eCryptfs: Allow 2 scatterlist entries for encrypted filenames
The buffers allocated while encrypting and decrypting long filenames can
sometimes straddle two pages. In this situation, virt_to_scatterlist()
will return -ENOMEM, causing the operation to fail and the user will get
scary error messages in their logs:
kernel: ecryptfs_write_tag_70_packet: Internal error whilst attempting
to convert filename memory to scatterlist; expected rc = 1; got rc =
[-12]. block_aligned_filename_size = [272]
kernel: ecryptfs_encrypt_filename: Error attempting to generate tag 70
packet; rc = [-12]
kernel: ecryptfs_encrypt_and_encode_filename: Error attempting to
encrypt filename; rc = [-12]
kernel: ecryptfs_lookup: Error attempting to encrypt and encode
filename; rc = [-12]
The solution is to allow up to 2 scatterlist entries to be used.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
index 03e609c..27a7fef 100644
--- a/fs/ecryptfs/keystore.c
+++ b/fs/ecryptfs/keystore.c
@@ -599,8 +599,8 @@
struct mutex *tfm_mutex;
char *block_aligned_filename;
struct ecryptfs_auth_tok *auth_tok;
- struct scatterlist src_sg;
- struct scatterlist dst_sg;
+ struct scatterlist src_sg[2];
+ struct scatterlist dst_sg[2];
struct blkcipher_desc desc;
char iv[ECRYPTFS_MAX_IV_BYTES];
char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
@@ -816,23 +816,21 @@
memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
filename_size);
rc = virt_to_scatterlist(s->block_aligned_filename,
- s->block_aligned_filename_size, &s->src_sg, 1);
- if (rc != 1) {
+ s->block_aligned_filename_size, s->src_sg, 2);
+ if (rc < 1) {
printk(KERN_ERR "%s: Internal error whilst attempting to "
- "convert filename memory to scatterlist; "
- "expected rc = 1; got rc = [%d]. "
+ "convert filename memory to scatterlist; rc = [%d]. "
"block_aligned_filename_size = [%zd]\n", __func__, rc,
s->block_aligned_filename_size);
goto out_release_free_unlock;
}
rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
- &s->dst_sg, 1);
- if (rc != 1) {
+ s->dst_sg, 2);
+ if (rc < 1) {
printk(KERN_ERR "%s: Internal error whilst attempting to "
"convert encrypted filename memory to scatterlist; "
- "expected rc = 1; got rc = [%d]. "
- "block_aligned_filename_size = [%zd]\n", __func__, rc,
- s->block_aligned_filename_size);
+ "rc = [%d]. block_aligned_filename_size = [%zd]\n",
+ __func__, rc, s->block_aligned_filename_size);
goto out_release_free_unlock;
}
/* The characters in the first block effectively do the job
@@ -855,7 +853,7 @@
mount_crypt_stat->global_default_fn_cipher_key_bytes);
goto out_release_free_unlock;
}
- rc = crypto_blkcipher_encrypt_iv(&s->desc, &s->dst_sg, &s->src_sg,
+ rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg,
s->block_aligned_filename_size);
if (rc) {
printk(KERN_ERR "%s: Error attempting to encrypt filename; "
@@ -891,8 +889,8 @@
struct mutex *tfm_mutex;
char *decrypted_filename;
struct ecryptfs_auth_tok *auth_tok;
- struct scatterlist src_sg;
- struct scatterlist dst_sg;
+ struct scatterlist src_sg[2];
+ struct scatterlist dst_sg[2];
struct blkcipher_desc desc;
char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
char iv[ECRYPTFS_MAX_IV_BYTES];
@@ -1008,13 +1006,12 @@
}
mutex_lock(s->tfm_mutex);
rc = virt_to_scatterlist(&data[(*packet_size)],
- s->block_aligned_filename_size, &s->src_sg, 1);
- if (rc != 1) {
+ s->block_aligned_filename_size, s->src_sg, 2);
+ if (rc < 1) {
printk(KERN_ERR "%s: Internal error whilst attempting to "
"convert encrypted filename memory to scatterlist; "
- "expected rc = 1; got rc = [%d]. "
- "block_aligned_filename_size = [%zd]\n", __func__, rc,
- s->block_aligned_filename_size);
+ "rc = [%d]. block_aligned_filename_size = [%zd]\n",
+ __func__, rc, s->block_aligned_filename_size);
goto out_unlock;
}
(*packet_size) += s->block_aligned_filename_size;
@@ -1028,13 +1025,12 @@
goto out_unlock;
}
rc = virt_to_scatterlist(s->decrypted_filename,
- s->block_aligned_filename_size, &s->dst_sg, 1);
- if (rc != 1) {
+ s->block_aligned_filename_size, s->dst_sg, 2);
+ if (rc < 1) {
printk(KERN_ERR "%s: Internal error whilst attempting to "
"convert decrypted filename memory to scatterlist; "
- "expected rc = 1; got rc = [%d]. "
- "block_aligned_filename_size = [%zd]\n", __func__, rc,
- s->block_aligned_filename_size);
+ "rc = [%d]. block_aligned_filename_size = [%zd]\n",
+ __func__, rc, s->block_aligned_filename_size);
goto out_free_unlock;
}
/* The characters in the first block effectively do the job of
@@ -1065,7 +1061,7 @@
mount_crypt_stat->global_default_fn_cipher_key_bytes);
goto out_free_unlock;
}
- rc = crypto_blkcipher_decrypt_iv(&s->desc, &s->dst_sg, &s->src_sg,
+ rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg,
s->block_aligned_filename_size);
if (rc) {
printk(KERN_ERR "%s: Error attempting to decrypt filename; "