[v3,03/19] firmware_loader: EFI firmware loader must handle pre-allocated buffer
diff mbox series

Message ID 20200724213640.389191-4-keescook@chromium.org
State New
Headers show
Series
  • Introduce partial kernel_read_file() support
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Commit Message

Kees Cook July 24, 2020, 9:36 p.m. UTC
The EFI platform firmware fallback would clobber any pre-allocated
buffers. Instead, correctly refuse to reallocate when too small (as
already done in the sysfs fallback), or perform allocation normally
when needed.

Fixes: e4c2c0ff00ec ("firmware: Add new platform fallback mechanism and firm ware_request_platform()")
Cc: stable@vger.kernel.org
Acked-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
To aid in backporting, this change is made before moving
kernel_read_file() to separate header/source files.
---
 drivers/base/firmware_loader/fallback_platform.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

Greg KH July 25, 2020, 10:07 a.m. UTC | #1
On Fri, Jul 24, 2020 at 02:36:24PM -0700, Kees Cook wrote:
> The EFI platform firmware fallback would clobber any pre-allocated
> buffers. Instead, correctly refuse to reallocate when too small (as
> already done in the sysfs fallback), or perform allocation normally
> when needed.
> 
> Fixes: e4c2c0ff00ec ("firmware: Add new platform fallback mechanism and firm ware_request_platform()")

"firmware_request_platform()" :)
Kees Cook July 25, 2020, 3:50 p.m. UTC | #2
On Sat, Jul 25, 2020 at 12:07:00PM +0200, Greg Kroah-Hartman wrote:
> On Fri, Jul 24, 2020 at 02:36:24PM -0700, Kees Cook wrote:
> > The EFI platform firmware fallback would clobber any pre-allocated
> > buffers. Instead, correctly refuse to reallocate when too small (as
> > already done in the sysfs fallback), or perform allocation normally
> > when needed.
> > 
> > Fixes: e4c2c0ff00ec ("firmware: Add new platform fallback mechanism and firm ware_request_platform()")
> 
> "firmware_request_platform()" :)

Weird... I'm not sure where that mangling happened. Perhaps a bad
cut/paste at 80 columns? Hmpf; thanks for catching. I've updated it on
my end (I assume you fixed this manually, though?)

Thanks!
Greg KH July 25, 2020, 5:20 p.m. UTC | #3
On Sat, Jul 25, 2020 at 08:50:33AM -0700, Kees Cook wrote:
> On Sat, Jul 25, 2020 at 12:07:00PM +0200, Greg Kroah-Hartman wrote:
> > On Fri, Jul 24, 2020 at 02:36:24PM -0700, Kees Cook wrote:
> > > The EFI platform firmware fallback would clobber any pre-allocated
> > > buffers. Instead, correctly refuse to reallocate when too small (as
> > > already done in the sysfs fallback), or perform allocation normally
> > > when needed.
> > > 
> > > Fixes: e4c2c0ff00ec ("firmware: Add new platform fallback mechanism and firm ware_request_platform()")
> > 
> > "firmware_request_platform()" :)
> 
> Weird... I'm not sure where that mangling happened. Perhaps a bad
> cut/paste at 80 columns? Hmpf; thanks for catching. I've updated it on
> my end (I assume you fixed this manually, though?)

Yes, I fixed it up already, no worries.

greg k-h

Patch
diff mbox series

diff --git a/drivers/base/firmware_loader/fallback_platform.c b/drivers/base/firmware_loader/fallback_platform.c
index cdd2c9a9f38a..685edb7dd05a 100644
--- a/drivers/base/firmware_loader/fallback_platform.c
+++ b/drivers/base/firmware_loader/fallback_platform.c
@@ -25,7 +25,10 @@  int firmware_fallback_platform(struct fw_priv *fw_priv, u32 opt_flags)
 	if (rc)
 		return rc; /* rc == -ENOENT when the fw was not found */
 
-	fw_priv->data = vmalloc(size);
+	if (fw_priv->data && size > fw_priv->allocated_size)
+		return -ENOMEM;
+	if (!fw_priv->data)
+		fw_priv->data = vmalloc(size);
 	if (!fw_priv->data)
 		return -ENOMEM;