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UBI: fix overflow bug 

I was experiencing overflows in multiplications for
volume->used_bytes in vmt.c & vtbl.c, while creating & resizing large volumes.

vol->used_bytes is long long however its 2 operands vol->used_ebs &
vol->usable_leb_size
are int. So their multiplication for larger values causes integer overflows.
Typecasting them solves the problem.

My machine & flash details:

64Bit dual-core AMD opteron, 1 GB RAM, linux 2.6.18.3.
mtd size = 6GB, volume size= 5GB, peb_size = 4MB.

heres patch which does the fix.

Signed-off-by: Vinit Agnihotri <vinit.agnihotri@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This commit is contained in:
Vinit Agnihotri 2007-07-10 13:04:59 +03:00 committed by Artem Bityutskiy
parent 2f3cdb55ee
commit d08c3b78b8
2 changed files with 11 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/mtd/ubi/vmt.c
View File

@ -280,7 +280,8 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
vol->used_ebs = vol->reserved_pebs;
vol->last_eb_bytes = vol->usable_leb_size;
vol->used_bytes = vol->used_ebs * vol->usable_leb_size;
vol->used_bytes =
(long long)vol->used_ebs * vol->usable_leb_size;
} else {
bytes = vol->used_bytes;
vol->last_eb_bytes = do_div(bytes, vol->usable_leb_size);
@ -538,7 +539,8 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
vol->used_ebs = reserved_pebs;
vol->last_eb_bytes = vol->usable_leb_size;
vol->used_bytes = vol->used_ebs * vol->usable_leb_size;
vol->used_bytes =
(long long)vol->used_ebs * vol->usable_leb_size;
}
paranoid_check_volumes(ubi);
@ -739,7 +741,7 @@ static void paranoid_check_volume(struct ubi_device *ubi, int vol_id)
goto fail;
}
n = vol->used_ebs * vol->usable_leb_size;
n = (long long)vol->used_ebs * vol->usable_leb_size;
if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
if (vol->corrupted != 0) {
ubi_err("corrupted dynamic volume");

9
drivers/mtd/ubi/vtbl.c
View File

@ -531,7 +531,8 @@ static int init_volumes(struct ubi_device *ubi, const struct ubi_scan_info *si,
if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
vol->used_ebs = vol->reserved_pebs;
vol->last_eb_bytes = vol->usable_leb_size;
vol->used_bytes = vol->used_ebs * vol->usable_leb_size;
vol->used_bytes =
(long long)vol->used_ebs * vol->usable_leb_size;
continue;
}
@ -561,7 +562,8 @@ static int init_volumes(struct ubi_device *ubi, const struct ubi_scan_info *si,
}
vol->used_ebs = sv->used_ebs;
vol->used_bytes = (vol->used_ebs - 1) * vol->usable_leb_size;
vol->used_bytes =
(long long)(vol->used_ebs - 1) * vol->usable_leb_size;
vol->used_bytes += sv->last_data_size;
vol->last_eb_bytes = sv->last_data_size;
}
@ -578,7 +580,8 @@ static int init_volumes(struct ubi_device *ubi, const struct ubi_scan_info *si,
vol->usable_leb_size = ubi->leb_size;
vol->used_ebs = vol->reserved_pebs;
vol->last_eb_bytes = vol->reserved_pebs;
vol->used_bytes = vol->used_ebs * (ubi->leb_size - vol->data_pad);
vol->used_bytes =
(long long)vol->used_ebs * (ubi->leb_size - vol->data_pad);
vol->vol_id = UBI_LAYOUT_VOL_ID;
ubi_assert(!ubi->volumes[i]);