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X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Claude Opus 4.6 \(1M context\)" Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-5.2 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: [PATCH 4/5] fs: ext4: reject dirents with too-small direntlen to prevent infinite loops X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) ext4fs_iterate_dir() and ext4fs_get_ino() walk directory entries using dirent->direntlen from disk to advance the position. If a crafted filesystem has direntlen == 0, the position never advances, causing an infinite loop that can only be broken by a reset. Reject directory entries where direntlen is smaller than the minimum dirent struct size. This catches the zero case and also prevents reading overlapping dirents. Signed-off-by: Sascha Hauer Co-Authored-By: Claude Opus 4.6 (1M context) --- fs/ext4/ext4_common.c | 2 ++ fs/ext4/ext_barebox.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c index 5d252b4a2c..b0c78f9e9a 100644 --- a/fs/ext4/ext4_common.c +++ b/fs/ext4/ext4_common.c @@ -359,6 +359,8 @@ int ext4fs_iterate_dir(struct ext2fs_node *dir, char *name, free(fdiro); } + if (le16_to_cpu(dirent.direntlen) < sizeof(struct ext2_dirent)) + return -EINVAL; fpos += le16_to_cpu(dirent.direntlen); } return -ENOENT; diff --git a/fs/ext4/ext_barebox.c b/fs/ext4/ext_barebox.c index ef1a71368d..f9a978c10c 100644 --- a/fs/ext4/ext_barebox.c +++ b/fs/ext4/ext_barebox.c @@ -106,6 +106,8 @@ static int ext4fs_get_ino(struct ext2fs_node *dir, struct qstr *name, int *inum) return 0; } } + if (le16_to_cpu(dirent.direntlen) < sizeof(struct ext2_dirent)) + return -EINVAL; fpos += le16_to_cpu(dirent.direntlen); } -- 2.47.3