6.10-stable review patch. If anyone has any objections, please let me know.
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From: Dan Carpenter dan.carpenter@linaro.org
[ Upstream commit 0627cef36145c9ff9845bdfd7ddf485bbac1f981 ]
There are actually two bugs here. First, we need to ensure that count is at least sizeof(u32) or msg.len will be uninitialized data.
The "msg.len" variable is a u32 that comes from the user. On 32bit systems the "sizeof_field(struct ipmi_ssif_msg, len) + msg.len" addition can overflow if "msg.len" is greater than U32_MAX - 4.
Valid lengths for "msg.len" are 1-254. Add a check for that to prevent the integer overflow.
Fixes: dd2bc5cc9e25 ("ipmi: ssif_bmc: Add SSIF BMC driver") Signed-off-by: Dan Carpenter dan.carpenter@linaro.org Message-Id: 1431ca2e-4e9c-4520-bfc0-6879313c30e9@moroto.mountain Signed-off-by: Corey Minyard corey@minyard.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/char/ipmi/ssif_bmc.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c index 56346fb328727..ab4e87a99f087 100644 --- a/drivers/char/ipmi/ssif_bmc.c +++ b/drivers/char/ipmi/ssif_bmc.c @@ -177,13 +177,15 @@ static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t unsigned long flags; ssize_t ret;
- if (count > sizeof(struct ipmi_ssif_msg)) + if (count < sizeof(msg.len) || + count > sizeof(struct ipmi_ssif_msg)) return -EINVAL;
if (copy_from_user(&msg, buf, count)) return -EFAULT;
- if (!msg.len || count < sizeof_field(struct ipmi_ssif_msg, len) + msg.len) + if (!msg.len || msg.len > IPMI_SSIF_PAYLOAD_MAX || + count < sizeof_field(struct ipmi_ssif_msg, len) + msg.len) return -EINVAL;
spin_lock_irqsave(&ssif_bmc->lock, flags);