md: do overflow check for sb->bblog_shift in super_1_load()
In super_1_load(), sb->bblog_shift is an __u8 type value loaded from on-
disk superblock. It is used for badblocks API badblocks_set() by the
following sequence,
1930 rdev->badblocks.shift = sb->bblog_shift;
1931 for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) {
1932 u64 bb = le64_to_cpu(*bbp);
1933 int count = bb & (0x3ff);
1934 u64 sector = bb >> 10;
1935 sector <<= sb->bblog_shift;
1936 count <<= sb->bblog_shift;
1937 if (bb + 1 == 0)
1938 break;
1939 if (!badblocks_set(&rdev->badblocks, sector, count, 1))
1940 return -EINVAL;
1941 }
bb->bblog_shit is in range of 0-255, variable sector is 64bit width, for
an invalid bb->bblog_shit, it is possible to make sector be overflowed
by the following calculation,
1935 sector <<= sb->bblog_shift;
Then in turn when call badblocks_set() at line 1939 with the invalid
rdev->badblocks.shift set at line 1930, may result an overflow inside
_badblocks_clear() in block/badblocks.c.
Although there are many places to call badblocks APIs, the non-zero
shift value is only used in super_1_load(), other places always use 0 as
the shift value. Therefore it is unnecessary to do a general shift value
overflow check inside badblock API, and just check here as the caller.
This may avoid unnecessary check, make the badblocks API code more simple
and elegant.
| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4817-1 | linux-6.12 security update |
Debian DLA |
DLA-4841-1 | linux security update |
Debian DSA |
DSA-6528-1 | linux security update |
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Fri, 16 Oct 2026 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Mon, 14 Sep 2026 12:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Sun, 13 Sep 2026 06:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
cvssV3_1
|
cvssV3_1
|
Sat, 12 Sep 2026 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-190 | |
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Fri, 11 Sep 2026 23:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: md: do overflow check for sb->bblog_shift in super_1_load() In super_1_load(), sb->bblog_shift is an __u8 type value loaded from on- disk superblock. It is used for badblocks API badblocks_set() by the following sequence, 1930 rdev->badblocks.shift = sb->bblog_shift; 1931 for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) { 1932 u64 bb = le64_to_cpu(*bbp); 1933 int count = bb & (0x3ff); 1934 u64 sector = bb >> 10; 1935 sector <<= sb->bblog_shift; 1936 count <<= sb->bblog_shift; 1937 if (bb + 1 == 0) 1938 break; 1939 if (!badblocks_set(&rdev->badblocks, sector, count, 1)) 1940 return -EINVAL; 1941 } bb->bblog_shit is in range of 0-255, variable sector is 64bit width, for an invalid bb->bblog_shit, it is possible to make sector be overflowed by the following calculation, 1935 sector <<= sb->bblog_shift; Then in turn when call badblocks_set() at line 1939 with the invalid rdev->badblocks.shift set at line 1930, may result an overflow inside _badblocks_clear() in block/badblocks.c. Although there are many places to call badblocks APIs, the non-zero shift value is only used in super_1_load(), other places always use 0 as the shift value. Therefore it is unnecessary to do a general shift value overflow check inside badblock API, and just check here as the caller. This may avoid unnecessary check, make the badblocks API code more simple and elegant. | |
| Title | md: do overflow check for sb->bblog_shift in super_1_load() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
Sign in to view the affected projects.
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-19T08:48:50.070Z
Reserved: 2026-09-11T19:38:34.724Z
Link: CVE-2026-89557
Updated: 2026-10-16T19:24:08.001Z
Status : Received
Published: 2026-09-11T20:19:39.403
Modified: 2026-10-19T09:17:51.190
Link: CVE-2026-89557
OpenCVE Enrichment
Updated: 2026-09-15T22:00:17Z
Debian DLA
Debian DSA