SMB3 servers can respond with MaxTransactSize of more than 4M that can cause a memory allocation error returned from kmalloc in a lock codepath. Also the client doesn't support multicredit requests now and allows buffer sizes of 65536 bytes only. Set MaxTransactSize to this maximum supported value.
Cc: [email protected] # 3.7+ Signed-off-by: Pavel Shilovsky <[email protected]> --- fs/cifs/smb2glob.h | 3 +++ fs/cifs/smb2ops.c | 14 ++++---------- fs/cifs/smb2pdu.c | 4 +++- 3 files changed, 10 insertions(+), 11 deletions(-) diff --git a/fs/cifs/smb2glob.h b/fs/cifs/smb2glob.h index c383508..bc0bb9c 100644 --- a/fs/cifs/smb2glob.h +++ b/fs/cifs/smb2glob.h @@ -57,4 +57,7 @@ #define SMB2_CMACAES_SIZE (16) #define SMB3_SIGNKEY_SIZE (16) +/* Maximum buffer size value we can send with 1 credit */ +#define SMB2_MAX_BUFFER_SIZE 65536 + #endif /* _SMB2_GLOB_H */ diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 757da3e..192f51a 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -182,11 +182,8 @@ smb2_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *volume_info) /* start with specified wsize, or default */ wsize = volume_info->wsize ? volume_info->wsize : CIFS_DEFAULT_IOSIZE; wsize = min_t(unsigned int, wsize, server->max_write); - /* - * limit write size to 2 ** 16, because we don't support multicredit - * requests now. - */ - wsize = min_t(unsigned int, wsize, 2 << 15); + /* set it to the maximum buffer size value we can send with 1 credit */ + wsize = min_t(unsigned int, wsize, SMB2_MAX_BUFFER_SIZE); return wsize; } @@ -200,11 +197,8 @@ smb2_negotiate_rsize(struct cifs_tcon *tcon, struct smb_vol *volume_info) /* start with specified rsize, or default */ rsize = volume_info->rsize ? volume_info->rsize : CIFS_DEFAULT_IOSIZE; rsize = min_t(unsigned int, rsize, server->max_read); - /* - * limit write size to 2 ** 16, because we don't support multicredit - * requests now. - */ - rsize = min_t(unsigned int, rsize, 2 << 15); + /* set it to the maximum buffer size value we can send with 1 credit */ + rsize = min_t(unsigned int, rsize, SMB2_MAX_BUFFER_SIZE); return rsize; } diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 2013234..787e171 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -413,7 +413,9 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses) /* SMB2 only has an extended negflavor */ server->negflavor = CIFS_NEGFLAVOR_EXTENDED; - server->maxBuf = le32_to_cpu(rsp->MaxTransactSize); + /* set it to the maximum buffer size value we can send with 1 credit */ + server->maxBuf = min_t(unsigned int, le32_to_cpu(rsp->MaxTransactSize), + SMB2_MAX_BUFFER_SIZE); server->max_read = le32_to_cpu(rsp->MaxReadSize); server->max_write = le32_to_cpu(rsp->MaxWriteSize); /* BB Do we need to validate the SecurityMode? */ -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
