lkml.org 
[lkml]   [2022]   [Nov]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH] x86/kexec: Fix double-free of elf header buffer
CC kexec@lists.infradead.org

On 11/22/22 at 12:51pm, Takashi Iwai wrote:
> The recent fix for memory leaks forgot to clear the error path that
> already does vfree() for the elf headers. This may result in a
> double-free.

Good catch.

The log can be improved to make the issue more obvious. How about this:
======
With commit b3e34a47f989 ("x86/kexec: fix memory leak of elf header
buffer"), freeing up image->elf_headers in error path of
crash_load_segments() is not needed, because later
kimage_file_post_load_cleanup() will cover it. And not clearing it could
result in a double-free.

Drop the superfluous vfree() call at the error path of
crash_load_segments().
========

Other than the log part, LGTM. Thanks.

Acked-by: Baoquan He <bhe@redhat.com>

>
> Drop the superfluous vfree() call at the error path of
> crash_load_segments().
>
> Fixes: b3e34a47f989 ("x86/kexec: fix memory leak of elf header buffer")
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> ---
> arch/x86/kernel/crash.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
> index 9730c88530fc..305514431f26 100644
> --- a/arch/x86/kernel/crash.c
> +++ b/arch/x86/kernel/crash.c
> @@ -401,10 +401,8 @@ int crash_load_segments(struct kimage *image)
> kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
> kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
> ret = kexec_add_buffer(&kbuf);
> - if (ret) {
> - vfree((void *)image->elf_headers);
> + if (ret)
> return ret;
> - }
> image->elf_load_addr = kbuf.mem;
> pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
> image->elf_load_addr, kbuf.bufsz, kbuf.memsz);
> --
> 2.35.3
>

\
 
 \ /
  Last update: 2022-11-23 10:21    [W:1.874 / U:0.228 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site