From: Namjae Jeon <linkinjeon@kernel.org> mainline inclusion from mainline-v6.4-rc6 commit 5fe7f7b78290638806211046a99f031ff26164e1 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I7ST5T CVE: CVE-2023-3865 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h... -------------------------------- ksmbd_smb2_check_message doesn't validate hdr->NextCommand. If ->NextCommand is bigger than Offset + Length of smb2 write, It will allow oversized smb2 write length. It will cause OOB read in smb2_write. Cc: stable@vger.kernel.org Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-21164 Signed-off-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com> Conflict: fs/ksmbd/smb2misc.c Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com> --- fs/ksmbd/smb2misc.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/fs/ksmbd/smb2misc.c b/fs/ksmbd/smb2misc.c index 62e90b229ad7..58c61482be19 100644 --- a/fs/ksmbd/smb2misc.c +++ b/fs/ksmbd/smb2misc.c @@ -356,9 +356,16 @@ int ksmbd_smb2_check_message(struct ksmbd_work *work) int command; __u32 clc_len; /* calculated length */ __u32 len = get_rfc1002_len(work->request_buf); + __u32 next_cmd = le32_to_cpu(hdr->NextCommand); - if (le32_to_cpu(hdr->NextCommand) > 0) - len = le32_to_cpu(hdr->NextCommand); + if ((u64)work->next_smb2_rcv_hdr_off + next_cmd > len) { + pr_err("next command(%u) offset exceeds smb msg size\n", + next_cmd); + return 1; + } + + if (next_cmd > 0) + len = next_cmd; else if (work->next_smb2_rcv_hdr_off) len -= work->next_smb2_rcv_hdr_off; -- 2.31.1