--- /dev/null
+From af3ff8045bbf3e32f1a448542e73abb4c8ceb6f1 Mon Sep 17 00:00:00 2001
+From: Eric Biggers <ebiggers@google.com>
+Date: Tue, 28 Nov 2017 18:01:38 -0800
+Subject: crypto: hmac - require that the underlying hash algorithm is unkeyed
+
+From: Eric Biggers <ebiggers@google.com>
+
+commit af3ff8045bbf3e32f1a448542e73abb4c8ceb6f1 upstream.
+
+Because the HMAC template didn't check that its underlying hash
+algorithm is unkeyed, trying to use "hmac(hmac(sha3-512-generic))"
+through AF_ALG or through KEYCTL_DH_COMPUTE resulted in the inner HMAC
+being used without having been keyed, resulting in sha3_update() being
+called without sha3_init(), causing a stack buffer overflow.
+
+This is a very old bug, but it seems to have only started causing real
+problems when SHA-3 support was added (requires CONFIG_CRYPTO_SHA3)
+because the innermost hash's state is ->import()ed from a zeroed buffer,
+and it just so happens that other hash algorithms are fine with that,
+but SHA-3 is not. However, there could be arch or hardware-dependent
+hash algorithms also affected; I couldn't test everything.
+
+Fix the bug by introducing a function crypto_shash_alg_has_setkey()
+which tests whether a shash algorithm is keyed. Then update the HMAC
+template to require that its underlying hash algorithm is unkeyed.
+
+Here is a reproducer:
+
+ #include <linux/if_alg.h>
+ #include <sys/socket.h>
+
+ int main()
+ {
+ int algfd;
+ struct sockaddr_alg addr = {
+ .salg_type = "hash",
+ .salg_name = "hmac(hmac(sha3-512-generic))",
+ };
+ char key[4096] = { 0 };
+
+ algfd = socket(AF_ALG, SOCK_SEQPACKET, 0);
+ bind(algfd, (const struct sockaddr *)&addr, sizeof(addr));
+ setsockopt(algfd, SOL_ALG, ALG_SET_KEY, key, sizeof(key));
+ }
+
+Here was the KASAN report from syzbot:
+
+ BUG: KASAN: stack-out-of-bounds in memcpy include/linux/string.h:341 [inline]
+ BUG: KASAN: stack-out-of-bounds in sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161
+ Write of size 4096 at addr ffff8801cca07c40 by task syzkaller076574/3044
+
+ CPU: 1 PID: 3044 Comm: syzkaller076574 Not tainted 4.14.0-mm1+ #25
+ Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
+ Call Trace:
+ __dump_stack lib/dump_stack.c:17 [inline]
+ dump_stack+0x194/0x257 lib/dump_stack.c:53
+ print_address_description+0x73/0x250 mm/kasan/report.c:252
+ kasan_report_error mm/kasan/report.c:351 [inline]
+ kasan_report+0x25b/0x340 mm/kasan/report.c:409
+ check_memory_region_inline mm/kasan/kasan.c:260 [inline]
+ check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
+ memcpy+0x37/0x50 mm/kasan/kasan.c:303
+ memcpy include/linux/string.h:341 [inline]
+ sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161
+ crypto_shash_update+0xcb/0x220 crypto/shash.c:109
+ shash_finup_unaligned+0x2a/0x60 crypto/shash.c:151
+ crypto_shash_finup+0xc4/0x120 crypto/shash.c:165
+ hmac_finup+0x182/0x330 crypto/hmac.c:152
+ crypto_shash_finup+0xc4/0x120 crypto/shash.c:165
+ shash_digest_unaligned+0x9e/0xd0 crypto/shash.c:172
+ crypto_shash_digest+0xc4/0x120 crypto/shash.c:186
+ hmac_setkey+0x36a/0x690 crypto/hmac.c:66
+ crypto_shash_setkey+0xad/0x190 crypto/shash.c:64
+ shash_async_setkey+0x47/0x60 crypto/shash.c:207
+ crypto_ahash_setkey+0xaf/0x180 crypto/ahash.c:200
+ hash_setkey+0x40/0x90 crypto/algif_hash.c:446
+ alg_setkey crypto/af_alg.c:221 [inline]
+ alg_setsockopt+0x2a1/0x350 crypto/af_alg.c:254
+ SYSC_setsockopt net/socket.c:1851 [inline]
+ SyS_setsockopt+0x189/0x360 net/socket.c:1830
+ entry_SYSCALL_64_fastpath+0x1f/0x96
+
+Reported-by: syzbot <syzkaller@googlegroups.com>
+Signed-off-by: Eric Biggers <ebiggers@google.com>
+Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ crypto/hmac.c | 6 +++++-
+ crypto/shash.c | 5 +++--
+ include/crypto/internal/hash.h | 8 ++++++++
+ 3 files changed, 16 insertions(+), 3 deletions(-)
+
+--- a/crypto/hmac.c
++++ b/crypto/hmac.c
+@@ -194,11 +194,15 @@ static int hmac_create(struct crypto_tem
+ salg = shash_attr_alg(tb[1], 0, 0);
+ if (IS_ERR(salg))
+ return PTR_ERR(salg);
++ alg = &salg->base;
+
++ /* The underlying hash algorithm must be unkeyed */
+ err = -EINVAL;
++ if (crypto_shash_alg_has_setkey(salg))
++ goto out_put_alg;
++
+ ds = salg->digestsize;
+ ss = salg->statesize;
+- alg = &salg->base;
+ if (ds > alg->cra_blocksize ||
+ ss < alg->cra_blocksize)
+ goto out_put_alg;
+--- a/crypto/shash.c
++++ b/crypto/shash.c
+@@ -24,11 +24,12 @@
+
+ static const struct crypto_type crypto_shash_type;
+
+-static int shash_no_setkey(struct crypto_shash *tfm, const u8 *key,
+- unsigned int keylen)
++int shash_no_setkey(struct crypto_shash *tfm, const u8 *key,
++ unsigned int keylen)
+ {
+ return -ENOSYS;
+ }
++EXPORT_SYMBOL_GPL(shash_no_setkey);
+
+ static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key,
+ unsigned int keylen)
+--- a/include/crypto/internal/hash.h
++++ b/include/crypto/internal/hash.h
+@@ -83,6 +83,14 @@ int ahash_register_instance(struct crypt
+ struct ahash_instance *inst);
+ void ahash_free_instance(struct crypto_instance *inst);
+
++int shash_no_setkey(struct crypto_shash *tfm, const u8 *key,
++ unsigned int keylen);
++
++static inline bool crypto_shash_alg_has_setkey(struct shash_alg *alg)
++{
++ return alg->setkey != shash_no_setkey;
++}
++
+ int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
+ struct hash_alg_common *alg,
+ struct crypto_instance *inst);
--- /dev/null
+From ecaaab5649781c5a0effdaf298a925063020500e Mon Sep 17 00:00:00 2001
+From: Eric Biggers <ebiggers@google.com>
+Date: Tue, 28 Nov 2017 20:56:59 -0800
+Subject: crypto: salsa20 - fix blkcipher_walk API usage
+
+From: Eric Biggers <ebiggers@google.com>
+
+commit ecaaab5649781c5a0effdaf298a925063020500e upstream.
+
+When asked to encrypt or decrypt 0 bytes, both the generic and x86
+implementations of Salsa20 crash in blkcipher_walk_done(), either when
+doing 'kfree(walk->buffer)' or 'free_page((unsigned long)walk->page)',
+because walk->buffer and walk->page have not been initialized.
+
+The bug is that Salsa20 is calling blkcipher_walk_done() even when
+nothing is in 'walk.nbytes'. But blkcipher_walk_done() is only meant to
+be called when a nonzero number of bytes have been provided.
+
+The broken code is part of an optimization that tries to make only one
+call to salsa20_encrypt_bytes() to process inputs that are not evenly
+divisible by 64 bytes. To fix the bug, just remove this "optimization"
+and use the blkcipher_walk API the same way all the other users do.
+
+Reproducer:
+
+ #include <linux/if_alg.h>
+ #include <sys/socket.h>
+ #include <unistd.h>
+
+ int main()
+ {
+ int algfd, reqfd;
+ struct sockaddr_alg addr = {
+ .salg_type = "skcipher",
+ .salg_name = "salsa20",
+ };
+ char key[16] = { 0 };
+
+ algfd = socket(AF_ALG, SOCK_SEQPACKET, 0);
+ bind(algfd, (void *)&addr, sizeof(addr));
+ reqfd = accept(algfd, 0, 0);
+ setsockopt(algfd, SOL_ALG, ALG_SET_KEY, key, sizeof(key));
+ read(reqfd, key, sizeof(key));
+ }
+
+Reported-by: syzbot <syzkaller@googlegroups.com>
+Fixes: eb6f13eb9f81 ("[CRYPTO] salsa20_generic: Fix multi-page processing")
+Signed-off-by: Eric Biggers <ebiggers@google.com>
+Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/x86/crypto/salsa20_glue.c | 7 -------
+ crypto/salsa20_generic.c | 7 -------
+ 2 files changed, 14 deletions(-)
+
+--- a/arch/x86/crypto/salsa20_glue.c
++++ b/arch/x86/crypto/salsa20_glue.c
+@@ -59,13 +59,6 @@ static int encrypt(struct blkcipher_desc
+
+ salsa20_ivsetup(ctx, walk.iv);
+
+- if (likely(walk.nbytes == nbytes))
+- {
+- salsa20_encrypt_bytes(ctx, walk.src.virt.addr,
+- walk.dst.virt.addr, nbytes);
+- return blkcipher_walk_done(desc, &walk, 0);
+- }
+-
+ while (walk.nbytes >= 64) {
+ salsa20_encrypt_bytes(ctx, walk.src.virt.addr,
+ walk.dst.virt.addr,
+--- a/crypto/salsa20_generic.c
++++ b/crypto/salsa20_generic.c
+@@ -188,13 +188,6 @@ static int encrypt(struct blkcipher_desc
+
+ salsa20_ivsetup(ctx, walk.iv);
+
+- if (likely(walk.nbytes == nbytes))
+- {
+- salsa20_encrypt_bytes(ctx, walk.dst.virt.addr,
+- walk.src.virt.addr, nbytes);
+- return blkcipher_walk_done(desc, &walk, 0);
+- }
+-
+ while (walk.nbytes >= 64) {
+ salsa20_encrypt_bytes(ctx, walk.dst.virt.addr,
+ walk.src.virt.addr,
projects / thirdparty / kernel / stable-queue.git / commitdiff
