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smb: client: fix "df: Resource temporarily unavailable" on 5.15 stable kernel

PATCH New [email protected] 1 participant 2 messages Feb 6, 2024

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#0 lore raw

cover smb: client: fix "df: Resource temporarily unavailable" on 5.15 stable kernel

ATTENTION!
Before applying this patch a conflict patch in the queue needs to be removed:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/tree/queue-5.15/cifs-fix-off-by-one-in-smb2_query_info_init.patch

Describe bug:
After mounting a remote cifs resource, it becomes unavailable:
df: /mnt/sambashare: Resource temporarily unavailable It was tested on the following Linux kernel:
Linux altlinux 5.15.148

The error appeared starting from kernel 5.15.147 after adding the commit [1] "smb: client: fix OOB in SMB2_query_info_init()", in which the buffer length increases by 1 as a result of changes:
.
- iov[0].iov_len = total_len - 1 + input_len;
+ iov[0].iov_len = len;
.

[1] https://patchwork.kernel.org/project/cifs-client/patch/[email protected]/

Error fixed by backported commit in next patch adapted for the 5.15 kernel:
[PATCH 5.15.y 1/1] smb3: Replace smb2pdu 1-element arrays with flex-arrays

P.S.
I have already backported similar changes for the 5.10.y kernel [2], but I did not know that there was the same error on 5.15,
since I only deal with kernels 5.10 and 6.1.
Therefore, this patch is to follow the rules of backport to stable branches.

[2] https://lore.kernel.org/all/2024012613-woozy-exhume-7b9d@gregkh/T/

#1 lore raw

PATCH 1/1 smb3: Replace smb2pdu 1-element arrays with flex-arrays

From: Kees Cook <[email protected]>

commit eb3e28c1e89b4984308777231887e41aa8a0151f upstream.

The kernel is globally removing the ambiguous 0-length and 1-element arrays in favor of flexible arrays, so that we can gain both compile-time and run-time array bounds checking[1].

Replace the trailing 1-element array with a flexible array in the following structures:

struct smb2_err_rsp
struct smb2_tree_connect_req
struct smb2_negotiate_rsp
struct smb2_sess_setup_req
struct smb2_sess_setup_rsp
struct smb2_read_req
struct smb2_read_rsp
struct smb2_write_req
struct smb2_write_rsp
struct smb2_query_directory_req
struct smb2_query_directory_rsp
struct smb2_set_info_req
struct smb2_change_notify_rsp
struct smb2_create_rsp
struct smb2_query_info_req
struct smb2_query_info_rsp

Replace the trailing 1-element array with a flexible array, but leave the existing structure padding:

struct smb2_file_all_info
struct smb2_lock_req

Adjust all related size calculations to match the changes to sizeof().

No machine code output or .data section differences are produced after these changes.

[1] For lots of details, see both:
https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays
https://people.kernel.org/kees/bounded-flexible-arrays-in-c

Cc Steve French <[email protected]>
Cc Paulo Alcantara <[email protected]>
Cc Ronnie Sahlberg <[email protected]>
Cc Shyam Prasad N <[email protected]>
Cc Tom Talpey <[email protected]>
Cc Namjae Jeon <[email protected]>
Cc Sergey Senozhatsky <[email protected]>
---
 fs/cifs/smb2misc.c |  2 +-
 fs/cifs/smb2ops.c  | 14 +++++++-------
 fs/cifs/smb2pdu.c  | 13 ++++++-------
 fs/cifs/smb2pdu.h  | 42 ++++++++++++++++++++++++------------------
 4 files changed, 38 insertions(+), 33 deletions(-)
fs/cifs/smb2misc.c +1 -1
index e2f401c8c5ce71..8f409404aee1e2 100644
@@ -113,7 +113,7 @@ static __u32 get_neg_ctxt_len(struct smb2_sync_hdr *hdr, __u32 len,
 	} else if (nc_offset + 1 == non_ctxlen) {
 		cifs_dbg(FYI, "no SPNEGO security blob in negprot rsp\n");
 		size_of_pad_before_neg_ctxts = 0;
-	} else if (non_ctxlen == SMB311_NEGPROT_BASE_SIZE)
+	} else if (non_ctxlen == SMB311_NEGPROT_BASE_SIZE + 1)
 		/* has padding, but no SPNEGO blob */
 		size_of_pad_before_neg_ctxts = nc_offset - non_ctxlen + 1;
 	else
fs/cifs/smb2ops.c +7 -7
index f31da2647d042c..f8847546d6ac95 100644
@@ -5826,7 +5826,7 @@ struct smb_version_values smb20_values = {
 	.header_size = sizeof(struct smb2_sync_hdr),
 	.header_preamble_size = 0,
 	.max_header_size = MAX_SMB2_HDR_SIZE,
-	.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
+	.read_rsp_size = sizeof(struct smb2_read_rsp),
 	.lock_cmd = SMB2_LOCK,
 	.cap_unix = 0,
 	.cap_nt_find = SMB2_NT_FIND,
@@ -5848,7 +5848,7 @@ struct smb_version_values smb21_values = {
 	.header_size = sizeof(struct smb2_sync_hdr),
 	.header_preamble_size = 0,
 	.max_header_size = MAX_SMB2_HDR_SIZE,
-	.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
+	.read_rsp_size = sizeof(struct smb2_read_rsp),
 	.lock_cmd = SMB2_LOCK,
 	.cap_unix = 0,
 	.cap_nt_find = SMB2_NT_FIND,
@@ -5869,7 +5869,7 @@ struct smb_version_values smb3any_values = {
 	.header_size = sizeof(struct smb2_sync_hdr),
 	.header_preamble_size = 0,
 	.max_header_size = MAX_SMB2_HDR_SIZE,
-	.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
+	.read_rsp_size = sizeof(struct smb2_read_rsp),
 	.lock_cmd = SMB2_LOCK,
 	.cap_unix = 0,
 	.cap_nt_find = SMB2_NT_FIND,
@@ -5890,7 +5890,7 @@ struct smb_version_values smbdefault_values = {
 	.header_size = sizeof(struct smb2_sync_hdr),
 	.header_preamble_size = 0,
 	.max_header_size = MAX_SMB2_HDR_SIZE,
-	.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
+	.read_rsp_size = sizeof(struct smb2_read_rsp),
 	.lock_cmd = SMB2_LOCK,
 	.cap_unix = 0,
 	.cap_nt_find = SMB2_NT_FIND,
@@ -5911,7 +5911,7 @@ struct smb_version_values smb30_values = {
 	.header_size = sizeof(struct smb2_sync_hdr),
 	.header_preamble_size = 0,
 	.max_header_size = MAX_SMB2_HDR_SIZE,
-	.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
+	.read_rsp_size = sizeof(struct smb2_read_rsp),
 	.lock_cmd = SMB2_LOCK,
 	.cap_unix = 0,
 	.cap_nt_find = SMB2_NT_FIND,
@@ -5932,7 +5932,7 @@ struct smb_version_values smb302_values = {
 	.header_size = sizeof(struct smb2_sync_hdr),
 	.header_preamble_size = 0,
 	.max_header_size = MAX_SMB2_HDR_SIZE,
-	.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
+	.read_rsp_size = sizeof(struct smb2_read_rsp),
 	.lock_cmd = SMB2_LOCK,
 	.cap_unix = 0,
 	.cap_nt_find = SMB2_NT_FIND,
@@ -5953,7 +5953,7 @@ struct smb_version_values smb311_values = {
 	.header_size = sizeof(struct smb2_sync_hdr),
 	.header_preamble_size = 0,
 	.max_header_size = MAX_SMB2_HDR_SIZE,
-	.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
+	.read_rsp_size = sizeof(struct smb2_read_rsp),
 	.lock_cmd = SMB2_LOCK,
 	.cap_unix = 0,
 	.cap_nt_find = SMB2_NT_FIND,
fs/cifs/smb2pdu.c +6 -7
index 6714e9db0ee837..a21eeb23f8e1c0 100644
@@ -1327,7 +1327,7 @@ SMB2_sess_sendreceive(struct SMB2_sess_data *sess_data)
 
 	/* Testing shows that buffer offset must be at location of Buffer[0] */
 	req->SecurityBufferOffset =
-		cpu_to_le16(sizeof(struct smb2_sess_setup_req) - 1 /* pad */);
+		cpu_to_le16(sizeof(struct smb2_sess_setup_req));
 	req->SecurityBufferLength = cpu_to_le16(sess_data->iov[1].iov_len);
 
 	memset(&rqst, 0, sizeof(struct smb_rqst));
@@ -1826,8 +1826,7 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
 	iov[0].iov_len = total_len - 1;
 
 	/* Testing shows that buffer offset must be at location of Buffer[0] */
-	req->PathOffset = cpu_to_le16(sizeof(struct smb2_tree_connect_req)
-			- 1 /* pad */);
+	req->PathOffset = cpu_to_le16(sizeof(struct smb2_tree_connect_req));
 	req->PathLength = cpu_to_le16(unc_path_len - 2);
 	iov[1].iov_base = unc_path;
 	iov[1].iov_len = unc_path_len;
@@ -4748,7 +4747,7 @@ int SMB2_query_directory_init(const unsigned int xid,
 	memcpy(bufptr, &asteriks, len);
 
 	req->FileNameOffset =
-		cpu_to_le16(sizeof(struct smb2_query_directory_req) - 1);
+		cpu_to_le16(sizeof(struct smb2_query_directory_req));
 	req->FileNameLength = cpu_to_le16(len);
 	/*
 	 * BB could be 30 bytes or so longer if we used SMB2 specific
@@ -4945,7 +4944,7 @@ SMB2_set_info_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
 	req->AdditionalInformation = cpu_to_le32(additional_info);
 
 	req->BufferOffset =
-			cpu_to_le16(sizeof(struct smb2_set_info_req) - 1);
+			cpu_to_le16(sizeof(struct smb2_set_info_req));
 	req->BufferLength = cpu_to_le32(*size);
 
 	memcpy(req->Buffer, *data, *size);
@@ -5177,9 +5176,9 @@ build_qfs_info_req(struct kvec *iov, struct cifs_tcon *tcon,
 	req->VolatileFileId = volatile_fid;
 	/* 1 for pad */
 	req->InputBufferOffset =
-			cpu_to_le16(sizeof(struct smb2_query_info_req) - 1);
+			cpu_to_le16(sizeof(struct smb2_query_info_req));
 	req->OutputBufferLength = cpu_to_le32(
-		outbuf_len + sizeof(struct smb2_query_info_rsp) - 1);
+		outbuf_len + sizeof(struct smb2_query_info_rsp));
 
 	iov->iov_base = (char *)req;
 	iov->iov_len = total_len;
fs/cifs/smb2pdu.h +24 -18

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