From a637c8386f0522f1b253ba58f497f31ac4fa981a Mon Sep 17 00:00:00 2001 From: pfg Date: Tue, 21 Aug 2018 01:17:28 +0000 Subject: [PATCH] MFC r337422: libc: fix cases of undefined behavior. These were found by the Undefined Behavior GsoC project at NetBSD: Avoid undefined behavior in ftok(3) Do not change the signedness bit with a left shift operation. Cast to unsigned integer to prevent this. ftok.c:56:10, left shift of 123456789 by 24 places cannot be represented in type 'int' ftok.c:56:10, left shift of 4160 by 24 places cannot be represented in type 'int' Avoid undefined behavior in an inet_addr.c Do not change the signedness bit with a left shift operation. Cast to unsigned integer to prevent this. inet_addr.c:218:20, left shift of 131 by 24 places cannot be represented in type 'int' Detected with micro-UBSan in the user mode. Obtained from: NetBSD --- lib/libc/gen/ftok.c | 3 ++- lib/libc/inet/inet_addr.c | 7 ++++--- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/lib/libc/gen/ftok.c b/lib/libc/gen/ftok.c index 2fad66e64ee..89eb42eebfd 100644 --- a/lib/libc/gen/ftok.c +++ b/lib/libc/gen/ftok.c @@ -40,5 +40,6 @@ ftok(const char *path, int id) if (stat(path, &st) < 0) return (key_t)-1; - return (key_t) (id << 24 | (st.st_dev & 0xff) << 16 | (st.st_ino & 0xffff)); + return ((key_t)((unsigned int)id << 24 | (st.st_dev & 0xff) << 16 | + (st.st_ino & 0xffff))); } diff --git a/lib/libc/inet/inet_addr.c b/lib/libc/inet/inet_addr.c index 2f97175826a..861aeee0522 100644 --- a/lib/libc/inet/inet_addr.c +++ b/lib/libc/inet/inet_addr.c @@ -182,19 +182,20 @@ inet_aton(const char *cp, struct in_addr *addr) { case 2: /*%< a.b -- 8.24 bits */ if (val > 0xffffffU) return (0); - val |= parts[0] << 24; + val |= (uint32_t)parts[0] << 24; break; case 3: /*%< a.b.c -- 8.8.16 bits */ if (val > 0xffffU) return (0); - val |= (parts[0] << 24) | (parts[1] << 16); + val |= ((uint32_t)parts[0] << 24) | (parts[1] << 16); break; case 4: /*%< a.b.c.d -- 8.8.8.8 bits */ if (val > 0xffU) return (0); - val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8); + val |= ((uint32_t)parts[0] << 24) | (parts[1] << 16) | + (parts[2] << 8); break; } if (addr != NULL) -- 2.45.0