From: George Wilson Date: Fri, 7 Aug 2026 16:59:00 +0000 (-0500) Subject: powerpc/pseries: lparcfg - fix kbuf[] underflow X-Git-Tag: v7.2-rc7~12^2 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=fb442a6673ff1046bf67754957d95880fdb394b5;p=thirdparty%2Flinux.git powerpc/pseries: lparcfg - fix kbuf[] underflow In lparcfg_write(), a count of 0 results in kbuf[] being indexed at -1. Check for count == 0 in the existing check for count > sizeof(kbuf) and return -EINVAL if true. Fixes: 74422e2b1939 ("powerpc/pseries: Remove VLA from lparcfg_write()") Acked-by: Nayna Jain Tested-by: R Nageswara Sastry Cc: stable@vger.kernel.org # 4.20 Signed-off-by: George Wilson Signed-off-by: Madhavan Srinivasan --- diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c index 54b7ecf375b5..3280b7968cab 100644 --- a/arch/powerpc/platforms/pseries/lparcfg.c +++ b/arch/powerpc/platforms/pseries/lparcfg.c @@ -699,7 +699,7 @@ static ssize_t lparcfg_write(struct file *file, const char __user * buf, if (!firmware_has_feature(FW_FEATURE_SPLPAR)) return -EINVAL; - if (count > sizeof(kbuf)) + if (count == 0 || count > sizeof(kbuf)) return -EINVAL; if (copy_from_user(kbuf, buf, count))