From: Daan De Meyer Date: Thu, 21 May 2026 07:51:13 +0000 (+0000) Subject: btrfs: add 32-bit compat ioctl for BTRFS_IOC_GET_SUBVOL_INFO X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=538e5bdbc8996d3f6ce65565dda7df58e6e97e04;p=thirdparty%2Flinux.git btrfs: add 32-bit compat ioctl for BTRFS_IOC_GET_SUBVOL_INFO On 64-bit kernels with 32-bit userspace, struct btrfs_ioctl_timespec is laid out as 16 bytes (8B sec + 4B nsec + 4B trailing padding) instead of the 12 bytes a 32-bit userspace expects, because the surrounding struct is not packed. As a result, struct btrfs_ioctl_get_subvol_info_args has a different size and layout in 32-bit userspace than in the 64-bit kernel, and BTRFS_IOC_GET_SUBVOL_INFO returns garbage to 32-bit callers. Mirror what was done for BTRFS_IOC_SET_RECEIVED_SUBVOL: add a packed btrfs_ioctl_get_subvol_info_args_32 with btrfs_ioctl_timespec_32 fields, define BTRFS_IOC_GET_SUBVOL_INFO_32 with that struct as the size argument, factor the existing handler into a shared _btrfs_ioctl_get_ subvol_info() helper, and add btrfs_ioctl_get_subvol_info_32() which fills the kernel struct and translates field-by-field into the 32-bit struct before copy_to_user(). Signed-off-by: Daan De Meyer Reviewed-by: David Sterba Signed-off-by: David Sterba --- diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index d4981d2a42d71..5512b32752030 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -83,6 +83,30 @@ struct btrfs_ioctl_received_subvol_args_32 { #define BTRFS_IOC_SET_RECEIVED_SUBVOL_32 _IOWR(BTRFS_IOCTL_MAGIC, 37, \ struct btrfs_ioctl_received_subvol_args_32) + +struct btrfs_ioctl_get_subvol_info_args_32 { + __u64 treeid; + char name[BTRFS_VOL_NAME_MAX + 1]; + __u64 parent_id; + __u64 dirid; + __u64 generation; + __u64 flags; + __u8 uuid[BTRFS_UUID_SIZE]; + __u8 parent_uuid[BTRFS_UUID_SIZE]; + __u8 received_uuid[BTRFS_UUID_SIZE]; + __u64 ctransid; + __u64 otransid; + __u64 stransid; + __u64 rtransid; + struct btrfs_ioctl_timespec_32 ctime; + struct btrfs_ioctl_timespec_32 otime; + struct btrfs_ioctl_timespec_32 stime; + struct btrfs_ioctl_timespec_32 rtime; + __u64 reserved[8]; +} __attribute__ ((__packed__)); + +#define BTRFS_IOC_GET_SUBVOL_INFO_32 _IOR(BTRFS_IOCTL_MAGIC, 60, \ + struct btrfs_ioctl_get_subvol_info_args_32) #endif #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT) @@ -1924,9 +1948,9 @@ static int btrfs_ioctl_ino_lookup_user(struct file *file, void __user *argp) } /* Get the subvolume information in BTRFS_ROOT_ITEM and BTRFS_ROOT_BACKREF */ -static int btrfs_ioctl_get_subvol_info(struct inode *inode, void __user *argp) +static int _btrfs_ioctl_get_subvol_info(struct inode *inode, + struct btrfs_ioctl_get_subvol_info_args *subvol_info) { - struct btrfs_ioctl_get_subvol_info_args AUTO_KFREE(subvol_info); struct btrfs_fs_info *fs_info; struct btrfs_root *root; struct btrfs_path *path; @@ -1942,12 +1966,6 @@ static int btrfs_ioctl_get_subvol_info(struct inode *inode, void __user *argp) if (!path) return -ENOMEM; - subvol_info = kzalloc_obj(*subvol_info); - if (!subvol_info) { - btrfs_free_path(path); - return -ENOMEM; - } - fs_info = BTRFS_I(inode)->root->fs_info; /* Get root_item of inode's subvolume */ @@ -2026,11 +2044,6 @@ static int btrfs_ioctl_get_subvol_info(struct inode *inode, void __user *argp) } } - btrfs_free_path(path); - path = NULL; - if (copy_to_user(argp, subvol_info, sizeof(*subvol_info))) - ret = -EFAULT; - out: btrfs_put_root(root); out_free: @@ -2038,6 +2051,70 @@ out_free: return ret; } +#ifdef CONFIG_64BIT +static int btrfs_ioctl_get_subvol_info_32(struct inode *inode, void __user *argp) +{ + struct btrfs_ioctl_get_subvol_info_args AUTO_KFREE(subvol_info); + struct btrfs_ioctl_get_subvol_info_args_32 AUTO_KFREE(subvol_info_32); + int ret; + + subvol_info = kzalloc_obj(*subvol_info); + if (!subvol_info) + return -ENOMEM; + + subvol_info_32 = kzalloc_obj(*subvol_info_32); + if (!subvol_info_32) + return -ENOMEM; + + ret = _btrfs_ioctl_get_subvol_info(inode, subvol_info); + if (ret) + return ret; + + subvol_info_32->treeid = subvol_info->treeid; + memcpy(subvol_info_32->name, subvol_info->name, sizeof(subvol_info_32->name)); + subvol_info_32->parent_id = subvol_info->parent_id; + subvol_info_32->dirid = subvol_info->dirid; + subvol_info_32->generation = subvol_info->generation; + subvol_info_32->flags = subvol_info->flags; + memcpy(subvol_info_32->uuid, subvol_info->uuid, BTRFS_UUID_SIZE); + memcpy(subvol_info_32->parent_uuid, subvol_info->parent_uuid, BTRFS_UUID_SIZE); + memcpy(subvol_info_32->received_uuid, subvol_info->received_uuid, BTRFS_UUID_SIZE); + subvol_info_32->ctransid = subvol_info->ctransid; + subvol_info_32->otransid = subvol_info->otransid; + subvol_info_32->stransid = subvol_info->stransid; + subvol_info_32->rtransid = subvol_info->rtransid; + subvol_info_32->ctime.sec = subvol_info->ctime.sec; + subvol_info_32->ctime.nsec = subvol_info->ctime.nsec; + subvol_info_32->otime.sec = subvol_info->otime.sec; + subvol_info_32->otime.nsec = subvol_info->otime.nsec; + subvol_info_32->stime.sec = subvol_info->stime.sec; + subvol_info_32->stime.nsec = subvol_info->stime.nsec; + subvol_info_32->rtime.sec = subvol_info->rtime.sec; + subvol_info_32->rtime.nsec = subvol_info->rtime.nsec; + + if (copy_to_user(argp, subvol_info_32, sizeof(*subvol_info_32))) + ret = -EFAULT; + + return ret; +} +#endif + +static int btrfs_ioctl_get_subvol_info(struct inode *inode, void __user *argp) +{ + struct btrfs_ioctl_get_subvol_info_args AUTO_KFREE(subvol_info); + int ret; + + subvol_info = kzalloc_obj(*subvol_info); + if (!subvol_info) + return -ENOMEM; + + ret = _btrfs_ioctl_get_subvol_info(inode, subvol_info); + if (!ret && copy_to_user(argp, subvol_info, sizeof(*subvol_info))) + ret = -EFAULT; + + return ret; +} + /* * Return ROOT_REF information of the subvolume containing this inode * except the subvolume name. @@ -5529,6 +5606,10 @@ long btrfs_ioctl(struct file *file, unsigned int return btrfs_ioctl_set_features(file, argp); case BTRFS_IOC_GET_SUBVOL_INFO: return btrfs_ioctl_get_subvol_info(inode, argp); +#ifdef CONFIG_64BIT + case BTRFS_IOC_GET_SUBVOL_INFO_32: + return btrfs_ioctl_get_subvol_info_32(inode, argp); +#endif case BTRFS_IOC_GET_SUBVOL_ROOTREF: return btrfs_ioctl_get_subvol_rootref(root, argp); case BTRFS_IOC_INO_LOOKUP_USER: