Blame SOURCES/0480-efi-net-Fix-malformed-device-path-arithmetic-errors-.patch

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Thomas Frauendorfer | Miray Software <tf@miray.de>
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Date: Tue, 4 Aug 2020 17:13:05 +0200
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Subject: [PATCH] efi/net: Fix malformed device path arithmetic errors in efi
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 net methods
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---
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 grub-core/net/efi/net.c | 26 ++++++++++++++++++++------
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 1 file changed, 20 insertions(+), 6 deletions(-)
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diff --git a/grub-core/net/efi/net.c b/grub-core/net/efi/net.c
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index 3ae1fbbe3..a58c24f63 100644
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--- a/grub-core/net/efi/net.c
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+++ b/grub-core/net/efi/net.c
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@@ -1318,11 +1318,18 @@ grub_efi_net_boot_from_https (void)
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   dp = grub_efi_get_device_path (image->device_handle);
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-  while (1)
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+  while (dp)
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     {
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+      grub_efi_uint16_t len = GRUB_EFI_DEVICE_PATH_LENGTH (dp);
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+      if (len < 4)
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+      {
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+	grub_error(GRUB_ERR_OUT_OF_RANGE,
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+		   "malformed EFI Device Path node has length=%d", len);
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+	break;
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+      }
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+
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       grub_efi_uint8_t type = GRUB_EFI_DEVICE_PATH_TYPE (dp);
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       grub_efi_uint8_t subtype = GRUB_EFI_DEVICE_PATH_SUBTYPE (dp);
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-      grub_efi_uint16_t len = GRUB_EFI_DEVICE_PATH_LENGTH (dp);
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       if ((type == GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE)
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 	  && (subtype == GRUB_EFI_URI_DEVICE_PATH_SUBTYPE))
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@@ -1335,7 +1342,7 @@ grub_efi_net_boot_from_https (void)
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       if (GRUB_EFI_END_ENTIRE_DEVICE_PATH (dp))
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         break;
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-      dp = (grub_efi_device_path_t *) ((char *) dp + len);
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+      dp = GRUB_EFI_NEXT_DEVICE_PATH(dp);
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     }
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   return 0;
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@@ -1353,11 +1360,18 @@ grub_efi_net_boot_from_opa (void)
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   dp = grub_efi_get_device_path (image->device_handle);
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-  while (1)
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+  while (dp)
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     {
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+      grub_efi_uint16_t len = GRUB_EFI_DEVICE_PATH_LENGTH (dp);
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+      if (len < 4)
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+      {
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+	grub_error(GRUB_ERR_OUT_OF_RANGE,
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+		   "malformed EFI Device Path node has length=%d", len);
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+	break;
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+      }
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+
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       grub_efi_uint8_t type = GRUB_EFI_DEVICE_PATH_TYPE (dp);
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       grub_efi_uint8_t subtype = GRUB_EFI_DEVICE_PATH_SUBTYPE (dp);
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-      grub_efi_uint16_t len = GRUB_EFI_DEVICE_PATH_LENGTH (dp);
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       if ((type == GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE)
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 	  && (subtype == GRUB_EFI_MAC_ADDRESS_DEVICE_PATH_SUBTYPE))
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@@ -1368,7 +1382,7 @@ grub_efi_net_boot_from_opa (void)
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       if (GRUB_EFI_END_ENTIRE_DEVICE_PATH (dp))
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         break;
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-      dp = (grub_efi_device_path_t *) ((char *) dp + len);
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+      dp = GRUB_EFI_NEXT_DEVICE_PATH(dp);
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     }
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   return 0;