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fat: fix VFAT compat ioctls on 64-bit systems
If you compile and run the below test case in an msdos or vfat directory on
an x86-64 system with -m32 you'll get garbage in the kernel_dirent struct
followed by a SIGSEGV.
The patch fixes this.
Reported and initial fix by Bart Oldeman
#include <sys/types.h>
#include <sys/ioctl.h>
#include <dirent.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
struct kernel_dirent {
long d_ino;
long d_off;
unsigned short d_reclen;
char d_name[256]; /* We must not include limits.h! */
};
#define VFAT_IOCTL_READDIR_BOTH _IOR('r', 1, struct kernel_dirent [2])
#define VFAT_IOCTL_READDIR_SHORT _IOR('r', 2, struct kernel_dirent [2])
int main(void)
{
int fd = open(".", O_RDONLY);
struct kernel_dirent de[2];
while (1) {
int i = ioctl(fd, VFAT_IOCTL_READDIR_BOTH, (long)de);
if (i == -1) break;
if (de[0].d_reclen == 0) break;
printf("SFN: reclen=%2d off=%d ino=%d, %-12s",
de[0].d_reclen, de[0].d_off, de[0].d_ino, de[0].d_name);
if (de[1].d_reclen)
printf("\tLFN: reclen=%2d off=%d ino=%d, %s",
de[1].d_reclen, de[1].d_off, de[1].d_ino, de[1].d_name);
printf("\n");
}
return 0;
}
Signed-off-by: Bart Oldeman <bartoldeman@users.sourceforge.net>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
OGAWA Hirofumi
Linus Torvalds
parent
b247e8aaf2
commit
c483bab099
201
fs/fat/dir.c
201
fs/fat/dir.c
@ -422,7 +422,7 @@ EODir:
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EXPORT_SYMBOL_GPL(fat_search_long);
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struct fat_ioctl_filldir_callback {
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struct dirent __user *dirent;
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void __user *dirent;
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int result;
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/* for dir ioctl */
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const char *longname;
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@ -647,62 +647,85 @@ static int fat_readdir(struct file *filp, void *dirent, filldir_t filldir)
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return __fat_readdir(inode, filp, dirent, filldir, 0, 0);
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}
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static int fat_ioctl_filldir(void *__buf, const char *name, int name_len,
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loff_t offset, u64 ino, unsigned int d_type)
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{
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struct fat_ioctl_filldir_callback *buf = __buf;
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struct dirent __user *d1 = buf->dirent;
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struct dirent __user *d2 = d1 + 1;
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if (buf->result)
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return -EINVAL;
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buf->result++;
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if (name != NULL) {
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/* dirent has only short name */
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if (name_len >= sizeof(d1->d_name))
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name_len = sizeof(d1->d_name) - 1;
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if (put_user(0, d2->d_name) ||
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put_user(0, &d2->d_reclen) ||
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copy_to_user(d1->d_name, name, name_len) ||
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put_user(0, d1->d_name + name_len) ||
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put_user(name_len, &d1->d_reclen))
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goto efault;
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} else {
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/* dirent has short and long name */
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const char *longname = buf->longname;
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int long_len = buf->long_len;
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const char *shortname = buf->shortname;
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int short_len = buf->short_len;
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if (long_len >= sizeof(d1->d_name))
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long_len = sizeof(d1->d_name) - 1;
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if (short_len >= sizeof(d1->d_name))
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short_len = sizeof(d1->d_name) - 1;
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if (copy_to_user(d2->d_name, longname, long_len) ||
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put_user(0, d2->d_name + long_len) ||
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put_user(long_len, &d2->d_reclen) ||
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put_user(ino, &d2->d_ino) ||
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put_user(offset, &d2->d_off) ||
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copy_to_user(d1->d_name, shortname, short_len) ||
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put_user(0, d1->d_name + short_len) ||
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put_user(short_len, &d1->d_reclen))
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goto efault;
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}
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return 0;
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efault:
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buf->result = -EFAULT;
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return -EFAULT;
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#define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type) \
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static int func(void *__buf, const char *name, int name_len, \
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loff_t offset, u64 ino, unsigned int d_type) \
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{ \
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struct fat_ioctl_filldir_callback *buf = __buf; \
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struct dirent_type __user *d1 = buf->dirent; \
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struct dirent_type __user *d2 = d1 + 1; \
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\
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if (buf->result) \
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return -EINVAL; \
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buf->result++; \
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\
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if (name != NULL) { \
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/* dirent has only short name */ \
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if (name_len >= sizeof(d1->d_name)) \
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name_len = sizeof(d1->d_name) - 1; \
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\
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if (put_user(0, d2->d_name) || \
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put_user(0, &d2->d_reclen) || \
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copy_to_user(d1->d_name, name, name_len) || \
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put_user(0, d1->d_name + name_len) || \
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put_user(name_len, &d1->d_reclen)) \
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goto efault; \
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} else { \
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/* dirent has short and long name */ \
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const char *longname = buf->longname; \
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int long_len = buf->long_len; \
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const char *shortname = buf->shortname; \
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int short_len = buf->short_len; \
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\
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if (long_len >= sizeof(d1->d_name)) \
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long_len = sizeof(d1->d_name) - 1; \
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if (short_len >= sizeof(d1->d_name)) \
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short_len = sizeof(d1->d_name) - 1; \
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\
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if (copy_to_user(d2->d_name, longname, long_len) || \
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put_user(0, d2->d_name + long_len) || \
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put_user(long_len, &d2->d_reclen) || \
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put_user(ino, &d2->d_ino) || \
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put_user(offset, &d2->d_off) || \
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copy_to_user(d1->d_name, shortname, short_len) || \
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put_user(0, d1->d_name + short_len) || \
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put_user(short_len, &d1->d_reclen)) \
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goto efault; \
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} \
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return 0; \
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efault: \
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buf->result = -EFAULT; \
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return -EFAULT; \
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}
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static int fat_dir_ioctl(struct inode * inode, struct file * filp,
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unsigned int cmd, unsigned long arg)
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FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, dirent)
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static int fat_ioctl_readdir(struct inode *inode, struct file *filp,
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void __user *dirent, filldir_t filldir,
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int short_only, int both)
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{
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struct fat_ioctl_filldir_callback buf;
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struct dirent __user *d1;
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int ret, short_only, both;
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int ret;
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buf.dirent = dirent;
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buf.result = 0;
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mutex_lock(&inode->i_mutex);
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ret = -ENOENT;
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if (!IS_DEADDIR(inode)) {
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ret = __fat_readdir(inode, filp, &buf, filldir,
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short_only, both);
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}
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mutex_unlock(&inode->i_mutex);
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if (ret >= 0)
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ret = buf.result;
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return ret;
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}
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static int fat_dir_ioctl(struct inode *inode, struct file *filp,
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unsigned int cmd, unsigned long arg)
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{
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struct dirent __user *d1 = (struct dirent __user *)arg;
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int short_only, both;
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switch (cmd) {
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case VFAT_IOCTL_READDIR_SHORT:
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@ -717,7 +740,6 @@ static int fat_dir_ioctl(struct inode * inode, struct file * filp,
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return fat_generic_ioctl(inode, filp, cmd, arg);
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}
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d1 = (struct dirent __user *)arg;
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if (!access_ok(VERIFY_WRITE, d1, sizeof(struct dirent[2])))
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return -EFAULT;
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/*
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@ -728,69 +750,48 @@ static int fat_dir_ioctl(struct inode * inode, struct file * filp,
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if (put_user(0, &d1->d_reclen))
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return -EFAULT;
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buf.dirent = d1;
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buf.result = 0;
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mutex_lock(&inode->i_mutex);
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ret = -ENOENT;
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if (!IS_DEADDIR(inode)) {
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ret = __fat_readdir(inode, filp, &buf, fat_ioctl_filldir,
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short_only, both);
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}
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mutex_unlock(&inode->i_mutex);
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if (ret >= 0)
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ret = buf.result;
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return ret;
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return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
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short_only, both);
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}
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#ifdef CONFIG_COMPAT
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#define VFAT_IOCTL_READDIR_BOTH32 _IOR('r', 1, struct compat_dirent[2])
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#define VFAT_IOCTL_READDIR_SHORT32 _IOR('r', 2, struct compat_dirent[2])
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static long fat_compat_put_dirent32(struct dirent *d,
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struct compat_dirent __user *d32)
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{
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if (!access_ok(VERIFY_WRITE, d32, sizeof(struct compat_dirent)))
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return -EFAULT;
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FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
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__put_user(d->d_ino, &d32->d_ino);
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__put_user(d->d_off, &d32->d_off);
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__put_user(d->d_reclen, &d32->d_reclen);
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if (__copy_to_user(d32->d_name, d->d_name, d->d_reclen))
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return -EFAULT;
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return 0;
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}
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static long fat_compat_dir_ioctl(struct file *file, unsigned cmd,
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static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
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unsigned long arg)
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{
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struct compat_dirent __user *p = compat_ptr(arg);
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int ret;
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mm_segment_t oldfs = get_fs();
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struct dirent d[2];
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struct inode *inode = filp->f_path.dentry->d_inode;
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struct compat_dirent __user *d1 = compat_ptr(arg);
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int short_only, both;
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switch (cmd) {
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case VFAT_IOCTL_READDIR_BOTH32:
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cmd = VFAT_IOCTL_READDIR_BOTH;
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break;
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case VFAT_IOCTL_READDIR_SHORT32:
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cmd = VFAT_IOCTL_READDIR_SHORT;
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short_only = 1;
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both = 0;
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break;
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case VFAT_IOCTL_READDIR_BOTH32:
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short_only = 0;
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both = 1;
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break;
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default:
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return -ENOIOCTLCMD;
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}
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set_fs(KERNEL_DS);
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lock_kernel();
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ret = fat_dir_ioctl(file->f_path.dentry->d_inode, file,
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cmd, (unsigned long) &d);
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unlock_kernel();
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set_fs(oldfs);
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if (ret >= 0) {
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ret |= fat_compat_put_dirent32(&d[0], p);
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ret |= fat_compat_put_dirent32(&d[1], p + 1);
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}
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return ret;
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if (!access_ok(VERIFY_WRITE, d1, sizeof(struct compat_dirent[2])))
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return -EFAULT;
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/*
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* Yes, we don't need this put_user() absolutely. However old
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* code didn't return the right value. So, app use this value,
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* in order to check whether it is EOF.
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*/
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if (put_user(0, &d1->d_reclen))
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return -EFAULT;
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return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
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short_only, both);
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}
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#endif /* CONFIG_COMPAT */
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