diff options
| -rw-r--r-- | drivers/block/loop.c | 44 |
1 files changed, 29 insertions, 15 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 0d567397c254..68b205a9338f 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -161,17 +161,19 @@ static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = { &xor_funcs }; -static loff_t get_loop_size(struct loop_device *lo, struct file *file) +static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file) { - loff_t size, offset, loopsize; + loff_t size, loopsize; /* Compute loopsize in bytes */ size = i_size_read(file->f_mapping->host); - offset = lo->lo_offset; loopsize = size - offset; - if (lo->lo_sizelimit > 0 && lo->lo_sizelimit < loopsize) - loopsize = lo->lo_sizelimit; + /* offset is beyond i_size, wierd but possible */ + if (loopsize < 0) + return 0; + if (sizelimit > 0 && sizelimit < loopsize) + loopsize = sizelimit; /* * Unfortunately, if we want to do I/O on the device, * the number of 512-byte sectors has to fit into a sector_t. @@ -179,17 +181,25 @@ static loff_t get_loop_size(struct loop_device *lo, struct file *file) return loopsize >> 9; } +static loff_t get_loop_size(struct loop_device *lo, struct file *file) +{ + return get_size(lo->lo_offset, lo->lo_sizelimit, file); +} + static int -figure_loop_size(struct loop_device *lo) +figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit) { - loff_t size = get_loop_size(lo, lo->lo_backing_file); + loff_t size = get_size(offset, sizelimit, lo->lo_backing_file); sector_t x = (sector_t)size; if (unlikely((loff_t)x != size)) return -EFBIG; - + if (lo->lo_offset != offset) + lo->lo_offset = offset; + if (lo->lo_sizelimit != sizelimit) + lo->lo_sizelimit = sizelimit; set_capacity(lo->lo_disk, x); - return 0; + return 0; } static inline int @@ -1059,9 +1069,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) if (lo->lo_offset != info->lo_offset || lo->lo_sizelimit != info->lo_sizelimit) { - lo->lo_offset = info->lo_offset; - lo->lo_sizelimit = info->lo_sizelimit; - if (figure_loop_size(lo)) + if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) return -EFBIG; } loop_config_discard(lo); @@ -1247,7 +1255,7 @@ static int loop_set_capacity(struct loop_device *lo, struct block_device *bdev) err = -ENXIO; if (unlikely(lo->lo_state != Lo_bound)) goto out; - err = figure_loop_size(lo); + err = figure_loop_size(lo, lo->lo_offset, lo->lo_sizelimit); if (unlikely(err)) goto out; sec = get_capacity(lo->lo_disk); @@ -1285,13 +1293,19 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode, goto out_unlocked; break; case LOOP_SET_STATUS: - err = loop_set_status_old(lo, (struct loop_info __user *) arg); + err = -EPERM; + if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) + err = loop_set_status_old(lo, + (struct loop_info __user *)arg); break; case LOOP_GET_STATUS: err = loop_get_status_old(lo, (struct loop_info __user *) arg); break; case LOOP_SET_STATUS64: - err = loop_set_status64(lo, (struct loop_info64 __user *) arg); + err = -EPERM; + if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) + err = loop_set_status64(lo, + (struct loop_info64 __user *) arg); break; case LOOP_GET_STATUS64: err = loop_get_status64(lo, (struct loop_info64 __user *) arg); |