From: Pavel Shilovsky pshilov@microsoft.com
[ Upstream commit 3edeb4a4146dc3b54d6fa71b7ee0585cb52ebfdf ]
When a reconnect happens in the middle of processing a compound chain the code leaks a buffer from the memory pool. Fix this by properly checking for a return code and freeing buffers in case of error.
Also maintain a buf variable to be equal to either smallbuf or bigbuf depending on a response buffer size while parsing a chain and when returning to the caller.
Signed-off-by: Pavel Shilovsky pshilov@microsoft.com Reviewed-by: Ronnie Sahlberg lsahlber@redhat.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/cifs/smb2ops.c | 29 +++++++++++++++++------------ 1 file changed, 17 insertions(+), 12 deletions(-)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 0ccf8f9b63a2e..97fdbec54db97 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -3121,7 +3121,6 @@ receive_encrypted_standard(struct TCP_Server_Info *server, { int ret, length; char *buf = server->smallbuf; - char *tmpbuf; struct smb2_sync_hdr *shdr; unsigned int pdu_length = server->pdu_size; unsigned int buf_size; @@ -3151,18 +3150,15 @@ receive_encrypted_standard(struct TCP_Server_Info *server, return length;
next_is_large = server->large_buf; - one_more: +one_more: shdr = (struct smb2_sync_hdr *)buf; if (shdr->NextCommand) { - if (next_is_large) { - tmpbuf = server->bigbuf; + if (next_is_large) next_buffer = (char *)cifs_buf_get(); - } else { - tmpbuf = server->smallbuf; + else next_buffer = (char *)cifs_small_buf_get(); - } memcpy(next_buffer, - tmpbuf + le32_to_cpu(shdr->NextCommand), + buf + le32_to_cpu(shdr->NextCommand), pdu_length - le32_to_cpu(shdr->NextCommand)); }
@@ -3191,12 +3187,21 @@ receive_encrypted_standard(struct TCP_Server_Info *server, pdu_length -= le32_to_cpu(shdr->NextCommand); server->large_buf = next_is_large; if (next_is_large) - server->bigbuf = next_buffer; + server->bigbuf = buf = next_buffer; else - server->smallbuf = next_buffer; - - buf += le32_to_cpu(shdr->NextCommand); + server->smallbuf = buf = next_buffer; goto one_more; + } else if (ret != 0) { + /* + * ret != 0 here means that we didn't get to handle_mid() thus + * server->smallbuf and server->bigbuf are still valid. We need + * to free next_buffer because it is not going to be used + * anywhere. + */ + if (next_is_large) + free_rsp_buf(CIFS_LARGE_BUFFER, next_buffer); + else + free_rsp_buf(CIFS_SMALL_BUFFER, next_buffer); }
return ret;