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authorRonnie Sahlberg <lsahlber@redhat.com>2019-07-09 18:41:11 +1000
committerSteve French <stfrench@microsoft.com>2019-07-10 16:15:45 -0500
commitdf070afd9b8c952eacf49db54cae7138eb9deaeb (patch)
tree537e6118629e984ee62764f450abe0bf66738f3b
parentf5f111c231f56e56e186c9a61a9d22fb8bf05faa (diff)
cifs: fix parsing of symbolic link error response
RHBZ: 1672539 In smb2_query_symlink(), if we are parsing the error buffer but it is not something we recognize as a symlink we should return -EINVAL and not -ENOENT. I.e. the entry does exist, it is just not something we recognize. Additionally, add check to verify that that the errortag and the reparsetag all make sense. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Acked-by: Paulo Alcantara <palcantara@suse.de> Signed-off-by: Steve French <stfrench@microsoft.com>
-rw-r--r--fs/cifs/smb2ops.c14
-rw-r--r--fs/cifs/smb2pdu.h2
2 files changed, 12 insertions, 4 deletions
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 4b0b14946343..e704e04891fb 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -2605,26 +2605,32 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
err_buf = err_iov.iov_base;
if (le32_to_cpu(err_buf->ByteCount) < sizeof(struct smb2_symlink_err_rsp) ||
err_iov.iov_len < SMB2_SYMLINK_STRUCT_SIZE) {
- rc = -ENOENT;
+ rc = -EINVAL;
+ goto querty_exit;
+ }
+
+ symlink = (struct smb2_symlink_err_rsp *)err_buf->ErrorData;
+ if (le32_to_cpu(symlink->SymLinkErrorTag) != SYMLINK_ERROR_TAG ||
+ le32_to_cpu(symlink->ReparseTag) != IO_REPARSE_TAG_SYMLINK) {
+ rc = -EINVAL;
goto querty_exit;
}
/* open must fail on symlink - reset rc */
rc = 0;
- symlink = (struct smb2_symlink_err_rsp *)err_buf->ErrorData;
sub_len = le16_to_cpu(symlink->SubstituteNameLength);
sub_offset = le16_to_cpu(symlink->SubstituteNameOffset);
print_len = le16_to_cpu(symlink->PrintNameLength);
print_offset = le16_to_cpu(symlink->PrintNameOffset);
if (err_iov.iov_len < SMB2_SYMLINK_STRUCT_SIZE + sub_offset + sub_len) {
- rc = -ENOENT;
+ rc = -EINVAL;
goto querty_exit;
}
if (err_iov.iov_len <
SMB2_SYMLINK_STRUCT_SIZE + print_offset + print_len) {
- rc = -ENOENT;
+ rc = -EINVAL;
goto querty_exit;
}
diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index 458bad01ca74..7e2e782f8edd 100644
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -166,6 +166,8 @@ struct smb2_err_rsp {
__u8 ErrorData[1]; /* variable length */
} __packed;
+#define SYMLINK_ERROR_TAG 0x4c4d5953
+
struct smb2_symlink_err_rsp {
__le32 SymLinkLength;
__le32 SymLinkErrorTag;