76 lines
2.2 KiB
Diff
76 lines
2.2 KiB
Diff
From e563bc3dcd17d91861d3b363ed19d30228f409e1 Mon Sep 17 00:00:00 2001
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From: Javier Martinez Canillas <javierm@redhat.com>
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Date: Fri, 7 Sep 2018 15:10:51 +0200
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Subject: [PATCH] shim: Prevent shim to set itself as a second stage loader
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When shim is invoked from a relative path (e.g: from the UEFI shell), the
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Loaded Image handle LoadOptions can be set to the binary relative path.
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But the is_our_path() function only checks if LoadOptions is set to the
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absolute path of shim to ignore it. So if a relative path is there, shim
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would set itself as the secondary loader and invoke itself in a loop.
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To prevent that, use the path in LoadOptions to calculate the absolute
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path and compare it with the one in the Loader Image handle FilePath.
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Resolves: bz#1622485
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Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
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Reviewed-by: Maran Wilson maran.wilson@oracle.com
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Tested-by: Maran Wilson maran.wilson@oracle.com
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---
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shim.c | 17 ++++++++++++++---
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1 file changed, 14 insertions(+), 3 deletions(-)
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diff --git a/shim.c b/shim.c
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index 32d2772b279..8abc0c267cf 100644
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--- a/shim.c
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+++ b/shim.c
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@@ -2116,21 +2116,32 @@ get_load_option_optional_data(UINT8 *data, UINTN data_size,
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return EFI_SUCCESS;
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}
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-static int is_our_path(EFI_LOADED_IMAGE *li, CHAR16 *path, UINTN len)
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+static int is_our_path(EFI_LOADED_IMAGE *li, CHAR16 *path)
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{
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CHAR16 *dppath = NULL;
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+ CHAR16 *PathName = NULL;
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+ EFI_STATUS efi_status;
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int ret = 1;
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dppath = DevicePathToStr(li->FilePath);
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if (!dppath)
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return 0;
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+ efi_status = generate_path_from_image_path(li, path, &PathName);
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+ if (EFI_ERROR(efi_status)) {
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+ perror(L"Unable to generate path %s: %r\n", path,
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+ efi_status);
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+ goto done;
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+ }
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+
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dprint(L"dppath: %s\n", dppath);
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dprint(L"path: %s\n", path);
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- if (StrnCaseCmp(dppath, path, len))
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+ if (StrnCaseCmp(dppath, PathName, strlen(dppath)))
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ret = 0;
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+done:
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FreePool(dppath);
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+ FreePool(PathName);
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return ret;
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}
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@@ -2319,7 +2330,7 @@ EFI_STATUS set_second_stage (EFI_HANDLE image_handle)
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* which is just cruel... So yeah, just don't use it.
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*/
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- if (strings == 1 && is_our_path(li, start, loader_len))
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+ if (strings == 1 && is_our_path(li, start))
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return EFI_SUCCESS;
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/*
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--
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2.21.0
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