From c1ad35dd0548ce947d97aaf92f7f2f9a202951cf Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 10 May 2022 12:36:04 +0200
Subject: [PATCH] udf: Avoid using stale lengthOfImpUse
udf_write_fi() uses lengthOfImpUse of the entry it is writing to.
However this field has not yet been initialized so it either contains
completely bogus value or value from last directory entry at that place.
In either case this is wrong and can lead to filesystem corruption or
kernel crashes.
Reported-by: butt3rflyh4ck <butterflyhuangxx@gmail.com>
CC: stable@vger.kernel.org
Fixes: 979a6e28dd96 ("udf: Get rid of 0-length arrays in struct fileIdentDesc")
Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/udf/namei.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index 0ed4861b038f6..b3d5f97f16cdb 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -75,11 +75,11 @@ int udf_write_fi(struct inode *inode, struct fileIdentDesc *cfi,
if (fileident) {
if (adinicb || (offset + lfi < 0)) {
- memcpy(udf_get_fi_ident(sfi), fileident, lfi);
+ memcpy(sfi->impUse + liu, fileident, lfi);
} else if (offset >= 0) {
memcpy(fibh->ebh->b_data + offset, fileident, lfi);
} else {
- memcpy(udf_get_fi_ident(sfi), fileident, -offset);
+ memcpy(sfi->impUse + liu, fileident, -offset);
memcpy(fibh->ebh->b_data, fileident - offset,
lfi + offset);
}
@@ -88,11 +88,11 @@ int udf_write_fi(struct inode *inode, struct fileIdentDesc *cfi,
offset += lfi;
if (adinicb || (offset + padlen < 0)) {
- memset(udf_get_fi_ident(sfi) + lfi, 0x00, padlen);
+ memset(sfi->impUse + liu + lfi, 0x00, padlen);
} else if (offset >= 0) {
memset(fibh->ebh->b_data + offset, 0x00, padlen);
} else {
- memset(udf_get_fi_ident(sfi) + lfi, 0x00, -offset);
+ memset(sfi->impUse + liu + lfi, 0x00, -offset);
memset(fibh->ebh->b_data, 0x00, padlen + offset);
}
--
2.30.2