+ drivers-rapidio-rio_cmc-prevent-possible-used-uninitialized.patch added to mm-hotfixes-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: drivers/rapidio/rio_cm.c: prevent possible used-uninitialized
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     drivers-rapidio-rio_cmc-prevent-possible-used-uninitialized.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/drivers-rapidio-rio_cmc-prevent-possible-used-uninitialized.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Andrew Morton <akpm@linux-foundation.org>
Subject: drivers/rapidio/rio_cm.c: prevent possible used-uninitialized
Date: Sat Jun  7 05:43:18 PM PDT 2025

In

riocm_cdev_ioctl(RIO_CM_CHAN_SEND)
   -> cm_chan_msg_send()
      -> riocm_ch_send()

cm_chan_msg_send() checks that userspace didn't send too much data but
riocm_ch_send() failed to check that userspace sent sufficient data.  The
result is that riocm_ch_send() can access fields in the rio_ch_chan_hdr
which were never copied in from userspace.

Address this by teaching riocm_ch_send() to check that the entire
rio_ch_chan_hdr was copied in from userspace.

Reported-by: maher azz <maherazz04@gmail.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Alexandre Bounine <alex.bou9@gmail.com>
Cc: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/rapidio/rio_cm.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/rapidio/rio_cm.c~drivers-rapidio-rio_cmc-prevent-possible-used-uninitialized
+++ a/drivers/rapidio/rio_cm.c
@@ -783,6 +783,9 @@ static int riocm_ch_send(u16 ch_id, void
 	if (buf == NULL || ch_id == 0 || len == 0 || len > RIO_MAX_MSG_SIZE)
 		return -EINVAL;
 
+	if (len < sizeof(struct rio_ch_chan_hdr))
+		return -EINVAL;		/* insufficient data from user */
+
 	ch = riocm_get_channel(ch_id);
 	if (!ch) {
 		riocm_error("%s(%d) ch_%d not found", current->comm,
_

Patches currently in -mm which might be from akpm@linux-foundation.org are

docs-proc-update-vmflags-documentation-in-smaps-fix.patch
fs-proc-task_mmu-add-vm_shadow_stack-for-arm64-when-support-gcs-fix.patch
drivers-rapidio-rio_cmc-prevent-possible-used-uninitialized.patch
mm-add-zblock-allocator-fix.patch
mm-add-zblock-allocator-fix-2.patch
mm-add-zblock-allocator-fix-2-fix.patch
mm-add-zblock-allocator-fix-3.patch
mm-zblock-avoid-failing-the-build-fix.patch