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ubifs: fix wrong use of crypto_shash_descsize() 

[ Upstream commit 3c3c32f85b ]

crypto_shash_descsize() returns the size of the shash_desc context
needed to compute the hash, not the size of the hash itself.

crypto_shash_digestsize() would be correct, or alternatively using
c->hash_len and c->hmac_desc_len which already store the correct values.
But actually it's simpler to just use stack arrays, so do that instead.

Fixes: 49525e5eec ("ubifs: Add helper functions for authentication support")
Fixes: da8ef65f95 ("ubifs: Authenticate replayed journal")
Cc: <stable@vger.kernel.org> # v4.20+
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Eric Biggers 2020-05-01 22:59:45 -07:00 committed by Greg Kroah-Hartman
parent 48bbd44f5f
commit 3be8ece114
2 changed files with 6 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
fs/ubifs/auth.c
View File

@ -79,13 +79,9 @@ int ubifs_prepare_auth_node(struct ubifs_info *c, void *node,
struct shash_desc *inhash)
{
struct ubifs_auth_node *auth = node;
u8 *hash;
u8 hash[UBIFS_HASH_ARR_SZ];
int err;
hash = kmalloc(crypto_shash_descsize(c->hash_tfm), GFP_NOFS);
if (!hash)
return -ENOMEM;
{
SHASH_DESC_ON_STACK(hash_desc, c->hash_tfm);
@ -94,21 +90,16 @@ int ubifs_prepare_auth_node(struct ubifs_info *c, void *node,
err = crypto_shash_final(hash_desc, hash);
if (err)
goto out;
return err;
}
err = ubifs_hash_calc_hmac(c, hash, auth->hmac);
if (err)
goto out;
return err;
auth->ch.node_type = UBIFS_AUTH_NODE;
ubifs_prepare_node(c, auth, ubifs_auth_node_sz(c), 0);
err = 0;
out:
kfree(hash);
return err;
return 0;
}
static struct shash_desc *ubifs_get_desc(const struct ubifs_info *c,

13
fs/ubifs/replay.c
View File

@ -601,18 +601,12 @@ static int authenticate_sleb(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
struct ubifs_scan_node *snod;
int n_nodes = 0;
int err;
u8 *hash, *hmac;
u8 hash[UBIFS_HASH_ARR_SZ];
u8 hmac[UBIFS_HMAC_ARR_SZ];
if (!ubifs_authenticated(c))
return sleb->nodes_cnt;
hash = kmalloc(crypto_shash_descsize(c->hash_tfm), GFP_NOFS);
hmac = kmalloc(c->hmac_desc_len, GFP_NOFS);
if (!hash || !hmac) {
err = -ENOMEM;
goto out;
}
list_for_each_entry(snod, &sleb->nodes, list) {
n_nodes++;
@ -662,9 +656,6 @@ static int authenticate_sleb(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
err = 0;
}
out:
kfree(hash);
kfree(hmac);
return err ? err : n_nodes - n_not_auth;
}