From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Eric W. Biederman" Subject: [PATCH 11/23] mm: Teach mmap to use file_hotplug_lock Date: Mon, 1 Jun 2009 14:50:36 -0700 Message-ID: <1243893048-17031-11-git-send-email-ebiederm@xmission.com> References: Cc: , , , , Hugh Dickins , Tejun Heo , Alexey Dobriyan , Linus Torvalds , Alan Cox , Greg Kroah-Hartman , Nick Piggin , Andrew Morton , Christoph Hellwig , "Eric W. Biederman" , "Eric W. Biederman" To: Al Viro Return-path: In-Reply-To: Sender: linux-pci-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org From: Eric W. Biederman Signed-off-by: Eric W. Biederman --- mm/mmap.c | 78 +++++++++++++++++++++++++++++++++++++++-------------------- mm/nommu.c | 21 +++++++++++++++- 2 files changed, 71 insertions(+), 28 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 6b7b1a9..f13251a 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -914,9 +914,13 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, struct mm_struct * mm = current->mm; struct inode *inode; unsigned int vm_flags; - int error; + unsigned long retval; unsigned long reqprot = prot; + retval = -EIO; + if (file && !file_hotplug_read_trylock(file)) + goto out; + /* * Does the application expect PROT_READ to imply PROT_EXEC? * @@ -927,35 +931,40 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC))) prot |= PROT_EXEC; + retval = -EINVAL; if (!len) - return -EINVAL; + goto out_unlock; if (!(flags & MAP_FIXED)) addr = round_hint_to_min(addr); - error = arch_mmap_check(addr, len, flags); - if (error) - return error; + retval = arch_mmap_check(addr, len, flags); + if (retval) + goto out_unlock; /* Careful about overflows.. */ + retval = -ENOMEM; len = PAGE_ALIGN(len); if (!len || len > TASK_SIZE) - return -ENOMEM; + goto out_unlock; /* offset overflow? */ + retval = -EOVERFLOW; if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) - return -EOVERFLOW; + goto out_unlock; /* Too many mappings? */ + retval = -ENOMEM; if (mm->map_count > sysctl_max_map_count) - return -ENOMEM; + goto out_unlock; /* Obtain the address to map to. we verify (or select) it and ensure * that it represents a valid section of the address space. */ addr = get_unmapped_area(file, addr, len, pgoff, flags); + retval = addr; if (addr & ~PAGE_MASK) - return addr; + goto out_unlock; /* Do simple checking here so the lower-level routines won't have * to. we assume access permissions have been handled by the open @@ -965,8 +974,9 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; if (flags & MAP_LOCKED) { + retval = -EPERM; if (!can_do_mlock()) - return -EPERM; + goto out_unlock; vm_flags |= VM_LOCKED; } @@ -977,8 +987,9 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, locked += mm->locked_vm; lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; lock_limit >>= PAGE_SHIFT; + retval = -EAGAIN; if (locked > lock_limit && !capable(CAP_IPC_LOCK)) - return -EAGAIN; + goto out_unlock; } inode = file ? file->f_path.dentry->d_inode : NULL; @@ -986,21 +997,24 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, if (file) { switch (flags & MAP_TYPE) { case MAP_SHARED: + retval = -EACCES; if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) - return -EACCES; + goto out_unlock; /* * Make sure we don't allow writing to an append-only * file.. */ + retval = -EACCES; if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) - return -EACCES; + goto out_unlock; /* * Make sure there are no mandatory locks on the file. */ + retval = -EAGAIN; if (locks_verify_locked(inode)) - return -EAGAIN; + goto out_unlock; vm_flags |= VM_SHARED | VM_MAYSHARE; if (!(file->f_mode & FMODE_WRITE)) @@ -1008,20 +1022,24 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, /* fall through */ case MAP_PRIVATE: + retval = -EACCES; if (!(file->f_mode & FMODE_READ)) - return -EACCES; + goto out_unlock; if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { + retval = -EPERM; if (vm_flags & VM_EXEC) - return -EPERM; + goto out_unlock; vm_flags &= ~VM_MAYEXEC; } + retval = -ENODEV; if (!file->f_op || !file->f_op->mmap) - return -ENODEV; + goto out_unlock; break; default: - return -EINVAL; + retval = -EINVAL; + goto out_unlock; } } else { switch (flags & MAP_TYPE) { @@ -1039,18 +1057,24 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, pgoff = addr >> PAGE_SHIFT; break; default: - return -EINVAL; + retval = -EINVAL; + goto out_unlock; } } - error = security_file_mmap(file, reqprot, prot, flags, addr, 0); - if (error) - return error; - error = ima_file_mmap(file, prot); - if (error) - return error; + retval = security_file_mmap(file, reqprot, prot, flags, addr, 0); + if (retval) + goto out_unlock; + retval = ima_file_mmap(file, prot); + if (retval) + goto out_unlock; + retval = mmap_region(file, addr, len, flags, vm_flags, pgoff); - return mmap_region(file, addr, len, flags, vm_flags, pgoff); +out_unlock: + if (file) + file_hotplug_read_unlock(file); +out: + return retval; } EXPORT_SYMBOL(do_mmap_pgoff); diff --git a/mm/nommu.c b/mm/nommu.c index b571ef7..08038b7 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1165,7 +1165,7 @@ enomem: /* * handle mapping creation for uClinux */ -unsigned long do_mmap_pgoff(struct file *file, +static unsigned long __do_mmap_pgoff(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, @@ -1402,6 +1402,25 @@ error_getting_region: show_free_areas(); return -ENOMEM; } + +unsigned long do_mmap_pgoff(struct file *file, + unsigned long addr, + unsigned long len, + unsigned long prot, + unsigned long flags, + unsigned long pgoff) +{ + unsigned long result = -EIO; + if (file && !file_hotplug_read_trylock(file)) + goto out; + + result = __do_mmap_pgoff(file, addr, len, prot, flags, pgoff); + + if (file) + file_hotplug_read_unlock(file); +out: + return result; +} EXPORT_SYMBOL(do_mmap_pgoff); /* -- 1.6.3.1.54.g99dd.dirty