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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Steve French <sfrench@samba.org>,
	Pavel Shilovsky <pshilov@microsoft.com>
Cc: linux-cifs@vger.kernel.org, samba-technical@lists.samba.org,
	kernel-janitors@vger.kernel.org
Subject: [PATCH] smbfs_client: fix a sign extension bug
Date: Tue, 21 Sep 2021 23:33:35 +0300	[thread overview]
Message-ID: <20210921203335.GB16529@kili> (raw)

The problem is the mismatched types between "ctx->total_len" which is
an unsigned int, "rc" which is an int, and "ctx->rc" which is a
ssize_t.  The code does:

	ctx->rc = (rc == 0) ? ctx->total_len : rc;

We want "ctx->rc" to store the negative "rc" error code.  But what
happens is that "rc" is type promoted to a high unsigned int and
'ctx->rc" will store the high positive value instead of a negative
value.

The fix is to change "rc" from an int to a ssize_t.

Fixes: c610c4b619e5 ("CIFS: Add asynchronous write support through kernel AIO")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 fs/smbfs_client/file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/smbfs_client/file.c b/fs/smbfs_client/file.c
index 4d10c9343890..7db9ddb3381f 100644
--- a/fs/smbfs_client/file.c
+++ b/fs/smbfs_client/file.c
@@ -3111,7 +3111,7 @@ static void collect_uncached_write_data(struct cifs_aio_ctx *ctx)
 	struct cifs_tcon *tcon;
 	struct cifs_sb_info *cifs_sb;
 	struct dentry *dentry = ctx->cfile->dentry;
-	int rc;
+	ssize_t rc;
 
 	tcon = tlink_tcon(ctx->cfile->tlink);
 	cifs_sb = CIFS_SB(dentry->d_sb);
-- 
2.20.1


             reply	other threads:[~2021-09-21 20:34 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-21 20:33 Dan Carpenter [this message]
2021-09-22  1:52 ` Steve French

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