linux-kernel - [PATCH 1/1] efi/libstub: setup_graphics() do not return random data

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Message-Id: <20200426194946.112768-1-xypron.glpk@gmx.de>
Date:   Sun, 26 Apr 2020 21:49:46 +0200
From:   Heinrich Schuchardt <xypron.glpk@....de>
To:     Ard Biesheuvel <ardb@...nel.org>
Cc:     Ingo Molnar <mingo@...nel.org>, linux-efi@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Heinrich Schuchardt <xypron.glpk@....de>
Subject: [PATCH 1/1] efi/libstub: setup_graphics() do not return random data

Currently setup_graphics() ignores the return value of efi_setup_gop(). As
AllocatePool() does not zero out memory the screen information table will
contain random data in this case.

We should free the screen information table if efi_setup_gop() returns an
error code.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@....de>
---
 drivers/firmware/efi/libstub/efi-stub.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/libstub/efi-stub.c b/drivers/firmware/efi/libstub/efi-stub.c
index ee225b323687..60377e5ceab3 100644
--- a/drivers/firmware/efi/libstub/efi-stub.c
+++ b/drivers/firmware/efi/libstub/efi-stub.c
@@ -55,7 +55,11 @@ static struct screen_info *setup_graphics(void)
 		si = alloc_screen_info();
 		if (!si)
 			return NULL;
-		efi_setup_gop(si, &gop_proto, size);
+		status = efi_setup_gop(si, &gop_proto, size);
+		if (status != EFI_SUCCESS) {
+			free_screen_info(si);
+			return NULL;
+		}
 	}
 	return si;
 }
--
2.26.2