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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Luiz Sampaio <sampaio.ime@gmail.com>,
	Miguel Ojeda <ojeda@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 5.15 01/16] auxdisplay: charlcd: checking for pointer reference before dereferencing
Date: Mon,  3 Jan 2022 12:28:34 -0500	[thread overview]
Message-ID: <20220103172849.1612731-1-sashal@kernel.org> (raw)

From: Luiz Sampaio <sampaio.ime@gmail.com>

[ Upstream commit 4daa9ff89ef27be43c15995412d6aee393a78200 ]

Check if the pointer lcd->ops->init_display exists before dereferencing it.
If a driver called charlcd_init() without defining the ops, this would
return segmentation fault, as happened to me when implementing a charlcd
driver.  Checking the pointer before dereferencing protects from
segmentation fault.

Signed-off-by: Luiz Sampaio <sampaio.ime@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/auxdisplay/charlcd.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c
index 304accde365c8..6c010d4efa4ae 100644
--- a/drivers/auxdisplay/charlcd.c
+++ b/drivers/auxdisplay/charlcd.c
@@ -578,6 +578,9 @@ static int charlcd_init(struct charlcd *lcd)
 	 * Since charlcd_init_display() needs to write data, we have to
 	 * enable mark the LCD initialized just before.
 	 */
+	if (WARN_ON(!lcd->ops->init_display))
+		return -EINVAL;
+
 	ret = lcd->ops->init_display(lcd);
 	if (ret)
 		return ret;
-- 
2.34.1


             reply	other threads:[~2022-01-03 17:28 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-03 17:28 Sasha Levin [this message]
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 02/16] drm/amdgpu: fix dropped backing store handling in amdgpu_dma_buf_move_notify Sasha Levin
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 03/16] drm/amd/pm: Fix xgmi link control on aldebaran Sasha Levin
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 04/16] usb: mtu3: fix interval value for intr and isoc Sasha Levin
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 05/16] scsi: libiscsi: Fix UAF in iscsi_conn_get_param()/iscsi_conn_teardown() Sasha Levin
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 06/16] ip6_vti: initialize __ip6_tnl_parm struct in vti6_siocdevprivate Sasha Levin
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 07/16] net: udp: fix alignment problem in udp4_seq_show() Sasha Levin
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 08/16] atlantic: Fix buff_ring OOB in aq_ring_rx_clean Sasha Levin
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 09/16] drm/amd/pm: skip setting gfx cgpg in the s0ix suspend-resume Sasha Levin
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 10/16] drm/amdgpu: always reset the asic in suspend (v2) Sasha Levin
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 11/16] drm/amdgpu: put SMU into proper state on runpm suspending for BOCO capable platform Sasha Levin
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 12/16] mISDN: change function names to avoid conflicts Sasha Levin
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 13/16] drm/amd/display: fix B0 TMDS deepcolor no dislay issue Sasha Levin
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 14/16] drm/amd/display: Added power down for DCN10 Sasha Levin
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 15/16] ipv6: raw: check passed optlen before reading Sasha Levin
2022-01-03 17:28 ` [PATCH AUTOSEL 5.15 16/16] userfaultfd/selftests: fix hugetlb area allocations Sasha Levin

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