From ac97b9f9a2d0b83488e0bbcb8517b229d5c9b142 Mon Sep 17 00:00:00 2001 From: Michael Halcrow Date: Wed, 19 Nov 2008 15:36:28 -0800 Subject: [PATCH] eCryptfs: Allocate up to two scatterlists for crypto ops on keys I have received some reports of out-of-memory errors on some older AMD architectures. These errors are what I would expect to see if crypt_stat->key were split between two separate pages. eCryptfs should not assume that any of the memory sent through virt_to_scatterlist() is all contained in a single page, and so this patch allocates two scatterlist structs instead of one when processing keys. I have received confirmation from one person affected by this bug that this patch resolves the issue for him, and so I am submitting it for inclusion in a future stable release. Note that virt_to_scatterlist() runs sg_init_table() on the scatterlist structs passed to it, so the calls to sg_init_table() in decrypt_passphrase_encrypted_session_key() are redundant. Signed-off-by: Michael Halcrow Reported-by: Paulo J. S. Silva Cc: "Leon Woestenberg" Cc: Tim Gardner Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ecryptfs/keystore.c | 31 ++++++++++++++----------------- 1 file changed, 14 insertions(+), 17 deletions(-) diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c index e22bc396134..0d713b69194 100644 --- a/fs/ecryptfs/keystore.c +++ b/fs/ecryptfs/keystore.c @@ -1037,17 +1037,14 @@ static int decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, struct ecryptfs_crypt_stat *crypt_stat) { - struct scatterlist dst_sg; - struct scatterlist src_sg; + struct scatterlist dst_sg[2]; + struct scatterlist src_sg[2]; struct mutex *tfm_mutex; struct blkcipher_desc desc = { .flags = CRYPTO_TFM_REQ_MAY_SLEEP }; int rc = 0; - sg_init_table(&dst_sg, 1); - sg_init_table(&src_sg, 1); - if (unlikely(ecryptfs_verbosity > 0)) { ecryptfs_printk( KERN_DEBUG, "Session key encryption key (size [%d]):\n", @@ -1066,8 +1063,8 @@ decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, } rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key, auth_tok->session_key.encrypted_key_size, - &src_sg, 1); - if (rc != 1) { + src_sg, 2); + if (rc < 1 || rc > 2) { printk(KERN_ERR "Internal error whilst attempting to convert " "auth_tok->session_key.encrypted_key to scatterlist; " "expected rc = 1; got rc = [%d]. " @@ -1079,8 +1076,8 @@ decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, auth_tok->session_key.encrypted_key_size; rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key, auth_tok->session_key.decrypted_key_size, - &dst_sg, 1); - if (rc != 1) { + dst_sg, 2); + if (rc < 1 || rc > 2) { printk(KERN_ERR "Internal error whilst attempting to convert " "auth_tok->session_key.decrypted_key to scatterlist; " "expected rc = 1; got rc = [%d]\n", rc); @@ -1096,7 +1093,7 @@ decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, rc = -EINVAL; goto out; } - rc = crypto_blkcipher_decrypt(&desc, &dst_sg, &src_sg, + rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg, auth_tok->session_key.encrypted_key_size); mutex_unlock(tfm_mutex); if (unlikely(rc)) { @@ -1539,8 +1536,8 @@ write_tag_3_packet(char *dest, size_t *remaining_bytes, size_t i; size_t encrypted_session_key_valid = 0; char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES]; - struct scatterlist dst_sg; - struct scatterlist src_sg; + struct scatterlist dst_sg[2]; + struct scatterlist src_sg[2]; struct mutex *tfm_mutex = NULL; u8 cipher_code; size_t packet_size_length; @@ -1619,8 +1616,8 @@ write_tag_3_packet(char *dest, size_t *remaining_bytes, ecryptfs_dump_hex(session_key_encryption_key, 16); } rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size, - &src_sg, 1); - if (rc != 1) { + src_sg, 2); + if (rc < 1 || rc > 2) { ecryptfs_printk(KERN_ERR, "Error generating scatterlist " "for crypt_stat session key; expected rc = 1; " "got rc = [%d]. key_rec->enc_key_size = [%d]\n", @@ -1629,8 +1626,8 @@ write_tag_3_packet(char *dest, size_t *remaining_bytes, goto out; } rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size, - &dst_sg, 1); - if (rc != 1) { + dst_sg, 2); + if (rc < 1 || rc > 2) { ecryptfs_printk(KERN_ERR, "Error generating scatterlist " "for crypt_stat encrypted session key; " "expected rc = 1; got rc = [%d]. " @@ -1651,7 +1648,7 @@ write_tag_3_packet(char *dest, size_t *remaining_bytes, rc = 0; ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes of the key\n", crypt_stat->key_size); - rc = crypto_blkcipher_encrypt(&desc, &dst_sg, &src_sg, + rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg, (*key_rec).enc_key_size); mutex_unlock(tfm_mutex); if (rc) { -- 2.41.1