October 2024 - Linux-stable-mirror

[PATCH OLK-6.6 3/3] LoongArch: Define __ARCH_WANT_NEW_STAT in unistd.h

by Hongchen Zhang

From: Huacai Chen <chenhuacai(a)loongson.cn> mainline inclusion from mainline-v6.11-rc1 commit 7697a0fe0154468f5df35c23ebd7aa48994c2cdc category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IAZ33N CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… ---------------------------------------------------------------------- Chromium sandbox apparently wants to deny statx [1] so it could properly inspect arguments after the sandboxed process later falls back to fstat. Because there's currently not a "fd-only" version of statx, so that the sandbox has no way to ensure the path argument is empty without being able to peek into the sandboxed process's memory. For architectures able to do newfstatat though, glibc falls back to newfstatat after getting -ENOSYS for statx, then the respective SIGSYS handler [2] takes care of inspecting the path argument, transforming allowed newfstatat's into fstat instead which is allowed and has the same type of return value. But, as LoongArch is the first architecture to not have fstat nor newfstatat, the LoongArch glibc does not attempt falling back at all when it gets -ENOSYS for statx -- and you see the problem there! Actually, back when the LoongArch port was under review, people were aware of the same problem with sandboxing clone3 [3], so clone was eventually kept. Unfortunately it seemed at that time no one had noticed statx, so besides restoring fstat/newfstatat to LoongArch uapi (and postponing the problem further), it seems inevitable that we would need to tackle seccomp deep argument inspection. However, this is obviously a decision that shouldn't be taken lightly, so we just restore fstat/newfstatat by defining __ARCH_WANT_NEW_STAT in unistd.h. This is the simplest solution for now, and so we hope the community will tackle the long-standing problem of seccomp deep argument inspection in the future [4][5]. Also add "newstat" to syscall_abis_64 in Makefile.syscalls due to upstream asm-generic changes. More infomation please reading this thread [6]. [1] https://chromium-review.googlesource.com/c/chromium/src/+/2823150 [2] https://chromium.googlesource.com/chromium/src/sandbox/+/c085b51940bd/linux… [3] https://lore.kernel.org/linux-arch/20220511211231.GG7074@brightrain.aerifal… [4] https://lwn.net/Articles/799557/ [5] https://lpc.events/event/4/contributions/560/attachments/397/640/deep-arg-i… [6] https://lore.kernel.org/loongarch/20240226-granit-seilschaft-eccc2433014d@b… Cc: stable(a)vger.kernel.org Signed-off-by: Huacai Chen <chenhuacai(a)loongson.cn> --- arch/loongarch/include/asm/unistd.h | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/loongarch/include/asm/unistd.h b/arch/loongarch/include/asm/unistd.h index cfddb0116a8c..f1d2b7e5c062 100644 --- a/arch/loongarch/include/asm/unistd.h +++ b/arch/loongarch/include/asm/unistd.h @@ -8,4 +8,5 @@ #include <uapi/asm/unistd.h> +#define __ARCH_WANT_NEW_STAT #define NR_syscalls (__NR_syscalls) -- 2.33.0

10 months, 4 weeks

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[PATCH] mm: avoid unconditional one-tick sleep when swapcache_prepare fails

by Barry Song

From: Barry Song <v-songbaohua(a)oppo.com> Commit 13ddaf26be32 ("mm/swap: fix race when skipping swapcache") introduced an unconditional one-tick sleep when `swapcache_prepare()` fails, which has led to reports of UI stuttering on latency-sensitive Android devices. To address this, we can use a waitqueue to wake up tasks that fail `swapcache_prepare()` sooner, instead of always sleeping for a full tick. While tasks may occasionally be woken by an unrelated `do_swap_page()`, this method is preferable to two scenarios: rapid re-entry into page faults, which can cause livelocks, and multiple millisecond sleeps, which visibly degrade user experience. Oven's testing shows that a single waitqueue resolves the UI stuttering issue. If a 'thundering herd' problem becomes apparent later, a waitqueue hash similar to `folio_wait_table[PAGE_WAIT_TABLE_SIZE]` for page bit locks can be introduced. Fixes: 13ddaf26be32 ("mm/swap: fix race when skipping swapcache") Cc: Kairui Song <kasong(a)tencent.com> Cc: "Huang, Ying" <ying.huang(a)intel.com> Cc: Yu Zhao <yuzhao(a)google.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: Chris Li <chrisl(a)kernel.org> Cc: Hugh Dickins <hughd(a)google.com> Cc: Johannes Weiner <hannes(a)cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: Michal Hocko <mhocko(a)suse.com> Cc: Minchan Kim <minchan(a)kernel.org> Cc: Yosry Ahmed <yosryahmed(a)google.com> Cc: SeongJae Park <sj(a)kernel.org> Cc: Kalesh Singh <kaleshsingh(a)google.com> Cc: Suren Baghdasaryan <surenb(a)google.com> Cc: <stable(a)vger.kernel.org> Reported-by: Oven Liyang <liyangouwen1(a)oppo.com> Tested-by: Oven Liyang <liyangouwen1(a)oppo.com> Signed-off-by: Barry Song <v-songbaohua(a)oppo.com> --- mm/memory.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 2366578015ad..6913174f7f41 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4192,6 +4192,8 @@ static struct folio *alloc_swap_folio(struct vm_fault *vmf) } #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ +static DECLARE_WAIT_QUEUE_HEAD(swapcache_wq); + /* * We enter with non-exclusive mmap_lock (to exclude vma changes, * but allow concurrent faults), and pte mapped but not yet locked. @@ -4204,6 +4206,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) { struct vm_area_struct *vma = vmf->vma; struct folio *swapcache, *folio = NULL; + DECLARE_WAITQUEUE(wait, current); struct page *page; struct swap_info_struct *si = NULL; rmap_t rmap_flags = RMAP_NONE; @@ -4302,7 +4305,9 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) * Relax a bit to prevent rapid * repeated page faults. */ + add_wait_queue(&swapcache_wq, &wait); schedule_timeout_uninterruptible(1); + remove_wait_queue(&swapcache_wq, &wait); goto out_page; } need_clear_cache = true; @@ -4609,8 +4614,10 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) pte_unmap_unlock(vmf->pte, vmf->ptl); out: /* Clear the swap cache pin for direct swapin after PTL unlock */ - if (need_clear_cache) + if (need_clear_cache) { swapcache_clear(si, entry, nr_pages); + wake_up(&swapcache_wq); + } if (si) put_swap_device(si); return ret; @@ -4625,8 +4632,10 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) folio_unlock(swapcache); folio_put(swapcache); } - if (need_clear_cache) + if (need_clear_cache) { swapcache_clear(si, entry, nr_pages); + wake_up(&swapcache_wq); + } if (si) put_swap_device(si); return ret; -- 2.34.1

10 months, 4 weeks

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[PATCH] blk-mq: Make blk_mq_quiesce_tagset() hold the tag list mutex less long

by Bart Van Assche

Make sure that the tag_list_lock mutex is no longer held than necessary. This change reduces latency if e.g. blk_mq_quiesce_tagset() is called concurrently from more than one thread. This function is used by the NVMe core and also by the UFS driver. Reported-by: Peter Wang <peter.wang(a)mediatek.com> Cc: Chao Leng <lengchao(a)huawei.com> Cc: Ming Lei <ming.lei(a)redhat.com> Cc: stable(a)vger.kernel.org Fixes: commit 414dd48e882c ("blk-mq: add tagset quiesce interface") Signed-off-by: Bart Van Assche <bvanassche(a)acm.org> --- block/blk-mq.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 4b2c8e940f59..1ef227dfb9ba 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -283,8 +283,9 @@ void blk_mq_quiesce_tagset(struct blk_mq_tag_set *set) if (!blk_queue_skip_tagset_quiesce(q)) blk_mq_quiesce_queue_nowait(q); } - blk_mq_wait_quiesce_done(set); mutex_unlock(&set->tag_list_lock); + + blk_mq_wait_quiesce_done(set); } EXPORT_SYMBOL_GPL(blk_mq_quiesce_tagset);

10 months, 4 weeks

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[PATCH 0/5] cxl: Initialization and shutdown fixes

by Dan Williams

Gregory's modest proposal to fix CXL cxl_mem_probe() failures due to delayed arrival of the CXL "root" infrastructure [1] prompted questions of how the existing mechanism for retrying cxl_mem_probe() could be failing. The critical missing piece in the debug was that Gregory's setup had almost all CXL modules built-in to the kernel. On the way to that discovery several other bugs and init-order corner cases were discovered. The main fix is to make sure the drivers/cxl/Makefile object order supports root CXL ports being fully initialized upon cxl_acpi_probe() exit. The modular case has some similar potential holes that are fixed with MODULE_SOFTDEP() and other fix ups. Finally, an attempt to update cxl_test to reproduce the original report resulted in the discovery of a separate long standing use after free bug in cxl_region_detach(). [1]: http://lore.kernel.org/20241004212504.1246-1-gourry@gourry.net --- Dan Williams (5): cxl/port: Fix CXL port initialization order when the subsystem is built-in cxl/port: Fix cxl_bus_rescan() vs bus_rescan_devices() cxl/acpi: Ensure ports ready at cxl_acpi_probe() return cxl/port: Fix use-after-free, permit out-of-order decoder shutdown cxl/test: Improve init-order fidelity relative to real-world systems drivers/base/core.c | 35 +++++++ drivers/cxl/Kconfig | 1 drivers/cxl/Makefile | 12 +-- drivers/cxl/acpi.c | 7 + drivers/cxl/core/hdm.c | 50 +++++++++-- drivers/cxl/core/port.c | 13 ++- drivers/cxl/core/region.c | 48 +++------- drivers/cxl/cxl.h | 3 - include/linux/device.h | 3 + tools/testing/cxl/test/cxl.c | 200 +++++++++++++++++++++++------------------- tools/testing/cxl/test/mem.c | 1 11 files changed, 228 insertions(+), 145 deletions(-) base-commit: 8cf0b93919e13d1e8d4466eb4080a4c4d9d66d7b

10 months, 4 weeks

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[merged] nilfs2-fix-kernel-bug-due-to-missing-clearing-of-buffer-delay-flag.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: nilfs2: fix kernel bug due to missing clearing of buffer delay flag has been removed from the -mm tree. Its filename was nilfs2-fix-kernel-bug-due-to-missing-clearing-of-buffer-delay-flag.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Ryusuke Konishi <konishi.ryusuke(a)gmail.com> Subject: nilfs2: fix kernel bug due to missing clearing of buffer delay flag Date: Wed, 16 Oct 2024 06:32:07 +0900 Syzbot reported that after nilfs2 reads a corrupted file system image and degrades to read-only, the BUG_ON check for the buffer delay flag in submit_bh_wbc() may fail, causing a kernel bug. This is because the buffer delay flag is not cleared when clearing the buffer state flags to discard a page/folio or a buffer head. So, fix this. This became necessary when the use of nilfs2's own page clear routine was expanded. This state inconsistency does not occur if the buffer is written normally by log writing. Link: https://lkml.kernel.org/r/20241015213300.7114-1-konishi.ryusuke@gmail.com Fixes: 8c26c4e2694a ("nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption") Signed-off-by: Ryusuke Konishi <konishi.ryusuke(a)gmail.com> Reported-by: syzbot+985ada84bf055a575c07(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=985ada84bf055a575c07 Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/nilfs2/page.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/fs/nilfs2/page.c~nilfs2-fix-kernel-bug-due-to-missing-clearing-of-buffer-delay-flag +++ a/fs/nilfs2/page.c @@ -77,7 +77,8 @@ void nilfs_forget_buffer(struct buffer_h const unsigned long clear_bits = (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) | BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) | - BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected)); + BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected) | + BIT(BH_Delay)); lock_buffer(bh); set_mask_bits(&bh->b_state, clear_bits, 0); @@ -406,7 +407,8 @@ void nilfs_clear_folio_dirty(struct foli const unsigned long clear_bits = (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) | BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) | - BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected)); + BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected) | + BIT(BH_Delay)); bh = head; do { _ Patches currently in -mm which might be from konishi.ryusuke(a)gmail.com are nilfs2-fix-kernel-bug-due-to-missing-clearing-of-checked-flag.patch

10 months, 4 weeks

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[PATCH v2] ASoC: qcom: sc7280: Fix missing Soundwire runtime stream alloc

by Krzysztof Kozlowski

Commit 15c7fab0e047 ("ASoC: qcom: Move Soundwire runtime stream alloc to soundcards") moved the allocation of Soundwire stream runtime from the Qualcomm Soundwire driver to each individual machine sound card driver, except that it forgot to update SC7280 card. Just like for other Qualcomm sound cards using Soundwire, the card driver should allocate and release the runtime. Otherwise sound playback will result in a NULL pointer dereference or other effect of uninitialized memory accesses (which was confirmed on SDM845 having similar issue). Cc: stable(a)vger.kernel.org Cc: Alexey Klimov <alexey.klimov(a)linaro.org> Cc: Steev Klimaszewski <steev(a)kali.org> Fixes: 15c7fab0e047 ("ASoC: qcom: Move Soundwire runtime stream alloc to soundcards") Link: https://lore.kernel.org/r/20241010054109.16938-1-krzysztof.kozlowski@linaro… Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski(a)linaro.org> --- Changes in v2: 1. Add missing 'select SND_SOC_QCOM_SDW' as reported by LKP --- sound/soc/qcom/Kconfig | 1 + sound/soc/qcom/sc7280.c | 10 +++++++++- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/sound/soc/qcom/Kconfig b/sound/soc/qcom/Kconfig index 3687b9db5ed4..ca7a30ebd26a 100644 --- a/sound/soc/qcom/Kconfig +++ b/sound/soc/qcom/Kconfig @@ -209,6 +209,7 @@ config SND_SOC_SC7280 tristate "SoC Machine driver for SC7280 boards" depends on I2C && SOUNDWIRE select SND_SOC_QCOM_COMMON + select SND_SOC_QCOM_SDW select SND_SOC_LPASS_SC7280 select SND_SOC_MAX98357A select SND_SOC_WCD938X_SDW diff --git a/sound/soc/qcom/sc7280.c b/sound/soc/qcom/sc7280.c index 207ac5da4dd4..230af8d7b205 100644 --- a/sound/soc/qcom/sc7280.c +++ b/sound/soc/qcom/sc7280.c @@ -23,6 +23,7 @@ #include "common.h" #include "lpass.h" #include "qdsp6/q6afe.h" +#include "sdw.h" #define DEFAULT_MCLK_RATE 19200000 #define RT5682_PLL_FREQ (48000 * 512) @@ -316,6 +317,7 @@ static void sc7280_snd_shutdown(struct snd_pcm_substream *substream) struct snd_soc_card *card = rtd->card; struct sc7280_snd_data *data = snd_soc_card_get_drvdata(card); struct snd_soc_dai *cpu_dai = snd_soc_rtd_to_cpu(rtd, 0); + struct sdw_stream_runtime *sruntime = data->sruntime[cpu_dai->id]; switch (cpu_dai->id) { case MI2S_PRIMARY: @@ -333,6 +335,9 @@ static void sc7280_snd_shutdown(struct snd_pcm_substream *substream) default: break; } + + data->sruntime[cpu_dai->id] = NULL; + sdw_release_stream(sruntime); } static int sc7280_snd_startup(struct snd_pcm_substream *substream) @@ -347,6 +352,8 @@ static int sc7280_snd_startup(struct snd_pcm_substream *substream) switch (cpu_dai->id) { case MI2S_PRIMARY: ret = sc7280_rt5682_init(rtd); + if (ret) + return ret; break; case SECONDARY_MI2S_RX: codec_dai_fmt |= SND_SOC_DAIFMT_NB_NF | SND_SOC_DAIFMT_I2S; @@ -360,7 +367,8 @@ static int sc7280_snd_startup(struct snd_pcm_substream *substream) default: break; } - return ret; + + return qcom_snd_sdw_startup(substream); } static const struct snd_soc_ops sc7280_ops = { -- 2.43.0

10 months, 4 weeks

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[tip: locking/core] locking/lockdep: Avoid creating new name string literals in lockdep_set_subclass()

by tip-bot2 for Ahmed Ehab

The following commit has been merged into the locking/core branch of tip: Commit-ID: d7fe143cb115076fed0126ad8cf5ba6c3e575e43 Gitweb: https://git.kernel.org/tip/d7fe143cb115076fed0126ad8cf5ba6c3e575e43 Author: Ahmed Ehab <bottaawesome633(a)gmail.com> AuthorDate: Sun, 25 Aug 2024 01:10:30 +03:00 Committer: Boqun Feng <boqun.feng(a)gmail.com> CommitterDate: Thu, 17 Oct 2024 20:07:23 -07:00 locking/lockdep: Avoid creating new name string literals in lockdep_set_subclass() Syzbot reports a problem that a warning will be triggered while searching a lock class in look_up_lock_class(). The cause of the issue is that a new name is created and used by lockdep_set_subclass() instead of using the existing one. This results in a lock instance has a different name pointer than previous registered one stored in lock class, and WARN_ONCE() is triggered because of that in look_up_lock_class(). To fix this, change lockdep_set_subclass() to use the existing name instead of a new one. Hence, no new name will be created by lockdep_set_subclass(). Hence, the warning is avoided. [boqun: Reword the commit log to state the correct issue] Reported-by: <syzbot+7f4a6f7f7051474e40ad(a)syzkaller.appspotmail.com> Fixes: de8f5e4f2dc1f ("lockdep: Introduce wait-type checks") Cc: stable(a)vger.kernel.org Signed-off-by: Ahmed Ehab <bottaawesome633(a)gmail.com> Signed-off-by: Boqun Feng <boqun.feng(a)gmail.com> Link: https://lore.kernel.org/lkml/20240824221031.7751-1-bottaawesome633@gmail.co… --- include/linux/lockdep.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 217f7ab..67964dc 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -173,7 +173,7 @@ static inline void lockdep_init_map(struct lockdep_map *lock, const char *name, (lock)->dep_map.lock_type) #define lockdep_set_subclass(lock, sub) \ - lockdep_init_map_type(&(lock)->dep_map, #lock, (lock)->dep_map.key, sub,\ + lockdep_init_map_type(&(lock)->dep_map, (lock)->dep_map.name, (lock)->dep_map.key, sub,\ (lock)->dep_map.wait_type_inner, \ (lock)->dep_map.wait_type_outer, \ (lock)->dep_map.lock_type)

10 months, 4 weeks

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[PATCH 5.10] exec: don't WARN for racy path_noexec check

by Thadeu Lima de Souza Cascardo

From: Mateusz Guzik <mjguzik(a)gmail.com> [ Upstream commit 0d196e7589cefe207d5d41f37a0a28a1fdeeb7c6 ] Both i_mode and noexec checks wrapped in WARN_ON stem from an artifact of the previous implementation. They used to legitimately check for the condition, but that got moved up in two commits: 633fb6ac3980 ("exec: move S_ISREG() check earlier") 0fd338b2d2cd ("exec: move path_noexec() check earlier") Instead of being removed said checks are WARN_ON'ed instead, which has some debug value. However, the spurious path_noexec check is racy, resulting in unwarranted warnings should someone race with setting the noexec flag. One can note there is more to perm-checking whether execve is allowed and none of the conditions are guaranteed to still hold after they were tested for. Additionally this does not validate whether the code path did any perm checking to begin with -- it will pass if the inode happens to be regular. Keep the redundant path_noexec() check even though it's mindless nonsense checking for guarantee that isn't given so drop the WARN. Reword the commentary and do small tidy ups while here. Signed-off-by: Mateusz Guzik <mjguzik(a)gmail.com> Link: https://lore.kernel.org/r/20240805131721.765484-1-mjguzik@gmail.com [brauner: keep redundant path_noexec() check] Signed-off-by: Christian Brauner <brauner(a)kernel.org> [cascardo: keep exit label and use it] Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo(a)igalia.com> --- fs/exec.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 6e5324c7e9b6..7144c541818f 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -144,13 +144,11 @@ SYSCALL_DEFINE1(uselib, const char __user *, library) goto out; /* - * may_open() has already checked for this, so it should be - * impossible to trip now. But we need to be extra cautious - * and check again at the very end too. + * Check do_open_execat() for an explanation. */ error = -EACCES; - if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) || - path_noexec(&file->f_path))) + if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode)) || + path_noexec(&file->f_path)) goto exit; fsnotify_open(file); @@ -919,16 +917,16 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags) file = do_filp_open(fd, name, &open_exec_flags); if (IS_ERR(file)) - goto out; + return file; /* - * may_open() has already checked for this, so it should be - * impossible to trip now. But we need to be extra cautious - * and check again at the very end too. + * In the past the regular type check was here. It moved to may_open() in + * 633fb6ac3980 ("exec: move S_ISREG() check earlier"). Since then it is + * an invariant that all non-regular files error out before we get here. */ err = -EACCES; - if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) || - path_noexec(&file->f_path))) + if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode)) || + path_noexec(&file->f_path)) goto exit; err = deny_write_access(file); @@ -938,7 +936,6 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags) if (name->name[0] != '\0') fsnotify_open(file); -out: return file; exit: -- 2.34.1

10 months, 4 weeks

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[PATCH 5.15] exec: don't WARN for racy path_noexec check

by Thadeu Lima de Souza Cascardo

From: Mateusz Guzik <mjguzik(a)gmail.com> [ Upstream commit 0d196e7589cefe207d5d41f37a0a28a1fdeeb7c6 ] Both i_mode and noexec checks wrapped in WARN_ON stem from an artifact of the previous implementation. They used to legitimately check for the condition, but that got moved up in two commits: 633fb6ac3980 ("exec: move S_ISREG() check earlier") 0fd338b2d2cd ("exec: move path_noexec() check earlier") Instead of being removed said checks are WARN_ON'ed instead, which has some debug value. However, the spurious path_noexec check is racy, resulting in unwarranted warnings should someone race with setting the noexec flag. One can note there is more to perm-checking whether execve is allowed and none of the conditions are guaranteed to still hold after they were tested for. Additionally this does not validate whether the code path did any perm checking to begin with -- it will pass if the inode happens to be regular. Keep the redundant path_noexec() check even though it's mindless nonsense checking for guarantee that isn't given so drop the WARN. Reword the commentary and do small tidy ups while here. Signed-off-by: Mateusz Guzik <mjguzik(a)gmail.com> Link: https://lore.kernel.org/r/20240805131721.765484-1-mjguzik@gmail.com [brauner: keep redundant path_noexec() check] Signed-off-by: Christian Brauner <brauner(a)kernel.org> [cascardo: keep exit label and use it] Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo(a)igalia.com> --- fs/exec.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 26f0b79cb4f9..8395e7ff7b94 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -142,13 +142,11 @@ SYSCALL_DEFINE1(uselib, const char __user *, library) goto out; /* - * may_open() has already checked for this, so it should be - * impossible to trip now. But we need to be extra cautious - * and check again at the very end too. + * Check do_open_execat() for an explanation. */ error = -EACCES; - if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) || - path_noexec(&file->f_path))) + if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode)) || + path_noexec(&file->f_path)) goto exit; fsnotify_open(file); @@ -919,16 +917,16 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags) file = do_filp_open(fd, name, &open_exec_flags); if (IS_ERR(file)) - goto out; + return file; /* - * may_open() has already checked for this, so it should be - * impossible to trip now. But we need to be extra cautious - * and check again at the very end too. + * In the past the regular type check was here. It moved to may_open() in + * 633fb6ac3980 ("exec: move S_ISREG() check earlier"). Since then it is + * an invariant that all non-regular files error out before we get here. */ err = -EACCES; - if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) || - path_noexec(&file->f_path))) + if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode)) || + path_noexec(&file->f_path)) goto exit; err = deny_write_access(file); @@ -938,7 +936,6 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags) if (name->name[0] != '\0') fsnotify_open(file); -out: return file; exit: -- 2.34.1

10 months, 4 weeks

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[PATCH 6.1] exec: don't WARN for racy path_noexec check

by Thadeu Lima de Souza Cascardo

From: Mateusz Guzik <mjguzik(a)gmail.com> [ Upstream commit 0d196e7589cefe207d5d41f37a0a28a1fdeeb7c6 ] Both i_mode and noexec checks wrapped in WARN_ON stem from an artifact of the previous implementation. They used to legitimately check for the condition, but that got moved up in two commits: 633fb6ac3980 ("exec: move S_ISREG() check earlier") 0fd338b2d2cd ("exec: move path_noexec() check earlier") Instead of being removed said checks are WARN_ON'ed instead, which has some debug value. However, the spurious path_noexec check is racy, resulting in unwarranted warnings should someone race with setting the noexec flag. One can note there is more to perm-checking whether execve is allowed and none of the conditions are guaranteed to still hold after they were tested for. Additionally this does not validate whether the code path did any perm checking to begin with -- it will pass if the inode happens to be regular. Keep the redundant path_noexec() check even though it's mindless nonsense checking for guarantee that isn't given so drop the WARN. Reword the commentary and do small tidy ups while here. Signed-off-by: Mateusz Guzik <mjguzik(a)gmail.com> Link: https://lore.kernel.org/r/20240805131721.765484-1-mjguzik@gmail.com [brauner: keep redundant path_noexec() check] Signed-off-by: Christian Brauner <brauner(a)kernel.org> [cascardo: keep exit label and use it] Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo(a)igalia.com> --- fs/exec.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 65d3ebc24fd3..a42c9b8b070d 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -141,13 +141,11 @@ SYSCALL_DEFINE1(uselib, const char __user *, library) goto out; /* - * may_open() has already checked for this, so it should be - * impossible to trip now. But we need to be extra cautious - * and check again at the very end too. + * Check do_open_execat() for an explanation. */ error = -EACCES; - if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) || - path_noexec(&file->f_path))) + if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode)) || + path_noexec(&file->f_path)) goto exit; fsnotify_open(file); @@ -927,16 +925,16 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags) file = do_filp_open(fd, name, &open_exec_flags); if (IS_ERR(file)) - goto out; + return file; /* - * may_open() has already checked for this, so it should be - * impossible to trip now. But we need to be extra cautious - * and check again at the very end too. + * In the past the regular type check was here. It moved to may_open() in + * 633fb6ac3980 ("exec: move S_ISREG() check earlier"). Since then it is + * an invariant that all non-regular files error out before we get here. */ err = -EACCES; - if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) || - path_noexec(&file->f_path))) + if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode)) || + path_noexec(&file->f_path)) goto exit; err = deny_write_access(file); @@ -946,7 +944,6 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags) if (name->name[0] != '\0') fsnotify_open(file); -out: return file; exit: -- 2.34.1

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Linux-stable-mirror October 2024