Re: [PATCH] ecryptfs: check for existing key_tfm at mount time
On Thu, 20 Dec 2007 23:18:49 -0600 Eric Sandeen <[EMAIL PROTECTED]> wrote:
> Jeff Moyer pointed out that a mount; umount loop of ecryptfs,
> with the same cipher & other mount options, created a new
> ecryptfs_key_tfm_cache item each time, and the cache could
> grow quite large this way.
>
> Looking at this with mhalcrow, we saw that ecryptfs_parse_options()
> unconditionally called ecryptfs_add_new_key_tfm(), which is what
> was adding these items.
>
> Refactor ecryptfs_get_tfm_and_mutex_for_cipher_name() to create a
> new helper function, ecryptfs_tfm_exists(), which checks for the
> cipher on the cached key_tfm_list, and sets a pointer
> to it if it exists. This can then be called from
> ecryptfs_parse_options(), and new key_tfm's can be added only when
> a cached one is not found.
>
This change looks fishy.
> +/**
> + * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
> + * @cipher_name: the name of the cipher to search for
> + * @key_tfm: set to corresponding tfm if found
> + *
> + * Returns 1 if found, with key_tfm set
> + * Returns 0 if not found, key_tfm set to NULL
> + */
> +int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
> +{
> + struct ecryptfs_key_tfm *tmp_key_tfm;
> +
> + mutex_lock(_tfm_list_mutex);
> + list_for_each_entry(tmp_key_tfm, _tfm_list, key_tfm_list) {
> + if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
> + mutex_unlock(_tfm_list_mutex);
> + if (key_tfm)
> + (*key_tfm) = tmp_key_tfm;
Here we return a pointer to an object without holding the lock and without
taking a refcount on it. What prevents it from getting moved/freed/etc
while this thread of control is playing with it?
> + return 1;
> + }
> + }
> + mutex_unlock(_tfm_list_mutex);
> + if (key_tfm)
> + (*key_tfm) = NULL;
> + return 0;
> +}
> +
> int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
> struct mutex **tfm_mutex,
> char *cipher_name)
> @@ -1877,22 +1904,15 @@ int ecryptfs_get_tfm_and_mutex_for_ciphe
>
> (*tfm) = NULL;
> (*tfm_mutex) = NULL;
> - mutex_lock(_tfm_list_mutex);
> - list_for_each_entry(key_tfm, _tfm_list, key_tfm_list) {
> - if (strcmp(key_tfm->cipher_name, cipher_name) == 0) {
> - (*tfm) = key_tfm->key_tfm;
> - (*tfm_mutex) = _tfm->key_tfm_mutex;
> - mutex_unlock(_tfm_list_mutex);
> +
> + if (!ecryptfs_tfm_exists(cipher_name, _tfm)) {
And given that we've just unlocked key_tfm_list_mutex, how do we know that
the return value from ecryptfs_tfm_exists() is still true in this window?
> + rc = ecryptfs_add_new_key_tfm(_tfm, cipher_name, 0);
> + if (rc) {
> + printk(KERN_ERR "Error adding new key_tfm to list; "
> + "rc = [%d]\n", rc);
> goto out;
> }
> }
> - mutex_unlock(_tfm_list_mutex);
It would all look a lot more solid if this locking was retained and both
ecryptfs_tfm_exists() and ecryptfs_add_new_key_tfm() were designed to be
called under key_tfm_list_mutex.
> @@ -410,9 +410,11 @@ static int ecryptfs_parse_options(struct
> if (!cipher_key_bytes_set) {
> mount_crypt_stat->global_default_cipher_key_size = 0;
> }
> - rc = ecryptfs_add_new_key_tfm(
> - NULL, mount_crypt_stat->global_default_cipher_name,
> - mount_crypt_stat->global_default_cipher_key_size);
> + if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
> + NULL))
> + rc = ecryptfs_add_new_key_tfm(
> + NULL, mount_crypt_stat->global_default_cipher_name,
> + mount_crypt_stat->global_default_cipher_key_size);
dittoes.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] ecryptfs: check for existing key_tfm at mount time
On Thu, Dec 20, 2007 at 11:18:49PM -0600, Eric Sandeen wrote:
> Jeff Moyer pointed out that a mount; umount loop of ecryptfs,
> with the same cipher & other mount options, created a new
> ecryptfs_key_tfm_cache item each time, and the cache could
> grow quite large this way.
>
> Looking at this with mhalcrow, we saw that ecryptfs_parse_options()
> unconditionally called ecryptfs_add_new_key_tfm(), which is what
> was adding these items.
>
> Refactor ecryptfs_get_tfm_and_mutex_for_cipher_name() to create a
> new helper function, ecryptfs_tfm_exists(), which checks for the
> cipher on the cached key_tfm_list, and sets a pointer
> to it if it exists. This can then be called from
> ecryptfs_parse_options(), and new key_tfm's can be added only when
> a cached one is not found.
>
> Signed-off-by: Eric Sandeen <[EMAIL PROTECTED]>
Acked-by: Mike Halcrow <[EMAIL PROTECTED]>
> ---
>
> Index: linux-2.6.24-rc3/fs/ecryptfs/crypto.c
> ===
> --- linux-2.6.24-rc3.orig/fs/ecryptfs/crypto.c
> +++ linux-2.6.24-rc3/fs/ecryptfs/crypto.c
> @@ -1868,6 +1868,33 @@ out:
> return rc;
> }
>
> +/**
> + * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
> + * @cipher_name: the name of the cipher to search for
> + * @key_tfm: set to corresponding tfm if found
> + *
> + * Returns 1 if found, with key_tfm set
> + * Returns 0 if not found, key_tfm set to NULL
> + */
> +int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
> +{
> + struct ecryptfs_key_tfm *tmp_key_tfm;
> +
> + mutex_lock(_tfm_list_mutex);
> + list_for_each_entry(tmp_key_tfm, _tfm_list, key_tfm_list) {
> + if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
> + mutex_unlock(_tfm_list_mutex);
> + if (key_tfm)
> + (*key_tfm) = tmp_key_tfm;
> + return 1;
> + }
> + }
> + mutex_unlock(_tfm_list_mutex);
> + if (key_tfm)
> + (*key_tfm) = NULL;
> + return 0;
> +}
> +
> int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
> struct mutex **tfm_mutex,
> char *cipher_name)
> @@ -1877,22 +1904,15 @@ int ecryptfs_get_tfm_and_mutex_for_ciphe
>
> (*tfm) = NULL;
> (*tfm_mutex) = NULL;
> - mutex_lock(_tfm_list_mutex);
> - list_for_each_entry(key_tfm, _tfm_list, key_tfm_list) {
> - if (strcmp(key_tfm->cipher_name, cipher_name) == 0) {
> - (*tfm) = key_tfm->key_tfm;
> - (*tfm_mutex) = _tfm->key_tfm_mutex;
> - mutex_unlock(_tfm_list_mutex);
> +
> + if (!ecryptfs_tfm_exists(cipher_name, _tfm)) {
> + rc = ecryptfs_add_new_key_tfm(_tfm, cipher_name, 0);
> + if (rc) {
> + printk(KERN_ERR "Error adding new key_tfm to list; "
> + "rc = [%d]\n", rc);
> goto out;
> }
> }
> - mutex_unlock(_tfm_list_mutex);
> - rc = ecryptfs_add_new_key_tfm(_tfm, cipher_name, 0);
> - if (rc) {
> - printk(KERN_ERR "Error adding new key_tfm to list; rc = [%d]\n",
> -rc);
> - goto out;
> - }
> (*tfm) = key_tfm->key_tfm;
> (*tfm_mutex) = _tfm->key_tfm_mutex;
> out:
> Index: linux-2.6.24-rc3/fs/ecryptfs/ecryptfs_kernel.h
> ===
> --- linux-2.6.24-rc3.orig/fs/ecryptfs/ecryptfs_kernel.h
> +++ linux-2.6.24-rc3/fs/ecryptfs/ecryptfs_kernel.h
> @@ -623,6 +623,7 @@ ecryptfs_add_new_key_tfm(struct ecryptfs
>size_t key_size);
> int ecryptfs_init_crypto(void);
> int ecryptfs_destroy_crypto(void);
> +int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm
> **key_tfm);
> int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
> struct mutex **tfm_mutex,
> char *cipher_name);
> Index: linux-2.6.24-rc3/fs/ecryptfs/main.c
> ===
> --- linux-2.6.24-rc3.orig/fs/ecryptfs/main.c
> +++ linux-2.6.24-rc3/fs/ecryptfs/main.c
> @@ -410,9 +410,11 @@ static int ecryptfs_parse_options(struct
> if (!cipher_key_bytes_set) {
> mount_crypt_stat->global_default_cipher_key_size = 0;
> }
> - rc = ecryptfs_add_new_key_tfm(
> - NULL, mount_crypt_stat->global_default_cipher_name,
> - mount_crypt_stat->global_default_cipher_key_size);
> + if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
> + NULL))
> + rc = ecryptfs_add_new_key_tfm(
> + NULL,
Re: [PATCH] ecryptfs: check for existing key_tfm at mount time
On Thu, Dec 20, 2007 at 11:18:49PM -0600, Eric Sandeen wrote:
Jeff Moyer pointed out that a mount; umount loop of ecryptfs,
with the same cipher other mount options, created a new
ecryptfs_key_tfm_cache item each time, and the cache could
grow quite large this way.
Looking at this with mhalcrow, we saw that ecryptfs_parse_options()
unconditionally called ecryptfs_add_new_key_tfm(), which is what
was adding these items.
Refactor ecryptfs_get_tfm_and_mutex_for_cipher_name() to create a
new helper function, ecryptfs_tfm_exists(), which checks for the
cipher on the cached key_tfm_list, and sets a pointer
to it if it exists. This can then be called from
ecryptfs_parse_options(), and new key_tfm's can be added only when
a cached one is not found.
Signed-off-by: Eric Sandeen [EMAIL PROTECTED]
Acked-by: Mike Halcrow [EMAIL PROTECTED]
---
Index: linux-2.6.24-rc3/fs/ecryptfs/crypto.c
===
--- linux-2.6.24-rc3.orig/fs/ecryptfs/crypto.c
+++ linux-2.6.24-rc3/fs/ecryptfs/crypto.c
@@ -1868,6 +1868,33 @@ out:
return rc;
}
+/**
+ * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
+ * @cipher_name: the name of the cipher to search for
+ * @key_tfm: set to corresponding tfm if found
+ *
+ * Returns 1 if found, with key_tfm set
+ * Returns 0 if not found, key_tfm set to NULL
+ */
+int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
+{
+ struct ecryptfs_key_tfm *tmp_key_tfm;
+
+ mutex_lock(key_tfm_list_mutex);
+ list_for_each_entry(tmp_key_tfm, key_tfm_list, key_tfm_list) {
+ if (strcmp(tmp_key_tfm-cipher_name, cipher_name) == 0) {
+ mutex_unlock(key_tfm_list_mutex);
+ if (key_tfm)
+ (*key_tfm) = tmp_key_tfm;
+ return 1;
+ }
+ }
+ mutex_unlock(key_tfm_list_mutex);
+ if (key_tfm)
+ (*key_tfm) = NULL;
+ return 0;
+}
+
int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
struct mutex **tfm_mutex,
char *cipher_name)
@@ -1877,22 +1904,15 @@ int ecryptfs_get_tfm_and_mutex_for_ciphe
(*tfm) = NULL;
(*tfm_mutex) = NULL;
- mutex_lock(key_tfm_list_mutex);
- list_for_each_entry(key_tfm, key_tfm_list, key_tfm_list) {
- if (strcmp(key_tfm-cipher_name, cipher_name) == 0) {
- (*tfm) = key_tfm-key_tfm;
- (*tfm_mutex) = key_tfm-key_tfm_mutex;
- mutex_unlock(key_tfm_list_mutex);
+
+ if (!ecryptfs_tfm_exists(cipher_name, key_tfm)) {
+ rc = ecryptfs_add_new_key_tfm(key_tfm, cipher_name, 0);
+ if (rc) {
+ printk(KERN_ERR Error adding new key_tfm to list;
+ rc = [%d]\n, rc);
goto out;
}
}
- mutex_unlock(key_tfm_list_mutex);
- rc = ecryptfs_add_new_key_tfm(key_tfm, cipher_name, 0);
- if (rc) {
- printk(KERN_ERR Error adding new key_tfm to list; rc = [%d]\n,
-rc);
- goto out;
- }
(*tfm) = key_tfm-key_tfm;
(*tfm_mutex) = key_tfm-key_tfm_mutex;
out:
Index: linux-2.6.24-rc3/fs/ecryptfs/ecryptfs_kernel.h
===
--- linux-2.6.24-rc3.orig/fs/ecryptfs/ecryptfs_kernel.h
+++ linux-2.6.24-rc3/fs/ecryptfs/ecryptfs_kernel.h
@@ -623,6 +623,7 @@ ecryptfs_add_new_key_tfm(struct ecryptfs
size_t key_size);
int ecryptfs_init_crypto(void);
int ecryptfs_destroy_crypto(void);
+int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm
**key_tfm);
int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
struct mutex **tfm_mutex,
char *cipher_name);
Index: linux-2.6.24-rc3/fs/ecryptfs/main.c
===
--- linux-2.6.24-rc3.orig/fs/ecryptfs/main.c
+++ linux-2.6.24-rc3/fs/ecryptfs/main.c
@@ -410,9 +410,11 @@ static int ecryptfs_parse_options(struct
if (!cipher_key_bytes_set) {
mount_crypt_stat-global_default_cipher_key_size = 0;
}
- rc = ecryptfs_add_new_key_tfm(
- NULL, mount_crypt_stat-global_default_cipher_name,
- mount_crypt_stat-global_default_cipher_key_size);
+ if (!ecryptfs_tfm_exists(mount_crypt_stat-global_default_cipher_name,
+ NULL))
+ rc = ecryptfs_add_new_key_tfm(
+ NULL, mount_crypt_stat-global_default_cipher_name,
+ mount_crypt_stat-global_default_cipher_key_size);
if (rc)
Re: [PATCH] ecryptfs: check for existing key_tfm at mount time
On Thu, 20 Dec 2007 23:18:49 -0600 Eric Sandeen [EMAIL PROTECTED] wrote:
Jeff Moyer pointed out that a mount; umount loop of ecryptfs,
with the same cipher other mount options, created a new
ecryptfs_key_tfm_cache item each time, and the cache could
grow quite large this way.
Looking at this with mhalcrow, we saw that ecryptfs_parse_options()
unconditionally called ecryptfs_add_new_key_tfm(), which is what
was adding these items.
Refactor ecryptfs_get_tfm_and_mutex_for_cipher_name() to create a
new helper function, ecryptfs_tfm_exists(), which checks for the
cipher on the cached key_tfm_list, and sets a pointer
to it if it exists. This can then be called from
ecryptfs_parse_options(), and new key_tfm's can be added only when
a cached one is not found.
This change looks fishy.
+/**
+ * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
+ * @cipher_name: the name of the cipher to search for
+ * @key_tfm: set to corresponding tfm if found
+ *
+ * Returns 1 if found, with key_tfm set
+ * Returns 0 if not found, key_tfm set to NULL
+ */
+int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
+{
+ struct ecryptfs_key_tfm *tmp_key_tfm;
+
+ mutex_lock(key_tfm_list_mutex);
+ list_for_each_entry(tmp_key_tfm, key_tfm_list, key_tfm_list) {
+ if (strcmp(tmp_key_tfm-cipher_name, cipher_name) == 0) {
+ mutex_unlock(key_tfm_list_mutex);
+ if (key_tfm)
+ (*key_tfm) = tmp_key_tfm;
Here we return a pointer to an object without holding the lock and without
taking a refcount on it. What prevents it from getting moved/freed/etc
while this thread of control is playing with it?
+ return 1;
+ }
+ }
+ mutex_unlock(key_tfm_list_mutex);
+ if (key_tfm)
+ (*key_tfm) = NULL;
+ return 0;
+}
+
int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
struct mutex **tfm_mutex,
char *cipher_name)
@@ -1877,22 +1904,15 @@ int ecryptfs_get_tfm_and_mutex_for_ciphe
(*tfm) = NULL;
(*tfm_mutex) = NULL;
- mutex_lock(key_tfm_list_mutex);
- list_for_each_entry(key_tfm, key_tfm_list, key_tfm_list) {
- if (strcmp(key_tfm-cipher_name, cipher_name) == 0) {
- (*tfm) = key_tfm-key_tfm;
- (*tfm_mutex) = key_tfm-key_tfm_mutex;
- mutex_unlock(key_tfm_list_mutex);
+
+ if (!ecryptfs_tfm_exists(cipher_name, key_tfm)) {
And given that we've just unlocked key_tfm_list_mutex, how do we know that
the return value from ecryptfs_tfm_exists() is still true in this window?
+ rc = ecryptfs_add_new_key_tfm(key_tfm, cipher_name, 0);
+ if (rc) {
+ printk(KERN_ERR Error adding new key_tfm to list;
+ rc = [%d]\n, rc);
goto out;
}
}
- mutex_unlock(key_tfm_list_mutex);
It would all look a lot more solid if this locking was retained and both
ecryptfs_tfm_exists() and ecryptfs_add_new_key_tfm() were designed to be
called under key_tfm_list_mutex.
@@ -410,9 +410,11 @@ static int ecryptfs_parse_options(struct
if (!cipher_key_bytes_set) {
mount_crypt_stat-global_default_cipher_key_size = 0;
}
- rc = ecryptfs_add_new_key_tfm(
- NULL, mount_crypt_stat-global_default_cipher_name,
- mount_crypt_stat-global_default_cipher_key_size);
+ if (!ecryptfs_tfm_exists(mount_crypt_stat-global_default_cipher_name,
+ NULL))
+ rc = ecryptfs_add_new_key_tfm(
+ NULL, mount_crypt_stat-global_default_cipher_name,
+ mount_crypt_stat-global_default_cipher_key_size);
dittoes.
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[PATCH] ecryptfs: check for existing key_tfm at mount time
Jeff Moyer pointed out that a mount; umount loop of ecryptfs,
with the same cipher & other mount options, created a new
ecryptfs_key_tfm_cache item each time, and the cache could
grow quite large this way.
Looking at this with mhalcrow, we saw that ecryptfs_parse_options()
unconditionally called ecryptfs_add_new_key_tfm(), which is what
was adding these items.
Refactor ecryptfs_get_tfm_and_mutex_for_cipher_name() to create a
new helper function, ecryptfs_tfm_exists(), which checks for the
cipher on the cached key_tfm_list, and sets a pointer
to it if it exists. This can then be called from
ecryptfs_parse_options(), and new key_tfm's can be added only when
a cached one is not found.
Signed-off-by: Eric Sandeen <[EMAIL PROTECTED]>
---
Index: linux-2.6.24-rc3/fs/ecryptfs/crypto.c
===
--- linux-2.6.24-rc3.orig/fs/ecryptfs/crypto.c
+++ linux-2.6.24-rc3/fs/ecryptfs/crypto.c
@@ -1868,6 +1868,33 @@ out:
return rc;
}
+/**
+ * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
+ * @cipher_name: the name of the cipher to search for
+ * @key_tfm: set to corresponding tfm if found
+ *
+ * Returns 1 if found, with key_tfm set
+ * Returns 0 if not found, key_tfm set to NULL
+ */
+int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
+{
+ struct ecryptfs_key_tfm *tmp_key_tfm;
+
+ mutex_lock(_tfm_list_mutex);
+ list_for_each_entry(tmp_key_tfm, _tfm_list, key_tfm_list) {
+ if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
+ mutex_unlock(_tfm_list_mutex);
+ if (key_tfm)
+ (*key_tfm) = tmp_key_tfm;
+ return 1;
+ }
+ }
+ mutex_unlock(_tfm_list_mutex);
+ if (key_tfm)
+ (*key_tfm) = NULL;
+ return 0;
+}
+
int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
struct mutex **tfm_mutex,
char *cipher_name)
@@ -1877,22 +1904,15 @@ int ecryptfs_get_tfm_and_mutex_for_ciphe
(*tfm) = NULL;
(*tfm_mutex) = NULL;
- mutex_lock(_tfm_list_mutex);
- list_for_each_entry(key_tfm, _tfm_list, key_tfm_list) {
- if (strcmp(key_tfm->cipher_name, cipher_name) == 0) {
- (*tfm) = key_tfm->key_tfm;
- (*tfm_mutex) = _tfm->key_tfm_mutex;
- mutex_unlock(_tfm_list_mutex);
+
+ if (!ecryptfs_tfm_exists(cipher_name, _tfm)) {
+ rc = ecryptfs_add_new_key_tfm(_tfm, cipher_name, 0);
+ if (rc) {
+ printk(KERN_ERR "Error adding new key_tfm to list; "
+ "rc = [%d]\n", rc);
goto out;
}
}
- mutex_unlock(_tfm_list_mutex);
- rc = ecryptfs_add_new_key_tfm(_tfm, cipher_name, 0);
- if (rc) {
- printk(KERN_ERR "Error adding new key_tfm to list; rc = [%d]\n",
- rc);
- goto out;
- }
(*tfm) = key_tfm->key_tfm;
(*tfm_mutex) = _tfm->key_tfm_mutex;
out:
Index: linux-2.6.24-rc3/fs/ecryptfs/ecryptfs_kernel.h
===
--- linux-2.6.24-rc3.orig/fs/ecryptfs/ecryptfs_kernel.h
+++ linux-2.6.24-rc3/fs/ecryptfs/ecryptfs_kernel.h
@@ -623,6 +623,7 @@ ecryptfs_add_new_key_tfm(struct ecryptfs
size_t key_size);
int ecryptfs_init_crypto(void);
int ecryptfs_destroy_crypto(void);
+int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm);
int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
struct mutex **tfm_mutex,
char *cipher_name);
Index: linux-2.6.24-rc3/fs/ecryptfs/main.c
===
--- linux-2.6.24-rc3.orig/fs/ecryptfs/main.c
+++ linux-2.6.24-rc3/fs/ecryptfs/main.c
@@ -410,9 +410,11 @@ static int ecryptfs_parse_options(struct
if (!cipher_key_bytes_set) {
mount_crypt_stat->global_default_cipher_key_size = 0;
}
- rc = ecryptfs_add_new_key_tfm(
- NULL, mount_crypt_stat->global_default_cipher_name,
- mount_crypt_stat->global_default_cipher_key_size);
+ if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
+NULL))
+ rc = ecryptfs_add_new_key_tfm(
+ NULL, mount_crypt_stat->global_default_cipher_name,
+ mount_crypt_stat->global_default_cipher_key_size);
if (rc) {
printk(KERN_ERR "Error attempting to initialize cipher with "
"name = [%s] and key
[PATCH] ecryptfs: check for existing key_tfm at mount time
Jeff Moyer pointed out that a mount; umount loop of ecryptfs,
with the same cipher other mount options, created a new
ecryptfs_key_tfm_cache item each time, and the cache could
grow quite large this way.
Looking at this with mhalcrow, we saw that ecryptfs_parse_options()
unconditionally called ecryptfs_add_new_key_tfm(), which is what
was adding these items.
Refactor ecryptfs_get_tfm_and_mutex_for_cipher_name() to create a
new helper function, ecryptfs_tfm_exists(), which checks for the
cipher on the cached key_tfm_list, and sets a pointer
to it if it exists. This can then be called from
ecryptfs_parse_options(), and new key_tfm's can be added only when
a cached one is not found.
Signed-off-by: Eric Sandeen [EMAIL PROTECTED]
---
Index: linux-2.6.24-rc3/fs/ecryptfs/crypto.c
===
--- linux-2.6.24-rc3.orig/fs/ecryptfs/crypto.c
+++ linux-2.6.24-rc3/fs/ecryptfs/crypto.c
@@ -1868,6 +1868,33 @@ out:
return rc;
}
+/**
+ * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
+ * @cipher_name: the name of the cipher to search for
+ * @key_tfm: set to corresponding tfm if found
+ *
+ * Returns 1 if found, with key_tfm set
+ * Returns 0 if not found, key_tfm set to NULL
+ */
+int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
+{
+ struct ecryptfs_key_tfm *tmp_key_tfm;
+
+ mutex_lock(key_tfm_list_mutex);
+ list_for_each_entry(tmp_key_tfm, key_tfm_list, key_tfm_list) {
+ if (strcmp(tmp_key_tfm-cipher_name, cipher_name) == 0) {
+ mutex_unlock(key_tfm_list_mutex);
+ if (key_tfm)
+ (*key_tfm) = tmp_key_tfm;
+ return 1;
+ }
+ }
+ mutex_unlock(key_tfm_list_mutex);
+ if (key_tfm)
+ (*key_tfm) = NULL;
+ return 0;
+}
+
int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
struct mutex **tfm_mutex,
char *cipher_name)
@@ -1877,22 +1904,15 @@ int ecryptfs_get_tfm_and_mutex_for_ciphe
(*tfm) = NULL;
(*tfm_mutex) = NULL;
- mutex_lock(key_tfm_list_mutex);
- list_for_each_entry(key_tfm, key_tfm_list, key_tfm_list) {
- if (strcmp(key_tfm-cipher_name, cipher_name) == 0) {
- (*tfm) = key_tfm-key_tfm;
- (*tfm_mutex) = key_tfm-key_tfm_mutex;
- mutex_unlock(key_tfm_list_mutex);
+
+ if (!ecryptfs_tfm_exists(cipher_name, key_tfm)) {
+ rc = ecryptfs_add_new_key_tfm(key_tfm, cipher_name, 0);
+ if (rc) {
+ printk(KERN_ERR Error adding new key_tfm to list;
+ rc = [%d]\n, rc);
goto out;
}
}
- mutex_unlock(key_tfm_list_mutex);
- rc = ecryptfs_add_new_key_tfm(key_tfm, cipher_name, 0);
- if (rc) {
- printk(KERN_ERR Error adding new key_tfm to list; rc = [%d]\n,
- rc);
- goto out;
- }
(*tfm) = key_tfm-key_tfm;
(*tfm_mutex) = key_tfm-key_tfm_mutex;
out:
Index: linux-2.6.24-rc3/fs/ecryptfs/ecryptfs_kernel.h
===
--- linux-2.6.24-rc3.orig/fs/ecryptfs/ecryptfs_kernel.h
+++ linux-2.6.24-rc3/fs/ecryptfs/ecryptfs_kernel.h
@@ -623,6 +623,7 @@ ecryptfs_add_new_key_tfm(struct ecryptfs
size_t key_size);
int ecryptfs_init_crypto(void);
int ecryptfs_destroy_crypto(void);
+int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm);
int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
struct mutex **tfm_mutex,
char *cipher_name);
Index: linux-2.6.24-rc3/fs/ecryptfs/main.c
===
--- linux-2.6.24-rc3.orig/fs/ecryptfs/main.c
+++ linux-2.6.24-rc3/fs/ecryptfs/main.c
@@ -410,9 +410,11 @@ static int ecryptfs_parse_options(struct
if (!cipher_key_bytes_set) {
mount_crypt_stat-global_default_cipher_key_size = 0;
}
- rc = ecryptfs_add_new_key_tfm(
- NULL, mount_crypt_stat-global_default_cipher_name,
- mount_crypt_stat-global_default_cipher_key_size);
+ if (!ecryptfs_tfm_exists(mount_crypt_stat-global_default_cipher_name,
+NULL))
+ rc = ecryptfs_add_new_key_tfm(
+ NULL, mount_crypt_stat-global_default_cipher_name,
+ mount_crypt_stat-global_default_cipher_key_size);
if (rc) {
printk(KERN_ERR Error attempting to initialize cipher with
name
