Re: [PATCH v2] acpi: nfit: vmalloc-out-of-bounds Read in acpi_nfit_ctl

[Alison Schofield <alison.schofield@intel.com>]

On Tue, Nov 12, 2024 at 10:50:35AM +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 sized appropriately as a `struct nd_cmd_pkg`. This
> could lead to out-of-bounds access and undefined behavior if the
> buffer does not have sufficient space.
> 
> To address this issue, a check was added in `acpi_nfit_ctl()` to
> ensure that `buf` is not `NULL` and `buf_len` is greater than or
> equal to `sizeof(struct nd_cmd_pkg)` before casting `buf` to
> `struct nd_cmd_pkg *`. This ensures safe access to the members of
> `call_pkg`, including the `nd_reserved2` array.
> 
> This change preventing out-of-bounds reads.
> 
> Reported-by: syzbot+7534f060ebda6b8b51b3@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=7534f060ebda6b8b51b3
> Tested-by: syzbot+7534f060ebda6b8b51b3@syzkaller.appspotmail.com
> Fixes: 2d5404caa8c7 ("Linux 6.12-rc7")
> Signed-off-by: Suraj Sonawane <surajsonawane0215@gmail.com>

Suraj,

The fixes tag needs to be where the issue originated, not
where you discovered it (which I'm guessing was using 6.12-rc7).

Here's how I find the tag:

$ git blame drivers/acpi/nfit/core.c | grep call_pkg | grep buf
ebe9f6f19d80d drivers/acpi/nfit/core.c (Dan Williams       2019-02-07 14:56:50 -0800  458) 		call_pkg = buf;

$ git log -1 --pretty=fixes ebe9f6f19d80d
Fixes: ebe9f6f19d80 ("acpi/nfit: Fix bus command validation")

I think ^ should be your Fixes tag. 



snip

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