[PATCH] ksmbd: free ppace array on error in parse_dacl

[PATCH] ksmbd: free ppace array on error in parse_dacl

[Fedor Pchelkin]

Free the ppace array if one of the init_acl_state() calls inside
parse_dacl() fails. At the moment the function may fail only due to the
memory allocation errors so it's highly unlikely in this case but
nevertheless a fix is needed.

Found by Linux Verification Center (linuxtesting.org).

Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
---
 fs/smb/server/smbacl.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/smb/server/smbacl.c b/fs/smb/server/smbacl.c
index 1164365533f0..e6d0537cab49 100644
--- a/fs/smb/server/smbacl.c
+++ b/fs/smb/server/smbacl.c
@@ -406,11 +406,14 @@ static void parse_dacl(struct mnt_idmap *idmap,
 		return;
 
 	ret = init_acl_state(&acl_state, num_aces);
-	if (ret)
+	if (ret) {
+		kfree(ppace);
 		return;
+	}
 	ret = init_acl_state(&default_acl_state, num_aces);
 	if (ret) {
 		free_acl_state(&acl_state);
+		kfree(ppace);
 		return;
 	}
 
-- 
2.43.0

Re: [PATCH] ksmbd: free ppace array on error in parse_dacl

[Namjae Jeon]

2024-01-09 22:34 GMT+09:00, Fedor Pchelkin <pchelkin@ispras.ru>:
> Free the ppace array if one of the init_acl_state() calls inside
> parse_dacl() fails. At the moment the function may fail only due to the
> memory allocation errors so it's highly unlikely in this case but
> nevertheless a fix is needed.
>
> Found by Linux Verification Center (linuxtesting.org).
>
> Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
> Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
> ---
>  fs/smb/server/smbacl.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/fs/smb/server/smbacl.c b/fs/smb/server/smbacl.c
> index 1164365533f0..e6d0537cab49 100644
> --- a/fs/smb/server/smbacl.c
> +++ b/fs/smb/server/smbacl.c
> @@ -406,11 +406,14 @@ static void parse_dacl(struct mnt_idmap *idmap,
>  		return;
>
>  	ret = init_acl_state(&acl_state, num_aces);
> -	if (ret)
> +	if (ret) {
> +		kfree(ppace);
>  		return;
> +	}
>  	ret = init_acl_state(&default_acl_state, num_aces);
>  	if (ret) {
>  		free_acl_state(&acl_state);
> +		kfree(ppace);
>  		return;
>  	}
Looks good to me.
But rather than this, How about moving ppace allocation here ?

Thanks for your patch.
>
> --
> 2.43.0
>
>

[PATCH v2] ksmbd: free ppace array on error in parse_dacl

[Fedor Pchelkin]

The ppace array is not freed if one of the init_acl_state() calls inside
parse_dacl() fails. At the moment the function may fail only due to the
memory allocation errors so it's highly unlikely in this case but
nevertheless a fix is needed.

Move ppace allocation after the init_acl_state() calls with proper error
handling.

Found by Linux Verification Center (linuxtesting.org).

Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
---
v2: refine the patch with moving ppace allocation into another place per
    Namjae's suggestion; update the commit description accordingly.

 fs/smb/server/smbacl.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/fs/smb/server/smbacl.c b/fs/smb/server/smbacl.c
index 1164365533f0..1c9775f1efa5 100644
--- a/fs/smb/server/smbacl.c
+++ b/fs/smb/server/smbacl.c
@@ -401,10 +401,6 @@ static void parse_dacl(struct mnt_idmap *idmap,
 	if (num_aces > ULONG_MAX / sizeof(struct smb_ace *))
 		return;
 
-	ppace = kmalloc_array(num_aces, sizeof(struct smb_ace *), GFP_KERNEL);
-	if (!ppace)
-		return;
-
 	ret = init_acl_state(&acl_state, num_aces);
 	if (ret)
 		return;
@@ -414,6 +410,13 @@ static void parse_dacl(struct mnt_idmap *idmap,
 		return;
 	}
 
+	ppace = kmalloc_array(num_aces, sizeof(struct smb_ace *), GFP_KERNEL);
+	if (!ppace) {
+		free_acl_state(&default_acl_state);
+		free_acl_state(&acl_state);
+		return;
+	}
+
 	/*
 	 * reset rwx permissions for user/group/other.
 	 * Also, if num_aces is 0 i.e. DACL has no ACEs,
-- 
2.43.0

Re: [PATCH v2] ksmbd: free ppace array on error in parse_dacl

[Namjae Jeon]

2024-01-09 23:14 GMT+09:00, Fedor Pchelkin <pchelkin@ispras.ru>:
> The ppace array is not freed if one of the init_acl_state() calls inside
> parse_dacl() fails. At the moment the function may fail only due to the
> memory allocation errors so it's highly unlikely in this case but
> nevertheless a fix is needed.
>
> Move ppace allocation after the init_acl_state() calls with proper error
> handling.
>
> Found by Linux Verification Center (linuxtesting.org).
>
> Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
> Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Applied it to #ksmbd-for-next-next.

Thanks for your patch!