diff options
| -rw-r--r-- | fs/smb/client/smb2misc.c | 34 |
1 files changed, 25 insertions, 9 deletions
diff --git a/fs/smb/client/smb2misc.c b/fs/smb/client/smb2misc.c index 6270b33147d2..9068175e57cd 100644 --- a/fs/smb/client/smb2misc.c +++ b/fs/smb/client/smb2misc.c @@ -19,7 +19,8 @@ #include "nterr.h" #include "cached_dir.h" -static unsigned int __smb2_calc_size(void *buf, bool *have_data); +static unsigned int __smb2_calc_size(void *buf, bool *have_data, + bool *data_area_overlap); static int check_smb2_hdr(struct smb2_hdr *shdr, __u64 mid) @@ -148,6 +149,7 @@ smb2_check_message(char *buf, unsigned int pdu_len, unsigned int len, __u32 calc_len; /* calculated length */ __u64 mid; bool have_data; + bool data_area_overlap; /* If server is a channel, select the primary channel */ pserver = SERVER_IS_CHAN(server) ? server->primary_server : server; @@ -232,7 +234,12 @@ smb2_check_message(char *buf, unsigned int pdu_len, unsigned int len, } have_data = false; - calc_len = __smb2_calc_size(buf, &have_data); + data_area_overlap = false; + calc_len = __smb2_calc_size(buf, &have_data, &data_area_overlap); + + /* Reject responses whose data area overlaps the fixed area. */ + if (data_area_overlap) + return 1; /* For SMB2_IOCTL, OutputOffset and OutputLength are optional, so might * be 0, and not a real miscalculation */ @@ -416,14 +423,15 @@ smb2_get_data_area_len(int *off, int *len, struct smb2_hdr *shdr) } /* - * Calculate the size of the SMB message based on the fixed header - * portion, the number of word parameters and the data portion of the message. - * If have_data is non-NULL, it is set to true when a non-empty data area was - * found (data_length > 0), allowing callers to distinguish the implied bcc[0] - * case (no data area) from an overreported data length. + * Calculate the size of the SMB message based on the fixed header, fixed + * parameter area, and variable data area. + * + * If have_data is not NULL, it is set when a non-empty data area is found. + * If data_area_overlap is not NULL, it is set when the data area overlaps + * the fixed area. */ static unsigned int -__smb2_calc_size(void *buf, bool *have_data) +__smb2_calc_size(void *buf, bool *have_data, bool *data_area_overlap) { struct smb2_pdu *pdu = buf; struct smb2_hdr *shdr = &pdu->hdr; @@ -432,6 +440,11 @@ __smb2_calc_size(void *buf, bool *have_data) /* Structure Size has already been checked to make sure it is 64 */ int len = le16_to_cpu(shdr->StructureSize); + if (have_data) + *have_data = false; + if (data_area_overlap) + *data_area_overlap = false; + /* * StructureSize2, ie length of fixed parameter area has already * been checked to make sure it is the correct length. @@ -454,7 +467,10 @@ __smb2_calc_size(void *buf, bool *have_data) if (offset + 1 < len) { cifs_dbg(VFS, "data area offset %d overlaps SMB2 header %d\n", offset + 1, len); + if (data_area_overlap) + *data_area_overlap = true; data_length = 0; + goto calc_size_exit; } else { len = offset + data_length; } @@ -469,7 +485,7 @@ calc_size_exit: unsigned int smb2_calc_size(void *buf) { - return __smb2_calc_size(buf, NULL); + return __smb2_calc_size(buf, NULL, NULL); } /* Note: caller must free return buffer */ |