From: Alexey Dobriyan <adobriyan@gmail.com>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH 1/4] elf: don't be afraid of overflow
Date: Mon, 4 Feb 2019 23:27:15 +0300 [thread overview]
Message-ID: <20190204202715.GA27482@avx2> (raw)
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
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
fs/binfmt_elf.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
--- 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);
next reply other threads:[~2019-02-04 20:27 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-04 20:27 Alexey Dobriyan [this message]
2019-02-04 20:28 ` [PATCH 2/4] elf: use list_for_each_entry() Alexey Dobriyan
2019-02-04 20:28 ` [PATCH 3/4] elf: spread const a little Alexey Dobriyan
2019-02-04 20:33 ` [PATCH 4/4] elf: save allocation per exec Alexey Dobriyan
2019-02-12 15:49 ` [PATCH 2/4] elf: use list_for_each_entry() kbuild test robot
2019-02-12 16:21 ` kbuild test robot
2019-03-11 11:04 ` [PATCH 1/4] elf: don't be afraid of overflow Pavel Machek
2019-03-11 17:10 ` Alexey Dobriyan
2019-03-12 9:37 ` Pavel Machek
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