141 lines
5.7 KiB
Diff
141 lines
5.7 KiB
Diff
From 734668238fcc0ef691a080839e04f33854fa133a Mon Sep 17 00:00:00 2001
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From: Eric Biggers <ebiggers@google.com>
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Date: Thu, 29 Jun 2017 13:27:49 +0000
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Subject: [PATCH 043/229] Allow GRUB to mount ext2/3/4 filesystems that have
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the encryption feature.
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On such a filesystem, inodes may have EXT4_ENCRYPT_FLAG set.
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For a regular file, this means its contents are encrypted; for a
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directory, this means the filenames in its directory entries are
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encrypted; and for a symlink, this means its target is encrypted. Since
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GRUB cannot decrypt encrypted contents or filenames, just issue an error
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if it would need to do so. This is sufficient to allow unencrypted boot
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files to co-exist with encrypted files elsewhere on the filesystem.
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(Note that encrypted regular files and symlinks will not normally be
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encountered outside an encrypted directory; however, it's possible via
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hard links, so they still need to be handled.)
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Tested by booting from an ext4 /boot partition on which I had run
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'tune2fs -O encrypt'. I also verified that the expected error messages
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are printed when trying to access encrypted directories, files, and
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symlinks from the GRUB command line. Also ran 'sudo ./grub-fs-tester
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ext4_encrypt'; note that this requires e2fsprogs v1.43+ and Linux v4.1+.
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Signed-off-by: Eric Biggers <ebiggers@google.com>
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---
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grub-core/fs/ext2.c | 23 ++++++++++++++++++++++-
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tests/ext234_test.in | 1 +
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tests/util/grub-fs-tester.in | 10 ++++++++++
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3 files changed, 33 insertions(+), 1 deletion(-)
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diff --git a/grub-core/fs/ext2.c b/grub-core/fs/ext2.c
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index cdce63bcc9d..b8ad75a0ff7 100644
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--- a/grub-core/fs/ext2.c
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+++ b/grub-core/fs/ext2.c
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@@ -102,6 +102,7 @@ GRUB_MOD_LICENSE ("GPLv3+");
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#define EXT4_FEATURE_INCOMPAT_64BIT 0x0080
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#define EXT4_FEATURE_INCOMPAT_MMP 0x0100
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#define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
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+#define EXT4_FEATURE_INCOMPAT_ENCRYPT 0x10000
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/* The set of back-incompatible features this driver DOES support. Add (OR)
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* flags here as the related features are implemented into the driver. */
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@@ -109,7 +110,8 @@ GRUB_MOD_LICENSE ("GPLv3+");
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| EXT4_FEATURE_INCOMPAT_EXTENTS \
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| EXT4_FEATURE_INCOMPAT_FLEX_BG \
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| EXT2_FEATURE_INCOMPAT_META_BG \
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- | EXT4_FEATURE_INCOMPAT_64BIT)
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+ | EXT4_FEATURE_INCOMPAT_64BIT \
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+ | EXT4_FEATURE_INCOMPAT_ENCRYPT)
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/* List of rationales for the ignored "incompatible" features:
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* needs_recovery: Not really back-incompatible - was added as such to forbid
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* ext2 drivers from mounting an ext3 volume with a dirty
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@@ -138,6 +140,7 @@ GRUB_MOD_LICENSE ("GPLv3+");
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#define EXT3_JOURNAL_FLAG_DELETED 4
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#define EXT3_JOURNAL_FLAG_LAST_TAG 8
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+#define EXT4_ENCRYPT_FLAG 0x800
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#define EXT4_EXTENTS_FLAG 0x80000
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/* The ext2 superblock. */
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@@ -706,6 +709,12 @@ grub_ext2_read_symlink (grub_fshelp_node_t node)
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grub_ext2_read_inode (diro->data, diro->ino, &diro->inode);
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if (grub_errno)
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return 0;
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+
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+ if (diro->inode.flags & grub_cpu_to_le32_compile_time (EXT4_ENCRYPT_FLAG))
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+ {
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+ grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, "symlink is encrypted");
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+ return 0;
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+ }
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}
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symlink = grub_malloc (grub_le_to_cpu32 (diro->inode.size) + 1);
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@@ -749,6 +758,12 @@ grub_ext2_iterate_dir (grub_fshelp_node_t dir,
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return 0;
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}
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+ if (diro->inode.flags & grub_cpu_to_le32_compile_time (EXT4_ENCRYPT_FLAG))
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+ {
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+ grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, "directory is encrypted");
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+ return 0;
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+ }
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+
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/* Search the file. */
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while (fpos < grub_le_to_cpu32 (diro->inode.size))
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{
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@@ -859,6 +874,12 @@ grub_ext2_open (struct grub_file *file, const char *name)
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goto fail;
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}
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+ if (fdiro->inode.flags & grub_cpu_to_le32_compile_time (EXT4_ENCRYPT_FLAG))
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+ {
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+ err = grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, "file is encrypted");
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+ goto fail;
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+ }
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+
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grub_memcpy (data->inode, &fdiro->inode, sizeof (struct grub_ext2_inode));
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grub_free (fdiro);
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diff --git a/tests/ext234_test.in b/tests/ext234_test.in
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index 892b99cbdf6..4f1eb527eb2 100644
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--- a/tests/ext234_test.in
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+++ b/tests/ext234_test.in
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@@ -30,3 +30,4 @@ fi
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"@builddir@/grub-fs-tester" ext3
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"@builddir@/grub-fs-tester" ext4
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"@builddir@/grub-fs-tester" ext4_metabg
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+"@builddir@/grub-fs-tester" ext4_encrypt
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diff --git a/tests/util/grub-fs-tester.in b/tests/util/grub-fs-tester.in
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index 88cbe7365e9..fd7e0f14b68 100644
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--- a/tests/util/grub-fs-tester.in
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+++ b/tests/util/grub-fs-tester.in
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@@ -156,6 +156,12 @@ for LOGSECSIZE in $(range "$MINLOGSECSIZE" "$MAXLOGSECSIZE" 1); do
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# Could go further but what's the point?
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MAXBLKSIZE=$((65536*1024))
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;;
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+ xext4_encrypt)
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+ # OS LIMITATION: Linux currently only allows the 'encrypt' feature
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+ # in combination with block_size = PAGE_SIZE (4096 bytes on x86).
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+ MINBLKSIZE=$(getconf PAGE_SIZE)
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+ MAXBLKSIZE=$MINBLKSIZE
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+ ;;
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xext*)
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MINBLKSIZE=1024
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if [ $MINBLKSIZE -lt $SECSIZE ]; then
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@@ -796,6 +802,10 @@ for LOGSECSIZE in $(range "$MINLOGSECSIZE" "$MAXLOGSECSIZE" 1); do
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MKE2FS_DEVICE_SECTSIZE=$SECSIZE "mkfs.ext4" -O meta_bg,^resize_inode -b $BLKSIZE -L "$FSLABEL" -q "${MOUNTDEVICE}"
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MOUNTFS=ext4
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;;
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+ xext4_encrypt)
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+ MKE2FS_DEVICE_SECTSIZE=$SECSIZE "mkfs.ext4" -O encrypt -b $BLKSIZE -L "$FSLABEL" -q "${MOUNTDEVICE}"
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+ MOUNTFS=ext4
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+ ;;
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xext*)
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MKE2FS_DEVICE_SECTSIZE=$SECSIZE "mkfs.$fs" -b $BLKSIZE -L "$FSLABEL" -q "${MOUNTDEVICE}" ;;
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xxfs)
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--
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2.15.0
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