On 1/16/2025 2:29 AM, Liang Jie wrote:
From: Liang Jie <liangjie@xxxxxxxxxxx> The `smb2_symlink_err_rsp` structure was previously defined with `ErrorContextData` as a single `__u8` byte. However, the `ErrorContextData` field is intended to be a variable-length array based on `ErrorDataLength`. This mismatch leads to incorrect pointer arithmetic and potential memory access issues when processing error contexts. Updates the `ErrorContextData` field to be a flexible array (`__u8 ErrorContextData[]`). Additionally, it modifies the corresponding casts in the `symlink_data()` function to properly handle the flexible array, ensuring correct memory calculations and data handling.
Is there some reason you didn't also add the __counted_by_le attribute to reference the ErrorDataLength protocol field? Tom.
These changes improve the robustness of SMB2 symlink error processing. Signed-off-by: Liang Jie <liangjie@xxxxxxxxxxx> --- fs/smb/client/smb2file.c | 4 ++-- fs/smb/client/smb2pdu.h | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/smb/client/smb2file.c b/fs/smb/client/smb2file.c index e836bc2193dd..9ec44eab8dbc 100644 --- a/fs/smb/client/smb2file.c +++ b/fs/smb/client/smb2file.c @@ -42,14 +42,14 @@ static struct smb2_symlink_err_rsp *symlink_data(const struct kvec *iov) end = (struct smb2_error_context_rsp *)((u8 *)err + iov->iov_len); do { if (le32_to_cpu(p->ErrorId) == SMB2_ERROR_ID_DEFAULT) { - sym = (struct smb2_symlink_err_rsp *)&p->ErrorContextData; + sym = (struct smb2_symlink_err_rsp *)p->ErrorContextData; break; } cifs_dbg(FYI, "%s: skipping unhandled error context: 0x%x\n", __func__, le32_to_cpu(p->ErrorId));len = ALIGN(le32_to_cpu(p->ErrorDataLength), 8);- p = (struct smb2_error_context_rsp *)((u8 *)&p->ErrorContextData + len); + p = (struct smb2_error_context_rsp *)(p->ErrorContextData + len); } while (p < end); } else if (le32_to_cpu(err->ByteCount) >= sizeof(*sym) && iov->iov_len >= SMB2_SYMLINK_STRUCT_SIZE) { diff --git a/fs/smb/client/smb2pdu.h b/fs/smb/client/smb2pdu.h index 076d9e83e1a0..ba2696352634 100644 --- a/fs/smb/client/smb2pdu.h +++ b/fs/smb/client/smb2pdu.h @@ -79,7 +79,7 @@ struct smb2_symlink_err_rsp { struct smb2_error_context_rsp { __le32 ErrorDataLength; __le32 ErrorId; - __u8 ErrorContextData; /* ErrorDataLength long array */ + __u8 ErrorContextData[]; /* ErrorDataLength long array */ } __packed;/* ErrorId values */
