--- /dev/null
+From 81e69df38e2911b642ec121dec319fad2a4782f3 Mon Sep 17 00:00:00 2001
+From: Theodore Ts'o <tytso@mit.edu>
+Date: Sat, 14 Jul 2018 23:55:57 -0400
+Subject: random: mix rdrand with entropy sent in from userspace
+
+From: Theodore Ts'o <tytso@mit.edu>
+
+commit 81e69df38e2911b642ec121dec319fad2a4782f3 upstream.
+
+Fedora has integrated the jitter entropy daemon to work around slow
+boot problems, especially on VM's that don't support virtio-rng:
+
+ https://bugzilla.redhat.com/show_bug.cgi?id=1572944
+
+It's understandable why they did this, but the Jitter entropy daemon
+works fundamentally on the principle: "the CPU microarchitecture is
+**so** complicated and we can't figure it out, so it *must* be
+random". Yes, it uses statistical tests to "prove" it is secure, but
+AES_ENCRYPT(NSA_KEY, COUNTER++) will also pass statistical tests with
+flying colors.
+
+So if RDRAND is available, mix it into entropy submitted from
+userspace. It can't hurt, and if you believe the NSA has backdoored
+RDRAND, then they probably have enough details about the Intel
+microarchitecture that they can reverse engineer how the Jitter
+entropy daemon affects the microarchitecture, and attack its output
+stream. And if RDRAND is in fact an honest DRNG, it will immeasurably
+improve on what the Jitter entropy daemon might produce.
+
+This also provides some protection against someone who is able to read
+or set the entropy seed file.
+
+Signed-off-by: Theodore Ts'o <tytso@mit.edu>
+Cc: stable@vger.kernel.org
+Cc: Arnd Bergmann <arnd@arndb.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/char/random.c | 10 +++++++++-
+ 1 file changed, 9 insertions(+), 1 deletion(-)
+
+--- a/drivers/char/random.c
++++ b/drivers/char/random.c
+@@ -1417,14 +1417,22 @@ static int
+ write_pool(struct entropy_store *r, const char __user *buffer, size_t count)
+ {
+ size_t bytes;
+- __u32 buf[16];
++ __u32 t, buf[16];
+ const char __user *p = buffer;
+
+ while (count > 0) {
++ int b, i = 0;
++
+ bytes = min(count, sizeof(buf));
+ if (copy_from_user(&buf, p, bytes))
+ return -EFAULT;
+
++ for (b = bytes ; b > 0 ; b -= sizeof(__u32), i++) {
++ if (!arch_get_random_int(&t))
++ break;
++ buf[i] ^= t;
++ }
++
+ count -= bytes;
+ p += bytes;
+
--- /dev/null
+From 01cfb7937a9af2abb1136c7e89fbf3fd92952956 Mon Sep 17 00:00:00 2001
+From: Linus Torvalds <torvalds@linux-foundation.org>
+Date: Sun, 29 Jul 2018 12:44:46 -0700
+Subject: squashfs: be more careful about metadata corruption
+
+From: Linus Torvalds <torvalds@linux-foundation.org>
+
+commit 01cfb7937a9af2abb1136c7e89fbf3fd92952956 upstream.
+
+Anatoly Trosinenko reports that a corrupted squashfs image can cause a
+kernel oops. It turns out that squashfs can end up being confused about
+negative fragment lengths.
+
+The regular squashfs_read_data() does check for negative lengths, but
+squashfs_read_metadata() did not, and the fragment size code just
+blindly trusted the on-disk value. Fix both the fragment parsing and
+the metadata reading code.
+
+Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com>
+Cc: Al Viro <viro@zeniv.linux.org.uk>
+Cc: Phillip Lougher <phillip@squashfs.org.uk>
+Cc: stable@kernel.org
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ fs/squashfs/cache.c | 3 +++
+ fs/squashfs/file.c | 8 ++++++--
+ fs/squashfs/fragment.c | 4 +---
+ fs/squashfs/squashfs_fs.h | 6 ++++++
+ 4 files changed, 16 insertions(+), 5 deletions(-)
+
+--- a/fs/squashfs/cache.c
++++ b/fs/squashfs/cache.c
+@@ -350,6 +350,9 @@ int squashfs_read_metadata(struct super_
+
+ TRACE("Entered squashfs_read_metadata [%llx:%x]\n", *block, *offset);
+
++ if (unlikely(length < 0))
++ return -EIO;
++
+ while (length) {
+ entry = squashfs_cache_get(sb, msblk->block_cache, *block, 0);
+ if (entry->error) {
+--- a/fs/squashfs/file.c
++++ b/fs/squashfs/file.c
+@@ -194,7 +194,11 @@ static long long read_indexes(struct sup
+ }
+
+ for (i = 0; i < blocks; i++) {
+- int size = le32_to_cpu(blist[i]);
++ int size = squashfs_block_size(blist[i]);
++ if (size < 0) {
++ err = size;
++ goto failure;
++ }
+ block += SQUASHFS_COMPRESSED_SIZE_BLOCK(size);
+ }
+ n -= blocks;
+@@ -367,7 +371,7 @@ static int read_blocklist(struct inode *
+ sizeof(size));
+ if (res < 0)
+ return res;
+- return le32_to_cpu(size);
++ return squashfs_block_size(size);
+ }
+
+ /* Copy data into page cache */
+--- a/fs/squashfs/fragment.c
++++ b/fs/squashfs/fragment.c
+@@ -61,9 +61,7 @@ int squashfs_frag_lookup(struct super_bl
+ return size;
+
+ *fragment_block = le64_to_cpu(fragment_entry.start_block);
+- size = le32_to_cpu(fragment_entry.size);
+-
+- return size;
++ return squashfs_block_size(fragment_entry.size);
+ }
+
+
+--- a/fs/squashfs/squashfs_fs.h
++++ b/fs/squashfs/squashfs_fs.h
+@@ -129,6 +129,12 @@
+
+ #define SQUASHFS_COMPRESSED_BLOCK(B) (!((B) & SQUASHFS_COMPRESSED_BIT_BLOCK))
+
++static inline int squashfs_block_size(__le32 raw)
++{
++ u32 size = le32_to_cpu(raw);
++ return (size >> 25) ? -EIO : size;
++}
++
+ /*
+ * Inode number ops. Inodes consist of a compressed block number, and an
+ * uncompressed offset within that block
projects / thirdparty / kernel / stable-queue.git / commitdiff
