_NONE || desc == dp->desc); + if (is_type) { + type++; + /* + * Range from 'ostart' to 'dp->start' + * isn't covered by matched resource. + */ + if (dp->start > ostart) + break; + if (dp->end >= oend) { + covered = true; + break; + } + /* Remove covered range */ + ostart = max(ostart, dp->end + 1); + } + } + if (!covered) + other++; } if (type == 0)

1 week, 3 days

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FAILED: patch "[PATCH] resource: fix region_intersects() vs" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x b4afe4183ec77f230851ea139d91e5cf2644c68b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024100725-galore-pout-d68c@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: b4afe4183ec7 ("resource: fix region_intersects() vs add_memory_driver_managed()") 14b80582c43e ("resource: Introduce alloc_free_mem_region()") 27674ef6c73f ("mm: remove the extra ZONE_DEVICE struct page refcount") dc90f0846df4 ("mm: don't include <linux/memremap.h> in <linux/mm.h>") 895749455f60 ("mm: simplify freeing of devmap managed pages") 75e55d8a107e ("mm: move free_devmap_managed_page to memremap.c") 730ff52194cd ("mm: remove pointless includes from <linux/hmm.h>") f56caedaf94f ("Merge branch 'akpm' (patches from Andrew)") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From b4afe4183ec77f230851ea139d91e5cf2644c68b Mon Sep 17 00:00:00 2001 From: Huang Ying <ying.huang(a)intel.com> Date: Fri, 6 Sep 2024 11:07:11 +0800 Subject: [PATCH] resource: fix region_intersects() vs add_memory_driver_managed() On a system with CXL memory, the resource tree (/proc/iomem) related to CXL memory may look like something as follows. 490000000-50fffffff : CXL Window 0 490000000-50fffffff : region0 490000000-50fffffff : dax0.0 490000000-50fffffff : System RAM (kmem) Because drivers/dax/kmem.c calls add_memory_driver_managed() during onlining CXL memory, which makes "System RAM (kmem)" a descendant of "CXL Window X". This confuses region_intersects(), which expects all "System RAM" resources to be at the top level of iomem_resource. This can lead to bugs. For example, when the following command line is executed to write some memory in CXL memory range via /dev/mem, $ dd if=data of=/dev/mem bs=$((1 << 10)) seek=$((0x490000000 >> 10)) count=1 dd: error writing '/dev/mem': Bad address 1+0 records in 0+0 records out 0 bytes copied, 0.0283507 s, 0.0 kB/s the command fails as expected. However, the error code is wrong. It should be "Operation not permitted" instead of "Bad address". More seriously, the /dev/mem permission checking in devmem_is_allowed() passes incorrectly. Although the accessing is prevented later because ioremap() isn't allowed to map system RAM, it is a potential security issue. During command executing, the following warning is reported in the kernel log for calling ioremap() on system RAM. ioremap on RAM at 0x0000000490000000 - 0x0000000490000fff WARNING: CPU: 2 PID: 416 at arch/x86/mm/ioremap.c:216 __ioremap_caller.constprop.0+0x131/0x35d Call Trace: memremap+0xcb/0x184 xlate_dev_mem_ptr+0x25/0x2f write_mem+0x94/0xfb vfs_write+0x128/0x26d ksys_write+0xac/0xfe do_syscall_64+0x9a/0xfd entry_SYSCALL_64_after_hwframe+0x4b/0x53 The details of command execution process are as follows. In the above resource tree, "System RAM" is a descendant of "CXL Window 0" instead of a top level resource. So, region_intersects() will report no System RAM resources in the CXL memory region incorrectly, because it only checks the top level resources. Consequently, devmem_is_allowed() will return 1 (allow access via /dev/mem) for CXL memory region incorrectly. Fortunately, ioremap() doesn't allow to map System RAM and reject the access. So, region_intersects() needs to be fixed to work correctly with the resource tree with "System RAM" not at top level as above. To fix it, if we found a unmatched resource in the top level, we will continue to search matched resources in its descendant resources. So, we will not miss any matched resources in resource tree anymore. In the new implementation, an example resource tree |------------- "CXL Window 0" ------------| |-- "System RAM" --| will behave similar as the following fake resource tree for region_intersects(, IORESOURCE_SYSTEM_RAM, ), |-- "System RAM" --||-- "CXL Window 0a" --| Where "CXL Window 0a" is part of the original "CXL Window 0" that isn't covered by "System RAM". Link: https://lkml.kernel.org/r/20240906030713.204292-2-ying.huang@intel.com Fixes: c221c0b0308f ("device-dax: "Hotplug" persistent memory for use like normal RAM") Signed-off-by: "Huang, Ying" <ying.huang(a)intel.com> Cc: Dan Williams <dan.j.williams(a)intel.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: Davidlohr Bueso <dave(a)stgolabs.net> Cc: Jonathan Cameron <jonathan.cameron(a)huawei.com> Cc: Dave Jiang <dave.jiang(a)intel.com> Cc: Alison Schofield <alison.schofield(a)intel.com> Cc: Vishal Verma <vishal.l.verma(a)intel.com> Cc: Ira Weiny <ira.weiny(a)intel.com> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: Andy Shevchenko <andriy.shevchenko(a)linux.intel.com> Cc: Bjorn Helgaas <bhelgaas(a)google.com> Cc: Baoquan He <bhe(a)redhat.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/kernel/resource.c b/kernel/resource.c index 14777afb0a99..235dc77f8add 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -540,20 +540,62 @@ static int __region_intersects(struct resource *parent, resource_size_t start, size_t size, unsigned long flags, unsigned long desc) { - struct resource res; + resource_size_t ostart, oend; int type = 0; int other = 0; - struct resource *p; + struct resource *p, *dp; + bool is_type, covered; + struct resource res; res.start = start; res.end = start + size - 1; for (p = parent->child; p ; p = p->sibling) { - bool is_type = (((p->flags & flags) == flags) && - ((desc == IORES_DESC_NONE) || - (desc == p->desc))); - - if (resource_overlaps(p, &res)) - is_type ? type++ : other++; + if (!resource_overlaps(p, &res)) + continue; + is_type = (p->flags & flags) == flags && + (desc == IORES_DESC_NONE || desc == p->desc); + if (is_type) { + type++; + continue; + } + /* + * Continue to search in descendant resources as if the + * matched descendant resources cover some ranges of 'p'. + * + * |------------- "CXL Window 0" ------------| + * |-- "System RAM" --| + * + * will behave similar as the following fake resource + * tree when searching "System RAM". + * + * |-- "System RAM" --||-- "CXL Window 0a" --| + */ + covered = false; + ostart = max(res.start, p->start); + oend = min(res.end, p->end); + for_each_resource(p, dp, false) { + if (!resource_overlaps(dp, &res)) + continue; + is_type = (dp->flags & flags) == flags && + (desc == IORES_DESC_NONE || desc == dp->desc); + if (is_type) { + type++; + /* + * Range from 'ostart' to 'dp->start' + * isn't covered by matched resource. + */ + if (dp->start > ostart) + break; + if (dp->end >= oend) { + covered = true; + break; + } + /* Remove covered range */ + ostart = max(ostart, dp->end + 1); + } + } + if (!covered) + other++; } if (type == 0)

1 week, 3 days

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[PATCH 5.15.y] xfs: fix super block buf log item UAF during force shutdown

by Guo Xuenan

commit 575689fc0ffa6c4bb4e72fd18e31a6525a6124e0 upstream. xfs log io error will trigger xlog shut down, and end_io worker call xlog_state_shutdown_callbacks to unpin and release the buf log item. The race condition is that when there are some thread doing transaction commit and happened not to be intercepted by xlog_is_shutdown, then, these log item will be insert into CIL, when unpin and release these buf log item, UAF will occur. BTW, add delay before `xlog_cil_commit` can increase recurrence probability. The following call graph actually encountered this bad situation. fsstress io end worker kworker/0:1H-216 xlog_ioend_work ->xlog_force_shutdown ->xlog_state_shutdown_callbacks ->xlog_cil_process_committed ->xlog_cil_committed ->xfs_trans_committed_bulk ->xfs_trans_apply_sb_deltas ->li_ops->iop_unpin(lip, 1); ->xfs_trans_getsb ->_xfs_trans_bjoin ->xfs_buf_item_init ->if (bip) { return 0;} //relog ->xlog_cil_commit ->xlog_cil_insert_items //insert into CIL ->xfs_buf_ioend_fail(bp); ->xfs_buf_ioend ->xfs_buf_item_done ->xfs_buf_item_relse ->xfs_buf_item_free when cil push worker gather percpu cil and insert super block buf log item into ctx->log_items then uaf occurs. ================================================================== BUG: KASAN: use-after-free in xlog_cil_push_work+0x1c8f/0x22f0 Write of size 8 at addr ffff88801800f3f0 by task kworker/u4:4/105 CPU: 0 PID: 105 Comm: kworker/u4:4 Tainted: G W 6.1.0-rc1-00001-g274115149b42 #136 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Workqueue: xfs-cil/sda xlog_cil_push_work Call Trace: <TASK> dump_stack_lvl+0x4d/0x66 print_report+0x171/0x4a6 kasan_report+0xb3/0x130 xlog_cil_push_work+0x1c8f/0x22f0 process_one_work+0x6f9/0xf70 worker_thread+0x578/0xf30 kthread+0x28c/0x330 ret_from_fork+0x1f/0x30 </TASK> Allocated by task 2145: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 __kasan_slab_alloc+0x54/0x60 kmem_cache_alloc+0x14a/0x510 xfs_buf_item_init+0x160/0x6d0 _xfs_trans_bjoin+0x7f/0x2e0 xfs_trans_getsb+0xb6/0x3f0 xfs_trans_apply_sb_deltas+0x1f/0x8c0 __xfs_trans_commit+0xa25/0xe10 xfs_symlink+0xe23/0x1660 xfs_vn_symlink+0x157/0x280 vfs_symlink+0x491/0x790 do_symlinkat+0x128/0x220 __x64_sys_symlink+0x7a/0x90 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 216: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x2a/0x40 __kasan_slab_free+0x105/0x1a0 kmem_cache_free+0xb6/0x460 xfs_buf_ioend+0x1e9/0x11f0 xfs_buf_item_unpin+0x3d6/0x840 xfs_trans_committed_bulk+0x4c2/0x7c0 xlog_cil_committed+0xab6/0xfb0 xlog_cil_process_committed+0x117/0x1e0 xlog_state_shutdown_callbacks+0x208/0x440 xlog_force_shutdown+0x1b3/0x3a0 xlog_ioend_work+0xef/0x1d0 process_one_work+0x6f9/0xf70 worker_thread+0x578/0xf30 kthread+0x28c/0x330 ret_from_fork+0x1f/0x30 The buggy address belongs to the object at ffff88801800f388 which belongs to the cache xfs_buf_item of size 272 The buggy address is located 104 bytes inside of 272-byte region [ffff88801800f388, ffff88801800f498) The buggy address belongs to the physical page: page:ffffea0000600380 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88801800f208 pfn:0x1800e head:ffffea0000600380 order:1 compound_mapcount:0 compound_pincount:0 flags: 0x1fffff80010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff) raw: 001fffff80010200 ffffea0000699788 ffff88801319db50 ffff88800fb50640 raw: ffff88801800f208 000000000015000a 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88801800f280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801800f300: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88801800f380: fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88801800f400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801800f480: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== Disabling lock debugging due to kernel taint Signed-off-by: Guo Xuenan <guoxuenan(a)huawei.com> Reviewed-by: Darrick J. Wong <djwong(a)kernel.org> Signed-off-by: Darrick J. Wong <djwong(a)kernel.org> Signed-off-by: Chang Yu <marcus.yu.56(a)gmail.com> --- The fix 575689fc0ffa ("xfs: fix super block buf log item UAF during force shutdown") was first introduced in v6.2-rc1. Syzkaller reports that the UAF bug is still present in linux-5.15.y (https://syzkaller.appspot.com/bug?extid=4d9a694803b65e21655b). I think a backport should be beneficial here. --- fs/xfs/xfs_buf_item.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c index b1ab100c09e1..ffe318eb897f 100644 --- a/fs/xfs/xfs_buf_item.c +++ b/fs/xfs/xfs_buf_item.c @@ -1017,6 +1017,8 @@ xfs_buf_item_relse( trace_xfs_buf_item_relse(bp, _RET_IP_); ASSERT(!test_bit(XFS_LI_IN_AIL, &bip->bli_item.li_flags)); + if (atomic_read(&bip->bli_refcount)) + return; bp->b_log_item = NULL; xfs_buf_rele(bp); xfs_buf_item_free(bip); -- 2.46.2

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[PATCH 6.1] Drivers: hv: vmbus: Leak pages if set_memory_encrypted() fails

by Xiangyu Chen

From: Rick Edgecombe <rick.p.edgecombe(a)intel.com> In CoCo VMs it is possible for the untrusted host to cause set_memory_encrypted() or set_memory_decrypted() to fail such that an error is returned and the resulting memory is shared. Callers need to take care to handle these errors to avoid returning decrypted (shared) memory to the page allocator, which could lead to functional or security issues. VMBus code could free decrypted pages if set_memory_encrypted()/decrypted() fails. Leak the pages if this happens. Signed-off-by: Rick Edgecombe <rick.p.edgecombe(a)intel.com> Signed-off-by: Michael Kelley <mhklinux(a)outlook.com> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy(a)linux.intel.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Link: https://lore.kernel.org/r/20240311161558.1310-2-mhklinux@outlook.com Signed-off-by: Wei Liu <wei.liu(a)kernel.org> Message-ID: <20240311161558.1310-2-mhklinux(a)outlook.com> [Xiangyu: Modified to apply on 6.1.y] Signed-off-by: Xiangyu Chen <xiangyu.chen(a)windriver.com> --- drivers/hv/connection.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c index da51b50787df..c74088b69a5f 100644 --- a/drivers/hv/connection.c +++ b/drivers/hv/connection.c @@ -243,8 +243,17 @@ int vmbus_connect(void) ret |= set_memory_decrypted((unsigned long) vmbus_connection.monitor_pages[1], 1); - if (ret) + if (ret) { + /* + * If set_memory_decrypted() fails, the encryption state + * of the memory is unknown. So leak the memory instead + * of risking returning decrypted memory to the free list. + * For simplicity, always handle both pages the same. + */ + vmbus_connection.monitor_pages[0] = NULL; + vmbus_connection.monitor_pages[1] = NULL; goto cleanup; + } /* * Isolation VM with AMD SNP needs to access monitor page via -- 2.43.0

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