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=1793208317; b=21XrB+BaJg1f8ptOgTNqGMSmPh2WGwZX1d85v2mlviA7EvX2ALNKDqVa5Ef4uz8U4oMG b6pzTDm4nO0MuDcuW6n+kJV1VmuvS3TY5th09dnpzKsakzHoV+hAuyfbZPQCzbl9jyMcP TPye7A1dhpUpaQ+fDHYOcWxnbWUlumlM4wRdn71f3KAmrUguyNZzWEujhS5GxOr4TrWLe dE2cYdGv5j1/oRvhk6yXzzMe/I3wPfJdIGqCsk5NWHzlWf2A24IZUcxzD094FXBrcZBLP n7ANS9FFjDA4/hpNRHqxTOgfzA9xU+3b7UsZ53FjWyvanRvaxbatvOHu/cjnGiSrtIQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793208317; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=NNp7uLiz3RlTlr/Ctnwg4lB6QOulVszF1Rd3o/Oup9M=; b=b6UqcsgwOkI9be2aysoJxq0XI8K+fx049J4dDc4wlSVrNM7+rg8uKbSK7R1x+9jM3k+m 5f4Xt7vAIjBoJfmcwpOtKhzh3OK3pTkF3KqCpQ5ADVIaoniJkKDRt3yw5KoInPgxNRgOn rpBc3geps/qNvQEVmqiV82f6/DPkarSPSfT92zA+OSAoqWqm3OiHzAZ/RDSiWwrcIoL0A LwahwzK4gGykNf32jocMmIOqN9Uq6+TjR9Hm/0eJ943Acab/zn5EygV/WgiITBONE/79v KlHA0sJf6acmGtsSXo0gv7/o5KSx3CxnKsBHA6wmz7Wpgu83ZxS2b73c9kg+41gFXRQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=FQNjGNVK; 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 92F7C606A31A; Wed, 28 Oct 2026 17:25:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=FQNjGNVK Received: by smtp.kernel.org (Postfix) with ESMTPSA id E24EA1F01825; Wed, 28 Oct 2026 17:25:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793208317; bh=NNp7uLiz3RlTlr/Ctnwg4lB6QOulVszF1Rd3o/Oup9M=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=FQNjGNVKJAtJ5pWiPR0HUbtnUga+/HQ/30yHR/ffnbS6ENnxLFGsFQ+i3l6iRWVSJ gA85/+J9BQxh/txp8/y0ORXnl8AxC0g/C05jjnCi+GMZWG6PUE7100Jeqagc15jotN DA9h3xqJOCJr1ul/zrW2W1gcC6sZvPSWe6auwUQ0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+791be35f1fbcc85d06d7@syzkaller.appspotmail.com, stable , Jeffin Philip , Alan Stern , Sasha Levin Subject: [PATCH 5.10 077/516] usb: gadget: f_mass_storage: fix null pointer dereference in fsg_common_set_num_buffers() Date: Wed, 28 Oct 2026 17:53:49 +0100 Message-ID: <20261028170005.346526858@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170003.522232767@linuxfoundation.org> References: <20261028170003.522232767@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeffin Philip [ Upstream commit 2c0f5ca48674a5b5f9fa4a9c3325aa48053af0bc ] Previously fsg_num_buffers_validate() was removed as it was not necessary due to Kconfig setting the limits for n from 2 to 256 with default as 2. However, setting the page content in such a way that kstrtou8() reflects n value as either 0 or 1 bypasses these restrictions leading to a null pointer dereference if n is 0. Fix this by adding a check for n < 2 and returning -EINVAL if n is either 0 or 1 consistent with Kconfig logic. Reported-by: syzbot+791be35f1fbcc85d06d7@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=791be35f1fbcc85d06d7 Fixes: fe5a6c48fd95 ("usb: gadget: storage: get rid of fsg_num_buffers_validate()") Cc: stable Signed-off-by: Jeffin Philip Acked-by: Alan Stern Link: https://patch.msgid.link/20260818035904.10324-1-jeffinphilip14@gmail.com Signed-off-by: Greg Kroah-Hartman [ adjusted context to retain the branch’s existing kcalloc() call instead of kzalloc_objs(). ] Signed-off-by: Sasha Levin --- drivers/usb/gadget/function/f_mass_storage.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c index a9159a95707bd..4d47e5f25dc57 100644 --- a/drivers/usb/gadget/function/f_mass_storage.c +++ b/drivers/usb/gadget/function/f_mass_storage.c @@ -2624,6 +2624,9 @@ int fsg_common_set_num_buffers(struct fsg_common *common, unsigned int n) struct fsg_buffhd *bh, *buffhds; int i; + if (n < 2) + return -EINVAL; + buffhds = kcalloc(n, sizeof(*buffhds), GFP_KERNEL); if (!buffhds) return -ENOMEM; -- 2.53.0