Re: [PATCH] x86/efi: initialize status to ensure garbage is not returned on small size
From: Matt Fleming <hidden>
Date: 2016-07-27 14:38:21
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On Wed, 20 Jul, at 11:11:06AM, Colin Ian King wrote:
quoted hunk ↗ jump to hunk
From: Colin Ian King <redacted> Although very unlikey, if size is too small or zero, then we end up with status not being set and returning garbage. Instead, initializing status to EFI_INVALID_PARAMETER to indicate that size is invalid in the calls to setup_uga32 and setup_uga64. Signed-off-by: Colin Ian King <redacted> --- arch/x86/boot/compressed/eboot.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c index ff574da..ec6d2ef 100644 --- a/arch/x86/boot/compressed/eboot.c +++ b/arch/x86/boot/compressed/eboot.c@@ -578,7 +578,7 @@ setup_uga32(void **uga_handle, unsigned long size, u32 *width, u32 *height) efi_guid_t uga_proto = EFI_UGA_PROTOCOL_GUID; unsigned long nr_ugas; u32 *handles = (u32 *)uga_handle;; - efi_status_t status; + efi_status_t status = EFI_INVALID_PARAMETER; int i; first_uga = NULL;@@ -623,7 +623,7 @@ setup_uga64(void **uga_handle, unsigned long size, u32 *width, u32 *height) efi_guid_t uga_proto = EFI_UGA_PROTOCOL_GUID; unsigned long nr_ugas; u64 *handles = (u64 *)uga_handle;; - efi_status_t status; + efi_status_t status = EFI_INVALID_PARAMETER; int i; first_uga = NULL;
Can this ever happen in practice? This would imply that locate_protocol() found EFI_UGA_PROTOCOL_GUID but that the size returned is utterly bogus? If so, I have no problem applying the patch but want to make sure we're not tricking ourselves into thinking we're being protected from something when we're not.