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: ebe9f6f19d80 ("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>

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 5429ec9ef06f06535f32c82d38e968414bbc8e5b..a5d47819b3a4e295f7fe16e7f465c6d3c5fa792d 100644 (file)
--- a/drivers/acpi/nfit/core.c
+++ b/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;