From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + ipc-shm-handle-removed-segments-gracefully-in-shm_mmap.patch added to -mm tree Date: Mon, 01 Feb 2016 19:23:28 -0800 Message-ID: <56b02130.LVm+b4fBFwwLL72+%akpm@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Received: from mail.linuxfoundation.org ([140.211.169.12]:44073 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751912AbcBBDX3 (ORCPT ); Mon, 1 Feb 2016 22:23:29 -0500 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: kirill.shutemov@linux.intel.com, dave@stgolabs.net, dvyukov@google.com, manfred@colorfullife.com, stable@vger.kernel.org, mm-commits@vger.kernel.org The patch titled Subject: ipc/shm: handle removed segments gracefully in shm_mmap() has been added to the -mm tree. Its filename is ipc-shm-handle-removed-segments-gracefully-in-shm_mmap.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/ipc-shm-handle-removed-segments-gracefully-in-shm_mmap.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/ipc-shm-handle-removed-segments-gracefully-in-shm_mmap.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: "Kirill A. Shutemov" Subject: ipc/shm: handle removed segments gracefully in shm_mmap() remap_file_pages(2) emulation can reach file which represents removed IPC ID as long as a memory segment is mapped. It breaks expectations of IPC subsystem. Test case (rewritten to be more human readable, originally autogenerated by syzkaller[1]): #define _GNU_SOURCE #include #include #include #include #define PAGE_SIZE 4096 int main() { int id; void *p; id = shmget(IPC_PRIVATE, 3 * PAGE_SIZE, 0); p = shmat(id, NULL, 0); shmctl(id, IPC_RMID, NULL); remap_file_pages(p, 3 * PAGE_SIZE, 0, 7, 0); return 0; } The patch changes shm_mmap() and code around shm_lock() to propagate locking error back to caller of shm_mmap(). [1] http://github.com/google/syzkaller Signed-off-by: Kirill A. Shutemov Reported-by: Dmitry Vyukov Cc: Davidlohr Bueso Cc: Manfred Spraul Cc: Signed-off-by: Andrew Morton --- ipc/shm.c | 53 ++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 43 insertions(+), 10 deletions(-) diff -puN ipc/shm.c~ipc-shm-handle-removed-segments-gracefully-in-shm_mmap ipc/shm.c --- a/ipc/shm.c~ipc-shm-handle-removed-segments-gracefully-in-shm_mmap +++ a/ipc/shm.c @@ -156,11 +156,12 @@ static inline struct shmid_kernel *shm_l struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id); /* - * We raced in the idr lookup or with shm_destroy(). Either way, the - * ID is busted. + * Callers of shm_lock() must validate the status of the returned ipc + * object pointer (as returned by ipc_lock()), and error out as + * appropriate. */ - WARN_ON(IS_ERR(ipcp)); - + if (IS_ERR(ipcp)) + return (void *)ipcp; return container_of(ipcp, struct shmid_kernel, shm_perm); } @@ -186,18 +187,33 @@ static inline void shm_rmid(struct ipc_n } -/* This is called by fork, once for every shm attach. */ -static void shm_open(struct vm_area_struct *vma) +static int __shm_open(struct vm_area_struct *vma) { struct file *file = vma->vm_file; struct shm_file_data *sfd = shm_file_data(file); struct shmid_kernel *shp; shp = shm_lock(sfd->ns, sfd->id); + + if (IS_ERR(shp)) + return PTR_ERR(shp); + shp->shm_atim = get_seconds(); shp->shm_lprid = task_tgid_vnr(current); shp->shm_nattch++; shm_unlock(shp); + return 0; +} + +/* This is called by fork, once for every shm attach. */ +static void shm_open(struct vm_area_struct *vma) +{ + int err = __shm_open(vma); + /* + * We raced in the idr lookup or with shm_destroy(). + * Either way, the ID is busted. + */ + WARN_ON_ONCE(err); } /* @@ -260,6 +276,14 @@ static void shm_close(struct vm_area_str down_write(&shm_ids(ns).rwsem); /* remove from the list of attaches of the shm segment */ shp = shm_lock(ns, sfd->id); + + /* + * We raced in the idr lookup or with shm_destroy(). + * Either way, the ID is busted. + */ + if (WARN_ON_ONCE(IS_ERR(shp))) + goto done; /* no-op */ + shp->shm_lprid = task_tgid_vnr(current); shp->shm_dtim = get_seconds(); shp->shm_nattch--; @@ -267,6 +291,7 @@ static void shm_close(struct vm_area_str shm_destroy(ns, shp); else shm_unlock(shp); +done: up_write(&shm_ids(ns).rwsem); } @@ -388,17 +413,25 @@ static int shm_mmap(struct file *file, s struct shm_file_data *sfd = shm_file_data(file); int ret; + /* + * In case of remap_file_pages() emulation, the file can represent + * removed IPC ID: propogate shm_lock() error to caller. + */ + ret =__shm_open(vma); + if (ret) + return ret; + ret = sfd->file->f_op->mmap(sfd->file, vma); - if (ret != 0) + if (ret) { + shm_close(vma); return ret; + } sfd->vm_ops = vma->vm_ops; #ifdef CONFIG_MMU WARN_ON(!sfd->vm_ops->fault); #endif vma->vm_ops = &shm_vm_ops; - shm_open(vma); From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:44073 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751912AbcBBDX3 (ORCPT ); Mon, 1 Feb 2016 22:23:29 -0500 Date: Mon, 01 Feb 2016 19:23:28 -0800 From: akpm@linux-foundation.org To: kirill.shutemov@linux.intel.com, dave@stgolabs.net, dvyukov@google.com, manfred@colorfullife.com, stable@vger.kernel.org, mm-commits@vger.kernel.org Subject: + ipc-shm-handle-removed-segments-gracefully-in-shm_mmap.patch added to -mm tree Message-ID: <56b02130.LVm+b4fBFwwLL72+%akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: The patch titled Subject: ipc/shm: handle removed segments gracefully in shm_mmap() has been added to the -mm tree. Its filename is ipc-shm-handle-removed-segments-gracefully-in-shm_mmap.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/ipc-shm-handle-removed-segments-gracefully-in-shm_mmap.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/ipc-shm-handle-removed-segments-gracefully-in-shm_mmap.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: "Kirill A. Shutemov" Subject: ipc/shm: handle removed segments gracefully in shm_mmap() remap_file_pages(2) emulation can reach file which represents removed IPC ID as long as a memory segment is mapped. It breaks expectations of IPC subsystem. Test case (rewritten to be more human readable, originally autogenerated by syzkaller[1]): #define _GNU_SOURCE #include #include #include #include #define PAGE_SIZE 4096 int main() { int id; void *p; id = shmget(IPC_PRIVATE, 3 * PAGE_SIZE, 0); p = shmat(id, NULL, 0); shmctl(id, IPC_RMID, NULL); remap_file_pages(p, 3 * PAGE_SIZE, 0, 7, 0); return 0; } The patch changes shm_mmap() and code around shm_lock() to propagate locking error back to caller of shm_mmap(). [1] http://github.com/google/syzkaller Signed-off-by: Kirill A. Shutemov Reported-by: Dmitry Vyukov Cc: Davidlohr Bueso Cc: Manfred Spraul Cc: Signed-off-by: Andrew Morton --- ipc/shm.c | 53 ++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 43 insertions(+), 10 deletions(-) diff -puN ipc/shm.c~ipc-shm-handle-removed-segments-gracefully-in-shm_mmap ipc/shm.c --- a/ipc/shm.c~ipc-shm-handle-removed-segments-gracefully-in-shm_mmap +++ a/ipc/shm.c @@ -156,11 +156,12 @@ static inline struct shmid_kernel *shm_l struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id); /* - * We raced in the idr lookup or with shm_destroy(). Either way, the - * ID is busted. + * Callers of shm_lock() must validate the status of the returned ipc + * object pointer (as returned by ipc_lock()), and error out as + * appropriate. */ - WARN_ON(IS_ERR(ipcp)); - + if (IS_ERR(ipcp)) + return (void *)ipcp; return container_of(ipcp, struct shmid_kernel, shm_perm); } @@ -186,18 +187,33 @@ static inline void shm_rmid(struct ipc_n } -/* This is called by fork, once for every shm attach. */ -static void shm_open(struct vm_area_struct *vma) +static int __shm_open(struct vm_area_struct *vma) { struct file *file = vma->vm_file; struct shm_file_data *sfd = shm_file_data(file); struct shmid_kernel *shp; shp = shm_lock(sfd->ns, sfd->id); + + if (IS_ERR(shp)) + return PTR_ERR(shp); + shp->shm_atim = get_seconds(); shp->shm_lprid = task_tgid_vnr(current); shp->shm_nattch++; shm_unlock(shp); + return 0; +} + +/* This is called by fork, once for every shm attach. */ +static void shm_open(struct vm_area_struct *vma) +{ + int err = __shm_open(vma); + /* + * We raced in the idr lookup or with shm_destroy(). + * Either way, the ID is busted. + */ + WARN_ON_ONCE(err); } /* @@ -260,6 +276,14 @@ static void shm_close(struct vm_area_str down_write(&shm_ids(ns).rwsem); /* remove from the list of attaches of the shm segment */ shp = shm_lock(ns, sfd->id); + + /* + * We raced in the idr lookup or with shm_destroy(). + * Either way, the ID is busted. + */ + if (WARN_ON_ONCE(IS_ERR(shp))) + goto done; /* no-op */ + shp->shm_lprid = task_tgid_vnr(current); shp->shm_dtim = get_seconds(); shp->shm_nattch--; @@ -267,6 +291,7 @@ static void shm_close(struct vm_area_str shm_destroy(ns, shp); else shm_unlock(shp); +done: up_write(&shm_ids(ns).rwsem); } @@ -388,17 +413,25 @@ static int shm_mmap(struct file *file, s struct shm_file_data *sfd = shm_file_data(file); int ret; + /* + * In case of remap_file_pages() emulation, the file can represent + * removed IPC ID: propogate shm_lock() error to caller. + */ + ret =__shm_open(vma); + if (ret) + return ret; + ret = sfd->file->f_op->mmap(sfd->file, vma); - if (ret != 0) + if (ret) { + shm_close(vma); return ret; + } sfd->vm_ops = vma->vm_ops; #ifdef CONFIG_MMU WARN_ON(!sfd->vm_ops->fault); #endif vma->vm_ops = &shm_vm_ops; - shm_open(vma); - - return ret; + return 0; } static int shm_release(struct inode *ino, struct file *file) _ Patches currently in -mm which might be from kirill.shutemov@linux.intel.com are thp-make-split_queue-per-node.patch thp-change-deferred_split_count-to-return-number-of-thp-in-queue.patch thp-change-deferred_split_count-to-return-number-of-thp-in-queue-fix.patch thp-limit-number-of-object-to-scan-on-deferred_split_scan.patch drivers-scsi-sgc-mark-vma-as-vm_io-to-prevent-migration.patch mm-fix-bogus-vm_bug_on_page-in-isolate_lru_page.patch ipc-shm-handle-removed-segments-gracefully-in-shm_mmap.patch mempolicy-do-not-try-to-queue-pages-from-vma_migratable.patch mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix.patch mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix-2.patch mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix-3.patch