From 5c95bf274665cc9f5126e4a48a9da51114f7afd2 Mon Sep 17 00:00:00 2001 From: Peter Oberparleiter Date: Tue, 12 Sep 2023 16:47:32 +0200 Subject: s390/cert_store: fix string length handling MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Building cert_store.o with W=1 reveals this bug: CC arch/s390/kernel/cert_store.o arch/s390/kernel/cert_store.c:443:45: warning: ‘sprintf’ may write a terminating nul past the end of the destination [-Wformat-overflow=] 443 | sprintf(desc + name_len, ":%04u:%08u", vce->vce_hdr.vc_index, cs_token); | ^ arch/s390/kernel/cert_store.c:443:9: note: ‘sprintf’ output between 15 and 18 bytes into a destination of size 15 443 | sprintf(desc + name_len, ":%04u:%08u", vce->vce_hdr.vc_index, cs_token); Fix this by using the correct maximum width for each integer component in both buffer length calculation and format string. Also switch to using snprintf() to guard against potential future changes to the integer range of each component. Fixes: 8cf57d7217c3 ("s390: add support for user-defined certificates") Reported-by: Heiko Carstens Reviewed-by: Alexander Gordeev Signed-off-by: Peter Oberparleiter Signed-off-by: Vasily Gorbik --- arch/s390/kernel/cert_store.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'arch/s390') diff --git a/arch/s390/kernel/cert_store.c b/arch/s390/kernel/cert_store.c index 3986a044eb36..554447768bdd 100644 --- a/arch/s390/kernel/cert_store.c +++ b/arch/s390/kernel/cert_store.c @@ -432,15 +432,16 @@ static char *get_key_description(struct vcssb *vcssb, const struct vce *vce) char *desc; cs_token = vcssb->cs_token; - /* Description string contains "%64s:%04u:%08u\0". */ + /* Description string contains "%64s:%05u:%010u\0". */ name_len = sizeof(vce->vce_hdr.vc_name); - len = name_len + 1 + 4 + 1 + 8 + 1; + len = name_len + 1 + 5 + 1 + 10 + 1; desc = kmalloc(len, GFP_KERNEL); if (!desc) return NULL; memcpy(desc, vce->vce_hdr.vc_name, name_len); - sprintf(desc + name_len, ":%04u:%08u", vce->vce_hdr.vc_index, cs_token); + snprintf(desc + name_len, len - name_len, ":%05u:%010u", + vce->vce_hdr.vc_index, cs_token); return desc; } -- cgit v1.2.3