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cifs: fix crash in smb2_compound_op()/smb2_set_next_command() 

RHBZ: 1722704

In low memory situations the various SMB2_*_init() functions can fail
to allocate a request PDU and thus leave the request iovector as NULL.

If we don't check the return code for failure we end up calling
smb2_set_next_command() with a NULL iovector causing a crash when it tries
to dereference it.

CC: Stable <stable@vger.kernel.org>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Ronnie Sahlberg 2019-07-16 10:41:46 +10:00 committed by Steve French
parent ce465bf94b
commit 88a92c913c
2 changed files with 22 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
fs/cifs/smb2inode.c
View File

@ -120,6 +120,8 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
SMB2_O_INFO_FILE, 0,
sizeof(struct smb2_file_all_info) +
PATH_MAX * 2, 0, NULL);
if (rc)
goto finished;
smb2_set_next_command(tcon, &rqst[num_rqst]);
smb2_set_related(&rqst[num_rqst++]);
trace_smb3_query_info_compound_enter(xid, ses->Suid, tcon->tid,
@ -147,6 +149,8 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
COMPOUND_FID, current->tgid,
FILE_DISPOSITION_INFORMATION,
SMB2_O_INFO_FILE, 0, data, size);
if (rc)
goto finished;
smb2_set_next_command(tcon, &rqst[num_rqst]);
smb2_set_related(&rqst[num_rqst++]);
trace_smb3_rmdir_enter(xid, ses->Suid, tcon->tid, full_path);
@ -163,6 +167,8 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
COMPOUND_FID, current->tgid,
FILE_END_OF_FILE_INFORMATION,
SMB2_O_INFO_FILE, 0, data, size);
if (rc)
goto finished;
smb2_set_next_command(tcon, &rqst[num_rqst]);
smb2_set_related(&rqst[num_rqst++]);
trace_smb3_set_eof_enter(xid, ses->Suid, tcon->tid, full_path);
@ -180,6 +186,8 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
COMPOUND_FID, current->tgid,
FILE_BASIC_INFORMATION,
SMB2_O_INFO_FILE, 0, data, size);
if (rc)
goto finished;
smb2_set_next_command(tcon, &rqst[num_rqst]);
smb2_set_related(&rqst[num_rqst++]);
trace_smb3_set_info_compound_enter(xid, ses->Suid, tcon->tid,
@ -206,6 +214,8 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
COMPOUND_FID, current->tgid,
FILE_RENAME_INFORMATION,
SMB2_O_INFO_FILE, 0, data, size);
if (rc)
goto finished;
smb2_set_next_command(tcon, &rqst[num_rqst]);
smb2_set_related(&rqst[num_rqst++]);
trace_smb3_rename_enter(xid, ses->Suid, tcon->tid, full_path);
@ -231,6 +241,8 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
COMPOUND_FID, current->tgid,
FILE_LINK_INFORMATION,
SMB2_O_INFO_FILE, 0, data, size);
if (rc)
goto finished;
smb2_set_next_command(tcon, &rqst[num_rqst]);
smb2_set_related(&rqst[num_rqst++]);
trace_smb3_hardlink_enter(xid, ses->Suid, tcon->tid, full_path);

11
fs/cifs/smb2ops.c
View File

@ -2027,6 +2027,10 @@ smb2_set_related(struct smb_rqst *rqst)
struct smb2_sync_hdr *shdr;
shdr = (struct smb2_sync_hdr *)(rqst->rq_iov[0].iov_base);
if (shdr == NULL) {
cifs_dbg(FYI, "shdr NULL in smb2_set_related\n");
return;
}
shdr->Flags |= SMB2_FLAGS_RELATED_OPERATIONS;
}
@ -2041,6 +2045,12 @@ smb2_set_next_command(struct cifs_tcon *tcon, struct smb_rqst *rqst)
unsigned long len = smb_rqst_len(server, rqst);
int i, num_padding;
shdr = (struct smb2_sync_hdr *)(rqst->rq_iov[0].iov_base);
if (shdr == NULL) {
cifs_dbg(FYI, "shdr NULL in smb2_set_next_command\n");
return;
}
/* SMB headers in a compound are 8 byte aligned. */
/* No padding needed */
@ -2080,7 +2090,6 @@ smb2_set_next_command(struct cifs_tcon *tcon, struct smb_rqst *rqst)
}
finished:
shdr = (struct smb2_sync_hdr *)(rqst->rq_iov[0].iov_base);
shdr->NextCommand = cpu_to_le32(len);
}