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fat: Fix ATTR_RO in the case of (~umask & S_WUGO) == 0
If inode->i_mode doesn't have S_WUGO, current code assumes it means ATTR_RO. However, if (~[ufd]mask & S_WUGO) == 0, inode->i_mode can't hold S_WUGO. Therefore the updated directory entry will always have ATTR_RO. This adds fat_mode_can_hold_ro() to check it. And if inode->i_mode can't hold, uses -i_attrs to hold ATTR_RO instead. With this, we don't set ATTR_RO unless users change it via ioctl() if (~[ufd]mask & S_WUGO) == 0. And on FAT_IOCTL_GET_ATTRIBUTES path, this adds ->i_mutex to it for not returning the partially updated attributes by FAT_IOCTL_SET_ATTRIBUTES to userland. Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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parent
9c0aa1b87b
commit
9183482f5d
33
fs/fat/fat.h
33
fs/fat/fat.h
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@ -117,6 +117,25 @@ static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
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return container_of(inode, struct msdos_inode_info, vfs_inode);
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return container_of(inode, struct msdos_inode_info, vfs_inode);
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}
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}
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/*
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* If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
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* save ATTR_RO instead of ->i_mode.
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*/
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static inline int fat_mode_can_hold_ro(struct inode *inode)
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{
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struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
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mode_t mask;
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if (S_ISDIR(inode->i_mode))
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mask = ~sbi->options.fs_dmask;
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else
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mask = ~sbi->options.fs_fmask;
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if (!(mask & S_IWUGO))
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return 0;
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return 1;
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}
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/* Convert attribute bits and a mask to the UNIX mode. */
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/* Convert attribute bits and a mask to the UNIX mode. */
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static inline mode_t fat_make_mode(struct msdos_sb_info *sbi,
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static inline mode_t fat_make_mode(struct msdos_sb_info *sbi,
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u8 attrs, mode_t mode)
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u8 attrs, mode_t mode)
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@ -133,14 +152,20 @@ static inline mode_t fat_make_mode(struct msdos_sb_info *sbi,
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/* Return the FAT attribute byte for this inode */
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/* Return the FAT attribute byte for this inode */
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static inline u8 fat_make_attrs(struct inode *inode)
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static inline u8 fat_make_attrs(struct inode *inode)
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{
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{
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return ((inode->i_mode & S_IWUGO) ? ATTR_NONE : ATTR_RO) |
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u8 attrs = MSDOS_I(inode)->i_attrs;
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(S_ISDIR(inode->i_mode) ? ATTR_DIR : ATTR_NONE) |
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if (S_ISDIR(inode->i_mode))
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MSDOS_I(inode)->i_attrs;
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attrs |= ATTR_DIR;
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if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
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attrs |= ATTR_RO;
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return attrs;
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}
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}
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static inline void fat_save_attrs(struct inode *inode, u8 attrs)
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static inline void fat_save_attrs(struct inode *inode, u8 attrs)
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{
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{
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MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
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if (fat_mode_can_hold_ro(inode))
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MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
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else
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MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
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}
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}
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static inline unsigned char fat_checksum(const __u8 *name)
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static inline unsigned char fat_checksum(const __u8 *name)
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@ -27,7 +27,12 @@ int fat_generic_ioctl(struct inode *inode, struct file *filp,
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switch (cmd) {
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switch (cmd) {
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case FAT_IOCTL_GET_ATTRIBUTES:
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case FAT_IOCTL_GET_ATTRIBUTES:
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{
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{
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u32 attr = fat_make_attrs(inode);
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u32 attr;
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mutex_lock(&inode->i_mutex);
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attr = fat_make_attrs(inode);
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mutex_unlock(&inode->i_mutex);
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return put_user(attr, user_attr);
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return put_user(attr, user_attr);
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}
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}
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case FAT_IOCTL_SET_ATTRIBUTES:
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case FAT_IOCTL_SET_ATTRIBUTES:
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