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ksmbd: fix out-of-bound read in parse_lease_state()

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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>
This commit is contained in:
Namjae Jeon 2023-05-28 00:23:41 +09:00 committed by Steve French
parent f1a411873c
commit fc6c6a3c32
1 changed files with 24 additions and 42 deletions
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66
fs/smb/server/oplock.c
View file

@ -1415,56 +1415,38 @@ void create_lease_buf(u8 *rbuf, struct lease *lease)
*/ */
struct lease_ctx_info *parse_lease_state(void *open_req) struct lease_ctx_info *parse_lease_state(void *open_req)
{ {
char *data_offset;
struct create_context *cc; 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 smb2_create_req *req = (struct smb2_create_req *)open_req;
struct lease_ctx_info *lreq = kzalloc(sizeof(struct lease_ctx_info), struct lease_ctx_info *lreq;
GFP_KERNEL);
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) if (!lreq)
return NULL; return NULL;
data_offset = (char *)req + le32_to_cpu(req->CreateContextsOffset); if (sizeof(struct lease_context_v2) == le32_to_cpu(cc->DataLength)) {
cc = (struct create_context *)data_offset; struct create_lease_v2 *lc = (struct create_lease_v2 *)cc;
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 (found) { memcpy(lreq->lease_key, lc->lcontext.LeaseKey, SMB2_LEASE_KEY_SIZE);
if (sizeof(struct lease_context_v2) == le32_to_cpu(cc->DataLength)) { lreq->req_state = lc->lcontext.LeaseState;
struct create_lease_v2 *lc = (struct create_lease_v2 *)cc; 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); memcpy(lreq->lease_key, lc->lcontext.LeaseKey, SMB2_LEASE_KEY_SIZE);
lreq->req_state = lc->lcontext.LeaseState; lreq->req_state = lc->lcontext.LeaseState;
lreq->flags = lc->lcontext.LeaseFlags; lreq->flags = lc->lcontext.LeaseFlags;
lreq->duration = lc->lcontext.LeaseDuration; lreq->duration = lc->lcontext.LeaseDuration;
memcpy(lreq->parent_lease_key, lc->lcontext.ParentLeaseKey, lreq->version = 1;
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;
} }
return lreq;
kfree(lreq);
return NULL;
} }
/** /**