[ Upstream commit fc6c6a3c324c1b3e93a03d0cfa3749c781f23de0 ]
This bug is in parse_lease_state, and it is caused by the missing check of `struct create_context`. When the ksmbd traverses the create_contexts, it doesn't check if the field of `NameOffset` and `Next` is valid, The KASAN message is following:
[ 6.664323] BUG: KASAN: slab-out-of-bounds in parse_lease_state+0x7d/0x280 [ 6.664738] Read of size 2 at addr ffff888005c08988 by task kworker/0:3/103 ... [ 6.666644] Call Trace: [ 6.666796] <TASK> [ 6.666933] dump_stack_lvl+0x33/0x50 [ 6.667167] print_report+0xcc/0x620 [ 6.667903] kasan_report+0xae/0xe0 [ 6.668374] kasan_check_range+0x35/0x1b0 [ 6.668621] parse_lease_state+0x7d/0x280 [ 6.668868] smb2_open+0xbe8/0x4420 [ 6.675137] handle_ksmbd_work+0x282/0x820
Use smb2_find_context_vals() to find smb2 create request lease context. smb2_find_context_vals validate create context fields.
Cc: stable@vger.kernel.org Reported-by: Chih-Yen Chang cc85nod@gmail.com Tested-by: Chih-Yen Chang cc85nod@gmail.com Signed-off-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com --- fs/ksmbd/oplock.c | 66 +++++++++++++++++------------------------------ 1 file changed, 24 insertions(+), 42 deletions(-)
diff --git a/fs/ksmbd/oplock.c b/fs/ksmbd/oplock.c index 28c7f2193fb3..e2fb4631f8f7 100644 --- a/fs/ksmbd/oplock.c +++ b/fs/ksmbd/oplock.c @@ -1415,56 +1415,38 @@ void create_lease_buf(u8 *rbuf, struct lease *lease) */ struct lease_ctx_info *parse_lease_state(void *open_req) { - char *data_offset; struct create_context *cc; - unsigned int next = 0; - char *name; - bool found = false; struct smb2_create_req *req = (struct smb2_create_req *)open_req; - struct lease_ctx_info *lreq = kzalloc(sizeof(struct lease_ctx_info), - GFP_KERNEL); + struct lease_ctx_info *lreq; + + cc = smb2_find_context_vals(req, SMB2_CREATE_REQUEST_LEASE, 4); + if (IS_ERR_OR_NULL(cc)) + return NULL; + + lreq = kzalloc(sizeof(struct lease_ctx_info), GFP_KERNEL); if (!lreq) return NULL;
- data_offset = (char *)req + le32_to_cpu(req->CreateContextsOffset); - cc = (struct create_context *)data_offset; - do { - cc = (struct create_context *)((char *)cc + next); - name = le16_to_cpu(cc->NameOffset) + (char *)cc; - if (le16_to_cpu(cc->NameLength) != 4 || - strncmp(name, SMB2_CREATE_REQUEST_LEASE, 4)) { - next = le32_to_cpu(cc->Next); - continue; - } - found = true; - break; - } while (next != 0); + if (sizeof(struct lease_context_v2) == le32_to_cpu(cc->DataLength)) { + struct create_lease_v2 *lc = (struct create_lease_v2 *)cc;
- if (found) { - if (sizeof(struct lease_context_v2) == le32_to_cpu(cc->DataLength)) { - struct create_lease_v2 *lc = (struct create_lease_v2 *)cc; - - memcpy(lreq->lease_key, lc->lcontext.LeaseKey, SMB2_LEASE_KEY_SIZE); - lreq->req_state = lc->lcontext.LeaseState; - lreq->flags = lc->lcontext.LeaseFlags; - lreq->duration = lc->lcontext.LeaseDuration; - memcpy(lreq->parent_lease_key, lc->lcontext.ParentLeaseKey, - SMB2_LEASE_KEY_SIZE); - lreq->version = 2; - } else { - struct create_lease *lc = (struct create_lease *)cc; + memcpy(lreq->lease_key, lc->lcontext.LeaseKey, SMB2_LEASE_KEY_SIZE); + lreq->req_state = lc->lcontext.LeaseState; + lreq->flags = lc->lcontext.LeaseFlags; + lreq->duration = lc->lcontext.LeaseDuration; + memcpy(lreq->parent_lease_key, lc->lcontext.ParentLeaseKey, + SMB2_LEASE_KEY_SIZE); + lreq->version = 2; + } else { + struct create_lease *lc = (struct create_lease *)cc;
- memcpy(lreq->lease_key, lc->lcontext.LeaseKey, SMB2_LEASE_KEY_SIZE); - lreq->req_state = lc->lcontext.LeaseState; - lreq->flags = lc->lcontext.LeaseFlags; - lreq->duration = lc->lcontext.LeaseDuration; - lreq->version = 1; - } - return lreq; + memcpy(lreq->lease_key, lc->lcontext.LeaseKey, SMB2_LEASE_KEY_SIZE); + lreq->req_state = lc->lcontext.LeaseState; + lreq->flags = lc->lcontext.LeaseFlags; + lreq->duration = lc->lcontext.LeaseDuration; + lreq->version = 1; } - - kfree(lreq); - return NULL; + return lreq; }
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