From 3f8324fde2128c3308f957891262d3372fb57ebf Mon Sep 17 00:00:00 2001 From: Anton Kling Date: Sun, 15 Dec 2024 19:20:04 +0100 Subject: libc: Fix undefined behavior for non positive VLA Apparently a VLA of zero size is undefined behavior. --- kernel/libc/string/memmove.c | 3 +++ userland/libc/string/memmove.c | 3 +++ 2 files changed, 6 insertions(+) diff --git a/kernel/libc/string/memmove.c b/kernel/libc/string/memmove.c index 5fc49f7..3446643 100644 --- a/kernel/libc/string/memmove.c +++ b/kernel/libc/string/memmove.c @@ -3,6 +3,9 @@ // copy bytes in memory with overlapping areas // https://pubs.opengroup.org/onlinepubs/9699919799/functions/memmove.html void *memmove(void *s1, const void *s2, size_t n) { + if(0 == n) { + return s1; + } // Copying takes place as if the n bytes from the object pointed to by s2 are // first copied into a temporary array of n bytes that does not overlap the // objects pointed to by s1 and s2, and then the n bytes from the temporary diff --git a/userland/libc/string/memmove.c b/userland/libc/string/memmove.c index 5fc49f7..d7da375 100644 --- a/userland/libc/string/memmove.c +++ b/userland/libc/string/memmove.c @@ -3,6 +3,9 @@ // copy bytes in memory with overlapping areas // https://pubs.opengroup.org/onlinepubs/9699919799/functions/memmove.html void *memmove(void *s1, const void *s2, size_t n) { + if (0 == n) { + return s1; + } // Copying takes place as if the n bytes from the object pointed to by s2 are // first copied into a temporary array of n bytes that does not overlap the // objects pointed to by s1 and s2, and then the n bytes from the temporary -- cgit v1.2.3