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Message-ID: <Z0ToRzLyx5L5xDGu@aschofie-mobl2.lan>
Date: Mon, 25 Nov 2024 13:12:39 -0800
From: Alison Schofield <alison.schofield@...el.com>
To: Suraj Sonawane <surajsonawane0215@...il.com>
Cc: dan.j.williams@...el.com, vishal.l.verma@...el.com,
dave.jiang@...el.com, ira.weiny@...el.com, rafael@...nel.org,
lenb@...nel.org, nvdimm@...ts.linux.dev, linux-acpi@...r.kernel.org,
linux-kernel@...r.kernel.org,
syzbot+7534f060ebda6b8b51b3@...kaller.appspotmail.com
Subject: Re: [PATCH v6] acpi: nfit: vmalloc-out-of-bounds Read in
acpi_nfit_ctl
On Mon, Nov 18, 2024 at 09:56:09PM +0530, Suraj Sonawane wrote:
> 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.
>
Reviewed-by: Alison Schofield <alison.schofield@...el.com>
> Reported-by: syzbot+7534f060ebda6b8b51b3@...kaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=7534f060ebda6b8b51b3
> Tested-by: syzbot+7534f060ebda6b8b51b3@...kaller.appspotmail.com
> Fixes: ebe9f6f19d80 ("acpi/nfit: Fix bus command validation")
> Signed-off-by: Suraj Sonawane <surajsonawane0215@...il.com>
> ---
> V1: https://lore.kernel.org/lkml/20241111080429.9861-1-surajsonawane0215@gmail.com/
> 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
>
>
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