[PATCH 0/2] fsverity: simplify initcall and move sysctl registration

[PATCH 0/2] fsverity: simplify initcall and move sysctl registration

[Eric Biggers]

This series simplifies handling of errors during the fsverity_init()
initcall, and moves the sysctl registration out of signature.c so that
it is not unnecessarily tied to the builtin signature feature.

Eric Biggers (2):
  fsverity: simplify handling of errors during initcall
  fsverity: move sysctl registration out of signature.c

 fs/verity/fsverity_private.h | 12 +++----
 fs/verity/init.c             | 56 ++++++++++++++++++++-------------
 fs/verity/open.c             | 18 +++--------
 fs/verity/signature.c        | 61 +++++-------------------------------
 fs/verity/verify.c           | 11 ++-----
 5 files changed, 55 insertions(+), 103 deletions(-)


base-commit: ace1ba1c9038b30f29c5759bc4726bbed7748f15
-- 
2.41.0

[PATCH 1/2] fsverity: simplify handling of errors during initcall

[Eric Biggers]

From: Eric Biggers <ebiggers@google.com>

Since CONFIG_FS_VERITY is a bool, not a tristate, fs/verity/ can only be
builtin or absent entirely; it can't be a loadable module.  Therefore,
the error code that gets returned from the fsverity_init() initcall is
never used.  If any part of the initcall does fail, which should never
happen, the kernel will be left in a bad state.

Following the usual convention for builtin code, just panic the kernel
if any of part of the initcall fails.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/verity/fsverity_private.h | 11 ++++------
 fs/verity/init.c             | 24 +++------------------
 fs/verity/open.c             | 18 +++++-----------
 fs/verity/signature.c        | 42 ++++++++++++------------------------
 fs/verity/verify.c           | 11 ++--------
 5 files changed, 28 insertions(+), 78 deletions(-)

diff --git a/fs/verity/fsverity_private.h b/fs/verity/fsverity_private.h
index 49bf3a1eb2a02..c5ab9023dd2d3 100644
--- a/fs/verity/fsverity_private.h
+++ b/fs/verity/fsverity_private.h
@@ -118,8 +118,7 @@ void fsverity_free_info(struct fsverity_info *vi);
 int fsverity_get_descriptor(struct inode *inode,
 			    struct fsverity_descriptor **desc_ret);
 
-int __init fsverity_init_info_cache(void);
-void __init fsverity_exit_info_cache(void);
+void __init fsverity_init_info_cache(void);
 
 /* signature.c */
 
@@ -127,7 +126,7 @@ void __init fsverity_exit_info_cache(void);
 int fsverity_verify_signature(const struct fsverity_info *vi,
 			      const u8 *signature, size_t sig_size);
 
-int __init fsverity_init_signature(void);
+void __init fsverity_init_signature(void);
 #else /* !CONFIG_FS_VERITY_BUILTIN_SIGNATURES */
 static inline int
 fsverity_verify_signature(const struct fsverity_info *vi,
@@ -136,15 +135,13 @@ fsverity_verify_signature(const struct fsverity_info *vi,
 	return 0;
 }
 
-static inline int fsverity_init_signature(void)
+static inline void fsverity_init_signature(void)
 {
-	return 0;
 }
 #endif /* !CONFIG_FS_VERITY_BUILTIN_SIGNATURES */
 
 /* verify.c */
 
-int __init fsverity_init_workqueue(void);
-void __init fsverity_exit_workqueue(void);
+void __init fsverity_init_workqueue(void);
 
 #endif /* _FSVERITY_PRIVATE_H */
diff --git a/fs/verity/init.c b/fs/verity/init.c
index 0239051510355..bcd11d63eb1ca 100644
--- a/fs/verity/init.c
+++ b/fs/verity/init.c
@@ -33,28 +33,10 @@ void fsverity_msg(const struct inode *inode, const char *level,
 
 static int __init fsverity_init(void)
 {
-	int err;
-
 	fsverity_check_hash_algs();
-
-	err = fsverity_init_info_cache();
-	if (err)
-		return err;
-
-	err = fsverity_init_workqueue();
-	if (err)
-		goto err_exit_info_cache;
-
-	err = fsverity_init_signature();
-	if (err)
-		goto err_exit_workqueue;
-
+	fsverity_init_info_cache();
+	fsverity_init_workqueue();
+	fsverity_init_signature();
 	return 0;
-
-err_exit_workqueue:
-	fsverity_exit_workqueue();
-err_exit_info_cache:
-	fsverity_exit_info_cache();
-	return err;
 }
 late_initcall(fsverity_init)
diff --git a/fs/verity/open.c b/fs/verity/open.c
index 1db5106a9c385..6c31a871b84bc 100644
--- a/fs/verity/open.c
+++ b/fs/verity/open.c
@@ -408,18 +408,10 @@ void __fsverity_cleanup_inode(struct inode *inode)
 }
 EXPORT_SYMBOL_GPL(__fsverity_cleanup_inode);
 
-int __init fsverity_init_info_cache(void)
+void __init fsverity_init_info_cache(void)
 {
-	fsverity_info_cachep = KMEM_CACHE_USERCOPY(fsverity_info,
-						   SLAB_RECLAIM_ACCOUNT,
-						   file_digest);
-	if (!fsverity_info_cachep)
-		return -ENOMEM;
-	return 0;
-}
-
-void __init fsverity_exit_info_cache(void)
-{
-	kmem_cache_destroy(fsverity_info_cachep);
-	fsverity_info_cachep = NULL;
+	fsverity_info_cachep = KMEM_CACHE_USERCOPY(
+					fsverity_info,
+					SLAB_RECLAIM_ACCOUNT | SLAB_PANIC,
+					file_digest);
 }
diff --git a/fs/verity/signature.c b/fs/verity/signature.c
index 72034bc71c9d9..ec75ffec069ed 100644
--- a/fs/verity/signature.c
+++ b/fs/verity/signature.c
@@ -109,43 +109,29 @@ static struct ctl_table fsverity_sysctl_table[] = {
 	{ }
 };
 
-static int __init fsverity_sysctl_init(void)
+static void __init fsverity_sysctl_init(void)
 {
-	fsverity_sysctl_header = register_sysctl("fs/verity", fsverity_sysctl_table);
-	if (!fsverity_sysctl_header) {
-		pr_err("sysctl registration failed!\n");
-		return -ENOMEM;
-	}
-	return 0;
+	fsverity_sysctl_header = register_sysctl("fs/verity",
+						 fsverity_sysctl_table);
+	if (!fsverity_sysctl_header)
+		panic("fsverity sysctl registration failed");
 }
 #else /* !CONFIG_SYSCTL */
-static inline int __init fsverity_sysctl_init(void)
+static inline void fsverity_sysctl_init(void)
 {
-	return 0;
 }
 #endif /* !CONFIG_SYSCTL */
 
-int __init fsverity_init_signature(void)
+void __init fsverity_init_signature(void)
 {
-	struct key *ring;
-	int err;
-
-	ring = keyring_alloc(".fs-verity", KUIDT_INIT(0), KGIDT_INIT(0),
-			     current_cred(), KEY_POS_SEARCH |
+	fsverity_keyring =
+		keyring_alloc(".fs-verity", KUIDT_INIT(0), KGIDT_INIT(0),
+			      current_cred(), KEY_POS_SEARCH |
 				KEY_USR_VIEW | KEY_USR_READ | KEY_USR_WRITE |
 				KEY_USR_SEARCH | KEY_USR_SETATTR,
-			     KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
-	if (IS_ERR(ring))
-		return PTR_ERR(ring);
-
-	err = fsverity_sysctl_init();
-	if (err)
-		goto err_put_ring;
-
-	fsverity_keyring = ring;
-	return 0;
+			      KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
+	if (IS_ERR(fsverity_keyring))
+		panic("failed to allocate \".fs-verity\" keyring");
 
-err_put_ring:
-	key_put(ring);
-	return err;
+	fsverity_sysctl_init();
 }
diff --git a/fs/verity/verify.c b/fs/verity/verify.c
index 433cef51f5f6b..904ccd7e8e162 100644
--- a/fs/verity/verify.c
+++ b/fs/verity/verify.c
@@ -346,7 +346,7 @@ void fsverity_enqueue_verify_work(struct work_struct *work)
 }
 EXPORT_SYMBOL_GPL(fsverity_enqueue_verify_work);
 
-int __init fsverity_init_workqueue(void)
+void __init fsverity_init_workqueue(void)
 {
 	/*
 	 * Use a high-priority workqueue to prioritize verification work, which
@@ -360,12 +360,5 @@ int __init fsverity_init_workqueue(void)
 						  WQ_HIGHPRI,
 						  num_online_cpus());
 	if (!fsverity_read_workqueue)
-		return -ENOMEM;
-	return 0;
-}
-
-void __init fsverity_exit_workqueue(void)
-{
-	destroy_workqueue(fsverity_read_workqueue);
-	fsverity_read_workqueue = NULL;
+		panic("failed to allocate fsverity_read_queue");
 }

base-commit: ace1ba1c9038b30f29c5759bc4726bbed7748f15
-- 
2.41.0

[PATCH 2/2] fsverity: move sysctl registration out of signature.c

[Eric Biggers]

From: Eric Biggers <ebiggers@google.com>

Currently the registration of the fsverity sysctls happens in
signature.c, which couples it to CONFIG_FS_VERITY_BUILTIN_SIGNATURES.

This makes it hard to add new sysctls unrelated to builtin signatures.

Also, some users have started checking whether the directory
/proc/sys/fs/verity exists as a way to tell whether fsverity is
supported.  This isn't the intended method; instead, the existence of
/sys/fs/$fstype/features/verity should be checked, or users should just
try to use the fsverity ioctls.  Regardlesss, it should be made to work
as expected without a dependency on CONFIG_FS_VERITY_BUILTIN_SIGNATURES.

Therefore, move the sysctl registration into init.c.  With
CONFIG_FS_VERITY_BUILTIN_SIGNATURES, nothing changes.  Without it, but
with CONFIG_FS_VERITY, an empty list of sysctls is now registered.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/verity/fsverity_private.h |  1 +
 fs/verity/init.c             | 32 ++++++++++++++++++++++++++++++++
 fs/verity/signature.c        | 33 +--------------------------------
 3 files changed, 34 insertions(+), 32 deletions(-)

diff --git a/fs/verity/fsverity_private.h b/fs/verity/fsverity_private.h
index c5ab9023dd2d3..d071a6e32581e 100644
--- a/fs/verity/fsverity_private.h
+++ b/fs/verity/fsverity_private.h
@@ -123,6 +123,7 @@ void __init fsverity_init_info_cache(void);
 /* signature.c */
 
 #ifdef CONFIG_FS_VERITY_BUILTIN_SIGNATURES
+extern int fsverity_require_signatures;
 int fsverity_verify_signature(const struct fsverity_info *vi,
 			      const u8 *signature, size_t sig_size);
 
diff --git a/fs/verity/init.c b/fs/verity/init.c
index bcd11d63eb1ca..a29f062f6047b 100644
--- a/fs/verity/init.c
+++ b/fs/verity/init.c
@@ -9,6 +9,37 @@
 
 #include <linux/ratelimit.h>
 
+#ifdef CONFIG_SYSCTL
+static struct ctl_table_header *fsverity_sysctl_header;
+
+static struct ctl_table fsverity_sysctl_table[] = {
+#ifdef CONFIG_FS_VERITY_BUILTIN_SIGNATURES
+	{
+		.procname       = "require_signatures",
+		.data           = &fsverity_require_signatures,
+		.maxlen         = sizeof(int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec_minmax,
+		.extra1         = SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE,
+	},
+#endif
+	{ }
+};
+
+static void __init fsverity_init_sysctl(void)
+{
+	fsverity_sysctl_header = register_sysctl("fs/verity",
+						 fsverity_sysctl_table);
+	if (!fsverity_sysctl_header)
+		panic("fsverity sysctl registration failed");
+}
+#else /* CONFIG_SYSCTL */
+static inline void fsverity_init_sysctl(void)
+{
+}
+#endif /* !CONFIG_SYSCTL */
+
 void fsverity_msg(const struct inode *inode, const char *level,
 		  const char *fmt, ...)
 {
@@ -36,6 +67,7 @@ static int __init fsverity_init(void)
 	fsverity_check_hash_algs();
 	fsverity_init_info_cache();
 	fsverity_init_workqueue();
+	fsverity_init_sysctl();
 	fsverity_init_signature();
 	return 0;
 }
diff --git a/fs/verity/signature.c b/fs/verity/signature.c
index ec75ffec069ed..b95acae64eac6 100644
--- a/fs/verity/signature.c
+++ b/fs/verity/signature.c
@@ -24,7 +24,7 @@
  * /proc/sys/fs/verity/require_signatures
  * If 1, all verity files must have a valid builtin signature.
  */
-static int fsverity_require_signatures;
+int fsverity_require_signatures;
 
 /*
  * Keyring that contains the trusted X.509 certificates.
@@ -93,35 +93,6 @@ int fsverity_verify_signature(const struct fsverity_info *vi,
 	return 0;
 }
 
-#ifdef CONFIG_SYSCTL
-static struct ctl_table_header *fsverity_sysctl_header;
-
-static struct ctl_table fsverity_sysctl_table[] = {
-	{
-		.procname       = "require_signatures",
-		.data           = &fsverity_require_signatures,
-		.maxlen         = sizeof(int),
-		.mode           = 0644,
-		.proc_handler   = proc_dointvec_minmax,
-		.extra1         = SYSCTL_ZERO,
-		.extra2         = SYSCTL_ONE,
-	},
-	{ }
-};
-
-static void __init fsverity_sysctl_init(void)
-{
-	fsverity_sysctl_header = register_sysctl("fs/verity",
-						 fsverity_sysctl_table);
-	if (!fsverity_sysctl_header)
-		panic("fsverity sysctl registration failed");
-}
-#else /* !CONFIG_SYSCTL */
-static inline void fsverity_sysctl_init(void)
-{
-}
-#endif /* !CONFIG_SYSCTL */
-
 void __init fsverity_init_signature(void)
 {
 	fsverity_keyring =
@@ -132,6 +103,4 @@ void __init fsverity_init_signature(void)
 			      KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
 	if (IS_ERR(fsverity_keyring))
 		panic("failed to allocate \".fs-verity\" keyring");
-
-	fsverity_sysctl_init();
 }
-- 
2.41.0

Re: [PATCH 2/2] fsverity: move sysctl registration out of signature.c

[Joel Granados]

[-- Attachment #1: Type: text/plain, Size: 3571 bytes --]

On Wed, Jul 05, 2023 at 02:27:43PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> Currently the registration of the fsverity sysctls happens in
> signature.c, which couples it to CONFIG_FS_VERITY_BUILTIN_SIGNATURES.
> 
> This makes it hard to add new sysctls unrelated to builtin signatures.
> 
> Also, some users have started checking whether the directory
> /proc/sys/fs/verity exists as a way to tell whether fsverity is
> supported.  This isn't the intended method; instead, the existence of
> /sys/fs/$fstype/features/verity should be checked, or users should just
> try to use the fsverity ioctls.  Regardlesss, it should be made to work
> as expected without a dependency on CONFIG_FS_VERITY_BUILTIN_SIGNATURES.
> 
> Therefore, move the sysctl registration into init.c.  With
> CONFIG_FS_VERITY_BUILTIN_SIGNATURES, nothing changes.  Without it, but
> with CONFIG_FS_VERITY, an empty list of sysctls is now registered.
> 
> Signed-off-by: Eric Biggers <ebiggers@google.com>
> ---
>  fs/verity/fsverity_private.h |  1 +
>  fs/verity/init.c             | 32 ++++++++++++++++++++++++++++++++
>  fs/verity/signature.c        | 33 +--------------------------------
>  3 files changed, 34 insertions(+), 32 deletions(-)
> 
> diff --git a/fs/verity/fsverity_private.h b/fs/verity/fsverity_private.h
> index c5ab9023dd2d3..d071a6e32581e 100644
> --- a/fs/verity/fsverity_private.h
> +++ b/fs/verity/fsverity_private.h
> @@ -123,6 +123,7 @@ void __init fsverity_init_info_cache(void);
>  /* signature.c */
>  
>  #ifdef CONFIG_FS_VERITY_BUILTIN_SIGNATURES
> +extern int fsverity_require_signatures;
>  int fsverity_verify_signature(const struct fsverity_info *vi,
>  			      const u8 *signature, size_t sig_size);
>  
> diff --git a/fs/verity/init.c b/fs/verity/init.c
> index bcd11d63eb1ca..a29f062f6047b 100644
> --- a/fs/verity/init.c
> +++ b/fs/verity/init.c
> @@ -9,6 +9,37 @@
>  
>  #include <linux/ratelimit.h>
>  
> +#ifdef CONFIG_SYSCTL
> +static struct ctl_table_header *fsverity_sysctl_header;
> +
> +static struct ctl_table fsverity_sysctl_table[] = {
> +#ifdef CONFIG_FS_VERITY_BUILTIN_SIGNATURES
> +	{
> +		.procname       = "require_signatures",
> +		.data           = &fsverity_require_signatures,
> +		.maxlen         = sizeof(int),
> +		.mode           = 0644,
> +		.proc_handler   = proc_dointvec_minmax,
> +		.extra1         = SYSCTL_ZERO,
> +		.extra2         = SYSCTL_ONE,
> +	},
> +#endif
> +	{ }
> +};
> +
Just to double check: When CONFIG_FS_VERITY_BUILTIN_SIGNATURES is not
defined then you expect an empty directory under "fs/verity". right?

I'm double checking as part of the ongoing "removing the sentinel" patch
set. Latest patchset here
https://lore.kernel.org/all/20230906-jag-sysctl_remove_empty_elem_arch-v1-0-3935d4854248@samsung.com/.
The filesystem chunk has not yet been publish, but I'm making it ready
for when that time comes.

> +static void __init fsverity_init_sysctl(void)
> +{
> +	fsverity_sysctl_header = register_sysctl("fs/verity",
> +						 fsverity_sysctl_table);
> +	if (!fsverity_sysctl_header)
> +		panic("fsverity sysctl registration failed");
> +}
> +#else /* CONFIG_SYSCTL */
> +static inline void fsverity_init_sysctl(void)
> +{
> +}
> +#endif /* !CONFIG_SYSCTL */
> +
>  void fsverity_msg(const struct inode *inode, const char *level,
>  		  const char *fmt, ...)
>  {
> @@ -36,6 +67,7 @@ static int __init fsverity_init(void)
>  	fsverity_check_hash_algs();
...

Best
-- 

Joel Granados

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 659 bytes --]

Re: [PATCH 2/2] fsverity: move sysctl registration out of signature.c

[Eric Biggers]

On Wed, Sep 06, 2023 at 03:49:04PM +0200, Joel Granados wrote:
> On Wed, Jul 05, 2023 at 02:27:43PM -0700, Eric Biggers wrote:
> > From: Eric Biggers <ebiggers@google.com>
> > 
> > Currently the registration of the fsverity sysctls happens in
> > signature.c, which couples it to CONFIG_FS_VERITY_BUILTIN_SIGNATURES.
> > 
> > This makes it hard to add new sysctls unrelated to builtin signatures.
> > 
> > Also, some users have started checking whether the directory
> > /proc/sys/fs/verity exists as a way to tell whether fsverity is
> > supported.  This isn't the intended method; instead, the existence of
> > /sys/fs/$fstype/features/verity should be checked, or users should just
> > try to use the fsverity ioctls.  Regardlesss, it should be made to work
> > as expected without a dependency on CONFIG_FS_VERITY_BUILTIN_SIGNATURES.
> > 
> > Therefore, move the sysctl registration into init.c.  With
> > CONFIG_FS_VERITY_BUILTIN_SIGNATURES, nothing changes.  Without it, but
> > with CONFIG_FS_VERITY, an empty list of sysctls is now registered.
> > 
> > Signed-off-by: Eric Biggers <ebiggers@google.com>
> > ---
> >  fs/verity/fsverity_private.h |  1 +
> >  fs/verity/init.c             | 32 ++++++++++++++++++++++++++++++++
> >  fs/verity/signature.c        | 33 +--------------------------------
> >  3 files changed, 34 insertions(+), 32 deletions(-)
> > 
> > diff --git a/fs/verity/fsverity_private.h b/fs/verity/fsverity_private.h
> > index c5ab9023dd2d3..d071a6e32581e 100644
> > --- a/fs/verity/fsverity_private.h
> > +++ b/fs/verity/fsverity_private.h
> > @@ -123,6 +123,7 @@ void __init fsverity_init_info_cache(void);
> >  /* signature.c */
> >  
> >  #ifdef CONFIG_FS_VERITY_BUILTIN_SIGNATURES
> > +extern int fsverity_require_signatures;
> >  int fsverity_verify_signature(const struct fsverity_info *vi,
> >  			      const u8 *signature, size_t sig_size);
> >  
> > diff --git a/fs/verity/init.c b/fs/verity/init.c
> > index bcd11d63eb1ca..a29f062f6047b 100644
> > --- a/fs/verity/init.c
> > +++ b/fs/verity/init.c
> > @@ -9,6 +9,37 @@
> >  
> >  #include <linux/ratelimit.h>
> >  
> > +#ifdef CONFIG_SYSCTL
> > +static struct ctl_table_header *fsverity_sysctl_header;
> > +
> > +static struct ctl_table fsverity_sysctl_table[] = {
> > +#ifdef CONFIG_FS_VERITY_BUILTIN_SIGNATURES
> > +	{
> > +		.procname       = "require_signatures",
> > +		.data           = &fsverity_require_signatures,
> > +		.maxlen         = sizeof(int),
> > +		.mode           = 0644,
> > +		.proc_handler   = proc_dointvec_minmax,
> > +		.extra1         = SYSCTL_ZERO,
> > +		.extra2         = SYSCTL_ONE,
> > +	},
> > +#endif
> > +	{ }
> > +};
> > +
> Just to double check: When CONFIG_FS_VERITY_BUILTIN_SIGNATURES is not
> defined then you expect an empty directory under "fs/verity". right?

Yes, that's correct.

- Eric

Re: [f2fs-dev] [PATCH 0/2] fsverity: simplify initcall and move sysctl registration

[patchwork-bot+f2fs]

Hello:

This series was applied to jaegeuk/f2fs.git (dev)
by Eric Biggers <ebiggers@google.com>:

On Wed,  5 Jul 2023 14:27:41 -0700 you wrote:
> This series simplifies handling of errors during the fsverity_init()
> initcall, and moves the sysctl registration out of signature.c so that
> it is not unnecessarily tied to the builtin signature feature.
> 
> Eric Biggers (2):
>   fsverity: simplify handling of errors during initcall
>   fsverity: move sysctl registration out of signature.c
> 
> [...]

Here is the summary with links:
  - [f2fs-dev,1/2] fsverity: simplify handling of errors during initcall
    https://git.kernel.org/jaegeuk/f2fs/c/e77000ccc531
  - [f2fs-dev,2/2] fsverity: move sysctl registration out of signature.c
    https://git.kernel.org/jaegeuk/f2fs/c/456ae5fe9b44

You are awesome, thank you!
-- 
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