2024-06-05 12:23:25

by Sasha Levin

[permalink] [raw]
Subject: [PATCH AUTOSEL 5.10 3/7] udf: udftime: prevent overflow in udf_disk_stamp_to_time()

From: Roman Smirnov <[email protected]>

[ Upstream commit 3b84adf460381169c085e4bc09e7b57e9e16db0a ]

An overflow can occur in a situation where src.centiseconds
takes the value of 255. This situation is unlikely, but there
is no validation check anywere in the code.

Found by Linux Verification Center (linuxtesting.org) with Svace.

Suggested-by: Jan Kara <[email protected]>
Signed-off-by: Roman Smirnov <[email protected]>
Reviewed-by: Sergey Shtylyov <[email protected]>
Signed-off-by: Jan Kara <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
fs/udf/udftime.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/fs/udf/udftime.c b/fs/udf/udftime.c
index fce4ad976c8c2..26169b1f482c3 100644
--- a/fs/udf/udftime.c
+++ b/fs/udf/udftime.c
@@ -60,13 +60,18 @@ udf_disk_stamp_to_time(struct timespec64 *dest, struct timestamp src)
dest->tv_sec = mktime64(year, src.month, src.day, src.hour, src.minute,
src.second);
dest->tv_sec -= offset * 60;
- dest->tv_nsec = 1000 * (src.centiseconds * 10000 +
- src.hundredsOfMicroseconds * 100 + src.microseconds);
+
/*
* Sanitize nanosecond field since reportedly some filesystems are
* recorded with bogus sub-second values.
*/
- dest->tv_nsec %= NSEC_PER_SEC;
+ if (src.centiseconds < 100 && src.hundredsOfMicroseconds < 100 &&
+ src.microseconds < 100) {
+ dest->tv_nsec = 1000 * (src.centiseconds * 10000 +
+ src.hundredsOfMicroseconds * 100 + src.microseconds);
+ } else {
+ dest->tv_nsec = 0;
+ }
}

void
--
2.43.0