acpi: nfit: vmalloc-out-of-bounds Read in acpi_nfit_ctl

JIRA: https://issues.redhat.com/browse/RHEL-75893
CVE: CVE-2024-56662

commit 265e98f
Author: Suraj Sonawane <surajsonawane0215@gmail.com>
Date:   Mon Nov 18 21:56:09 2024 +0530

    acpi: nfit: vmalloc-out-of-bounds Read in acpi_nfit_ctl
    
    Fix an issue detected by syzbot with KASAN:
    
    BUG: KASAN: vmalloc-out-of-bounds in cmd_to_func drivers/acpi/nfit/
    core.c:416 [inline]
    BUG: KASAN: vmalloc-out-of-bounds in acpi_nfit_ctl+0x20e8/0x24a0
    drivers/acpi/nfit/core.c:459
    
    The issue occurs in cmd_to_func when the call_pkg->nd_reserved2
    array is accessed without verifying that call_pkg points to a buffer
    that is appropriately sized as a struct nd_cmd_pkg. This can lead
    to out-of-bounds access and undefined behavior if the buffer does not
    have sufficient space.
    
    To address this, a check was added in acpi_nfit_ctl() to ensure that
    buf is not NULL and that buf_len is less than sizeof(*call_pkg)
    before accessing it. This ensures safe access to the members of
    call_pkg, including the nd_reserved2 array.
    
    Reported-by: syzbot+7534f060ebda6b8b51b3@syzkaller.appspotmail.com
    Closes: https://syzkaller.appspot.com/bug?extid=7534f060ebda6b8b51b3
    Tested-by: syzbot+7534f060ebda6b8b51b3@syzkaller.appspotmail.com
    Fixes: ebe9f6f ("acpi/nfit: Fix bus command validation")
    Signed-off-by: Suraj Sonawane <surajsonawane0215@gmail.com>
    Reviewed-by: Alison Schofield <alison.schofield@intel.com>
    Reviewed-by: Dave Jiang <dave.jiang@intel.com>
    Link: https://patch.msgid.link/20241118162609.29063-1-surajsonawane0215@gmail.com
    Signed-off-by: Ira Weiny <ira.weiny@intel.com>

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>

Author: JeffMoyer

drivers/acpi/nfit/core.c

@@ -454,8 +454,13 @@ int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm,
 	if (cmd_rc)
 		*cmd_rc = -EINVAL;
 
-	if (cmd == ND_CMD_CALL)
+	if (cmd == ND_CMD_CALL) {
+		if (!buf || buf_len < sizeof(*call_pkg))
+			return -EINVAL;
+
 		call_pkg = buf;
+	}
+
 	func = cmd_to_func(nfit_mem, cmd, call_pkg, &family);
 	if (func < 0)
 		return func;