From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793926177; b=rfarOwYMtTQNV1m61JXFz6igGiPjxcDPycCWYeQWZ5NdtkAudcGtYEmTai6QqRCPg2Ct SEcgQhsifjErshMXBGWf7KPGR0WWJjSjqnCkU2poFoJTO1S8W9orjvQimBhPCR4ptoECs hogfu+6ApjGdc3B+5cjGDP9I9SfzT0Kh8NW2W3ezoAKjHnQiduHlGQYnJ9mEO3jH/l/UW srbmsYTYbfh3LjOBeK/WdlfLIcCZzvIy5qceiWk2FBVSnAvv8ZjVL1gLFHldDDimUoVJo Qvr+i2mEPy2QqFkeQ5IS2eM8hakVDypoZka/tmQjx86mqoCvxC2iJ9Hk690o8cUBh0A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793926177; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=54jePDnVj9kBK3X2+ZZPS/tNJo0wkXHyvA/1b7epDOQ=; b=PPV2kA45nq2kx2VjhA/8Q7CO+oL2sBKl4M+fpYQ+274/JPdMiYK/7ChC4J9YxSMCH3uW sbuLhDVCXbPJHeFxCUZuAn/gEXNnch19QmDgKXQTVQA1Dbk4jNMp39XQjuJFeERBVBGdB ES5moF4Qg8A8Xk9ZSZl/7695cqgTWUIyzspQ4SBjDyXNajt3x+UsyVbA51tQgEQwBXVMh BZp7wJI5MnwUp2V1GDODtif/4fgov0dAdQz957xyz+ZnfeRGlvnvvZVFwo+GFZUzB6oyd gT+Y6tMkT4KJYHJ+60KPJp8lZOLItERcLoY/tDW1m32WJra8FoQj+2vxe8SOfJCev1Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="ED2GlPM/"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 49ABC606A331 for ; Fri, 6 Nov 2026 00:49:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=ED2GlPM/ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 61A111F008A4; Fri, 6 Nov 2026 00:49:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793926177; bh=54jePDnVj9kBK3X2+ZZPS/tNJo0wkXHyvA/1b7epDOQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ED2GlPM/NCzLV1repVjWosXYd6iIniUVcUDLK67dbDTwYJ5EUQcimD2UuVWtuM/lB 124ghAd/nF4+WESN4w0LuRMC4aq1Z8Nr7wZ+PxlRmw/8y2iLEOVUhWz6ACM5qpb8Y4 zfihg6vfGMgYUvdjlEr0I1o/niX3E47UEAGB5dMowCXdtrDKCT5o3vUEpcXtQjdJIw l5ochNNqhmx/iQPK51pjj+YPXvlEPsJ0NYJU71w19rYIHEz+czDfUicFnsZdoH/ype A+fW8TSsQHx+/TDKUbKEaBrsDUgAv7Cm0mMd5qJnAyA/rj4kXbEwXozmjp4xKSeL15 /4UYnO6YZ9P3w== From: Sasha Levin To: stable@vger.kernel.org Cc: Ratnaker Gautam , Namjae Jeon , Paulo Alcantara , Sasha Levin Subject: [PATCH 5.10.y] smb: client: bound POSIX lock data area by response length Date: Thu, 5 Nov 2026 19:49:35 -0500 Message-ID: <20261106004500.2755780-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026110408-eatery-delta-feb8@gregkh> References: <2026110408-eatery-delta-feb8@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Ratnaker Gautam [ Upstream commit 8fc9af68c57156ff64769f30e831553cd03b3000 ] CIFSSMBPosixLock() receives a TRANS2 response whose server-provided DataOffset and DataCount are not required by validate_t2() to describe an interval inside the response. A server can therefore make the client read a cifs_posix_lock beyond the response buffer and return those kernel bytes through F_GETLK. Use smbCalcSize() to obtain the full response length after any multipart TRANS2 reassembly, then reject data areas that extend past it before dereferencing them. Fixes: fc94cdb94462 ("[CIFS] Fix new POSIX Locking for setting lock_type correctly on unlock") Reported-by: Ratnaker Gautam Cc: stable@vger.kernel.org Signed-off-by: Ratnaker Gautam Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara [ sashal: adjusted response validation to subtract the 4-byte header from smbCalcSize() and use plain -EIO instead of traced errors ] Signed-off-by: Sasha Levin --- fs/cifs/cifssmb.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c index 67ff1669cab2a..08ae1d7d2c516 100644 --- a/fs/cifs/cifssmb.c +++ b/fs/cifs/cifssmb.c @@ -2592,6 +2592,7 @@ CIFSSMBPosixLock(const unsigned int xid, struct cifs_tcon *tcon, cifs_dbg(FYI, "Send error in Posix Lock = %d\n", rc); } else if (pLockData) { /* lock structure can be returned on get */ + unsigned int rsp_len; __u16 data_offset; __u16 data_count; rc = validate_t2((struct smb_t2_rsp *)pSMBr); @@ -2602,10 +2603,16 @@ CIFSSMBPosixLock(const unsigned int xid, struct cifs_tcon *tcon, } data_offset = le16_to_cpu(pSMBr->t2.DataOffset); data_count = le16_to_cpu(pSMBr->t2.DataCount); + rsp_len = smbCalcSize(&pSMBr->hdr) - 4; if (data_count < sizeof(struct cifs_posix_lock)) { rc = -EIO; goto plk_err_exit; } + if (data_offset > rsp_len || + data_count > rsp_len - data_offset) { + rc = -EIO; + goto plk_err_exit; + } parm_data = (struct cifs_posix_lock *) ((char *)&pSMBr->hdr.Protocol + data_offset); if (parm_data->lock_type == cpu_to_le16(CIFS_UNLCK)) -- 2.53.0