Hi all,
Someone mentioned the mess in evdev.c that is caused by the fact that the
structures that are passed to/from user mode via read/write require
conversion when this API is used from 32 bit tasks on 64 bit kernels.
Some "discussion" followed during which I suggested an idea originally
from Matthew Wilcox of an arch-specific is_compat_task() function so that
these places could be identified. However it was considered better to
instead implement compat_sys_read/write.
This patch implements those and uses them to clean up evdev.c somewhat.
Signed-off-by: Stephen Rothwell <[email protected]>
---
arch/ia64/ia32/ia32_entry.S | 4 -
arch/mips/kernel/scall64-n32.S | 4 -
arch/mips/kernel/scall64-o32.S | 4 -
arch/parisc/kernel/syscall_table.S | 4 -
arch/ppc64/kernel/misc.S | 4 -
arch/s390/kernel/compat_linux.c | 16 -------
arch/s390/kernel/compat_wrapper.S | 12 ++---
arch/s390/kernel/syscalls.S | 4 -
arch/sparc64/kernel/systbls.S | 2
arch/x86_64/ia32/ia32entry.S | 4 -
drivers/input/evdev.c | 54 +++++--------------------
fs/compat.c | 12 +++++
fs/read_write.c | 77 +++++++++++++++++++++++++++++-------- include/linux/fs.h | 6 ++
14 files changed, 112 insertions(+), 95 deletions(-)
--
Cheers,
Stephen Rothwell [email protected]
http://www.canb.auug.org.au/~sfr/
diff -ruN linus/arch/ia64/ia32/ia32_entry.S linus-compat_write.5/arch/ia64/ia32/ia32_entry.S
--- linus/arch/ia64/ia32/ia32_entry.S 2005-06-27 16:07:59.000000000 +1000
+++ linus-compat_write.5/arch/ia64/ia32/ia32_entry.S 2005-07-01 13:58:03.000000000 +1000
@@ -213,8 +213,8 @@
data8 sys_ni_syscall /* 0 - old "setup(" system call*/
data8 sys_exit
data8 sys32_fork
- data8 sys_read
- data8 sys_write
+ data8 compat_sys_read
+ data8 compat_sys_write
data8 sys32_open /* 5 */
data8 sys_close
data8 sys32_waitpid
diff -ruN linus/arch/mips/kernel/scall64-n32.S linus-compat_write.5/arch/mips/kernel/scall64-n32.S
--- linus/arch/mips/kernel/scall64-n32.S 2005-06-27 16:08:00.000000000 +1000
+++ linus-compat_write.5/arch/mips/kernel/scall64-n32.S 2005-07-01 13:59:26.000000000 +1000
@@ -117,8 +117,8 @@
END(handle_sysn32)
EXPORT(sysn32_call_table)
- PTR sys_read /* 6000 */
- PTR sys_write
+ PTR compat_sys_read /* 6000 */
+ PTR compat_sys_write
PTR sys_open
PTR sys_close
PTR sys_newstat
diff -ruN linus/arch/mips/kernel/scall64-o32.S linus-compat_write.5/arch/mips/kernel/scall64-o32.S
--- linus/arch/mips/kernel/scall64-o32.S 2005-06-27 16:08:00.000000000 +1000
+++ linus-compat_write.5/arch/mips/kernel/scall64-o32.S 2005-07-01 13:59:40.000000000 +1000
@@ -205,8 +205,8 @@
PTR sys32_syscall /* 4000 */
PTR sys_exit
PTR sys_fork
- PTR sys_read
- PTR sys_write
+ PTR compat_sys_read
+ PTR compat_sys_write
PTR sys_open /* 4005 */
PTR sys_close
PTR sys_waitpid
diff -ruN linus/arch/parisc/kernel/syscall_table.S linus-compat_write.5/arch/parisc/kernel/syscall_table.S
--- linus/arch/parisc/kernel/syscall_table.S 2005-06-27 16:08:00.000000000 +1000
+++ linus-compat_write.5/arch/parisc/kernel/syscall_table.S 2005-07-01 14:01:50.000000000 +1000
@@ -63,8 +63,8 @@
ENTRY_SAME(restart_syscall) /* 0 */
ENTRY_SAME(exit)
ENTRY_SAME(fork_wrapper)
- ENTRY_SAME(read)
- ENTRY_SAME(write)
+ ENTRY_COMP(read)
+ ENTRY_COMP(write)
ENTRY_SAME(open) /* 5 */
ENTRY_SAME(close)
ENTRY_SAME(waitpid)
diff -ruN linus/arch/ppc64/kernel/misc.S linus-compat_write.5/arch/ppc64/kernel/misc.S
--- linus/arch/ppc64/kernel/misc.S 2005-07-08 15:18:27.000000000 +1000
+++ linus-compat_write.5/arch/ppc64/kernel/misc.S 2005-07-08 15:25:17.000000000 +1000
@@ -857,8 +857,8 @@
.llong .sys_restart_syscall /* 0 */
.llong .sys_exit
.llong .ppc_fork
- .llong .sys_read
- .llong .sys_write
+ .llong .compat_sys_read
+ .llong .compat_sys_write
.llong .sys32_open /* 5 */
.llong .sys_close
.llong .sys32_waitpid
diff -ruN linus/arch/s390/kernel/compat_linux.c linus-compat_write.5/arch/s390/kernel/compat_linux.c
--- linus/arch/s390/kernel/compat_linux.c 2005-07-15 14:37:43.000000000 +1000
+++ linus-compat_write.5/arch/s390/kernel/compat_linux.c 2005-07-18 14:41:35.000000000 +1000
@@ -981,22 +981,6 @@
return error;
}
-asmlinkage long sys32_read(unsigned int fd, char * buf, size_t count)
-{
- if ((compat_ssize_t) count < 0)
- return -EINVAL;
-
- return sys_read(fd, buf, count);
-}
-
-asmlinkage long sys32_write(unsigned int fd, char * buf, size_t count)
-{
- if ((compat_ssize_t) count < 0)
- return -EINVAL;
-
- return sys_write(fd, buf, count);
-}
-
asmlinkage long sys32_clone(struct pt_regs regs)
{
unsigned long clone_flags;
diff -ruN linus/arch/s390/kernel/compat_wrapper.S linus-compat_write.5/arch/s390/kernel/compat_wrapper.S
--- linus/arch/s390/kernel/compat_wrapper.S 2005-07-15 14:37:43.000000000 +1000
+++ linus-compat_write.5/arch/s390/kernel/compat_wrapper.S 2005-07-18 14:41:54.000000000 +1000
@@ -13,19 +13,19 @@
lgfr %r2,%r2 # int
jg sys_exit # branch to sys_exit
- .globl sys32_read_wrapper
-sys32_read_wrapper:
+ .globl compat_read_wrapper
+compat_sys_read_wrapper:
llgfr %r2,%r2 # unsigned int
llgtr %r3,%r3 # char *
llgfr %r4,%r4 # size_t
- jg sys32_read # branch to sys_read
+ jg compat_sys_read # branch to sys_read
- .globl sys32_write_wrapper
-sys32_write_wrapper:
+ .globl compat_write_wrapper
+compat_sys_write_wrapper:
llgfr %r2,%r2 # unsigned int
llgtr %r3,%r3 # const char *
llgfr %r4,%r4 # size_t
- jg sys32_write # branch to system call
+ jg compat_sys_write # branch to system call
.globl sys32_open_wrapper
sys32_open_wrapper:
diff -ruN linus/arch/s390/kernel/syscalls.S linus-compat_write.5/arch/s390/kernel/syscalls.S
--- linus/arch/s390/kernel/syscalls.S 2005-06-27 16:08:00.000000000 +1000
+++ linus-compat_write.5/arch/s390/kernel/syscalls.S 2005-07-01 14:10:05.000000000 +1000
@@ -11,8 +11,8 @@
NI_SYSCALL /* 0 */
SYSCALL(sys_exit,sys_exit,sys32_exit_wrapper)
SYSCALL(sys_fork_glue,sys_fork_glue,sys_fork_glue)
-SYSCALL(sys_read,sys_read,sys32_read_wrapper)
-SYSCALL(sys_write,sys_write,sys32_write_wrapper)
+SYSCALL(sys_read,sys_read,compat_sys_read_wrapper)
+SYSCALL(sys_write,sys_write,compat_sys_write_wrapper)
SYSCALL(sys_open,sys_open,sys32_open_wrapper) /* 5 */
SYSCALL(sys_close,sys_close,sys32_close_wrapper)
SYSCALL(sys_restart_syscall,sys_restart_syscall,sys_restart_syscall)
diff -ruN linus/arch/sparc64/kernel/systbls.S linus-compat_write.5/arch/sparc64/kernel/systbls.S
--- linus/arch/sparc64/kernel/systbls.S 2005-07-12 10:39:02.000000000 +1000
+++ linus-compat_write.5/arch/sparc64/kernel/systbls.S 2005-07-12 11:28:11.000000000 +1000
@@ -20,7 +20,7 @@
.globl sys_call_table32
sys_call_table32:
-/*0*/ .word sys_restart_syscall, sys32_exit, sys_fork, sys_read, sys_write
+/*0*/ .word sys_restart_syscall, sys32_exit, sys_fork, compat_sys_read, compat_sys_write
/*5*/ .word sys32_open, sys_close, sys32_wait4, sys32_creat, sys_link
/*10*/ .word sys_unlink, sunos_execv, sys_chdir, sys32_chown16, sys32_mknod
/*15*/ .word sys_chmod, sys32_lchown16, sparc_brk, sys32_perfctr, sys32_lseek
diff -ruN linus/arch/x86_64/ia32/ia32entry.S linus-compat_write.5/arch/x86_64/ia32/ia32entry.S
--- linus/arch/x86_64/ia32/ia32entry.S 2005-06-27 16:08:00.000000000 +1000
+++ linus-compat_write.5/arch/x86_64/ia32/ia32entry.S 2005-07-01 14:12:50.000000000 +1000
@@ -305,8 +305,8 @@
.quad sys_restart_syscall
.quad sys_exit
.quad stub32_fork
- .quad sys_read
- .quad sys_write
+ .quad compat_sys_read
+ .quad compat_sys_write
.quad sys32_open /* 5 */
.quad sys_close
.quad sys32_waitpid
diff -ruN linus/drivers/input/evdev.c linus-compat_write.5/drivers/input/evdev.c
--- linus/drivers/input/evdev.c 2005-06-28 10:05:26.000000000 +1000
+++ linus-compat_write.5/drivers/input/evdev.c 2005-07-01 00:51:37.000000000 +1000
@@ -154,16 +154,6 @@
__s32 value;
};
-#ifdef CONFIG_X86_64
-# define COMPAT_TEST test_thread_flag(TIF_IA32)
-#elif defined(CONFIG_IA64)
-# define COMPAT_TEST IS_IA32_PROCESS(ia64_task_regs(current))
-#elif defined(CONFIG_ARCH_S390)
-# define COMPAT_TEST test_thread_flag(TIF_31BIT)
-#else
-# define COMPAT_TEST test_thread_flag(TIF_32BIT)
-#endif
-
static ssize_t evdev_write_compat(struct file * file, const char __user * buffer, size_t count, loff_t *ppos)
{
struct evdev_list *list = file->private_data;
@@ -179,6 +169,8 @@
return retval;
}
+#else
+#define evdev_write_compat NULL
#endif
static ssize_t evdev_write(struct file * file, const char __user * buffer, size_t count, loff_t *ppos)
@@ -189,11 +181,6 @@
if (!list->evdev->exist) return -ENODEV;
-#ifdef CONFIG_COMPAT
- if (COMPAT_TEST)
- return evdev_write_compat(file, buffer, count, ppos);
-#endif
-
while (retval < count) {
if (copy_from_user(&event, buffer + retval, sizeof(struct input_event)))
@@ -243,6 +230,8 @@
return retval;
}
+#else
+#define evdev_read_compat NULL
#endif
static ssize_t evdev_read(struct file * file, char __user * buffer, size_t count, loff_t *ppos)
@@ -250,11 +239,6 @@
struct evdev_list *list = file->private_data;
int retval;
-#ifdef CONFIG_COMPAT
- if (COMPAT_TEST)
- return evdev_read_compat(file, buffer, count, ppos);
-#endif
-
if (count < sizeof(struct input_event))
return -EINVAL;
@@ -484,34 +468,18 @@
#ifdef CONFIG_COMPAT
-#define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
-#define NBITS_COMPAT(x) ((((x)-1)/BITS_PER_LONG_COMPAT)+1)
-#define OFF_COMPAT(x) ((x)%BITS_PER_LONG_COMPAT)
+#define NBITS_COMPAT(x) ((((x)-1)/BITS_PER_COMPAT_LONG)+1)
+#define OFF_COMPAT(x) ((x)%BITS_PER_COMPAT_LONG)
#define BIT_COMPAT(x) (1UL<<OFF_COMPAT(x))
-#define LONG_COMPAT(x) ((x)/BITS_PER_LONG_COMPAT)
+#define LONG_COMPAT(x) ((x)/BITS_PER_COMPAT_LONG)
#define test_bit_compat(bit, array) ((array[LONG_COMPAT(bit)] >> OFF_COMPAT(bit)) & 1)
-#ifdef __BIG_ENDIAN
#define bit_to_user(bit, max) \
do { \
- int i; \
int len = NBITS_COMPAT((max)) * sizeof(compat_long_t); \
if (len > _IOC_SIZE(cmd)) len = _IOC_SIZE(cmd); \
- for (i = 0; i < len / sizeof(compat_long_t); i++) \
- if (copy_to_user((compat_long_t*) p + i, \
- (compat_long_t*) (bit) + i + 1 - ((i % 2) << 1), \
- sizeof(compat_long_t))) \
- return -EFAULT; \
- return len; \
+ return compat_put_bitmap(p, (bit), len * 8) ? -EFAULT : len; \
} while (0)
-#else
-#define bit_to_user(bit, max) \
-do { \
- int len = NBITS_COMPAT((max)) * sizeof(compat_long_t); \
- if (len > _IOC_SIZE(cmd)) len = _IOC_SIZE(cmd); \
- return copy_to_user(p, (bit), len) ? -EFAULT : len; \
-} while (0)
-#endif
static long evdev_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg)
{
@@ -631,19 +599,21 @@
}
return -EINVAL;
}
+#else
+#define evdev_ioctl_compat NULL
#endif
static struct file_operations evdev_fops = {
.owner = THIS_MODULE,
.read = evdev_read,
+ .compat_read = evdev_read_compat,
.write = evdev_write,
+ .compat_write = evdev_write_compat,
.poll = evdev_poll,
.open = evdev_open,
.release = evdev_release,
.unlocked_ioctl = evdev_ioctl,
-#ifdef CONFIG_COMPAT
.compat_ioctl = evdev_ioctl_compat,
-#endif
.fasync = evdev_fasync,
.flush = evdev_flush
};
diff -ruN linus/fs/compat.c linus-compat_write.5/fs/compat.c
--- linus/fs/compat.c 2005-07-13 15:13:18.000000000 +1000
+++ linus-compat_write.5/fs/compat.c 2005-07-13 16:35:28.000000000 +1000
@@ -51,6 +51,18 @@
#include <asm/mmu_context.h>
#include <asm/ioctls.h>
+asmlinkage ssize_t compat_sys_read(unsigned int fd, char __user * buf,
+ compat_size_t count)
+{
+ return do_sys_read(fd, buf, count, 1);
+}
+
+asmlinkage ssize_t compat_sys_write(unsigned int fd, const char __user * buf,
+ compat_size_t count)
+{
+ return do_sys_write(fd, buf, count, 1);
+}
+
/*
* Not all architectures have sys_utime, so implement this in terms
* of sys_utimes.
diff -ruN linus/fs/read_write.c linus-compat_write.5/fs/read_write.c
--- linus/fs/read_write.c 2005-07-13 15:13:18.000000000 +1000
+++ linus-compat_write.5/fs/read_write.c 2005-07-13 16:36:03.000000000 +1000
@@ -18,6 +18,26 @@
#include <asm/uaccess.h>
#include <asm/unistd.h>
+#ifdef CONFIG_COMPAT
+#define vfs_select_rw(file, func, compat) \
+ (((file)->f_op == NULL) ? NULL \
+ : (((compat) && ((file)->f_op->compat_ ## func != NULL)) \
+ ? (file)->f_op->compat_ ## func \
+ : (((file)->f_op->func != NULL) \
+ ? (file)->f_op->func \
+ : (((file)->f_op->aio_ ## func != NULL) \
+ ? do_sync_ ## func \
+ : NULL))))
+#else
+#define vfs_select_rw(file, func, compat) \
+ (((file)->f_op == NULL) ? NULL \
+ : (((file)->f_op->func != NULL) \
+ ? (file)->f_op->func \
+ : (((file)->f_op->aio_ ## func != NULL) \
+ ? do_sync_ ## func \
+ : NULL)))
+#endif /* CONFIG_COMPAT */
+
struct file_operations generic_ro_fops = {
.llseek = generic_file_llseek,
.read = generic_file_read,
@@ -232,13 +252,15 @@
EXPORT_SYMBOL(do_sync_read);
-ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
+static ssize_t do_vfs_read(struct file *file, char __user *buf, size_t count,
+ loff_t *pos, ssize_t (*read_func)(struct file *, char __user *,
+ size_t, loff_t *))
{
ssize_t ret;
if (!(file->f_mode & FMODE_READ))
return -EBADF;
- if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read))
+ if (!read_func)
return -EINVAL;
if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
return -EFAULT;
@@ -247,10 +269,7 @@
if (!ret) {
ret = security_file_permission (file, MAY_READ);
if (!ret) {
- if (file->f_op->read)
- ret = file->f_op->read(file, buf, count, pos);
- else
- ret = do_sync_read(file, buf, count, pos);
+ ret = read_func(file, buf, count, pos);
if (ret > 0) {
fsnotify_access(file->f_dentry);
current->rchar += ret;
@@ -262,6 +281,10 @@
return ret;
}
+ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
+{
+ return do_vfs_read(file, buf, count, pos, vfs_select_rw(file, read, 0));
+}
EXPORT_SYMBOL(vfs_read);
ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
@@ -283,13 +306,16 @@
EXPORT_SYMBOL(do_sync_write);
-ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
+static ssize_t do_vfs_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *pos,
+ ssize_t (*write_func)(struct file *, const char __user *,
+ size_t, loff_t *))
{
ssize_t ret;
if (!(file->f_mode & FMODE_WRITE))
return -EBADF;
- if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write))
+ if (!write_func)
return -EINVAL;
if (unlikely(!access_ok(VERIFY_READ, buf, count)))
return -EFAULT;
@@ -298,10 +324,7 @@
if (!ret) {
ret = security_file_permission (file, MAY_WRITE);
if (!ret) {
- if (file->f_op->write)
- ret = file->f_op->write(file, buf, count, pos);
- else
- ret = do_sync_write(file, buf, count, pos);
+ ret = write_func(file, buf, count, pos);
if (ret > 0) {
fsnotify_modify(file->f_dentry);
current->wchar += ret;
@@ -313,6 +336,13 @@
return ret;
}
+ssize_t vfs_write(struct file *file, const char __user *buf, size_t count,
+ loff_t *pos)
+{
+ return do_vfs_write(file, buf, count, pos,
+ vfs_select_rw(file, write, 0));
+}
+
EXPORT_SYMBOL(vfs_write);
static inline loff_t file_pos_read(struct file *file)
@@ -325,7 +355,8 @@
file->f_pos = pos;
}
-asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count)
+ssize_t do_sys_read(unsigned int fd, char __user * buf,
+ size_t count, int compat)
{
struct file *file;
ssize_t ret = -EBADF;
@@ -334,16 +365,23 @@
file = fget_light(fd, &fput_needed);
if (file) {
loff_t pos = file_pos_read(file);
- ret = vfs_read(file, buf, count, &pos);
+ ret = do_vfs_read(file, buf, count, &pos,
+ vfs_select_rw(file, read, compat));
file_pos_write(file, pos);
fput_light(file, fput_needed);
}
return ret;
}
+
+asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count)
+{
+ return do_sys_read(fd, buf, count, 0);
+}
EXPORT_SYMBOL_GPL(sys_read);
-asmlinkage ssize_t sys_write(unsigned int fd, const char __user * buf, size_t count)
+ssize_t do_sys_write(unsigned int fd, const char __user * buf, size_t count,
+ int compat)
{
struct file *file;
ssize_t ret = -EBADF;
@@ -352,7 +390,8 @@
file = fget_light(fd, &fput_needed);
if (file) {
loff_t pos = file_pos_read(file);
- ret = vfs_write(file, buf, count, &pos);
+ ret = do_vfs_write(file, buf, count, &pos,
+ vfs_select_rw(file, write, compat));
file_pos_write(file, pos);
fput_light(file, fput_needed);
}
@@ -360,6 +399,12 @@
return ret;
}
+asmlinkage ssize_t sys_write(unsigned int fd, const char __user * buf,
+ size_t count)
+{
+ return do_sys_write(fd, buf, count, 0);
+}
+
asmlinkage ssize_t sys_pread64(unsigned int fd, char __user *buf,
size_t count, loff_t pos)
{
diff -ruN linus/include/linux/fs.h linus-compat_write.5/include/linux/fs.h
--- linus/include/linux/fs.h 2005-07-15 14:37:43.000000000 +1000
+++ linus-compat_write.5/include/linux/fs.h 2005-07-18 14:40:56.000000000 +1000
@@ -954,8 +954,10 @@
loff_t (*llseek) (struct file *, loff_t, int);
ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
ssize_t (*aio_read) (struct kiocb *, char __user *, size_t, loff_t);
+ ssize_t (*compat_read) (struct file *, char __user *, size_t, loff_t *);
ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
ssize_t (*aio_write) (struct kiocb *, const char __user *, size_t, loff_t);
+ ssize_t (*compat_write) (struct file *, const char __user *, size_t, loff_t *);
int (*readdir) (struct file *, void *, filldir_t);
unsigned int (*poll) (struct file *, struct poll_table_struct *);
int (*ioctl) (struct inode *, struct file *, unsigned int, unsigned long);
@@ -1506,6 +1508,10 @@
unsigned long, loff_t, loff_t *, size_t, ssize_t);
extern ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos);
extern ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos);
+extern ssize_t do_sys_read(unsigned int fd, char __user * buf,
+ size_t count, int compat);
+extern ssize_t do_sys_write(unsigned int fd, const char __user * buf,
+ size_t count, int compat);
ssize_t generic_file_write_nolock(struct file *file, const struct iovec *iov,
unsigned long nr_segs, loff_t *ppos);
extern ssize_t generic_file_sendfile(struct file *, loff_t *, size_t, read_actor_t, void *);
-
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