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Subject[PATCH] efi-bgrt: Add error handling; inform the user when ignoring the BGRT
Gracefully handle failures to allocate memory for the image, which might
be arbitrarily large.

efi_bgrt_init can fail in various ways as well, usually because the
BIOS-provided BGRT structure does not match expectations. Add
appropriate error messages rather than failing silently.

Reported-by: Srihari Vijayaraghavan
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=81321
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
---
arch/x86/platform/efi/efi-bgrt.c | 36 ++++++++++++++++++++++++++++++------
1 file changed, 30 insertions(+), 6 deletions(-)

diff --git a/arch/x86/platform/efi/efi-bgrt.c b/arch/x86/platform/efi/efi-bgrt.c
index f15103d..d143d21 100644
--- a/arch/x86/platform/efi/efi-bgrt.c
+++ b/arch/x86/platform/efi/efi-bgrt.c
@@ -40,20 +40,40 @@ void __init efi_bgrt_init(void)
if (ACPI_FAILURE(status))
return;

- if (bgrt_tab->header.length < sizeof(*bgrt_tab))
+ if (bgrt_tab->header.length < sizeof(*bgrt_tab)) {
+ pr_err("Ignoring BGRT: invalid length %u (expected %zu)\n",
+ bgrt_tab->header.length, sizeof(*bgrt_tab));
return;
- if (bgrt_tab->version != 1 || bgrt_tab->status != 1)
+ }
+ if (bgrt_tab->version != 1) {
+ pr_err("Ignoring BGRT: invalid version %u (expected 1)\n",
+ bgrt_tab->version);
+ return;
+ }
+ if (bgrt_tab->status != 1) {
+ pr_err("Ignoring BGRT: invalid status %u (expected 1)\n",
+ bgrt_tab->status);
+ return;
+ }
+ if (bgrt_tab->image_type != 0) {
+ pr_err("Ignoring BGRT: invalid image type %u (expected 0)\n",
+ bgrt_tab->image_type);
return;
- if (bgrt_tab->image_type != 0 || !bgrt_tab->image_address)
+ }
+ if (!bgrt_tab->image_address) {
+ pr_err("Ignoring BGRT: null image address\n");
return;
+ }

image = efi_lookup_mapped_addr(bgrt_tab->image_address);
if (!image) {
image = early_memremap(bgrt_tab->image_address,
sizeof(bmp_header));
ioremapped = true;
- if (!image)
+ if (!image) {
+ pr_err("Ignoring BGRT: failed to map image header memory\n");
return;
+ }
}

memcpy_fromio(&bmp_header, image, sizeof(bmp_header));
@@ -61,14 +81,18 @@ void __init efi_bgrt_init(void)
early_iounmap(image, sizeof(bmp_header));
bgrt_image_size = bmp_header.size;

- bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL);
- if (!bgrt_image)
+ bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN);
+ if (!bgrt_image) {
+ pr_err("Ignoring BGRT: failed to allocate memory for image (wanted %zu bytes)\n",
+ bgrt_image_size);
return;
+ }

if (ioremapped) {
image = early_memremap(bgrt_tab->image_address,
bmp_header.size);
if (!image) {
+ pr_err("Ignoring BGRT: failed to map image memory\n");
kfree(bgrt_image);
bgrt_image = NULL;
return;
--
2.0.1


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