Commit faf1c315 authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Linus Torvalds

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@avx2Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a218cc49
...@@ -418,8 +418,9 @@ static struct elf_phdr *load_elf_phdrs(struct elfhdr *elf_ex, ...@@ -418,8 +418,9 @@ static struct elf_phdr *load_elf_phdrs(struct elfhdr *elf_ex,
struct file *elf_file) struct file *elf_file)
{ {
struct elf_phdr *elf_phdata = NULL; struct elf_phdr *elf_phdata = NULL;
int retval, size, err = -1; int retval, err = -1;
loff_t pos = elf_ex->e_phoff; loff_t pos = elf_ex->e_phoff;
unsigned int size;
/* /*
* If the size of this structure has changed, then punt, since * 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, ...@@ -429,13 +430,9 @@ static struct elf_phdr *load_elf_phdrs(struct elfhdr *elf_ex,
goto out; goto out;
/* Sanity check the number of program headers... */ /* 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. */ /* ...and their total size. */
size = sizeof(struct elf_phdr) * elf_ex->e_phnum; 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; goto out;
elf_phdata = kmalloc(size, GFP_KERNEL); elf_phdata = kmalloc(size, GFP_KERNEL);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment