[PATCH] fix error code overwriting in smb2_get_info_filesystem()

[PATCH] fix error code overwriting in smb2_get_info_filesystem()

[Matvey Kovalev]

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()

[Namjae Jeon]

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!

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

[Markus Elfring]

…
> ++ 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