fix error code overwriting in smb2_get_info_filesystem()

[PATCH] fix error code overwriting in smb2_get_info_filesystem()

Posted by Matvey Kovalev 4 months, 2 weeks ago

If client doesn't negotiate with SMB3.1.1 POSIX Extensions, 
then proper error code won't be returned due to overwriting.

Return error immediately.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: e2f34481b24db ("cifsd: add server-side procedures for SMB3")
Cc: stable@vger.kernel.org
Signed-off-by: Matvey Kovalev <matvey.kovalev@ispras.ru>
---
 fs/smb/server/smb2pdu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index a565fc36cee6d..a1db006ab6e92 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -5628,7 +5628,8 @@ static int smb2_get_info_filesystem(struct ksmbd_work *work,
 
 		if (!work->tcon->posix_extensions) {
 			pr_err("client doesn't negotiate with SMB3.1.1 POSIX Extensions\n");
-			rc = -EOPNOTSUPP;
+			path_put(&path);
+			return -EOPNOTSUPP;
 		} else {
 			info = (struct filesystem_posix_info *)(rsp->Buffer);
 			info->OptimalTransferSize = cpu_to_le32(stfs.f_bsize);
-- 
2.43.0.windows.1

Re: [PATCH] fix error code overwriting in smb2_get_info_filesystem()

Posted by Markus Elfring 4 months, 2 weeks ago

…
> ++ b/fs/smb/server/smb2pdu.c
> @@ -5628,7 +5628,8 @@ static int smb2_get_info_filesystem(struct ksmbd_work *work,
>  
>  		if (!work->tcon->posix_extensions) {
>  			pr_err("client doesn't negotiate with SMB3.1.1 POSIX Extensions\n");
> -			rc = -EOPNOTSUPP;
> +			path_put(&path);
> +			return -EOPNOTSUPP;
>  		} else {
>  			info = (struct filesystem_posix_info *)(rsp->Buffer);
>  			info->OptimalTransferSize = cpu_to_le32(stfs.f_bsize);
…

How do you think about to avoid duplicate source code another bit?
https://elixir.bootlin.com/linux/v6.17-rc7/source/fs/smb/server/smb2pdu.c#L5437-L5653
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/coding-style.rst?h=v6.17-rc7#n532

Would you like to choose a more appropriate subsystem specification?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.17-rc7#n646

Regards,
Markus

Re: [PATCH] fix error code overwriting in smb2_get_info_filesystem()

Posted by Namjae Jeon 4 months, 2 weeks ago

On Thu, Sep 25, 2025 at 9:14 PM Matvey Kovalev <matvey.kovalev@ispras.ru> wrote:
>
> If client doesn't negotiate with SMB3.1.1 POSIX Extensions,
> then proper error code won't be returned due to overwriting.
>
> Return error immediately.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: e2f34481b24db ("cifsd: add server-side procedures for SMB3")
> Cc: stable@vger.kernel.org
> Signed-off-by: Matvey Kovalev <matvey.kovalev@ispras.ru>
Applied it to #ksmbd-for-next-next.
Thanks!