From faf1c3152032275370f35dc757501ae0c47ded53 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Thu, 7 Mar 2019 16:28:56 -0800 Subject: fs/binfmt_elf.c: don't be afraid of overflow Number of ELF program headers is 16-bit by spec, so total size comfortably fits into "unsigned int". Space savings: 7 bytes! add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-7 (-7) Function old new delta load_elf_phdrs 137 130 -7 Link: http://lkml.kernel.org/r/20190204202715.GA27482@avx2 Signed-off-by: Alexey Dobriyan Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/binfmt_elf.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'fs') diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 54207327f98f..fd4b618c412e 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -418,8 +418,9 @@ static struct elf_phdr *load_elf_phdrs(struct elfhdr *elf_ex, struct file *elf_file) { struct elf_phdr *elf_phdata = NULL; - int retval, size, err = -1; + int retval, err = -1; loff_t pos = elf_ex->e_phoff; + unsigned int size; /* * If the size of this structure has changed, then punt, since @@ -429,13 +430,9 @@ static struct elf_phdr *load_elf_phdrs(struct elfhdr *elf_ex, goto out; /* Sanity check the number of program headers... */ - if (elf_ex->e_phnum < 1 || - elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr)) - goto out; - /* ...and their total size. */ size = sizeof(struct elf_phdr) * elf_ex->e_phnum; - if (size > ELF_MIN_ALIGN) + if (size == 0 || size > 65536 || size > ELF_MIN_ALIGN) goto out; elf_phdata = kmalloc(size, GFP_KERNEL); -- cgit v1.2.3-59-g8ed1b