From 9c6caa349a0e05500a378295874d16fc280bbb78 Mon Sep 17 00:00:00 2001 From: Jia-Ju Bai Date: Tue, 3 Oct 2017 10:25:22 +0800 Subject: crypto: shash - Fix a sleep-in-atomic bug in shash_setkey_unaligned The SCTP program may sleep under a spinlock, and the function call path is: sctp_generate_t3_rtx_event (acquire the spinlock) sctp_do_sm sctp_side_effects sctp_cmd_interpreter sctp_make_init_ack sctp_pack_cookie crypto_shash_setkey shash_setkey_unaligned kmalloc(GFP_KERNEL) For the same reason, the orinoco driver may sleep in interrupt handler, and the function call path is: orinoco_rx_isr_tasklet orinoco_rx orinoco_mic crypto_shash_setkey shash_setkey_unaligned kmalloc(GFP_KERNEL) To fix it, GFP_KERNEL is replaced with GFP_ATOMIC. This bug is found by my static analysis tool and my code review. Signed-off-by: Jia-Ju Bai Signed-off-by: Herbert Xu --- crypto/shash.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'crypto/shash.c') diff --git a/crypto/shash.c b/crypto/shash.c index 5e31c8d7..8fcecc66 100644 --- a/crypto/shash.c +++ b/crypto/shash.c @@ -41,7 +41,7 @@ static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key, int err; absize = keylen + (alignmask & ~(crypto_tfm_ctx_alignment() - 1)); - buffer = kmalloc(absize, GFP_KERNEL); + buffer = kmalloc(absize, GFP_ATOMIC); if (!buffer) return -ENOMEM; -- cgit v1.2.3 From 58425dc5a756e7d9cab4d4f0632c0455e1419279 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Mon, 9 Oct 2017 23:30:02 +0800 Subject: crypto: shash - Fix zero-length shash ahash digest crash MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The shash ahash digest adaptor function may crash if given a zero-length input together with a null SG list. This is because it tries to read the SG list before looking at the length. This patch fixes it by checking the length first. Cc: Reported-by: Stephan Müller Signed-off-by: Herbert Xu Tested-by: Stephan Müller --- crypto/shash.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'crypto/shash.c') diff --git a/crypto/shash.c b/crypto/shash.c index 8fcecc66..325a14da 100644 --- a/crypto/shash.c +++ b/crypto/shash.c @@ -275,12 +275,14 @@ static int shash_async_finup(struct ahash_request *req) int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc) { - struct scatterlist *sg = req->src; - unsigned int offset = sg->offset; unsigned int nbytes = req->nbytes; + struct scatterlist *sg; + unsigned int offset; int err; - if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) { + if (nbytes && + (sg = req->src, offset = sg->offset, + nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset))) { void *data; data = kmap_atomic(sg_page(sg)); -- cgit v1.2.3 From 07e0860db60dd8e31e3d2639771a090ebd9f8d35 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 28 Nov 2017 18:01:38 -0800 Subject: crypto: hmac - require that the underlying hash algorithm is unkeyed 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 #include 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 Cc: Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu --- crypto/hmac.c | 6 +++++- crypto/shash.c | 5 +++-- 2 files changed, 8 insertions(+), 3 deletions(-) (limited to 'crypto/shash.c') diff --git a/crypto/hmac.c b/crypto/hmac.c index 92871dc2..e7473022 100644 --- a/crypto/hmac.c +++ b/crypto/hmac.c @@ -195,11 +195,15 @@ static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb) 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; diff --git a/crypto/shash.c b/crypto/shash.c index 325a14da..e849d3ee 100644 --- a/crypto/shash.c +++ b/crypto/shash.c @@ -25,11 +25,12 @@ 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) -- cgit v1.2.3