binfmt: Use struct_size()

Use struct_size() instead of hand-writing it. It is less verbose, more
robust and more informative.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/53150beae5dc04dac513dba391a2e4ae8696a7f3.1685290790.git.christophe.jaillet@wanadoo.fr

diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index d76ad3d..237ce38 100644 (file)
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -748,7 +748,6 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params,
        struct elf32_phdr *phdr;
        unsigned long load_addr, stop;
        unsigned nloads, tmp;
-       size_t size;
        int loop, ret;
 
        /* allocate a load map table */
@@ -760,8 +759,7 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params,
        if (nloads == 0)
                return -ELIBBAD;
 
-       size = sizeof(*loadmap) + nloads * sizeof(*seg);
-       loadmap = kzalloc(size, GFP_KERNEL);
+       loadmap = kzalloc(struct_size(loadmap, segs, nloads), GFP_KERNEL);
        if (!loadmap)
                return -ENOMEM;