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authorKees Cook <keescook@chromium.org>2018-08-07 14:18:39 -0700
committerHerbert Xu <herbert@gondor.apana.org.au>2018-09-14 14:08:52 +0800
commit6d39a1241ebc3bdd61d654c3058f0955c28c13fd (patch)
tree96bb0af93ed1392637ac6dc974a55f36f0572d80 /drivers
parentcrypto: arm/chacha20 - faster 8-bit rotations and other optimizations (diff)
downloadlinux-dev-6d39a1241ebc3bdd61d654c3058f0955c28c13fd.tar.xz
linux-dev-6d39a1241ebc3bdd61d654c3058f0955c28c13fd.zip
dm: Remove VLA usage from hashes
In the quest to remove all stack VLA usage from the kernel[1], this uses the new HASH_MAX_DIGESTSIZE from the crypto layer to allocate the upper bounds on stack usage. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/md/dm-integrity.c23
-rw-r--r--drivers/md/dm-verity-fec.c5
2 files changed, 21 insertions, 7 deletions
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 378878599466..5c1197bc66f8 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -559,7 +559,12 @@ static void section_mac(struct dm_integrity_c *ic, unsigned section, __u8 result
}
memset(result + size, 0, JOURNAL_MAC_SIZE - size);
} else {
- __u8 digest[size];
+ __u8 digest[HASH_MAX_DIGESTSIZE];
+
+ if (WARN_ON(size > sizeof(digest))) {
+ dm_integrity_io_error(ic, "digest_size", -EINVAL);
+ goto err;
+ }
r = crypto_shash_final(desc, digest);
if (unlikely(r)) {
dm_integrity_io_error(ic, "crypto_shash_final", r);
@@ -1324,7 +1329,7 @@ static void integrity_metadata(struct work_struct *w)
struct bio *bio = dm_bio_from_per_bio_data(dio, sizeof(struct dm_integrity_io));
char *checksums;
unsigned extra_space = unlikely(digest_size > ic->tag_size) ? digest_size - ic->tag_size : 0;
- char checksums_onstack[ic->tag_size + extra_space];
+ char checksums_onstack[HASH_MAX_DIGESTSIZE];
unsigned sectors_to_process = dio->range.n_sectors;
sector_t sector = dio->range.logical_sector;
@@ -1333,8 +1338,14 @@ static void integrity_metadata(struct work_struct *w)
checksums = kmalloc((PAGE_SIZE >> SECTOR_SHIFT >> ic->sb->log2_sectors_per_block) * ic->tag_size + extra_space,
GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN);
- if (!checksums)
+ if (!checksums) {
checksums = checksums_onstack;
+ if (WARN_ON(extra_space &&
+ digest_size > sizeof(checksums_onstack))) {
+ r = -EINVAL;
+ goto error;
+ }
+ }
__bio_for_each_segment(bv, bio, iter, dio->orig_bi_iter) {
unsigned pos;
@@ -1546,7 +1557,7 @@ retry_kmap:
} while (++s < ic->sectors_per_block);
#ifdef INTERNAL_VERIFY
if (ic->internal_hash) {
- char checksums_onstack[max(crypto_shash_digestsize(ic->internal_hash), ic->tag_size)];
+ char checksums_onstack[max(HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
integrity_sector_checksum(ic, logical_sector, mem + bv.bv_offset, checksums_onstack);
if (unlikely(memcmp(checksums_onstack, journal_entry_tag(ic, je), ic->tag_size))) {
@@ -1596,7 +1607,7 @@ retry_kmap:
if (ic->internal_hash) {
unsigned digest_size = crypto_shash_digestsize(ic->internal_hash);
if (unlikely(digest_size > ic->tag_size)) {
- char checksums_onstack[digest_size];
+ char checksums_onstack[HASH_MAX_DIGESTSIZE];
integrity_sector_checksum(ic, logical_sector, (char *)js, checksums_onstack);
memcpy(journal_entry_tag(ic, je), checksums_onstack, ic->tag_size);
} else
@@ -2023,7 +2034,7 @@ static void do_journal_write(struct dm_integrity_c *ic, unsigned write_start,
unlikely(from_replay) &&
#endif
ic->internal_hash) {
- char test_tag[max(crypto_shash_digestsize(ic->internal_hash), ic->tag_size)];
+ char test_tag[max_t(size_t, HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
integrity_sector_checksum(ic, sec + ((l - j) << ic->sb->log2_sectors_per_block),
(char *)access_journal_data(ic, i, l), test_tag);
diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c
index 684af08d0747..0ce04e5b4afb 100644
--- a/drivers/md/dm-verity-fec.c
+++ b/drivers/md/dm-verity-fec.c
@@ -212,12 +212,15 @@ static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io,
struct dm_verity_fec_io *fio = fec_io(io);
u64 block, ileaved;
u8 *bbuf, *rs_block;
- u8 want_digest[v->digest_size];
+ u8 want_digest[HASH_MAX_DIGESTSIZE];
unsigned n, k;
if (neras)
*neras = 0;
+ if (WARN_ON(v->digest_size > sizeof(want_digest)))
+ return -EINVAL;
+
/*
* read each of the rsn data blocks that are part of the RS block, and
* interleave contents to available bufs