From 77b9040195dea3fcddf19e136c9e99a501351778 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 27 Nov 2019 21:25:36 +0100 Subject: compat_ioctl: simplify the implementation Now that both native and compat ioctl syscalls are in the same file, a couple of simplifications can be made, bringing the implementation closer together: - do_vfs_ioctl(), ioctl_preallocate(), and compat_ioctl_preallocate() can become static, allowing the compiler to optimize better - slightly update the coding style for consistency between the functions. - rather than listing each command in two switch statements for the compat case, just call a single function that has all the common commands. As a side-effect, FS_IOC_RESVSP/FS_IOC_RESVSP64 are now available to x86 compat tasks, along with FS_IOC_RESVSP_32/FS_IOC_RESVSP64_32. This is harmless for i386 emulation, and can be considered a bugfix for x32 emulation, which never supported these in the past. Reviewed-by: Ben Hutchings Signed-off-by: Arnd Bergmann --- fs/ioctl.c | 157 +++++++++++++++++++++++++------------------------------------ 1 file changed, 64 insertions(+), 93 deletions(-) (limited to 'fs/ioctl.c') diff --git a/fs/ioctl.c b/fs/ioctl.c index 8f22f7817edb..7c9a5df5a597 100644 --- a/fs/ioctl.c +++ b/fs/ioctl.c @@ -467,7 +467,7 @@ EXPORT_SYMBOL(generic_block_fiemap); * Only the l_start, l_len and l_whence fields of the 'struct space_resv' * are used here, rest are ignored. */ -int ioctl_preallocate(struct file *filp, int mode, void __user *argp) +static int ioctl_preallocate(struct file *filp, int mode, void __user *argp) { struct inode *inode = file_inode(filp); struct space_resv sr; @@ -495,8 +495,8 @@ int ioctl_preallocate(struct file *filp, int mode, void __user *argp) /* on ia32 l_start is on a 32-bit boundary */ #if defined CONFIG_COMPAT && defined(CONFIG_X86_64) /* just account for different alignment */ -int compat_ioctl_preallocate(struct file *file, int mode, - struct space_resv_32 __user *argp) +static int compat_ioctl_preallocate(struct file *file, int mode, + struct space_resv_32 __user *argp) { struct inode *inode = file_inode(file); struct space_resv_32 sr; @@ -521,11 +521,9 @@ int compat_ioctl_preallocate(struct file *file, int mode, } #endif -static int file_ioctl(struct file *filp, unsigned int cmd, - unsigned long arg) +static int file_ioctl(struct file *filp, unsigned int cmd, int __user *p) { struct inode *inode = file_inode(filp); - int __user *p = (int __user *)arg; switch (cmd) { case FIBMAP: @@ -542,7 +540,7 @@ static int file_ioctl(struct file *filp, unsigned int cmd, return ioctl_preallocate(filp, FALLOC_FL_ZERO_RANGE, p); } - return vfs_ioctl(filp, cmd, arg); + return -ENOIOCTLCMD; } static int ioctl_fionbio(struct file *filp, int __user *argp) @@ -661,53 +659,48 @@ out: } /* - * When you add any new common ioctls to the switches above and below - * please update compat_sys_ioctl() too. - * * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d. * It's just a simple helper for sys_ioctl and compat_sys_ioctl. + * + * When you add any new common ioctls to the switches above and below, + * please ensure they have compatible arguments in compat mode. */ -int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, - unsigned long arg) +static int do_vfs_ioctl(struct file *filp, unsigned int fd, + unsigned int cmd, unsigned long arg) { - int error = 0; void __user *argp = (void __user *)arg; struct inode *inode = file_inode(filp); switch (cmd) { case FIOCLEX: set_close_on_exec(fd, 1); - break; + return 0; case FIONCLEX: set_close_on_exec(fd, 0); - break; + return 0; case FIONBIO: - error = ioctl_fionbio(filp, argp); - break; + return ioctl_fionbio(filp, argp); case FIOASYNC: - error = ioctl_fioasync(fd, filp, argp); - break; + return ioctl_fioasync(fd, filp, argp); case FIOQSIZE: if (S_ISDIR(inode->i_mode) || S_ISREG(inode->i_mode) || S_ISLNK(inode->i_mode)) { loff_t res = inode_get_bytes(inode); - error = copy_to_user(argp, &res, sizeof(res)) ? - -EFAULT : 0; - } else - error = -ENOTTY; - break; + return copy_to_user(argp, &res, sizeof(res)) ? + -EFAULT : 0; + } + + return -ENOTTY; case FIFREEZE: - error = ioctl_fsfreeze(filp); - break; + return ioctl_fsfreeze(filp); case FITHAW: - error = ioctl_fsthaw(filp); - break; + return ioctl_fsthaw(filp); case FS_IOC_FIEMAP: return ioctl_fiemap(filp, argp); @@ -716,6 +709,7 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, /* anon_bdev filesystems may not have a block size */ if (!inode->i_sb->s_blocksize) return -EINVAL; + return put_user(inode->i_sb->s_blocksize, (int __user *)argp); case FICLONE: @@ -729,24 +723,30 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, default: if (S_ISREG(inode->i_mode)) - error = file_ioctl(filp, cmd, arg); - else - error = vfs_ioctl(filp, cmd, arg); + return file_ioctl(filp, cmd, argp); break; } - return error; + + return -ENOIOCTLCMD; } int ksys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg) { - int error; struct fd f = fdget(fd); + int error; if (!f.file) return -EBADF; + error = security_file_ioctl(f.file, cmd, arg); - if (!error) - error = do_vfs_ioctl(f.file, fd, cmd, arg); + if (error) + goto out; + + error = do_vfs_ioctl(f.file, fd, cmd, arg); + if (error == -ENOIOCTLCMD) + error = vfs_ioctl(f.file, cmd, arg); + +out: fdput(f); return error; } @@ -790,92 +790,63 @@ long compat_ptr_ioctl(struct file *file, unsigned int cmd, unsigned long arg) EXPORT_SYMBOL(compat_ptr_ioctl); COMPAT_SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, - compat_ulong_t, arg32) + compat_ulong_t, arg) { - unsigned long arg = arg32; struct fd f = fdget(fd); - int error = -EBADF; + int error; + if (!f.file) - goto out; + return -EBADF; /* RED-PEN how should LSM module know it's handling 32bit? */ error = security_file_ioctl(f.file, cmd, arg); if (error) - goto out_fput; + goto out; switch (cmd) { - /* these are never seen by ->ioctl(), no argument or int argument */ - case FIOCLEX: - case FIONCLEX: - case FIFREEZE: - case FITHAW: + /* FICLONE takes an int argument, so don't use compat_ptr() */ case FICLONE: - goto do_ioctl; - /* these are never seen by ->ioctl(), pointer argument */ - case FIONBIO: - case FIOASYNC: - case FIOQSIZE: - case FS_IOC_FIEMAP: - case FIGETBSZ: - case FICLONERANGE: - case FIDEDUPERANGE: - goto found_handler; - /* - * The next group is the stuff handled inside file_ioctl(). - * For regular files these never reach ->ioctl(); for - * devices, sockets, etc. they do and one (FIONREAD) is - * even accepted in some cases. In all those cases - * argument has the same type, so we can handle these - * here, shunting them towards do_vfs_ioctl(). - * ->compat_ioctl() will never see any of those. - */ - /* pointer argument, never actually handled by ->ioctl() */ - case FIBMAP: - goto found_handler; - /* handled by some ->ioctl(); always a pointer to int */ - case FIONREAD: - goto found_handler; - /* these get messy on amd64 due to alignment differences */ + error = ioctl_file_clone(f.file, arg, 0, 0, 0); + break; + #if defined(CONFIG_X86_64) + /* these get messy on amd64 due to alignment differences */ case FS_IOC_RESVSP_32: case FS_IOC_RESVSP64_32: error = compat_ioctl_preallocate(f.file, 0, compat_ptr(arg)); - goto out_fput; + break; case FS_IOC_UNRESVSP_32: case FS_IOC_UNRESVSP64_32: error = compat_ioctl_preallocate(f.file, FALLOC_FL_PUNCH_HOLE, compat_ptr(arg)); - goto out_fput; + break; case FS_IOC_ZERO_RANGE_32: error = compat_ioctl_preallocate(f.file, FALLOC_FL_ZERO_RANGE, compat_ptr(arg)); - goto out_fput; -#else - case FS_IOC_RESVSP: - case FS_IOC_RESVSP64: - case FS_IOC_UNRESVSP: - case FS_IOC_UNRESVSP64: - case FS_IOC_ZERO_RANGE: - goto found_handler; + break; #endif + /* + * everything else in do_vfs_ioctl() takes either a compatible + * pointer argument or no argument -- call it with a modified + * argument. + */ default: - if (f.file->f_op->compat_ioctl) { + error = do_vfs_ioctl(f.file, fd, cmd, + (unsigned long)compat_ptr(arg)); + if (error != -ENOIOCTLCMD) + break; + + if (f.file->f_op->compat_ioctl) error = f.file->f_op->compat_ioctl(f.file, cmd, arg); - if (error != -ENOIOCTLCMD) - goto out_fput; - } - error = -ENOTTY; - goto out_fput; + if (error == -ENOIOCTLCMD) + error = -ENOTTY; + break; } - found_handler: - arg = (unsigned long)compat_ptr(arg); - do_ioctl: - error = do_vfs_ioctl(f.file, fd, cmd, arg); - out_fput: - fdput(f); out: + fdput(f); + return error; } #endif -- cgit