A malicious user could pass an arbitrarily bad value to memdup_user_nul(), potentially causing kernel crash.

This follows the same pattern as commit ee76746387f6 ("netdevsim: prevent bad user input in nsim_dev_health_break_write()") and commit 7ef4c19d245f ("smackfs: restrict bytes count in smackfs write functions")

Found via static analysis and code review.

Fixes: 183238ffb886 ("misc: eeprom/idt_89hpesx: Switch to memdup_user_nul() helper") Cc: stable@vger.kernel.org Signed-off-by: Miaoqian Lin linmq006@gmail.com --- drivers/misc/eeprom/idt_89hpesx.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/drivers/misc/eeprom/idt_89hpesx.c b/drivers/misc/eeprom/idt_89hpesx.c index 60c42170d147..b2e771bfc6da 100644 --- a/drivers/misc/eeprom/idt_89hpesx.c +++ b/drivers/misc/eeprom/idt_89hpesx.c @@ -907,6 +907,9 @@ static ssize_t idt_dbgfs_csr_write(struct file *filep, const char __user *ubuf, if (*offp) return 0;

+ if (count == 0 || count > PAGE_SIZE) + return -EINVAL; + /* Copy data from User-space */ buf = memdup_user_nul(ubuf, count); if (IS_ERR(buf))