linux-kernel - [PATCH 4/6] efi/gop: Fix memory leak from __gop

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Message-Id: <20191206165542.31469-5-ardb@kernel.org>
Date:   Fri,  6 Dec 2019 16:55:40 +0000
From:   Ard Biesheuvel <ardb@...nel.org>
To:     linux-efi@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     Ard Biesheuvel <ardb@...nel.org>, linux-kernel@...r.kernel.org,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Arvind Sankar <nivedita@...m.mit.edu>,
        Bhupesh Sharma <bhsharma@...hat.com>,
        Masayoshi Mizuma <m.mizuma@...fujitsu.com>
Subject: [PATCH 4/6] efi/gop: Fix memory leak from __gop_query32/64

From: Arvind Sankar <nivedita@...m.mit.edu>

efi_graphics_output_protocol::query_mode() returns info in
callee-allocated memory which must be freed by the caller, which
we aren't doing.

We don't actually need to call query_mode in order to obtain the
info for the current graphics mode, which is already there in
gop->mode->info, so just access it directly in the setup_gop32/64
functions.

Also nothing uses the size of the info structure, so don't update the
passed-in size (which is the size of the gop_handle table in bytes)
unnecessarily.

Signed-off-by: Arvind Sankar <nivedita@...m.mit.edu>
Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
---
 drivers/firmware/efi/libstub/gop.c | 66 ++++++------------------------
 1 file changed, 12 insertions(+), 54 deletions(-)

diff --git a/drivers/firmware/efi/libstub/gop.c b/drivers/firmware/efi/libstub/gop.c
index 69b2b019a1d0..b7bf1e993b8b 100644
--- a/drivers/firmware/efi/libstub/gop.c
+++ b/drivers/firmware/efi/libstub/gop.c
@@ -83,30 +83,6 @@ setup_pixel_info(struct screen_info *si, u32 pixels_per_scan_line,
 	}
 }
 
-static efi_status_t
-__gop_query32(efi_system_table_t *sys_table_arg,
-	      struct efi_graphics_output_protocol_32 *gop32,
-	      struct efi_graphics_output_mode_info **info,
-	      unsigned long *size, u64 *fb_base)
-{
-	struct efi_graphics_output_protocol_mode_32 *mode;
-	efi_graphics_output_protocol_query_mode query_mode;
-	efi_status_t status;
-	unsigned long m;
-
-	m = gop32->mode;
-	mode = (struct efi_graphics_output_protocol_mode_32 *)m;
-	query_mode = (void *)(unsigned long)gop32->query_mode;
-
-	status = __efi_call_early(query_mode, (void *)gop32, mode->mode, size,
-				  info);
-	if (status != EFI_SUCCESS)
-		return status;
-
-	*fb_base = mode->frame_buffer_base;
-	return status;
-}
-
 static efi_status_t
 setup_gop32(efi_system_table_t *sys_table_arg, struct screen_info *si,
             efi_guid_t *proto, unsigned long size, void **gop_handle)
@@ -128,6 +104,7 @@ setup_gop32(efi_system_table_t *sys_table_arg, struct screen_info *si,
 
 	nr_gops = size / sizeof(u32);
 	for (i = 0; i < nr_gops; i++) {
+		struct efi_graphics_output_protocol_mode_32 *mode;
 		struct efi_graphics_output_mode_info *info = NULL;
 		efi_guid_t conout_proto = EFI_CONSOLE_OUT_DEVICE_GUID;
 		bool conout_found = false;
@@ -145,9 +122,11 @@ setup_gop32(efi_system_table_t *sys_table_arg, struct screen_info *si,
 		if (status == EFI_SUCCESS)
 			conout_found = true;
 
-		status = __gop_query32(sys_table_arg, gop32, &info, &size,
-				       &current_fb_base);
-		if (status == EFI_SUCCESS && (!first_gop || conout_found) &&
+		mode = (void *)(unsigned long)gop32->mode;
+		info = (void *)(unsigned long)mode->info;
+		current_fb_base = mode->frame_buffer_base;
+
+		if ((!first_gop || conout_found) &&
 		    info->pixel_format != PIXEL_BLT_ONLY) {
 			/*
 			 * Systems that use the UEFI Console Splitter may
@@ -201,30 +180,6 @@ setup_gop32(efi_system_table_t *sys_table_arg, struct screen_info *si,
 	return EFI_SUCCESS;
 }
 
-static efi_status_t
-__gop_query64(efi_system_table_t *sys_table_arg,
-	      struct efi_graphics_output_protocol_64 *gop64,
-	      struct efi_graphics_output_mode_info **info,
-	      unsigned long *size, u64 *fb_base)
-{
-	struct efi_graphics_output_protocol_mode_64 *mode;
-	efi_graphics_output_protocol_query_mode query_mode;
-	efi_status_t status;
-	unsigned long m;
-
-	m = gop64->mode;
-	mode = (struct efi_graphics_output_protocol_mode_64 *)m;
-	query_mode = (void *)(unsigned long)gop64->query_mode;
-
-	status = __efi_call_early(query_mode, (void *)gop64, mode->mode, size,
-				  info);
-	if (status != EFI_SUCCESS)
-		return status;
-
-	*fb_base = mode->frame_buffer_base;
-	return status;
-}
-
 static efi_status_t
 setup_gop64(efi_system_table_t *sys_table_arg, struct screen_info *si,
 	    efi_guid_t *proto, unsigned long size, void **gop_handle)
@@ -246,6 +201,7 @@ setup_gop64(efi_system_table_t *sys_table_arg, struct screen_info *si,
 
 	nr_gops = size / sizeof(u64);
 	for (i = 0; i < nr_gops; i++) {
+		struct efi_graphics_output_protocol_mode_64 *mode;
 		struct efi_graphics_output_mode_info *info = NULL;
 		efi_guid_t conout_proto = EFI_CONSOLE_OUT_DEVICE_GUID;
 		bool conout_found = false;
@@ -263,9 +219,11 @@ setup_gop64(efi_system_table_t *sys_table_arg, struct screen_info *si,
 		if (status == EFI_SUCCESS)
 			conout_found = true;
 
-		status = __gop_query64(sys_table_arg, gop64, &info, &size,
-				       &current_fb_base);
-		if (status == EFI_SUCCESS && (!first_gop || conout_found) &&
+		mode = (void *)(unsigned long)gop64->mode;
+		info = (void *)(unsigned long)mode->info;
+		current_fb_base = mode->frame_buffer_base;
+
+		if ((!first_gop || conout_found) &&
 		    info->pixel_format != PIXEL_BLT_ONLY) {
 			/*
 			 * Systems that use the UEFI Console Splitter may
-- 
2.17.1