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@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://syzkaller.appspot.com/bug?extid=7534f060ebda6b8b51b3 Tested-by: syzbot+7534f060ebda6b8b51b3@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: ebe9f6f19d80 ("acpi/nfit: Fix bus command validation") Signed-off-by: Suraj Sonawane <surajsonawane0215@xxxxxxxxx> --- V1: https://lore.kernel.org/lkml/20241111080429.9861-1-surajsonawane0215@xxxxxxxxx/ V2: Initialized `out_obj` to `NULL` in `acpi_nfit_ctl()` to prevent potential uninitialized variable usage if condition is true. V3: Changed the condition to if (!buf || buf_len < sizeof(*call_pkg)) and updated the Fixes tag to reference the correct commit. V4: Removed the explicit cast to maintain the original code style. V5: Re-Initialized `out_obj` to NULL. To prevent potential uninitialized variable usage if condition is true. V6: Remove the goto out condition from the error handling and directly returned -EINVAL in the check for buf and buf_len drivers/acpi/nfit/core.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index 5429ec9ef..a5d47819b 100644 --- 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; -- 2.34.1
