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smb: client: fix potential OOBs in smb2_parse_contexts()
Validate offsets and lengths before dereferencing create contexts in smb2_parse_contexts(). This fixes following oops when accessing invalid create contexts from server: BUG: unable to handle page fault for address: ffff8881178d8cc3 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 4a01067 P4D 4a01067 PUD 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 3 PID: 1736 Comm: mount.cifs Not tainted 6.7.0-rc4 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014 RIP: 0010:smb2_parse_contexts+0xa0/0x3a0 [cifs] Code: f8 10 75 13 48 b8 93 ad 25 50 9c b4 11 e7 49 39 06 0f 84 d2 00 00 00 8b 45 00 85 c0 74 61 41 29 c5 48 01 c5 41 83 fd 0f 76 55 <0f> b7 7d 04 0f b7 45 06 4c 8d 74 3d 00 66 83 f8 04 75 bc ba 04 00 RSP: 0018:ffffc900007939e0 EFLAGS: 00010216 RAX: ffffc90000793c78 RBX: ffff8880180cc000 RCX: ffffc90000793c90 RDX: ffffc90000793cc0 RSI: ffff8880178d8cc0 RDI: ffff8880180cc000 RBP: ffff8881178d8cbf R08: ffffc90000793c22 R09: 0000000000000000 R10: ffff8880180cc000 R11: 0000000000000024 R12: 0000000000000000 R13: 0000000000000020 R14: 0000000000000000 R15: ffffc90000793c22 FS: 00007f873753cbc0(0000) GS:ffff88806bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff8881178d8cc3 CR3: 00000000181ca000 CR4: 0000000000750ef0 PKRU: 55555554 Call Trace: <TASK> ? __die+0x23/0x70 ? page_fault_oops+0x181/0x480 ? search_module_extables+0x19/0x60 ? srso_alias_return_thunk+0x5/0xfbef5 ? exc_page_fault+0x1b6/0x1c0 ? asm_exc_page_fault+0x26/0x30 ? smb2_parse_contexts+0xa0/0x3a0 [cifs] SMB2_open+0x38d/0x5f0 [cifs] ? smb2_is_path_accessible+0x138/0x260 [cifs] smb2_is_path_accessible+0x138/0x260 [cifs] cifs_is_path_remote+0x8d/0x230 [cifs] cifs_mount+0x7e/0x350 [cifs] cifs_smb3_do_mount+0x128/0x780 [cifs] smb3_get_tree+0xd9/0x290 [cifs] vfs_get_tree+0x2c/0x100 ? capable+0x37/0x70 path_mount+0x2d7/0xb80 ? srso_alias_return_thunk+0x5/0xfbef5 ? _raw_spin_unlock_irqrestore+0x44/0x60 __x64_sys_mount+0x11a/0x150 do_syscall_64+0x47/0xf0 entry_SYSCALL_64_after_hwframe+0x6f/0x77 RIP: 0033:0x7f8737657b1e Reported-by: Robert Morris <rtm@csail.mit.edu> Cc: stable@vger.kernel.org Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Paulo Alcantara
Steve French
parent
eec04ea119
commit
af1689a9b7
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@ -291,16 +291,23 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
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oparms.fid->mid = le64_to_cpu(o_rsp->hdr.MessageId);
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#endif /* CIFS_DEBUG2 */
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rc = -EINVAL;
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if (o_rsp->OplockLevel != SMB2_OPLOCK_LEVEL_LEASE) {
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spin_unlock(&cfids->cfid_list_lock);
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rc = -EINVAL;
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goto oshr_free;
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}
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rc = smb2_parse_contexts(server, rsp_iov,
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&oparms.fid->epoch,
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oparms.fid->lease_key,
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&oplock, NULL, NULL);
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if (rc) {
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spin_unlock(&cfids->cfid_list_lock);
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goto oshr_free;
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}
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smb2_parse_contexts(server, o_rsp,
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&oparms.fid->epoch,
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oparms.fid->lease_key, &oplock,
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NULL, NULL);
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rc = -EINVAL;
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if (!(oplock & SMB2_LEASE_READ_CACHING_HE)) {
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spin_unlock(&cfids->cfid_list_lock);
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goto oshr_free;
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@ -2236,17 +2236,18 @@ parse_posix_ctxt(struct create_context *cc, struct smb2_file_all_info *info,
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posix->nlink, posix->mode, posix->reparse_tag);
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}
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void
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smb2_parse_contexts(struct TCP_Server_Info *server,
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struct smb2_create_rsp *rsp,
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unsigned int *epoch, char *lease_key, __u8 *oplock,
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struct smb2_file_all_info *buf,
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struct create_posix_rsp *posix)
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int smb2_parse_contexts(struct TCP_Server_Info *server,
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struct kvec *rsp_iov,
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unsigned int *epoch,
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char *lease_key, __u8 *oplock,
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struct smb2_file_all_info *buf,
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struct create_posix_rsp *posix)
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{
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char *data_offset;
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struct smb2_create_rsp *rsp = rsp_iov->iov_base;
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struct create_context *cc;
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unsigned int next;
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unsigned int remaining;
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size_t rem, off, len;
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size_t doff, dlen;
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size_t noff, nlen;
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char *name;
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static const char smb3_create_tag_posix[] = {
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0x93, 0xAD, 0x25, 0x50, 0x9C,
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@ -2255,45 +2256,63 @@ smb2_parse_contexts(struct TCP_Server_Info *server,
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};
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*oplock = 0;
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data_offset = (char *)rsp + le32_to_cpu(rsp->CreateContextsOffset);
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remaining = le32_to_cpu(rsp->CreateContextsLength);
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cc = (struct create_context *)data_offset;
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off = le32_to_cpu(rsp->CreateContextsOffset);
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rem = le32_to_cpu(rsp->CreateContextsLength);
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if (check_add_overflow(off, rem, &len) || len > rsp_iov->iov_len)
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return -EINVAL;
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cc = (struct create_context *)((u8 *)rsp + off);
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/* Initialize inode number to 0 in case no valid data in qfid context */
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if (buf)
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buf->IndexNumber = 0;
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while (remaining >= sizeof(struct create_context)) {
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name = le16_to_cpu(cc->NameOffset) + (char *)cc;
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if (le16_to_cpu(cc->NameLength) == 4 &&
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strncmp(name, SMB2_CREATE_REQUEST_LEASE, 4) == 0)
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*oplock = server->ops->parse_lease_buf(cc, epoch,
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lease_key);
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else if (buf && (le16_to_cpu(cc->NameLength) == 4) &&
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strncmp(name, SMB2_CREATE_QUERY_ON_DISK_ID, 4) == 0)
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parse_query_id_ctxt(cc, buf);
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else if ((le16_to_cpu(cc->NameLength) == 16)) {
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if (posix &&
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memcmp(name, smb3_create_tag_posix, 16) == 0)
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parse_posix_ctxt(cc, buf, posix);
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}
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/* else {
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cifs_dbg(FYI, "Context not matched with len %d\n",
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le16_to_cpu(cc->NameLength));
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cifs_dump_mem("Cctxt name: ", name, 4);
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} */
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while (rem >= sizeof(*cc)) {
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doff = le16_to_cpu(cc->DataOffset);
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dlen = le32_to_cpu(cc->DataLength);
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if (check_add_overflow(doff, dlen, &len) || len > rem)
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return -EINVAL;
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next = le32_to_cpu(cc->Next);
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if (!next)
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noff = le16_to_cpu(cc->NameOffset);
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nlen = le16_to_cpu(cc->NameLength);
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if (noff + nlen >= doff)
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return -EINVAL;
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name = (char *)cc + noff;
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switch (nlen) {
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case 4:
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if (!strncmp(name, SMB2_CREATE_REQUEST_LEASE, 4)) {
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*oplock = server->ops->parse_lease_buf(cc, epoch,
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lease_key);
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} else if (buf &&
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!strncmp(name, SMB2_CREATE_QUERY_ON_DISK_ID, 4)) {
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parse_query_id_ctxt(cc, buf);
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}
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break;
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remaining -= next;
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cc = (struct create_context *)((char *)cc + next);
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case 16:
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if (posix && !memcmp(name, smb3_create_tag_posix, 16))
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parse_posix_ctxt(cc, buf, posix);
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break;
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default:
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cifs_dbg(FYI, "%s: unhandled context (nlen=%zu dlen=%zu)\n",
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__func__, nlen, dlen);
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if (IS_ENABLED(CONFIG_CIFS_DEBUG2))
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cifs_dump_mem("context data: ", cc, dlen);
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break;
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}
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off = le32_to_cpu(cc->Next);
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if (!off)
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break;
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if (check_sub_overflow(rem, off, &rem))
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return -EINVAL;
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cc = (struct create_context *)((u8 *)cc + off);
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}
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if (rsp->OplockLevel != SMB2_OPLOCK_LEVEL_LEASE)
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*oplock = rsp->OplockLevel;
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return;
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return 0;
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}
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static int
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@ -3124,8 +3143,8 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
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}
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smb2_parse_contexts(server, rsp, &oparms->fid->epoch,
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oparms->fid->lease_key, oplock, buf, posix);
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rc = smb2_parse_contexts(server, &rsp_iov, &oparms->fid->epoch,
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oparms->fid->lease_key, oplock, buf, posix);
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creat_exit:
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SMB2_open_free(&rqst);
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free_rsp_buf(resp_buftype, rsp);
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@ -251,11 +251,13 @@ extern int smb3_validate_negotiate(const unsigned int, struct cifs_tcon *);
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extern enum securityEnum smb2_select_sectype(struct TCP_Server_Info *,
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enum securityEnum);
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extern void smb2_parse_contexts(struct TCP_Server_Info *server,
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struct smb2_create_rsp *rsp,
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unsigned int *epoch, char *lease_key,
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__u8 *oplock, struct smb2_file_all_info *buf,
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struct create_posix_rsp *posix);
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int smb2_parse_contexts(struct TCP_Server_Info *server,
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struct kvec *rsp_iov,
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unsigned int *epoch,
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char *lease_key, __u8 *oplock,
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struct smb2_file_all_info *buf,
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struct create_posix_rsp *posix);
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extern int smb3_encryption_required(const struct cifs_tcon *tcon);
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extern int smb2_validate_iov(unsigned int offset, unsigned int buffer_length,
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struct kvec *iov, unsigned int min_buf_size);
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