From: Michael Bommarito Date: Sun, 19 Apr 2026 23:35:19 +0000 (-0400) Subject: smb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path X-Git-Tag: v7.1-rc1~35^2~14 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e;p=thirdparty%2Fkernel%2Flinux.git smb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path smb2_ioctl_query_info() has two response-copy branches: PASSTHRU_FSCTL and the default QUERY_INFO path. The QUERY_INFO branch clamps qi.input_buffer_length to the server-reported OutputBufferLength and then copies qi.input_buffer_length bytes from qi_rsp->Buffer to userspace, but it never verifies that the flexible-array payload actually fits within rsp_iov[1].iov_len. A malicious server can return OutputBufferLength larger than the actual QUERY_INFO response, causing copy_to_user() to walk past the response buffer and expose adjacent kernel heap to userspace. Guard the QUERY_INFO copy with a bounds check on the actual Buffer payload. Use struct_size(qi_rsp, Buffer, qi.input_buffer_length) rather than an open-coded addition so the guard cannot overflow on 32-bit builds. Fixes: f5778c398713 ("SMB3: Allow SMB3 FSCTL queries to be sent to server from tools") Cc: stable@vger.kernel.org Signed-off-by: Michael Bommarito Assisted-by: Claude:claude-opus-4-6 Assisted-by: Codex:gpt-5-4 Signed-off-by: Steve French --- diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index a2105f4b54db..7f346ee50289 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -1783,6 +1783,12 @@ replay_again: qi_rsp = (struct smb2_query_info_rsp *)rsp_iov[1].iov_base; if (le32_to_cpu(qi_rsp->OutputBufferLength) < qi.input_buffer_length) qi.input_buffer_length = le32_to_cpu(qi_rsp->OutputBufferLength); + if (qi.input_buffer_length > 0 && + struct_size(qi_rsp, Buffer, qi.input_buffer_length) > + rsp_iov[1].iov_len) { + rc = -EFAULT; + goto out; + } if (copy_to_user(&pqi->input_buffer_length, &qi.input_buffer_length, sizeof(qi.input_buffer_length))) {