create_flow/destroy_flow fixes for v3.13

Currently, INIT_UDATA() does an implicit cast to a pointer, so that 'response' address, eg. output buffer, can be used as is to initialize a struct ib_udata:

         do {                                                    \
                 (udata)->inbuf  = (void __user *) (ibuf);       \
                 (udata)->outbuf = (void __user *) (obuf);       \
                 (udata)->inlen  = (ilen);                       \
                 (udata)->outlen = (olen);                       \
         } while (0)

...

INIT_UDATA(&udata, buf + sizeof cmd,
(unsigned long) cmd.response + sizeof resp, in_len - sizeof cmd, out_len - sizeof resp);

...

Hidding the integer to pointer conversion is prone to error that won't be catched by compiler/static analyzer is some case.

In the other hand, sparse reports an error if literal 0 is used to initialize inbuf or outbuf, for example in:

         INIT_UDATA(&ucore,
                    (hdr.in_words) ? buf : 0,
                    (unsigned long)ex_hdr.response,
                    hdr.in_words * 8,
                    hdr.out_words * 8);

It was reported by kbuild test robot in message[1]:

From: kbuild test robot <[email protected]>
Subject: "drivers/infiniband/core/uverbs_main.c:683:17:
sparse: Using plain integer as NULL pointer",
Message-Id: <528b3984.SVGs20ZWpcuR/Jls%[email protected]>

This patch fixes the warnings reported by sparse and allows the compiler to report a warning in case a plain integer get used to initialize a udata pointer.

This patch requires struct ib_udata to be modified to have a const void __user *inbuf field[2], otherwise compiler will report warnings regarding const to non const conversion:

drivers/infiniband/core/uverbs_main.c: In function ‘ib_uverbs_write’:
drivers/infiniband/core/uverbs_main.c:682:24: attention : assignment discards ‘const’ qualifier from pointer target type [enabled by default] drivers/infiniband/core/uverbs_main.c:688:22: attention : assignment discards ‘const’ qualifier from pointer target type [enabled by default] drivers/infiniband/core/uverbs_cmd.c: In function ‘ib_uverbs_get_context’:
drivers/infiniband/core/uverbs_cmd.c:307:23: attention : assignment discards ‘const’ qualifier from pointer target type [enabled by default] drivers/infiniband/core/uverbs_cmd.c: In function ‘ib_uverbs_alloc_pd’:
drivers/infiniband/core/uverbs_cmd.c:516:23: attention : assignment discards ‘const’ qualifier from pointer target type [enabled by default]
...

[1] https://lists.01.org/pipermail/kbuild-all/2013-November/002120.html

[2] https://patchwork.kernel.org/patch/2846202/

     http://marc.info/?i=3050a98379b4342ea59d59aeaf1ce162171df928.1376847403.git.ydroneaud-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org

Link http://marc.info/?i=cover.1385501822.git.ydroneaud-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org

Signed-off-by Yann Droneaud <[email protected]>

---
  drivers/infiniband/core/uverbs.h      | 12 ++++++------
  drivers/infiniband/core/uverbs_cmd.c  | 20 ++++++++++----------
  drivers/infiniband/core/uverbs_main.c | 13 ++++++++-----
  3 files changed, 24 insertions(+), 21 deletions(-)

drivers/infiniband/core/uverbs.h +6 -6

index 9879568aed8c..0dca1975d59d 100644
@@ -47,12 +47,12 @@
  #include <rdma/ib_umem.h>
  #include <rdma/ib_user_verbs.h>
 
-#define INIT_UDATA(udata, ibuf, obuf, ilen, olen)			\
-	do {								\
-		(udata)->inbuf  = (const void __user *) (ibuf);		\
-		(udata)->outbuf = (void __user *) (obuf);		\
-		(udata)->inlen  = (ilen);				\
-		(udata)->outlen = (olen);				\
+#define INIT_UDATA(udata, ibuf, obuf, ilen, olen)	\
+	do {						\
+		(udata)->inbuf  = (ibuf);		\
+		(udata)->outbuf = (obuf);		\
+		(udata)->inlen  = (ilen);		\
+		(udata)->outlen = (olen);		\
  	} while (0)
 
  /*

drivers/infiniband/core/uverbs_cmd.c +0 -0

index 65f6e7dc380c..d9d91c412628 100644

drivers/infiniband/core/uverbs_cmd.c +9 -9

  		   in_len - sizeof cmd, out_len - sizeof resp);
 
  	ucontext = ibdev->alloc_ucontext(ibdev, &udata);

@@ -514,7 +514,7 @@ ssize_t ib_uverbs_alloc_pd(struct ib_uverbs_file *file,
  		return -EFAULT;
 
  	INIT_UDATA(&udata, buf + sizeof cmd,
-		   (unsigned long) cmd.response + sizeof resp,
+		   (void __user *)(unsigned long)cmd.response + sizeof resp,
  		   in_len - sizeof cmd, out_len - sizeof resp);
 
  	uobj = kmalloc(sizeof *uobj, GFP_KERNEL);

@@ -711,7 +711,7 @@ ssize_t ib_uverbs_open_xrcd(struct ib_uverbs_file *file,
  		return -EFAULT;
 
  	INIT_UDATA(&udata, buf + sizeof cmd,
-		   (unsigned long) cmd.response + sizeof resp,
+		   (void __user *)(unsigned long)cmd.response + sizeof resp,
  		   in_len - sizeof cmd, out_len - sizeof  resp);
 
  	mutex_lock(&file->device->xrcd_tree_mutex);

@@ -923,7 +923,7 @@ ssize_t ib_uverbs_reg_mr(struct ib_uverbs_file *file,
  		return -EFAULT;
 
  	INIT_UDATA(&udata, buf + sizeof cmd,
-		   (unsigned long) cmd.response + sizeof resp,
+		   (void __user *)(unsigned long)cmd.response + sizeof resp,
  		   in_len - sizeof cmd, out_len - sizeof resp);
 
  	if ((cmd.start & ~PAGE_MASK) != (cmd.hca_va & ~PAGE_MASK))

@@ -1215,7 +1215,7 @@ ssize_t ib_uverbs_create_cq(struct ib_uverbs_file *file,
  		return -EFAULT;
 
  	INIT_UDATA(&udata, buf + sizeof cmd,
-		   (unsigned long) cmd.response + sizeof resp,
+		   (void __user *)(unsigned long)cmd.response + sizeof resp,
  		   in_len - sizeof cmd, out_len - sizeof resp);
 
  	if (cmd.comp_vector >= file->device->num_comp_vectors)

@@ -1311,7 +1311,7 @@ ssize_t ib_uverbs_resize_cq(struct ib_uverbs_file *file,
  		return -EFAULT;
 
  	INIT_UDATA(&udata, buf + sizeof cmd,
-		   (unsigned long) cmd.response + sizeof resp,
+		   (void __user *)(unsigned long)cmd.response + sizeof resp,
  		   in_len - sizeof cmd, out_len - sizeof resp);
 
  	cq = idr_read_cq(cmd.cq_handle, file->ucontext, 0);

@@ -1513,7 +1513,7 @@ ssize_t ib_uverbs_create_qp(struct ib_uverbs_file *file,
  		return -EPERM;
 
  	INIT_UDATA(&udata, buf + sizeof cmd,
-		   (unsigned long) cmd.response + sizeof resp,
+		   (void __user *)(unsigned long)cmd.response + sizeof resp,
  		   in_len - sizeof cmd, out_len - sizeof resp);
 
  	obj = kzalloc(sizeof *obj, GFP_KERNEL);

@@ -1700,7 +1700,7 @@ ssize_t ib_uverbs_open_qp(struct ib_uverbs_file *file,
  		return -EFAULT;
 
  	INIT_UDATA(&udata, buf + sizeof cmd,
-		   (unsigned long) cmd.response + sizeof resp,
+		   (void __user *)(unsigned long)cmd.response + sizeof resp,
  		   in_len - sizeof cmd, out_len - sizeof resp);
 
  	obj = kmalloc(sizeof *obj, GFP_KERNEL);

@@ -2976,7 +2976,7 @@ ssize_t ib_uverbs_create_srq(struct ib_uverbs_file *file,
  	xcmd.srq_limit	 = cmd.srq_limit;
 
  	INIT_UDATA(&udata, buf + sizeof cmd,
-		   (unsigned long) cmd.response + sizeof resp,
+		   (void __user *)(unsigned long)cmd.response + sizeof resp,
  		   in_len - sizeof cmd, out_len - sizeof resp);
 
  	ret = __uverbs_create_xsrq(file, &xcmd, &udata);

@@ -3001,7 +3001,7 @@ ssize_t ib_uverbs_create_xsrq(struct ib_uverbs_file *file,
  		return -EFAULT;
 
  	INIT_UDATA(&udata, buf + sizeof cmd,
-		   (unsigned long) cmd.response + sizeof resp,
+		   (void __user *)(unsigned long)cmd.response + sizeof resp,
  		   in_len - sizeof cmd, out_len - sizeof resp);
 
  	ret = __uverbs_create_xsrq(file, &cmd, &udata);

drivers/infiniband/core/uverbs_main.c +6 -3

index 34386943ebcf..14d864371050 100644
@@ -635,6 +635,7 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
  		__u32 command;
 
  		struct ib_uverbs_ex_cmd_hdr ex_hdr;
+		char __user *response;
  		struct ib_udata ucore;
  		struct ib_udata uhw;
  		int err;

@@ -668,7 +669,9 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
  		if ((hdr.in_words + ex_hdr.provider_in_words) * 8 != count)
  			return -EINVAL;
 
-		if (ex_hdr.response) {
+		response = (char __user *)(unsigned long)ex_hdr.response;
+
+		if (response) {
  			if (!hdr.out_words && !ex_hdr.provider_out_words)
  				return -EINVAL;
  		} else {

@@ -677,14 +680,14 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
  		}
 
  		INIT_UDATA(&ucore,
-			   (hdr.in_words) ? buf : 0,
-			   (unsigned long)ex_hdr.response,
+			   (hdr.in_words) ? buf : NULL,
+			   response,
  			   hdr.in_words * 8,

On 27/11/2013 12:02 AM, Yann Droneaud wrote:

Review

Quoted 3 lines

INIT_UDATA(&udata, buf + sizeof cmd,

(quoted diff) +1 -1

-		   (unsigned long) cmd.response + sizeof resp,
+		   (void __user *)(unsigned long)cmd.response + sizeof resp,

The response field is already __u64 and casting to (void __user *) should match the machine's pointer type size. Why do we have to cast to (unsigned long) and then cast to (void __user *) ?

Hi,

Please find a patchset against create_flow/destroy_flow and associated extended command scheme.

These are fixes that must be applied before making the new uverbs widely available.

This patchset gather some patches already sent independently:
- The first two patches were already sent[1] to address a warning reported by sparse.
- The next patch was already sent[2] to handle an uncommon type of extended command.

The three patches ensure that commands will be extensible:
- One patch add a missing check of comp_mask
- Two patches add checks on reserved fields following advice from an article read today[3].

The last patches fix an error path.

Please review and apply for v3.13.

Regards.

[1] [PATCH for-next 0/2] Fix "drivers/infiniband/core/uverbs_main.c:683:17: sparse: Using plain integer as NULL pointer" warning

     http://marc.info/?i=cover.1384869925.git.ydroneaud-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org

[2] [PATCH for-next] IB/uverbs: set ucore.outbuf to NULL if core response space is omitted

     http://marc.info/?i=1384872527-26154-1-git-send-email-ydroneaud-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org

[3] "Botching up ioctls" by Daniel Vetter

     http://blog.ffwll.ch/2013/11/botching-up-ioctls.html

Yann Droneaud (7):
IB/core: const'ify inbuf in struct ib_udata
IB/uverbs: remove implicit cast in INIT_UDATA() IB/uverbs: set outbuf to NULL when no core response space is provided IB/uverbs: check reserved field in extended command header IB/uverbs: check comp_mask in destroy_flow
IB/uverbs: check reserved fields in create_flow IB/uverbs: set error code when fail to consume all flow_spec items

  drivers/infiniband/core/uverbs.h      | 12 ++++++------
  drivers/infiniband/core/uverbs_cmd.c  | 31 +++++++++++++++++++++----------
  drivers/infiniband/core/uverbs_main.c | 16 +++++++++++-----
  include/rdma/ib_verbs.h               |  2 +-
  4 files changed, 39 insertions(+), 22 deletions(-)