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authorNorbert Szetei <norbert@doyensec.com>2025-05-02 08:21:58 +0900
committerSteve French <stfrench@microsoft.com>2025-05-06 08:36:36 -0500
commit0ca6df4f40cf4c32487944aaf48319cb6c25accc (patch)
tree6c6870faed751359efd301b052610fd7f04a1517
parenteb4447bcce915b43b691123118893fca4f372a8f (diff)
ksmbd: prevent out-of-bounds stream writes by validating *pos
ksmbd_vfs_stream_write() did not validate whether the write offset (*pos) was within the bounds of the existing stream data length (v_len). If *pos was greater than or equal to v_len, this could lead to an out-of-bounds memory write. This patch adds a check to ensure *pos is less than v_len before proceeding. If the condition fails, -EINVAL is returned. Cc: stable@vger.kernel.org Signed-off-by: Norbert Szetei <norbert@doyensec.com> Acked-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
-rw-r--r--fs/smb/server/vfs.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c
index 391d07da586c..482eba0f4dc1 100644
--- a/fs/smb/server/vfs.c
+++ b/fs/smb/server/vfs.c
@@ -426,6 +426,13 @@ static int ksmbd_vfs_stream_write(struct ksmbd_file *fp, char *buf, loff_t *pos,
goto out;
}
+ if (v_len <= *pos) {
+ pr_err("stream write position %lld is out of bounds (stream length: %zd)\n",
+ *pos, v_len);
+ err = -EINVAL;
+ goto out;
+ }
+
if (v_len < size) {
wbuf = kvzalloc(size, KSMBD_DEFAULT_GFP);
if (!wbuf) {