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 <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 5420732..fd4b618 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -418,8 +418,9 @@
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 @@
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);