linux-kernel - [PATCH] x86/kexec: Fix double-free of elf header buffer

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Message-Id: <20221122115122.13937-1-tiwai@suse.de>
Date:   Tue, 22 Nov 2022 12:51:22 +0100
From:   Takashi Iwai <tiwai@...e.de>
To:     x86@...nel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Baoquan He <bhe@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] x86/kexec: Fix double-free of elf header buffer

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.

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@...e.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