5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Coly Li <colyli@fygo.io>
commit 35d522bd32462afcf1981dab6da8a9256c26c1e0 upstream.
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.
Fixes: 2699b67223ac ("md: load/store badblock list from v1.x metadata")
Fixes: 1726c7746783 ("badblocks: improve badblocks_set() for multiple ranges handling")
Cc: <redacted>
Cc: Ramesh Adhikari <redacted>
Signed-off-by: Coly Li <colyli@fygo.io>
Reviewed-by: Yu Kuai <yukuai@fygo.io>
Link: https://patch.msgid.link/20260720111400.2120834-1-colyli@fygo.io (local)
Signed-off-by: Yu Kuai <yukuai@fygo.io>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/md/md.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1746,6 +1746,13 @@ static int super_1_load(struct md_rdev *
rdev->bb_page, REQ_OP_READ, 0, true))
return -EIO;
bbp = (__le64 *)page_address(rdev->bb_page);
+
+ /* check for badblocks api. */
+ if (sb->bblog_shift >= BITS_PER_TYPE(sector_t)) {
+ pr_err("md: %pg: bogus bblog_shift %u for badblocks.\n",
+ rdev->bdev, sb->bblog_shift);
+ return -EINVAL;
+ }
rdev->badblocks.shift = sb->bblog_shift;
for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) {
u64 bb = le64_to_cpu(*bbp);