strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
Check for strscpy()'s return value of -E2BIG on truncate for safe
replacement with strlcpy().
This is part of a tree-wide cleanup to remove the strlcpy() function
entirely from the kernel [2].
[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89
Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230512155749.1356958-1-azeemshaikh38@gmail.com
static int __init root_nfs_copy(char *dest, const char *src,
const size_t destlen)
{
- if (strlcpy(dest, src, destlen) > destlen)
+ if (strscpy(dest, src, destlen) == -E2BIG)
return -1;
return 0;
}